Ammonium Magnesium Phosphate Research Articles

Phosphorus removal and recovery from water and wastewater by the struvite crystallization

The precipitation of phosphorus naturally present in water, in the form of struvite, constitutes an interesting alternative for the phosphate water treatment. In this context, the main objective of the present study is to follow the crystallization of struvite, in a stirred tank, from real phosphated water (wastewater and natural water) at 25°C and at optimum pH 8.5 and to study the effect of environmental conditions on the crystallization stages (nucleation and crystal growth) and the morphology of struvite crystals.Various analytical methods (spectrophotometry, FTIR, SEM and XRD) were used to characterize the solid and liquid phases. In the light of the results obtained in this investigation, it appears that the precipitates formed in all the samples of treated waters were identified as ammonium magnesium phosphate (i.e. struvite). The precipitation of struvite in water allowed a significant elimination of phosphorus (up to 70%). On the other hand, the SEM analysis was able to highlight the presence of large clusters of large struvite crystals up to 146.8µm, as in the case of the precipitation of struvite with wastewater, where the conversion rate was the highest. The supersaturation ratio is the most important factor influencing the crystallization process.

Nutrients recovery from livestock wastewater by batch and gas bubble-column studies with biochar, nano-composite material, and ammonium magnesium phosphate hydrate

The breeding of livestock raises substantial environmental concerns, especially the efficient management of nutrients and pollution. This research is designed to assess the potency of char and modified char in diluting nutrient concentrations in livestock wastewater. The characteristics of graphene oxide, struvite, and calcium-modified char were inspected, defining their efficacy in both batch and bed-column investigations of nutrient sorption. Various factors, including sorption capacity, time of contact, ion levels, a decrease in ion levels over time, and sorption kinetics, have been considered, along with their appropriateness for respective models. The first evaluation of the options concluded that 600 °C char was better since it exhibited higher removal efficiency. Modified char sorption data at 600 °C was used to adjust the models “PSOM, Langmuir”, and “Thomas”. The models were applied to both batch and bed-column experiments. The maximum phosphate sorption was 110.8 mg/g, 85.73 mg/g, and 82.46 mg/g for B-GO, B-S, and B-C modified chars respectively, in the batch experiments. The highest phosphate sorption in column experiments, at a flow rate of 400 μl/min, was 51.23 mg per 10 g of sorbent. This corresponds to a sorption rate of 5.123 mg/g. B-GO and B-S modified chars showed higher sorption capacities; this was observed in both the batch and bed-column studies. This displayed the capability of graphene oxide and struvite-modified chars for efficient ion and nutrient uptake, whether in single or multi-ion environments, making them a very good candidate for nutrient filtration in livestock wastewater treatment. Additionally, B-GO char enhanced the sorption of phosphate, resulting in augmented seed germination and seedling growth. These results reveal that B-GO char can be used as a possible substitute for chemical fertilizers.

Fertilization efficiency of thirty marketed and experimental recycled phosphorus fertilizers

Recycling phosphorus (P) from waste streams like sewage sludge, animal manures or food industry by-products is required to sustain soil fertility without depleting non-renewable P resources. Several technologies are available for P recovery, leading to fertilizers differing in P solubility and bioavailability. In this study, thirty fertilizers obtained through different technologies were tested to assess if their fertilization efficiency was equivalent to mineral soluble fertilizer applied as triple superphosphate (TSP). The main selection criteria were (1) ensuring a wide chemical diversity, and (2) choosing products already on the market or at a late stage of development, to encompass a representative selection of current and future recycled fertilizers. The products were classified according to their organic carbon content and neutral ammonium citrate (NAC), and the main P species of each fertilizer was determined through K-edge and L2,3-edge X-ray absorption near edge structure spectroscopy (XANES). Three pot experiments with wheat, barley and ryegrass were conducted in three growing substrates with contrasting properties, all within a pH range of 5.8–6.9. Fertilizers containing ammonium magnesium phosphate, monoammonium phosphate, monocalcium phosphate, and dicalcium phosphate type species as dominant P species showed a similar fertilization efficiency to TSP, while fertilizers with hydroxyapatite, tricalcium phosphate, phytic acid or iron phosphates as their main P species had lower fertilization efficiencies. We conclude that while the trend towards high-efficiency, refined inorganic recycled P fertilizers is positive, lower-performing, mostly unrefined fertilizers must be assessed in light of their long-term P supply potential and additional benefits to soil health owing to their content of organic matter and other nutrients.

