Magnesium Ammonium Phosphate Hexahydrate Research Articles

High plasma magnesium and phosphorus levels and their correlation with struvite urolithiasis in buffaloes

BackgroundUrolithiasis is a common urinary tract disease in buffaloes, almost exclusively affects young males, and has significant economic and production impacts. We have investigated hemato-biochemical and urinary changes in an attempt to deduce their correlation with struvite urolithiasis in buffaloes. MethodsTen male buffalo calves with obstructive urolithiasis were used. Blood samples were used for hematology and elemental analysis. Urine samples were used for physico-chemical examination, microscopy, and elemental analysis. Uroliths were subjected to chemical functional group determination using the FTIR spectroscopy. ResultsThe mean neutrophil, leukocyte, and neutrophil-to-lymphocyte ratio was significantly (p < 0.05) higher in urolithic buffaloes than in healthy controls. The mean blood calcium and magnesium concentrations were significantly (p < 0.05) lower and higher in urolithic buffaloes than in healthy controls, respectively. Mean blood phosphorus concentration and calcium-phosphorus ratio were found to be non-significantly (p > 0.05) higher and lower in urolithic buffaloes than in healthy controls, respectively. The urine pH was highly alkaline. Multiple prismatic lid-shaped crystals, along with erythrocytes, leukocytes, and epithelial cells, were found in urine. The mean urinary magnesium and phosphorus concentrations were non-significantly (p < 0.05) higher in urolithic buffaloes than in healthy controls. A positive correlation of magnesium (r = 0.864, p = 0.001) and phosphorus (r = 0.849, p = 0.002) concentrations between the blood and urine was observed in urolithic buffaloes. The FTIR spectra of uroliths were similar to those of magnesium ammonium phosphate hexahydrate, MgNH4PO4·6H2O or struvite. ConclusionThe findings suggest that high plasma magnesium and phosphorus concentrations have a positive correlation with struvite urolithiasis in buffaloes.

Exploring the association between multiple factors and urolithiasis: A retrospective study and Mendelian randomization analysis.

To investigate the relationship between several factors and urinary stone as well as different stone compositions. To guide the diagnosis, treatment, and prevention of urinary stone recurrence. We used bidirectional Mendelian randomization to analyze the causal relationship between hypertension and urinary stones, diabetes and urinary stones, and body mass index (BMI) and urinary stones. We retrospectively analyzed the medical records of patients with urinary stones admitted to a tertiary care hospital in Chongqing, China, from July 2015 to October 2022. Patients were included when they were first diagnosed with urinary stones. The odds ratio of calculi on hypertension estimated by inverse variance weighted was 8.46 (95%CI: 4.00-17.90, P = 2.25 × 10-8). The stone composition analysis showed that there were 3101 (67.02%) mixed, 1322 (28.57%) calcium oxalate monohydrate, 148 (3.20%) anhydrous uric acid, 16 (0.35%) magnesium ammonium phosphate hexahydrate, 11 (0.24%) dicalcium phosphate dihydrate, 10 (0.22%) carbonate apatite, 8 (0.17%) L-cystine, 4 ammonium uric acid (0.09%), and 7 other stone types (0.15%). Mendelian randomization studies have proven that urinary stones may be a potential risk factor for hypertension, while there is no causal relationship between diabetes and stones, BMI, and stones. Our retrospective study has shown that urinary stone components are closely associated with sex, age, hypertension, diabetes, and BMI. It is reasonable to suspect that treating a single stone component is ineffective in preventing recurrence. We also found that the peak incidence of urinary stones was at the most active stage of most people's working lives.

Could Microbiota Edit Oxalate Nephrolithiasis’ Story?

