The gold protocol: A combined treatment approach for neck rejuvenation with calcium hydroxyapatite, botulinum toxin, and hyaluronic acid in the same session.

BACKGROUND: The signs of aging seem to be more visible on the neck compared to other locations, especially if a patient has already gone through facial rejuvenation procedures. Treatment of the aging neck imposes a challenge to the clinician, since one single approach is usually not enough to achieve the desired result, requiring multiple injections and sessions, which apart from being painful for the patients, is time-consuming for the clinician. AIM: To describe the use of calcium hydroxyapatite, incobotulinum toxin type A and Cohesive poly-densified matrix hyaluronic acid diluted in the same syringe and injected in the same session for neck rejuvenation. PATIENTS AND METHODS: Fifteen women, older than 18 years, with cervical skin flaccidity grade 1-4 in a previously validated 5-point rating scale (Dermatologic Surg, 2016; 42, S94), who sought neck rejuvenation were injected in this pilot study with a single session with a combined hybrid mixture of calcium hydroxyapatite, incobotulinum toxin type A, and Cohesive poly-densified matrix hyaluronic acid and followed up for 90-180 days. RESULTS: At the 4-month post injection evaluation, 93.3% of the patients presented at least 1-grade improvement in the 5-point scale as evaluated by the investigator. No serious adverse events were reported, being most mild and transient in nature. CONCLUSION: CaHA, incoBonTA, and CPM-HA have complementary mechanisms of action and may be injected from the same syringe in the same session, boosting the final outcome, with high patient satisfaction, and ease of process for both patients and clinicians.

Preparation of mesoporous silica/hydroxyapatite loaded quercetin nanoparticles and research on its antibacterial properties.

In this study, amino-functionalized mesoporous silica/hydroxyapatite nanoparticles (MSNS/HAP) with the property of acid dissociation have been prepared as a traditional Chinese medicine monomer carriers to improve the drug loading rate and antibacterial properties of antimicrobial quercetin (QUE) in vitro. The experimental results confirm that the drug loading rate of MSNs/HAP is 28.94 %, which is about 3.6 times higher than that of aminated mesoporous sililca nanoparticles (MSNs). The drug release of QUE on MSNs/HAP is pH-sensitive in phosphate buffered saline (pH=4.0-7.4). The above fabricated traditional Chinese medicine monomer modified nanocomposites (QUE@MSNs/HAP) displays concentration-dependent inhibitory effect, which shows better antibacterial effect than free QUE. The minimum inhibitory concentration for two tested bacteria, Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli), is 256 mg·L -1. In summary, QUE@MSNs/HAP have successfully prepared, which not only improves the bio-availability of QUE, but also has acid-sensitive drug release properties. Compared with free QUE, its antibacterial performance significantly enhances, which provides a theoretical basis for the application of Chinese medicine molecules in bacterial treatment.

Development and application of hydroxyapatite-based scaffolds for bone tissue regeneration: A systematic literature review.

Hydroxyapatite [HA, Ca10(PO4)6(OH)2], with its robust biocompatibility and bioactivity, has found extensive utility in bone grafting, replacement therapies, and supplemental medical materials. HA is highly regarded for its osteoconductive properties because it boasts hydrophilicity, nontoxicity, non-allergenicity, and non-mutagenicity. Nevertheless, HA's intrinsic mechanical weakness has spurred efforts to enhance its properties. This enhancement is achieved through ion incorporation, with elements such as magnesium, zinc, lithium, strontium, boron, and others being integrated into the HA structure. In the domain of orthopedics, HA-based scaffolds have emerged as a solution for addressing prevalent issues like bone deformities and defects stemming from congenital anomalies, injuries, trauma, infections, or tumors. The fabrication of three-dimensional scaffolds (3D scaffolds) has enabled advancements in bone regeneration and replacement, with a focus on practical applications such as repairing calvarial, skull, and femoral defects. In vitro and in vivo assessments have substantiated the effectiveness of 3D scaffolds for bone defect repair, regeneration, and tissue engineering. Beyond bone-related applications, scaffolds demonstrate versatility in enhancing cartilage healing and serving as bioimplants. The wide array of scaffold applications underscores their ongoing potential for further development in the realm of medical science.

Enhancing osteoblast proliferation and bone regeneration by poly (amino acid)/selenium-doped hydroxyapatite.