Effect of silica fume on the performance of high-early-strength UHPC prepared with magnesium ammonium phosphate cement

Although ultra-high performance concrete (UHPC) prepared from Portland cement has high long-term strength and durability, its early strength development is still can be enhanced for shortening the prefabrication period or using it as a rapid repair material. Therefore, magnesium ammonium phosphate cement ultra-high performance concrete (MAPC-UHPC) was prepared using magnesium ammonium phosphate cement (MAPC), sand, steel fiber, and silica fume (SF) in this study. The effects of replacing MAPC with SF (5%–15%) on the fluidity, strength, and microstructure of MAPC-UHPC were studied. The results showed that the spread diameter of the MAPC-UHPC mixture was greater than 200 mm, and the setting time was between 5.5 and 8.5 min. Meanwhile, the 6-h compressive strength of MAPC-UHPC was higher than 100 MPa and could reach about 140 MPa in 28 d. When the 5%–15% binder was replaced by SF, the MAPC-UHPC fluidity and setting time increased with the increase in SF content. When 5% SF was used, the 6-h and 28-d compressive strengths of MAPC-UHPC increased by 3.91% and 3.86%, respectively, compared with the plain sample. The addition of SF promoted the formation of struvite and refined the pore structure, which also increased the compactness of the microstructure.

Risk assessment and prevention of urolithiasis in urban areas of Baoding, China.

Urolithiasis, or the formation of calculi in the urinary system, represents a prevalent urological condition frequently encountered among individuals aged 30 to 55 years. An in-depth analysis of the composition of these calculi holds significant promise in shedding light on the underlying etiological and pathogenic factors contributing to this ailment. The primary objective of this study was to delineate the principal components comprising urinary system calculi within a cohort of patients who sought medical intervention at a tertiary grade A hospital located in Baoding City. Furthermore, our investigation entailed a comprehensive examination of the physical and morphological characteristics exhibited by these calculi. In this study, a total of 2307 individuals afflicted with urinary system calculi were recruited as participants, and a corresponding number of 2307 calculous specimens were subjected to thorough examination. The specimens were examined using infrared spectroscopy. We collected and examined patient data including gender, age, location of the calculi, employment status, residential area, and other factors. The middle-aged demographic exhibited a conspicuous predilection for urinary system calculi, wherein a notable gender disparity was observed, with a male-to-female ratio of 1.63 to 1. Among the enrolled patients, kidney calculi were prevalent in 1270 cases, ureteral calculi were documented in 983 cases, and bladder calculi were encountered in 46 instances. Notably, the principal components comprising these calculi were identified as calcium oxalate and apatite, while uric acid and ammonium magnesium phosphate were comparatively less frequently encountered. Furthermore, the analysis of calculus composition across patients residing in distinct geographical regions did not reveal any statistically significant variations. The identification of components within upper urinary tract calculi plays a pivotal role in elucidating the root causes of calculus formation. This valuable information empowers healthcare professionals, particularly nursing staff, to provide personalized dietary and health guidance to patients, thereby enhancing the quality of care and promoting more effective management of this condition.

High-cell-density cultivation of Vibrio natriegens in a low-chloride chemically defined medium

Vibrio natriegens is a halophilic bacterium with the fastest generation time of non-pathogenic bacteria reported so far. It therefore has high potential as a production strain for biotechnological production processes or other applications in biotechnology. Culture media for V. natriegens typically contain high sodium chloride concentrations. The corresponding high chloride concentrations can lead to corrosion processes on metal surfaces in bioreactors. Here we report the development of a low-chloride chemically defined medium for V. natriegens. Sodium chloride was completely replaced by the sodium salts disodium hydrogen phosphate, disodium sulfate, and sodium citrate, while keeping the total concentration of sodium ions constant. The use of citrate prevents the occurrence of precipitates, especially of ammonium magnesium phosphate. With this defined medium, high-cell-density fed-batch cultivations in laboratory-scale bioreactors using exponential feeding yielded biomass concentrations of more than 60 g L−1.Key pointsA defined medium for V. natriegens that only contains traces of chloride was developedCorrosion processes on metal surfaces in industrial bioreactors can thus be preventedHigh yields of biomass can be achieved in fed-batch cultivation with this medium