Abstract: Nephrolithiasis is a complex multifactorial pathology which contributes to the onset of genetics factors, environmental factors, diet and lifestyle, in addition this pathology has recently been associated with an increased risk of developing cardiovascular diseases increasing the burden of health care costs1. Nephrolithiasis is characterized by a complex of manifestations resulting from the formation and transit along the urinary tract of crystalline agglomerates stones, composed of poorly soluble substances. Kidney stones are elements of hard consistency, consisting of a solid component mixed with an organic matrix, i.e. proteins normally present in the urine. Most stones are calcium based, it is estimated that those of calcium oxalate (CaOx) and calcium phosphate (CaP) correspond to 80% of all calculations. In 9% of cases they are of uric acid, in 10% struvite (magnesium ammonium phosphate hexahydrate) and in 1% are other type (cystine, ammonium urate acid)2. Nephrolithiasis is a common cause of morbidity in the United States, responsible for hospitalization in 1 per 1000 of the population every year3-4, while in Asia the probability of forming kidney stones is very low (1-5%). The peak incidence was observed in subjects between 18 and 45 years, with a prevalence greater than 5-10 times in males. Was estimated that 5% of American women and 12% of men will develop an episode of calculating at some point in life5. 40% of patients with a first episode of nephrolithiasis have a second episode within 2-3 years and 75% relapse within 7-10 years. After 20 years, it is estimated that in less than 10% of patients do not develop stones again6

Inhibitory Effect of Alternanthera Sessilis, Cucurbita Maxima and Aerva Lanata on Whewellite Urinary Crystals

Phosphate stones, such as struvite (magnesium ammonium phosphate hexahydrate), brushite (calcium hydrogen phosphate dihydrate), and oxalates like whewellite (calcium oxalate monohydrate) are different kinds of urinary stones. Such kidney stones can be treated with herbs for natural healing and side effects-free results. These urinary crystals are traditionally created in the lab using the gel growth process and a silica gel medium at a specified pH. The inhibitory effects can be analysed by using the extracts of herbal plants. In the present study, ethanol extracts of leaves of Alternanthera sessilis, seeds of Cucurbita maxima and flowers of Aerva lanata are investigated for their inhibitory activity against the whewellite urinary crystals. They are characterized using Fourier transform infrared spectrum and their crystalline nature is examined through powder X-ray diffraction. Asymmetric and symmetric stretching unit of C=O in oxalate appears at 1620 cm-1 and 1400, 1310 cm-1 respectively. The monoclinic crystal system with a space group of P21/n is confirmed from the powder X-ray diffraction studies. The results indicated that among the three ethanol extracts, leaves of Alternanthera sessilis, seeds of Cucurbita maxima and flowers of Aerva lanata- the flowers of Aerva lanata exhibited inhibition towards whewellite crystals. KEYWORDS Extract, flowers, herbs, oxalates, pH, seeds

Predicting stone composition via machine-learning models trained on intra-operative endoscopic digital images

ObjectivesThe aim of this study was to use deep learning (DL) of intraoperative images of urinary stones to predict the composition of urinary stones. In this way, the laser frequency and intensity can be adjusted in real time to reduce operation time and surgical trauma.Materials and methodsA total of 490 patients who underwent holmium laser surgery during the two-year period from March 2021 to March 2023 and had stone analysis results were collected by the stone laboratory. A total of 1658 intraoperative stone images were obtained. The eight stone categories with the highest number of stones were selected by sorting. Single component stones include calcium oxalate monohydrate (W1), calcium oxalate dihydrate (W2), magnesium ammonium phosphate hexahydrate, apatite carbonate (CH) and anhydrous uric acid (U). Mixed stones include W2 + U, W1 + W2 and W1 + CH. All stones have intraoperative videos. More than 20 intraoperative high-resolution images of the stones, including the surface and core of the stones, were available for each patient via FFmpeg command screenshots. The deep convolutional neural network (CNN) ResNet-101 (ResNet, Microsoft) was applied to each image as a multiclass classification model.ResultsThe composition prediction rates for each component were as follows: calcium oxalate monohydrate 99% (n = 142), calcium oxalate dihydrate 100% (n = 29), apatite carbonate 100% (n = 131), anhydrous uric acid 98% (n = 57), W1 + W2 100% (n = 82), W1 + CH 100% ( n = 20) and W2 + U 100% (n = 24). The overall weighted recall of the cellular neural network component analysis for the entire cohort was 99%.ConclusionThis preliminary study suggests that DL is a promising method for identifying urinary stone components from intraoperative endoscopic images. Compared to intraoperative identification of stone components by the human eye, DL can discriminate single and mixed stone components more accurately and quickly. At the same time, based on the training of stone images in vitro, it is closer to the clinical application of stone images in vivo. This technology can be used to identify the composition of stones in real time and to adjust the frequency and energy intensity of the holmium laser in time. The prediction of stone composition can significantly shorten the operation time, improve the efficiency of stone surgery and prevent the risk of postoperative infection.