Among various biomaterials employed for bone repair, composites with good biocompatibility and osteogenic ability had received increasing attention from biomedical applications. In this study, we doped selenium (Se) into hydroxyapatite (Se-HA) by the precipitation method, and prepared different amounts of Se-HA-loaded poly (amino acid)/Se-HA (PAA/Se-HA) composites (0, 10 wt%, 20 wt%, 30 wt%) byin-situmelting polycondensation. The physical and chemical properties of PAA/Se-HA composites were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and their mechanical properties. XRD and FT-IR results showed that PAA/Se-HA composites contained characteristic peaks of PAA and Se-HA with amide linkage and HA structures. DSC and TGA results specified the PAA/Se-HA30 composite crystallization, melting, and maximum weight loss temperatures at 203.33 °C, 162.54 °C, and 468.92 °C, respectively, which implied good thermal stability. SEM results showed that Se-HA was uniformly dispersed in PAA. The mechanical properties of PAA/Se-HA30 composites included bending, compressive, and yield strengths at 83.07 ± 0.57, 106.56 ± 0.46, and 99.17 ± 1.11 MPa, respectively. The cellular responses of PAA/Se-HA compositesin vitrowere studied using bone marrow mesenchymal stem cells (BMSCs) by cell counting kit-8 assay, and results showed that PAA/Se-HA30 composites significantly promoted the proliferation of BMSCs at the concentration of 2 mg ml-1. The alkaline phosphatase activity (ALP) and alizarin red staining results showed that the introduction of Se-HA into PAA enhanced ALP activity and formation of calcium nodule. Western blotting and Real-time polymerase chain reaction results showed that the introduction of Se-HA into PAA could promoted the expression of osteogenic-related proteins and mRNA (integrin-binding sialoprotein, osteopontin, runt-related transcription factor 2 and Osterix) in BMSCs. A muscle defect at the back and a bone defect at the femoral condyle of New Zealand white rabbits were introduced for evaluating the enhancement of bone regeneration of PAA and PAA/Se-HA30 composites. The implantation of muscle tissue revealed good biocompatibility of PAA and PAA/Se-HA30 composites. The implantation of bone defect showed that PAA/Se-HA30 composites enhanced bone formation at the defect site (8 weeks), exhibiting good bone conductivity. Therefore, the PAA-based composite was a promising candidate material for bone tissue regeneration.

Genetics and metabolic responses of Artemisia annua L to the lake of phosphorus under the sparingly soluble phosphorus fertilizer: evidence from transcriptomics analysis.

The medicinal herb Artemisia annua L. is prized for its capacity to generate artemisinin, which is used to cure malaria. Potentially influencing the biomass and secondary metabolite synthesis of A. annua is plant nutrition, particularly phosphorus (P). However, most soil P exist as insoluble inorganic and organic phosphates, which results to low P availability limiting plant growth and development. Although plants have developed several adaptation strategies to low P levels, genetics and metabolic responses to P status remain largely unknown. In a controlled greenhouse experiment, the sparingly soluble P form, hydroxyapatite (Ca5OH(PO4)3/CaP) was used to simulate calcareous soils with low P availability. In contrast, the soluble P form KH2PO4/KP was used as a control. A. annua's morphological traits, growth, and artemisinin concentration were determined, and RNA sequencing was used to identify the differentially expressed genes (DEGs) under two different P forms. Total biomass, plant height, leaf number, and stem diameter, as well as leaf area, decreased by 64.83%, 27.49%, 30.47%, 38.70%, and 54.64% in CaP compared to KP; however, LC-MS tests showed an outstanding 37.97% rise in artemisinin content per unit biomass in CaP contrary to KP. Transcriptome analysis showed 2015 DEGs (1084 up-regulated and 931 down-regulated) between two P forms, including 39 transcription factor (TF) families. Further analysis showed that DEGs were mainly enriched in carbohydrate metabolism, secondary metabolites biosynthesis, enzyme catalytic activity, signal transduction, and so on, such as tricarboxylic acid (TCA) cycle, glycolysis, starch and sucrose metabolism, flavonoid biosynthesis, P metabolism, and plant hormone signal transduction. Meanwhile, several artemisinin biosynthesis genes were up-regulated, including DXS, GPPS, GGPS, MVD, and ALDH, potentially increasing artemisinin accumulation. Furthermore, 21 TF families, including WRKY, MYB, bHLH, and ERF, were up-regulated in reaction to CaP, confirming their importance in P absorption, internal P cycling, and artemisinin biosynthesis regulation. Our results will enable us to comprehend how low P availability impacts the parallel transcriptional control of plant development, growth, and artemisinin production in A. annua. This study could lay the groundwork for future research into the molecular mechanisms underlying A. annua's low P adaptation.