Urinary stone component identification by energy-resolved X-ray computed tomography

ABSTRACT Urinary stones have four main types of components: calcium, uric acid, ammonium magnesium phosphate, and cystine, and the type of treatment must be selected according to these types. Although X-ray computed tomography (CT) is currently the most promising method for differentiating the component types of urinary stones in vivo, both conventional and dual-energy CTs are subject to limits in this component differentiation. In this paper, we show the usefulness of an energy-resolved CT system for determining urinary stone components. Standard laboratory chemicals were used as substitutes for true urinary stones, and the effective atomic numbers of the chemicals were estimated to see if they could be used to identify the different types of urinary stones.

Postkeratoplasty Corneal Plaques: A Case Series.

To assess the risk factors and management of corneal plaques formed after keratoplasty. In this retrospective study, medical records of all eyes with plaques formed on top of corneal grafts performed in the period between January 2014 and January 2022 were reviewed. The retrieved data included prekeratoplasty corneal pathology, ocular risk factors, operative data and complications, plaque management, and chemical composition of the plaques using infrared spectrometer. Thirteen eyes were included in this study. Predisposing ocular comorbidities included ocular surface disorders with variable degrees of dry eye in nine patients, rheumatoid arthritis in three patients, history of herpetic keratitis in two eyes, and cicatrizing conjunctivitis in two patients. Surgical excision and amniotic membrane transplantation (AMT) were performed in 12 eyes. Postoperatively, five eyes showed recurrence after excision, two eyes developed graft vascularization and scarring, and one eye showed persistent epithelial defect and graft scarring, whereas four eyes showed complete epithelialization with mild haze. Rekeratoplasty and AMT were performed in two eyes with no plaque recurrence. Chemical analysis using infrared spectrometry showed that the plaques consisted of ammonium magnesium phosphate and calcium phosphate carbonate in 9 (75%) cases and pure mucus in 3 (25%) cases. Postkeratoplasty corneal plaque formation is an underestimated complication of keratoplasty that may occur after persistent epithelial defects. Ocular surface disorders are the primary predisposing risk factors. In our experience, the prognosis after medical treatment or surgical scraping is guarded, and regrafting can be the only solution to restore graft clarity.

Antimicrobial and antiurolithiatic activities of pure and silver doped copper oxide nanoparticles using Moringa Oleifera leaf extract on struvite urinary stones

The development of nanoparticles plays a significant role in contemporary medicament. Struvite stones are associated with urinary tract infection, there are several techniques provided including drug therapy, and extracorporeal shock wave lithotripsy (ESWL) in consequence, the present study was focused onto attain the antiurolithiatic activity of pure and 20% of Ag-doped CuO nanoparticles mediated from Moringa Oleifera leaf extract. The synthesized nanoparticles were characterized using X-ray Diffraction. The Monoclinic structure and the average crystallite size for pure and 20% Ag-doped CuO nanoparticles were found to be 15.22nm and 3.67nm. The surface morphology of the specimens was analyzed by Field-Emission Scanning Electron Microscopy and Transmission Electron Microscopy. FE-SEM images showed nanostructures for pure and 20% Ag-doped CuO nanoparticles. The average particle size obtained for the nanoparticles from FE-SEM was found to be in the range of 12.84 nm-14.52 nm & 2.55 nm-5.04 nm was in good agreement with the average crystallite size from XRD results. TEM images displayed that CuO nanoparticles were distributed uniformly and for 20% Ag-doped CuO nanoparticles, Ag nanoparticles adhered on the surface of CuO nanoparticles. The presence of the synthesized materials was detected by Energy Dispersive X-ray analysis. Functional groups were identified by Fourier Transform Infrared Spectroscopy. From, Zeta Potential analysis, the negative potential value of -34.23 mV and -36.12 mV for green synthesized nanoparticles were identified. The diffraction patterns and functional groups of struvite crystals were confirmed by X-ray diffraction and Fourier Transform Infrared Spectroscopy. The inhibitory effect of synthesized 20% Ag-doped CuO nanoparticles showed a percentage of inhibition of 86.95% as compared with pure CuO showed 81.52% at a 5% concentration. Maximum inhibition was observed for 20% Ag-doped CuO nanoparticles against bacterial pathogens such as S. aureus, Bacillus subtilis, and Escherichia coli (8mm) in diameter and fungal Candida albicans (6mm) in diameter. Therefore the present study revealed that the synthesized pure and 20% Ag-doped CuO Nps mediated from M. Oleifera leaf extract encourage the creation of ammonium magnesium phosphate hexahydrate crystals and reduction in nucleation rate of urinary tract infection causing struvite stones.