Treatability of high-strength real sheep slaughterhouse wastewater using struvite precipitation coupled Fenton's oxidation: The MAPFOX process

Struvite (MAP, magnesium ammonium phosphate hexahydrate, MgNH4PO4.6H2O) precipitation-aided Fenton's OXidation (MAPFOX process) was explored in the treatment of high-strength real sheep slaughterhouse wastewater (RSSW) for the first time under a comprehensive soft-computing-based modeling study. The experimental results showed that under the highest-efficiency conditions (chemical combination of MgCl2.6H2O + NaH2PO4.2H2O, a molar ratio of Mg2+:NH4+-N:PO43–P = 1.2:1:1, a reaction pH of 9.0 ± 0.10, [NH4+-N]0 = 240 ± 20 mg/L, and a reaction time of 15 min), MAP precipitation could effectively remove more than 80 %, 60 %, 55 %, and 70 % of color, total chemical oxygen demand (TCOD), soluble COD (SCOD), and ammonium nitrogen (NH4+-N) from the raw RSSW. The results of the Fenton's oxidation used as the post-treatment unit of the proposed MAPFOX system indicated that the integrated advanced oxidation process (AOP) was able to reduce the residual pollutant levels in the MAP-pretreated RSSW to the relevant discharge standards. Under the subsequent condition of [Fe2+]0 = 90 mmol/L, [H2O2]0 = 180 mmol/L, reaction pH = 3.25, and total reaction time = 60 min, more than 97 % of color, TCOD, SCOD, and NH4+-N could be removed from the RSSW via the Fenton's oxidation after the MAP-based physicochemical treatment. According to SEM micrographs, surface morphology of dehydrated struvite exhibited irregular-shaped and overlapping sharp-edged particles of various sizes with an average size of about 50.9 μm. The Fourier Transform Infrared (FTIR) spectroscopy confirmed the active functional groups and type of bonds for the high-strength RSSW-oriented struvite (heated) within the spectral range of 4000–450 cm−1. Thermogravimetric Analysis (TGA), Derivative Thermogravimetry (DTG), Differential Thermal Analysis (DTA), and Differential Scanning Calorimetry (DSC) of the dehydrated struvite revealed that the weight loss occurred in three temperature zones, the maximum weight loss rate of 0.252 mg/min was recorded at around 224 °C and at time of 20.83 min, and the sample had strong endothermic and medium exothermic peaks at about 241 °C and 679 °C, respectively. The predictive successes of the implemented soft-computing approaches were benchmarked in terms of various statistical goodness-of-fit parameters. The performance assessment indices corroborated the superiority of the support vector machines-Pearson VII universal kernel function (SVM-PUKF)-based model (correlation coefficient (CC) = 0.9999–1.0000), mean absolute error (MAE) = 0.0222–0.0389 %, mean absolute percentage error (MAPE) = 0.0270–0.0506 %, root mean squared error (RMSE) = 0.0258–0.0415 %, coefficient of variation of RMSE (CV(RMSE) = 0.0003–0.0008, Nash–Sutcliffe efficiency (NSE) = 0.9998–1.000, Legates and McCabe's index (LMI) = 0.9894–0.9952) over other data-intelligent models in predicting the pollutant removal efficiencies. The computational results also indicated that the narrowest uncertainty bands (±1.96Se = 0.0537–0.1483 %) and the lowest amounts of expanded uncertainty (U95 = 3.1224–5.3124 %) values for all efficiency sets were achieved for the applied SVM-PUKF-based strategy. This study demonstrated the first-ever and successful application of the proposed MAPFOX process in treatability of the RSSW and capability of the implemented soft-computing strategy in modeling a highly nonlinear treatment system.

Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formation.