High efficiency adsorption of uranium by magnesia-silica-fluoride co-doped hydroxyapatite.

Hydroxyapatite has a high affinity to uranium, and element doping can effectively improve its adsorption performance. In this study, magnesia-silica-fluoride co-doped hydroxyapatite composite was prepared by hydrothermal method, and the effect of single-phase and multiphase doping on the structure and properties of the composites was investigated. The results showed that the specific surface area of Mg-Si-F-nHA composites increased by 63.01% after doping. Comparing with nHA, U(VI) adsorption capacity of Si-nHA, Mg-Si-nHA and Mg-Si-F-nHA composites increased by 13.01%, 17.39% and 22.03%, respectively. The adsorption capacity of Mg-Si-F-nHA composite reached 1286.76 mg/g. Adsorbent dosage and pH obviously affected U(VI) adsorption, and the experimental data can be fitted well by PSO and Sips models. The physicochemical characterization before and after adsorption suggested that complexation, ion exchange and precipitation participated in uranium adsorption. In conclusion, different elements doping can effectively improve the uranium adsorption properties of hydroxyapatite composites.

Magnesium and Vascular Calcification in Chronic Kidney Disease: Current Insights.

Magnesium (Mg) plays crucial roles in multiple essential biological processes. As the kidneys are the primary organ responsible for maintaining the blood concentration of Mg, people with chronic kidney disease (CKD) may develop disturbances in Mg. While both hyper- and hypomagnesemia may lead to adverse effects, the consequences associated with hypomagnesemia are often more severe and lasting. Importantly, observational studies have shown that CKD patients with hypomagnesemia have greater vascular calcification. Vascular calcification is accelerated and contributes to a high mortality rate in the CKD population. Both in vitro and animal studies have demonstrated that Mg protects against vascular calcification via several potential mechanisms, such as inhibiting the formation of both hydroxyapatite and pathogenic calciprotein particles as well as limiting osteogenic differentiation, a process in which vascular smooth muscle cells in the media layer of the arteries transform into bone-like cells. These preclinical findings have led to several important clinical trials that have investigated the effects of Mg supplementation on vascular calcification in people with CKD. Interestingly, two major clinical studies produced contradictory findings, resulting in a state of equipoise. This narrative review provides an overview of our current knowledge in the renal handling of Mg in health and CKD and the underlying mechanisms by which Mg may protect against vascular calcification. Lastly, we evaluate the strength of evidence from clinical studies on the efficacy of Mg supplementation and discuss future research directions.

Designing bioinspired multifunctional nanoplatforms to support wound healing and skin regeneration: Mg-hydroxyapatite meets melanins.

Melanin is a multifunctional biological pigment that recently emerged as endowed with anti-inflammatory, antioxidant, and antimicrobial properties and with high potentialities in skin protection and regenerative medicine. Here, a biomimetic magnesium-doped nano-hydroxyapatite (MgHA) was synthesized and decorated with melanin molecules starting from two different monomeric precursors, i.e. 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and dopamine (DA), demonstrating to be able to polymerize on the surface of MgHA nanostructures, thus leading to a melanin coating. This functionalization was realized by a simple and green preparation method requiring mild conditions in an aqueous medium and room temperature. Complementary spectroscopy and electron imaging analyses were carried out to define the effective formation of a stable coating, the percentage of the organic compounds, and the structural properties of resulting melanin-coated nanostructures, which showed good antioxidant activity. The in vitro interaction with a cell model, i.e. mouse fibroblasts, was investigated. The excellent biocompatibility of all bioinspired nanostructures was confirmed from a suitable cell proliferation. Finally, the enhanced biological performances of the nanostructures coated with melanin from DHICA were confirmed by scratch assays. Jointly our findings indicated that low crystalline MgHA and melanin pigments can be efficiently combined, and the resulting nanostructures are promising candidates as multifunctional platforms for a more efficient approach for skin regeneration and protection.