Urinary Saturations in Children with or without Renal Lithiasis.

In lithogenesis, for a stone to form it is necessary that the urine is supersaturated with respect to the salt that will constitute the future stone. The objective was to analyze the urinary saturations of Calcium Oxalate (CaOxa), brushite (calcium phosphate), struvite (ammonium-magnesium phosphate) and uric acid (UA) in children with and without lithiasis. Correlate them with the different parameters involved in the lithiasic process. And compare saturations in children with or without overweight. We examined 108 healthy children and 53 patients diagnosed with lithiasis. In 24-h urine, the different biochemical parameters involved in lithiasis and the saturation levels of CaOxa, brushite, struvite and UA. We studied 108 healthy children with a mean age of 9.5 ± 3.9 years. Renal lithiasis was diagnosed in 53 patients with an average age of 10.5 ± 5.8 years. Children with lithiasis had higher saturation values of CaOxa (4.86 ± 2.71 vs. 3.15 ± 1.99, p < 0.01) and brushite (1.58 ± 1.23 vs. 0.86 ± 0.81, p < 0.001) compared to non-lithiasic children. UA saturation was higher in children with body mass index greater than 22 (5.25 ± 3.52 vs. 3.84 ± 3.5, p < 0.04). Finally, urinary pH, ammonium concentration and uricosuria influenced UA saturation. that the urinary pH regression coefficient in the uric acid saturation regression analysis was -4.5. The mean values of calcium oxalate and brushite saturations were higher in children with lithiasis. Uric acid saturation was elevated in overweight children. Finally, urinary pH greatly influenced uric acid saturation.

Implementation of a Technique Based on Hounsfield Units and Hounsfield Density to Determine Kidney Stone Composition.

Hounsfield units (HU) are a measure of radiodensity, related to the density of a tissue and the composition of kidney stones. Hounsfield density is what is related to the composition of kidney stones. In the standard acquisition method, these measures are arbitrary and dependent on the operator. This study describes the implementation of a technique based on the HU and Hounsfield density to predict the stone compositions of patients with nephrolithiasis. By conventional percutaneous nephrolithotomy, thirty kidney stone samples corresponding to the cortex, middle, and nucleus were obtained. The HU were obtained by CT scanning with a systematic grid. Hounsfield density was calculated as the HU value divided by the stone’s greatest diameter (HU/mm). With that method and after analyzing the samples by IR-spectroscopy, anhydrous uric acid and ammonium magnesium phosphate were identified as the compounds of kidney stones. Additionally, anhydrous uric acid, magnesium ammonium phosphate, and calcium oxalate monohydrate were identified via Hounsfield density calculation. The study identified HU ranges for stone compounds using a systematic technique that avoids bias in its analysis. In addition, this work could contribute to the timely diagnosis and development of personalized therapies for patients with this pathology.