The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH4PO4 · 6H2O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization. In this study, we use synchrotron-based in situ x-ray scattering complemented by cryogenic transmission electron microscopy to obtain new insights from the earliest stages of struvite formation. The holistic scattering data captured the structure of an entire assembly in a time-resolved manner. The structural features comprise the aqueous medium, the growing struvite crystals, and any potential heterogeneities or complex entities. By analysing the scattering data, we found that the onset of crystallization causes a perturbation in the structure of the surrounding aqueous medium. This perturbation is characterized by the occurrence and evolution of Ornstein-Zernike fluctuations on a scale of about 1nm, suggesting a non-classical nature of the system. We interpret this phenomenon as a liquid-liquid phase separation, which gives rise to the formation of the amorphous precursor phase preceding actual crystal growth of struvite. Our microscopy results confirm that the formation of Mg-struvite includes a short-lived amorphous phase, lasting >10s.

The implications of pulsating anode potential on the electrochemical recovery of phosphate as magnesium ammonium phosphate hexahydrate (struvite)

A sustainable approach to address the limited availability of rock phosphate is to electrochemically recover phosphorus (P) as struvite (magnesium ammonium phosphate hexahydrate, MgNH4PO4·6H2O) fertilizer. On Mg surfaces, however, magnesium hydroxide (Mg(OH)2) and/or struvite form resistive films that limit the release of divalent Mg ions and reduce struvite precipitation. The present work enhances struvite recovery through the application of a dynamic voltage with a sinusoidal waveform. Compared to a constant potential, our results demonstrated that a dynamic potential could enhance the rupture of the passivating film, and facilitate the release of Mg2+ from the metal anode, thereby overcoming passivation problems. Ammonium dihydrogen phosphate (NH4H2PO4, 10 mM) solutions at neutral pH were used as test solutions. A 160–192 % increase in magnesium release was observed versus constant voltage applications, resulting in a 1.3x increase in phosphate recovery. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) characterizations indicated that the precipitate recovered contained struvite. An analysis of electrode surfaces using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) confirms a greater extent of passivating film breakdown under dynamic voltages.

Near-Infrared Absorption Coefficients in Kidney Stone Minerals and Their Relation to Crystal Structure

To quantitatively understand laser ablation of kidney stones by near-infrared (NIR) lasers, accurate measurements of physical properties related to heating and mechanical failure are needed. While light scattering varies among individual stones, absorption coefficients for the materials that form the bulk of each kidney stone are measurable when scattering is controlled. We developed methods to grow single crystals with lengths and widths >20 μm for the minerals that form kidney stones: calcium oxalate monohydrate, calcium oxalate dihydrate, calcium hydrogen phosphate dihydrate, hydroxyapatite, anhydrous uric acid, and magnesium ammonium phosphate hexahydrate. These single crystals were used with an infrared microscope to measure their NIR absorption coefficients from 1.67 to 2.5 μm. The strong correlation between single crystal NIR spectra and diffuse reflectance NIR spectra indicates little anisotropy in absorption. Most minerals absorbed more strongly at 1.94 μm than 2.12 μm, the wavelengths of thulium fiber and holmium:YAG surgical lasers, respectively. For water bearing minerals, we attribute absorption mainly to water combination modes and assign NIR absorption peaks to specific water molecules and the OH bonds thereof where possible. Reported absorption coefficients can be used to quantitatively compare both laboratory investigations of ablation and surgical experience to physical properties for the first time.

Formation and composition of crust in the nephrostomy tube of patients undergoing percutaneous nephrostomy

To investigate the formation and composition of crust in the nephrostomy tube (NT) of patients undergoing percutaneous nephrostomy (PCN). Consecutive patients undergoing PCN for the treatment of obstructive nephropathy who then underwent NT exchange between January 2020 and May 2022 were included in the study. The composition of crust in NTs was analyzed using infrared spectrum automatic analysis system. A total of 46 NTs were collected from 46 consecutive patients (19 men, 27 women; mean age, 68.5 ± 13.4 years) who underwent PCN. The median indwelling time of NTs was 96 days (Q1, 90 days; Q3, 140 days). Among the 46 NTs, 20 (43.5%) were positive for the presence of crust. The mean indwelling time was significantly longer in NTs positive for crust than in those negative for crust (169.7 ± 55.7 days vs 86.5 ± 15.0 days; P < .01). In the NTs positive for crust, the crust was composed of mixed components (apatite carbonate and magnesium ammonium phosphate hexahydrate, n = 7; apatite carbonate and calcium oxalate monohydrate, n = 4) in 11 NTs and a single component (apatite carbonate, n = 5; anhydrous uric acid, n = 2; calcium oxalate monohydrate, n = 2) in 9 NTs. When the NT indwelling time was longer than 3 months, the incidence of crust formation in the NT was significantly increased. Crust was most commonly composed of mixed components. In light of these findings, we suggest that NTs should be exchanged every 3 to 4 months to prevent the formation of crust and thus prevent obstruction of the NT.