Selenium-phosphorus modified biochar reduces mercury methylation and bioavailability in agricultural soil.

Biochar is a frequently employed for solidifying and stabilizing mercury (Hg) contamination in soil. However, it often results in an elevated presence of soil methylmercury (MeHg), which introduces new environmental risks. Consequently, there is a necessity for developing a safer modified biochar for use in Hg-contaminated soil. This study employed sodium selenite (at a safe dosage for soil) and hydroxyapatite to modify straw biochar (BC) based on the interaction between selenium (Se) and phosphorus (P). This process led to the formation of Se-modified biochar (Se-BC), P-modified biochar (P-BC), and Se and P co-modified biochar (Se-P-BC). Additionally, solvent adsorption experiments and pot experiments (BC/soil mass ratio: 0.5 %) were conducted to investigate the impacts of these soil amendments on soil Hg methylation and bioavailability. Se and P co-modification substantially increased the surface area, pore volume, and Hg adsorption capacity of BC. BC treatment increased the simulated gastric acid-soluble Hg, organo-chelated Hg, and MeHg in the soil. Conversely, Se-P-BC significantly reduced these forms of Hg in the soil, indicating that Se-P-BC can transform soil Hg into less bioavailable states. Among the different biochar treatments, Se-P-BC exhibited the most pronounced reductions in soil MeHg, total Hg, and MeHg in water spinach, achieving reductions of 63 %, 71 %, and 70 %, respectively. The co-modification of Se and P displayed a synergistic reduction effect in managing soil Hg pollution, which is associated with the increase of available Se in the soil due to phosphorus addition. The significantly reduced dissolved organic carbon and the abnormally high SO42- concentration in the soil of Se-P-BC treatment also inhibited Hg methylation and bioavailability in the soil. In summary, Se-P-BC substantially increased reduction percentage in plant Hg content while mitigating the risk of secondary pollution arising from elevated soil MeHg.

Porous scaffold hydroxyapatite from sand lobster shells (Panulirus homarus) using polyethylene oxide/chitosan as polymeric porogen for bone tissue engineering.

The hydroxyapatite (HAp; Ca10 (PO4 )6 (OH)2 )) has good biocompatibility, bioactivity, and osteoconductivity as a bone implant because the main inorganic mineral of human bone is HAp. The use of scaffold HAp from biogenic resources that contain high calcium and polymer as a pore forming agent to support bone growth is a longstanding area of interest. In this study, porous scaffolds based on HAp were synthesized from sand lobster (SL; Panulirus homarus) shells as a source of calcium using the porogen leaching method with polyethylene oxide (PEO) and chitosan (Chs) as polymeric porogen. The present study aims to synthesize HAp derived from SL shells and evaluate the effect variations of PEO on the physicochemical properties of the scaffold and cytotoxicity in cell viability assay. Briefly, the SL shell powder was calcinated with temperature variations of 600°C, 800°C, and 1000°C for 6 h. Based on the characterization, it was shown that 1000°C was the optimum calcination temperature for SL shells to synthesize HAp using the precipitation method. The characterization results of HAp using energy dispersive x-ray (EDX) revealed that the molar ratio of Ca/P was 1.67. The Fourier transform infrared (FTIR) and x-ray diffractometer (XRD) spectral patterns indicated that HAp had been successfully synthesized with minor ß-tricalcium phosphate (ß-TCP), a calcium phosphate with high biocompatibility. Porous scaffolds were synthesized by varying the concentration of PEO at 0, 5, 10, and 15 wt %. Physicochemical analysis revealed that a higher concentration of PEO affected decreased crystallinity and compressive strength, but on the other hand, the porosity and pore sizes increased. Based on the physicochemical analysis, the synthesized porous scaffold showed that HAp/PEO/Chs 15 wt % had the most potential as a scaffold for biomedical applications. MTT Assay, after 24 h incubation, revealed that the scaffold was safe for use at low concentrations on the MC3T3E1 osteoblast cells, with a percentage of cell viability of 83.23 ± 3.18% at 23.4375 µg/mL. Although the cell viability decreased at higher concentrations, the HAp/PEO/Chs 15 wt % scaffold was cytocompatible with the cells. Thus, in the present study, HAp/PEO/Chs 15 wt % was the best scaffold based on pore structure, chemical composition, mechanical and crystalographic properties and cell viability.