Use of ammonium chloride to prevent urolithiasis in sheep

ABSTRACT Urolithiasis has a high incidence among confined sheep. It is multifactorial and may cause economic damage. Our aim was to determine the capacity of urinary acidification using ammonium chloride in sheep. Twenty-five 3-month-old male sheep were confined and randomly divided into three groups; the G200 and G500 groups received 200mg/kg/GW and 500mg/kg/GW of ammonium chloride daily for 56 consecutive days, respectively, whereas the CG group did not receive ammonium chloride. Sampling times and clinical evaluation were performed weekly, starting from the 14th day of confinement (M1 or immediately before administering ammonium chloride) until the 17th day (M9) of the feedlot. Hemogasometry, biochemical examination of serum urea and creatinine concentration and ultrasound evaluation of the urinary tract were performed. The urinalysis indicated a higher incidence of ammonium magnesium phosphate crystals at the beginning of the study, showing a migration to urate crystal formation, mainly in the G500 group because of urinary acidification. No hemogasometric, serum biochemistry, ruminal fluid, or ultrasonographic changes were observed. Urinary acidification was achieved and maintained after M7 during the administration of ammonium chloride in the G500 group, but not in the other study groups.

Optimization and semi‐automatic evaluation of a frosting process for a soda lime silicate glass based on phosphoric acid

AbstractChemical glass frosting processes are widely used to create visual attractive glass surfaces. A commonly used frosting bath mainly contains ammonium bifluoride (NH4HF2) mixed with hydrochloric acid (HCl). The frosting process consists of several baths. Firstly, the preliminary bath to clean the object. Secondly, the frosting bath which etches the rough light scattering structure into the glass surface. Finally, the washing baths to clean the frosted object. This is where the constituents of the preceding steps accumulate and have to be filtered from the sewage. In the present contribution, phosphoric acid (H3PO4) was used as a substitute for HCl to reduce the amount of ammonium (NH4+) and chloride (Cl−) dissolved in the waste water. In combination with magnesium carbonate (MgCO3), it allows the precipitation of ammonium within the sewage as ammonium magnesium phosphate (MgNH4PO4). However, a trivial replacement of HCl by H3PO4within the frosting process causes extensive frosting errors, such as inhomogeneous size distributions of the structures or domains that are not fully covered by these structures. By modifying the preliminary bath composition, it was possible to improve the frosting result considerably. To determine the optimal composition of the preliminary bath, a semi‐automatic evaluation method has been developed. This method renders the objective comparison of the resulting surface quality possible.

Nanoscale insight on the initial hydration mechanism of magnesium phosphate cement

The hydration rate, microstructure, mechanical properties and durability of Magnesium phosphate cement (MPC) prepared by different kinds of phosphates are quite different. These differences in macroscopic properties are essentially determined by microscopic chemical reactions. Therefore, in this paper, the adsorption mechanism of MgO interface to water and ions in the initial hydration process of MPC and the hydration structure of different ions were discussed at the molecular level. Herein, the structure and dynamics properties of water, NH4+, Na+, K+ and Cl− ions at MgO interface were analyzed by molecular dynamics method. The results show that the water molecules near the MgO interface can be connected to the matrix oxygen through hydrogen bonding and have a Coulomb interaction with the Mg on the interface. Therefore, the water molecules accumulate and stratify at the interface and the density distribution curve of water molecules forms a peak near the interface. This explains the stage of MgO adsorption of water molecules during the initial hydration of MPC. Besides, a large amount of ammonium ion, sodium ion and potassium ion are adsorbed on the MgO surface, and the cation density distribution curve also forms a peak near the interface. In addition, the radius of sodium ion is smaller and the Na-Os bond is stronger than that of NH4+ and K+ (Os represents the oxygen atom in MgO). Hence, the number of sodium ions adsorbed to the interface is the largest, the radial distribution function (RDF) of Na-Os forms a high-strength and sharp peak, The Os coordination number of Na+ is more than that of NH4+ and K+. This also explains the experimental phenomenon that sodium magnesium phosphate cement has a faster hydration rate and shorter setting time than ammonium magnesium phosphate cement and potassium magnesium phosphate cement. Due to the adsorption of the interface, the mean square displacement of cations has decreased to some extent compared with that in the corresponding pure solution models. This study provides a basic understanding of the initial hydration mechanism of MPC at the molecular level.