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.

Analysis of the Components of 236 Cases of Urinary Stones in Xinjiang Uyghur Children.

The aim of the study is to explore the relationship between clinical characteristics and urinary calculus in Xinjiang Uyghur children, and to provide clinical basis for the prevention as well as treatment of urinary stone. In total, 236 urinary tract stone samples were collected from pediatric patients from February 2017 to April 2019, and those samples were analyzed by infrared spectroscopy. Stone compositions were compared with demographic data. Among the 236 cases, 166 cases were boys (70.34%) and 70 cases were girls (29.66%), with a male-to-female ratio of 2.37:1. A total of 21 kinds of calculi were detected, including 107 cases with six kinds of simple calculi and 129 cases with 15 kinds of mixed calculi. In this study, magnesium ammonium phosphate hexahydrate was only found in boys, and the difference was statistically significant (6.6 vs. 0.0%, p = 0.037). There were statistical differences in the age distribution of children with ammonium hydrogen urate, calcium oxalate, and other stone components (p < 0.05), while there were no statistical differences in the age distribution of children with apatite carbonate, magnesium ammonium phosphate hexahydrate, and anhydrous uric acid. The results showed that there was a significant difference in the localization of calculi between male and female children (upper urinary tract stones: 78.9 vs. 98.6%, p < 0.001). Uyghur pediatric patients with urolithiasis were young and the majority of stones was mixed, The main components of calculi were ammonium hydrogen urate, calcium oxalate and apatite carbonate, and there are differences in the localization of calculi between genders.

Production of struvite by magnesium anode constant voltage electrolytic crystallisation from anaerobically digested chicken manure slurry

Nitrogen and phosphorus levels in livestock manure and digestive fluid are high, posing a threat to soil and water quality and necessitating nutrient removal and recovery. Phosphorus recovery has the potential to alleviate the global phosphorus resource crisis. This study proposed a magnesium anode constant voltage electrolysis method to crystallise struvite (magnesium ammonium phosphate hexahydrate, MgNH4PO4·6H2O) from anaerobically digested chicken manure slurry using reaction kinetics at variable constant voltages ranging from 2 V to 12 V. The recovery of nitrogen and phosphorus was shown to be effective over a wide initial pH range (3.00 ± 0.03–7.90 ± 0.10) using synthetic digestion fluids. Moreover, the pH gradually increased during the reaction without any external chemical adjustments. The phosphorus recovery rates conformed to the first-order kinetic model, with a maximum rate constant of 2.13 h−1. When the best voltage of 2 V was used at 25 ± 1 °C, the recovery rate reached 5.24 mg P h−1cm−2 in the synthetic digestion fluids during 90 min and 4.60 mg P h−1cm−2 in the anaerobically digested chicken manure slurry. The crystalline products recovered were identified as high-purity struvite by XRD and XPS. The purity of recovered struvite with an initial pH of 3.00 and 7.90 was 96.5% and 98.9%, respectively. These results demonstrated that the magnesium electrode could rapidly react with nitrogen and phosphorus to generate high-purity struvite.