Octacalcium phosphate, a promising bone substitute material: a narrative review.

Biomaterials have been used to supplement and restore function and structure by replacing or restoring parts of damaged tissues and organs. In ancient times, the medical use of biomaterials was limited owing to infection during surgery and poor surgical techniques. However, in modern times, the medical applications of biomaterials are diversifying owing to great developments in material science and medical technology. In this paper, we introduce biomaterials, focusing on calcium phosphate ceramics, including octacalcium phosphate, which has recently attracted attention as a bone graft material.

Pressure alopecias: A review.

Pressure-induced alopecias (PAs) are an infrequent group of scarring and nonscarring alopecias that occur after ischemic obstruction of capillaries that leads to circumscribed areas of hair loss. Initially described after prolonged surgeries or immobilization, type 1 PA occurs after sustained external pressure to the skin, mainly the scalp prominences. Alopecia induced by cosmetic procedures, referred in this review as type 2 PA, is reported with increased frequency in literature and predominantly emerges from pressure exerted by the volume of injectables. It is important to differentiate type 2 PA from vascular occlusion-induced alopecia because they represent distinct entities. Clinically, PA may present with erythema, swelling, and tenderness; however, alopecia might be the sole manifestation. Crusts and ulceration are associated with a worse outcome and a higher risk of scarring alopecia. Prompt diagnosis is paramount to prevent complications. Trichoscopy, although considered nonspecific, may provide relevant clues for an accurate diagnosis. Hair regrows in most cases, but prognosis depends on ischemia severity and timely treatment with reperfusion therapies or mobilization. Treatment of hair loss is usually not necessary because the disease in most cases is self-limited and reversible. The role of topical minoxidil and corticosteroids remains unknown.

Gypsum-Related Impact on Antibiotic-Loaded Composite Based on Highly Porous Hydroxyapatite-Advantages and Disadvantages.

Highly porous hydroxyapatite is sometimes considered toxic and useless as a biomaterial for bone tissue regeneration because of the high adsorption of calcium and phosphate ions from cell culture media. This negatively affects the osteoblast's growth in such ion-deprived media and suggests "false cytotoxicity" of tested hydroxyapatite. In our recent study, we showed that a small addition of calcium sulfate dihydrate (CSD) may compensate for this adsorption without a negative effect on other properties of hydroxyapatite-based biomaterials. This study was designed to verify whether such CSD-supplemented biomaterials may serve as antibiotic carriers. FTIR, roughness, mechanical strength analysis, drug release, hemocompatibility, cytotoxicity against human osteoblasts, and antibacterial activity were evaluated to characterize tested biomaterials. The results showed that the addition of 1.75% gypsum and gentamicin caused short-term calcium ion compensation in media incubated with the composite. The combination of both additives also increased antibacterial activity against bacteria representative of bone infections without affecting osteoblast proliferation, hemocompatibility, and mechanical parameters. Thus, gypsum and antibiotic supplementation may provide advanced functionality for bone-regeneration materials based on hydroxyapatite of a high surface area and increasingly high Ca2+ sorption capacity.

Mn-Doped Nano-Hydroxyapatites as Theranostic Agents with Tumor pH-Amplified MRI-Signal Capabilities for Guiding Photothermal Therapy.

Background: The integration of diagnostic and therapeutic functions into a biosafe nanoplatform with intelligent response functions at the tumor microenvironment (TME) is a promising strategy for cancer therapy. Methods: Mn-doped nano-hydroxyapatite (nHAPMn) nanoparticles were successfully prepared via a simple coprecipitation method for magnetic resonance imaging (MRI)-guided photothermal therapy. This study is the first to report on the use of Mn to render biodegradable hydroxyapatite suitable for MRI and effective photothermal therapy (PTT) simultaneously by regulating the pH of nHAPMn during the preparation process. Results: Combined with near-infrared (NIR) laser irradiation, a photothermal conversion efficiency of 26% and effective photothermal lethality in vitro were achieved. Moreover, the degradation of nHAPMn led to the release of Mn ions and amplified the MRI signals in an acidic TME, which confirmed that nHAPMn had a good pH-responsive MRI capacity in solid tumors. In animal experiments, tumors in the nHAPMn5+NIR group completely abated after 14 days of treatment, with no significant recurrence during the experiment. Conclusion: Therefore, nHAPMn is promising as a nanotheranostic agent and can be effective in clinical diagnosis and therapy for treating cancer.