A proposal of low-cost technology for nutrient recovery from leachate of anaerobic digester at a biological wastewater treatment plant

Removal of nutrients from wastewater with simultaneous recovery of phosphorus (P) and nitrogen (N) in the form assimilable by plants is possible by the precipitation of ammonium magnesium phosphate (struvite). This method benefits environmental protection but has not been widely implemented in Wastewater Treatment Plants (WWTPs). One of the reasons is the high costs of available technologies. The aim of the work is to investigate the low-cost methods of reduction and recovery of nutrients from wastewater. It involves the precipitation of struvite from phosphate-rich leachate from WWTP fermentation chambers. The reaction was carried out in the prototype of a simple horizontal reactor, ensuring the possibility of collecting sediment in the funnel. A cheap waste magnesium salt was used to precipitate the struvite, which significantly reduced the costs of its acquisition. The reduction of P exceeded 80% in most of performed tests in leachate waters. The precipitant removed from the reactor has the character of sludge with a significant degree of hydration (85%). After drying, it is a dusty powder with an average P content of 40% and a total N content of 8% and a trace of heavy metals. It was proposed to mix the obtained aqueous form of struvite sediments with compost produced from excessive sludge, without drying it. Studies have shown that one percent of struvite admixture in compost results in an increase of P and N content by 13% and 2.7%, respectively.

PHOSPHORUS RECOVERY FROM WASTE AS STRUVITE

The paper gives information on the depletion of phosphorus (P) as an important element for all forms of life and its pollution impact on the environment in case of intensive discharge of phosphorus compounds into water bodies. Two secondary waste sources of Phosphorus are under consideration, namely the domestic wastewater and sludge and animal manure. The characteristics of these two fluids regarding organic matter and nutrient content are summarized. Discussing the techniques for P extraction mostly attention is given to phosphorus precipitation as ammonium magnesium phosphate (struvite). Examples of effectiveness of P precipitation as struvite in Municipal Wastewater Treatment Plants (MWWTPs) with chemical and biological P removal are presented. The examples of struvite production from sewage and manure waste show evidently the great potential of utilization of such a waste as a source of phosphorus. The recovered product is valuable both as it is a slow release fertilizer and with its low content of heavy metals compared to the mineral fertilizers. In respect of the diminishing amount of natural P rocks, the sewagec wastewater and sludge and the animal manure can be regarded as an important secondary source of Phosphorus.

Urinary stone composition analysis of 3684 patients in the eastern Shandong region of China.

ObjectiveThere has not been a study that analyzed the composition of urinary stones from patients in the eastern Shandong region of China. Thus, we explored the composition of urinary stones in the eastern Shandong region of China and discuss the clinical significance of the findings.MethodsA total of 3684 urinary calculi from the eastern Shandong region were collected in our study. Compositions of the stones were analyzed using an Automatic Infrared Spectrum Analysis System (type LIIR-20). The results were verified through manual analysis of the spectrograms, which was accompanied by polarizing microscopy and chemical analysis if necessary.ResultsAmong the 3684 specimens, there were 1767 single-component stones and 1917 mixed-component stones. According to the main components of the stones, the stones were divided into the following types: calcium oxalate monohydrate stones (1779, 48.3%), anhydrous uric acid stones (1105, 30.0%), carbonate apatite stones (590, 16.0%), ammonium magnesium phosphate hexahydrate stones (143, 3.9%), calcium oxalate dihydrate stones (36, 1.0%), and cystine stones (31, 0.8%).ConclusionsThere was a relatively high rate of uric acid stones in patients from the eastern Shandong region of China.

Resources recovery from high-strength human waste anaerobic digestate using simple nitrification and denitrification filters

Simple trickling nitrification filters and submerged denitrification filters were developed to provide post-treatment to high-strength human waste anaerobic digestate with the aims to (i) effectively recover nutrients in a useful form as a fertilizer and to (ii) treat digestate such that it could be reused as flush water in water scarce regions. The tested filter media (biochar, granular activated carbon, rice and coconut husks, bamboo chips, sunflower seeds, and zeolite) are low cost and sustainable materials and can be locally sourced where on-site sanitation facilities are in high demand. Experimental data from laboratory operation with digestate from anaerobic digestion of dog feces and human urine revealed that the filters achieved a combined removal of chemical oxygen demand (COD), total nitrogen (TN), and phosphorus (PO4-P) up to 84%, 69%, and 89%, respectively. Post-treatment filters have also demonstrated successful recovery of vital nutrients by precipitating ammonium magnesium phosphate hydrate, a documented valuable slow-release solid fertilizer. These filters have a great potential for advancing access to improved sanitation while simultaneously increasing capacity for small-scale economic agricultural development in geographic regions lacking improved sanitation.