(Digital Presentation) Enhanced Electrochemical Phosphate Recovery from Wastewater: Implications of Pulsating Anode Potential

Electrochemical recovery of phosphorus (P) as struvite (or magnesium ammonium phosphate hexahydrate, MgNH4PO4.6H2O) fertilizer using a sacrificial pure magnesium (Mg) anode is considered a sustainable strategy to deal with the limited availability of rock phosphate. However, the formation of an electrically passive film of magnesium hydroxide (Mg(OH)2) and/or struvite on the surface of Mg upon immediate immersion in aqueous phosphate solution limits the release of divalent Mg ions and decreases struvite precipitation. The present work highlights struvite recovery by an electrochemical method upon application of a dynamic voltage with a sinusoidal waveform. Our results demonstrate that a dynamic potential, when compared to a constant potential, can enhance the rupture of the passivating film, and facilitate the release of Mg2+ from the metal thereby overcoming the problems related to electrical passivation.Aqueous solutions of ammonium dihydrogen phosphate (NH4H2PO4, 10 mM) at neutral pH were used as test solutions. Mg2+ release was notably increased by ~48% relative to constant voltage applications, which subsequently led to ~20% higher phosphate recovery. Characterization studies including X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated the presence of struvite in the recovered precipitate. Surface characterization of electrodes using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) also confirms a higher extent of passivating film breakdown in the presence of dynamic voltage.

Accelerated bone regeneration through rational design of magnesium phosphate cements

Results of several studies during past years suggested that magnesium phosphate cements (MPCs) not only show excellent biocompatibility and osteoconductivity, but they also provide improved regeneration capacity due to higher solubility compared to calcium phosphates. These findings also highlighted that chemical similarity of bone substitutes to the natural bone tissue is not a determinant factor in the success of regenerative strategies. The aim of this study was to further improve the degradation speed of MPCs for a fast bone ingrowth within a few months. We confirmed our hypothesis, that decreasing the powder-liquid ratio (PLR) of cement results in an increased content of highly soluble phases such as struvite (MgNH4PO4⋅6H2O) as well as K-struvite (MgKPO4⋅6H2O). Promising compositions with a low PLR of 1 g ml−1 were implanted in partially-loaded tibia defects in sheep. Both cements were partially degraded and replaced by bone tissue after 4 months. The degradation speed of the K-struvite cement was significantly higher compared to the struvite cement, initially resulting in the formation of a cell-rich resorption zone at the surface of some implants, as determined by histology. Overall, both MPCs investigated in this study seem to be promising as an alternative to the clinically well-established, but slowly degrading calcium phosphate cements, depending on defect size and desired degradation rate. Whereas the K-struvite cement might require further modification towards a slower resorption and reduced inflammatory response in vivo, the struvite cement appears promising for the treatment of bone defects due to its continuous degradation with simultaneous new bone formation. Statement of significanceCold setting bone cements are used for the treatment of bone defects that exceed a critical size and cannot heal on their own. They are applied pasty into the bone defect and harden afterwards so that the shape adapts to the individual defect. Magnesium phosphates such as magnesium ammonium phosphate hexahydrate (struvite) belong to a new class of these cold setting bone cements. They degrade much faster than the clinically established calcium phosphates. In this study, a magnesium phosphate that has hardly been investigated so far was implanted into partially-loaded defects in sheeps: Potassium magnesium phosphate hexahydrate. This showed even faster resorption compared to the struvite cement: after 4 months, 63% of the cement was already degraded.

Detection of the mineral constituents in human renal calculi by vibrational spectroscopic analysis combined with allied techniques Powder XRD, TGA, SEM, IR imaging and TXRF

Detection of the mineral constituents in a batch of 310 samples of human urinary calculi (kidney stones-235 and bladder stones-75) combined with a semi-quantitative analysis has been presented on the basis of Fourier Transform based IR and Raman spectral measurements. Some of the observed characteristic IR and Raman bands have been proposed as ‘Marker Bands’ for the most reliable identification of the constituents. A detailed vibrational spectral analysis combined with a DFT level calculation for the functional groups in Calcium Oxalate Monohydrate (COM), Magnesium Ammonium Phosphate Hexahydrate (MAPH), Calcium Hydrogen Phosphate Dihydrate (CHPD), Penta-Calcium Hydroxy-Triphosphate (PCHT) and Uric Acid (UA) has been proposed. It has been shown that the identified mineral constituents as major or minor components can be deduced from the application of Lambert-Beer law of radiation absorption and results are in agreement with quantitative Spectral Data base. This simple method has the potential to be integrated into the management of Urolithiasis, a process of forming renal calculi in the kidney, bladder and/or urethra. Employment of powder XRD, TGA, SEM, TXRF and IR Imaging techniques has provided additional support for the proposed foolproof identification of the mineral constituents. Among the mineral constituents, Calcium Oxalate Monohydrate, Calcium Oxalate Dihydrate or their mixture account for 85% of the total number of samples; the remaining 15% and 5% samples contain Phosphate and Uric acid stones respectively.