Removal of Aqueous Uranyl and Arsenate Mixtures after Reaction with Limestone, PO43-, and Ca2.

The co-occurrence of uranyl and arsenate in contaminated water caused by natural processes and mining is a concern for impacted communities, including in Native American lands in the U.S. Southwest. We investigated the simultaneous removal of aqueous uranyl and arsenate after the reaction with limestone and precipitated hydroxyapatite (HAp, Ca10(PO4)6(OH)2). In benchtop experiments with an initial pH of 3.0 and initial concentrations of 1 mM U and As, uranyl and arsenate coprecipitated in the presence of 1 g L-1 limestone. However, related experiments initiated under circumneutral pH conditions showed that uranyl and arsenate remained soluble. Upon addition of 1 mM PO43- and 3 mM Ca2+ in solution (initial concentration of 0.05 mM U and As) resulted in the rapid removal of over 97% of U via Ca-U-P precipitation. In experiments with 2 mM PO43- and 10 mM Ca2+ at pH rising from 7.0 to 11.0, aqueous concentrations of As decreased (between 30 and 98%) circa pH 9. HAp precipitation in solids was confirmed by powder X-ray diffraction and scanning electron microscopy/energy dispersive X-ray. Electron microprobe analysis indicated U was coprecipitated with Ca and P, while As was mainly immobilized through HAp adsorption. The results indicate that natural materials, such as HAp and limestone, can effectively remove uranyl and arsenate mixtures.

Hydroxyapatite fortified mango mousse: Formulation, characterization, and sensory data evaluation using fuzzy logic.

In this experimental study, hydroxyapatite (HAp), as a valuable calcium source, was extracted from discarded goat bone; raw and nano-biogenic powders were prepared through calcination and ultra-sonication. Resultant powders were characterized by using various spectroscopy techniques. As per the findings of atomic absorption spectroscopy, raw and nano-biogenic powders depicted 1439.7 ± 0.12 and 3194.8 ± 0.07 ppm calcium content, respectively. The range of particle size of nano-biogenic and raw powders was 47-139 and 183 nm, respectively. X-ray diffraction (XRD) confirmed crystalline behavior whereas laser-induced breakdown spectroscopy (LIBS)-derived Ca/P-ratio endorsed excellence in nano-biogenic 1.76 against 1.63 in raw powder. In vitro bioavailability of calcium in raw and nano-biogenic powder was ∼36% and ∼39%, respectively. Next, the powders were further used to develop calcium-fortified mango mousse with varied formulations. A maximum overrun of 23.31% was found in the case of "Raw-A," whereas a maximum viscosity of 8489.98 mPa s was found in the case of "Nano-A." Sensory data of mango mousse were obtained by fuzzy logic method, and PCA ranked the Nano-B and Nano-A samples the best in terms of overall acceptability. Meanwhile, the consumer responses toward product likeness and/or dislikeness were recorded by the hedonic scale that endorsed Nano-A and Nano-B formulations as the most preferred samples. PRACTICAL APPLICATION: The revolution in the eating habits of consumers from traditional foods to fast food imposes the development of new products having good nutritional values. Different waste biogenic food sources can provide an acceptable powdered form of ingredients for the development of novel food products. In this regard, the development of novel food products using calcium supplements has gained space in the food industry.

Biomimetic synthesis of polydopamine-graphene oxide/hydroxyapatite for efficient and fast uranium(VI) capture from aqueous solution.

A novel and efficient mesoporous nano-absorbent for U(VI) removal was developed through an environment-friendly route by inducing the biomimetic mineralization of hydroxyapatite (HAP) on the bioinspired surface of polydopamine-graphene oxide (PDA-GO). PDA-GO/HAP exhibited the greatly rapid and efficient U(VI) removal within 2 min, and much higher U(VI) adsorption capacity of 433.07 mg·g-1 than that of GO and PDA-GO. The enhanced adsorption capacity was mainly attributed to the synergistic effect of O-H, -C=N-, and PO43- functional groups and the incorporation of uranyl ions by the formation of a new phase (chernikovite, H2(UO2)2(PO4)2·8H2O). The adsorption process of U(VI) fitted well with pseudo-second-order kinetic and Langmuir isotherm model. Moreover, PDA-GO/HAP showed a high U(VI) adsorption capacity in a broad range of pH values and owned good thermal stability. PDA-GO/HAP with various excellent properties made it a greatly promising adsorbent for extracting uranium. Our work developed a good strategy for constructing fast and efficient uranium-adsorptive biomimetic materials.