Effect of strontium substitution on the material properties and osteogenic potential of 3D powder printed magnesium phosphate scaffolds

3D powder printing is a versatile method for the fabrication of individual bone implants and was used for the processing of in vivo degradable ceramic scaffolds based on ammonium magnesium phosphate hexahydrate (struvite). In this study, synergetic effects could be achieved by the substitution of magnesium phosphate cements with strontium carbonate. This substitution resulted in 8.2 wt%, 16.4 wt%, and 24.6 wt% Sr2+ doped scaffolds, with a 1.9–3.1 times increased radiopacity compared to pure struvite. The maximal compressive strength of (16.1 ± 1.1) MPa found for strontium substituted magnesium phosphate was in the range of cancelleous bone, which makes these 3D printed structures suitable for medical application in low-load-bearing bone areas. In an ion release study over a course of 18 days, the release of strontium, magnesium, calcium, and phosphate ions from scaffolds was analyzed by means of inductively coupled plasma mass spectrometry. Independent of the scaffold composition the Mg2+ concentrations (83–499 mg/l) continuously increased in the cell media. The Sr2+ release varied between 4.3 μg/day and 15.1 μg/day per g scaffold, corresponding to a Sr2+ concentration in media between 1.14 mg/l and 7.24 mg/l. Moreover, decreasing calcium and phosphate concentrations indicated the precipitation of an amorphous calcium phosphate phase. The superior osteogenic properties of strontium substituted magnesium phosphate, e.g. the increase of osteoblast activity and cell number and the simultaneous suppression of osteoclast differentiation could be verified in vitro by means of WST-assay, TRAP-staining, and SEM imaging.

Antibacterial and In Vitro Growth Inhibition Study of Struvite Urinary Stones Using Oxalis corniculata Linn. Leaf Extract and its Biofabricated Silver Nanoparticles.

Herbal drugs are gaining exponential scientific recognition due to their distinct advantages. In the last 2-3 decades, a gradual increase in worldwide patents on herbal nanoformulations has been noted to address the solubility and bioavailability issues of phytoceuticals. Struvite or ammonium magnesium phosphate hexahydrate (NH4MgPO4.6H2O) is among the important urinary infection stones causing painful urological ailment. These smaller stones may bind together to form bigger staghorn calculus. Urinary tract infections caused by some gram positive and gram negative bacteria further enhance the chance of formation of such stones. Oxalis corniculata Linn. is an edible plant, traditionally used in the treatment of bacterial infections and kidney stones. However, there is no scientific evidence to relate the use of O. corniculata against struvite kidney stones. Hence, the antibacterial and struvite stones inhibition activity of the aqueous extract of Oxalis corniculata Linn. leaves and its biofabricated silver nanoparticles (AgNPs) was studied. The aqueous extract of O. corniculata was prepared by Soxhlet extraction. AgNPs were synthesized using green technique and were characterized using UV and IR spectroscopy, XRD, TEM, DLS and zeta potential studies. Antibacterial activity of the aqueous extract and the silver nanoparticles was tested against E. coli (gram negative) and S. aureus (gram positive) species. Struvite stones were grown in a gel medium by in vitro single diffusion gel growth technique and its inhibition study was carried out using the extract and its biofabricated nanoparticles. The aqueous extract and its biofabricated AgNPs exhibited potent antibacterial activity against both gram positive and gram negative strains of bacteria. The aqueous extract also effectively repressed the growth of struvite stones and led to the dissolution of stones, but the inhibitory effect was further enhanced by its biofabricated AgNPs. The present work confirms the inhibitory activity of the aqueous extract of edible O. corniculata and its biofabricated silver nanoparticles against urinary tract infection (UTI) causing bacteria and urolithiasis. Therefore, the consumption of O. corniculata in our daily diet may reduce the risk of UTI and urolithiasis.