The Implications of Pulsating Anode Potential on the Electrochemical Recovery of Phosphate as Magnesium Ammonium Phosphate Hexahydrate (Struvite)

The Implications of Pulsating Anode Potential on the Electrochemical Recovery of Phosphate as Magnesium Ammonium Phosphate Hexahydrate (Struvite)

Optimization of Gas Scrubbing in the Calcination of Struvite

AbstractDuring the calcination of magnesium ammonium phosphate hexahydrate (struvite) in the process of recycling to obtain phosphoric acid, ammonia is released in addition to water and carbon dioxide. With a gas scrubber, e.g., in the form of a bubble column reactor, ammonia can be recovered as a usable valuable material. With water as an inexpensive and effective absorbent, almost complete absorption (92 %) of the ammonia from the exhaust air can be achieved.

Preliminary assessment of a portable Raman spectroscopy system for post-operative urinary stone analysis.

We aimed to evaluate the reliability of a portable device that applies Raman spectroscopy at an excitation wavelength of 1064nm for the post-operative analysis of urinary stone composition. Urinary stone samples were obtained post-operatively from 300 patients. All samples were analyzed by the portable Raman spectroscopy system at an excitation wavelength of 1064nm as well as by infrared spectroscopy (IR), and the results were compared. Both Raman spectroscopy and IR could detect multiple stone components, including calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate, uric acid, cystine, and magnesium ammonium phosphate hexahydrate. The results from 1064-nm Raman analysis matched those from IR analysis for 96.0% (288/300) of cases. Although IR detected multiple components within samples more often than Raman analysis (239 vs 131), the Raman analysis required less time to complete than IR data acquisition (5min vs 30min). These preliminary results indicate that 1064-nm Raman spectroscopy can be applied in a portable and automated analytical system for rapid detection of urinary stone composition in the post-operative clinical setting. Chinese Clinical Trail Register ID: ChiCTR2000039810 (approved WHO primary register) http://www.chictr.org.cn/showproj.aspx?proj=63662 .

Vaginal Calculi in the Eastern North Atlantic Common Dolphins Delphinus Delphis, Induction Mechanisms and Possible Effects on Fecundity

The proper management of cetacean populations requires life history and demographic parameters to be estimated at population level. In this study we focus on a reproductive pathology that has the potential to alter reproductive rate: the vaginal calculi or stones. The present work documents vaginal calculi prevalence and structure in the eastern North Atlantic common dolphin Delphinus delphis in order to infer their likely mechanisms of induction and possible effects on fecundity. The work is based on routine examinations and necropsies of stranded marine mammals reported by the French stranding scheme from 1972 to 2012. Vaginal calculi were described and measured, and their composition was analyzed by Fourrier-Transformed Infra-Red (FTIR) spectroscopy. Necropsies and reproductive tract examinations were performed on 435 female common dolphins since 1972 along the French coasts, of which 14 showed vaginal calculi, representing 3.2% of the examined females. All females with calculi were older than 7, and there was no relationship of calculus size with age. Histopathology revealed lesions due to an inflammatory response to the presence of the calculi: chronicle vaginitis, variable endometritis and cystitis. Calculus size varied from 1 to 21 cm in maximum dimension and 4–1,460 g in mass. Their internal structure was homogeneous, particularly due to the absence of core material, hence corresponding to the definition of primary calculi. All calculus spectra showed almost identical compositions, with struvite (magnesium ammonium phosphate hexahydrate) representing on average 87% of calculus mass. Dysfunction of the uro-genital tract, such as vesico-vaginal fistulae, would be the likely initial pathological condition that led to the formation of these stones. Both the initial chemical condition in the vagina and the resulting formation of a calculi are obstacles to successful reproduction.