Effectiveness of plant-mediated synthesis of hydroxyapatite nano-particles impregnated in Pistachio oleogum resin on mineral contents of human teeth. An in-situ single-blind controlled study.

OBJECTIVES: This study aimed to synthesize and characterize an environmentally friendly nanohydroxyapatite (n-HA) and evaluate its impact on enamel mineral content when incorporated into a Pistachio oleo gum resin (Saqqez) bio-chewing gum for in-situ models. We compared the effects of this green nano-hydroxyapatite (G n-HA) with those of a commercially available synthetic nano-hydroxyapatite (S n-HA). METHODS: Various analytical techniques were employed including XRD, FESEM, FT-IR, EDX/SEM and TGA/DTA to characterize the crystallinity, size and composition of the G n-HA powder. Three chewing gum groups were formulated: (1) Saqqez gum containing 10% wt G n-HA, (2) Saqqez gum containing 10% wt S n-HA, and (3) pure Saqqez gum. In order to evaluate the impact of these chewing gums on enamel, intraoral appliances were fabricated, each containing six enamel specimens. Participants were instructed to chew the gums while wearing these appliances. The calcium (Ca+2) and phosphorus (P) levels in enamel specimens, both with and without exposure to an acid challenge, were quantified using EDX/SEM. FE-SEM was employed to capture the microstructure of the enamel surface. In terms of the statistical analysis, one-way ANOVA and Tukey's post hoc tests were utilized to compare the data, where the significance level (α) was set at 0.05. RESULTS: The characterization tests confirmed the successful synthesis of G n-HA. Furthermore, EDX/SEM analysis of the enamel specimens from the intraoral appliance revealed significant variations in calcium (Ca+2) content among the enamel specimens (P = 0.000). The S n-HA group, in particular, exhibited the highest Ca+2 content, while the pure Saqqez group displayed the lowest. Nonetheless, there was no statistically significant differences in phosphorus (P) content observed among the three groups (P = 0.27). CONCLUSIONS: Saqqez gum can be considered a wholesome natural chewing gum that serves, as a carrier for delivering remineralization agents to the tooth surfaces. This was evident in the groups containing n-HA, exhibiting elevated Ca+2 levels. It's noteworthy that G n-HA demonstrated less efficacy in enamel remineralization compared to S n-HA.

Study of nano-hydroxyapatite tagged alkaline protease isolated from Himalayan sub-alpine Forest soil bacteria and role in recalcitrant feather waste degradation.

Purified calcium serine metalloprotease from Stenotrophomonas maltophilia strain SMPB12 exhibits highest enzyme activity at pH 9 and temperature range between 15 °C-25 °C. Enzyme supplemented with 40 µM Ca-Hap-NP (NP-protease) showed maximum elevated activity of 17.29 µmole/min/ml (1.9-fold of original protease activity). The thermostability of the enzyme was maintained for 1 h at 60 °C over an alkaline pH range 7.5-10, as compared to the NP untreated enzyme whose activity was of 8.97 µmole/min/ml. A significant loss of activity with EDTA (1.05 µmole/min/ml, 11.75 %), PMSF (0.93 µmole/min/ml, 10.46 %) and Hg2+ (3.81 µmole/min/ml, 42.49 %) was also observed. Kinetics study of NP-protease showed maximum decreases in Km (28.11 %) from 0.28 mM (NP untreated enzyme) to 0.22 mM (NP-protease) along with maximum increase in Vmax (42.88 %) from 1.25 µmole/min/ml to 1.79 µmole/min/ml at varying temperatures. The enhanced activity of NP-protease was able to efficiently degrade recalcitrant solid wastes like feather to produce value-added products like amino acids and helps in declogging recalcitrant solid wastes. The nano-enabled protease may be utilized in a smaller amount for degrading in bulk recalcitrant solid proteinaceous waste at 15 °C temperature as declogging agents providing an eco-friendly efficient process.