Electron Microscopy for the Stability Assessment of Parenteral Nutrition Admixtures: Focus on Precipitation.

(1) Background: parenteral nutrition (PN) is indispensable for patients unable to receive oral or enteral feeding. However, the complexity of PN solutions presents challenges regarding stability and compatibility. Precipitation reactions may occur. The most frequent is the formation of calcium phosphate (Ca-P). The different factors influencing these reactions must be considered to ensure patient safety. (2) Methods: eight paediatric PN solutions were prepared, following standard protocols. Samples were stored at room temperature and in a refrigerator. Electron microscopy, coupled with energy dispersive X-ray spectroscopy (EDS), was employed. Precipitates were analysed for composition and morphology. (3) Results: precipitates were observed in all samples, even at day 0. Crystalline structures, predominantly composed of calcium or magnesium, sometimes associated with chlorine or phosphorus, were detected. Additionally, amorphous precipitates, contained heterogeneous compositions, including unexpected elements, were identified. (4) Conclusions: various precipitates, primarily calcium- or magnesium-based, can form in PN solutions, although it is not expected that they can form under the real conditions of use. Calcium oxalate precipitation has been characterised, but the use of organic calcium and phosphate salts appears to mitigate calcium phosphate precipitation. Electron microscopy provides interesting results on NP precipitation, but sample preparation may present technical limitations that affect the interpretation of the results.

Evaluation of enhanced nanofiltration membranes for improving magnesium recovery schemes from seawater/brine: Integrating experimental performing data with a techno-economic assessment.

The global demand for valuable metals and minerals necessitates the exploration of alternative, sustainable approaches to mineral recovery. Seawater mining has emerged as a promising option, offering a vast reserve of minerals and an environmentally friendly alternative to land-based mining. Among the various techniques, Nanofiltration (NF) has gained significant attention as a preliminary treatment step in Minimum Liquid Discharge (MLD) and Zero Liquid Discharge (ZLD) schemes. This study focused on the potential of two underexplored commercial polyamide based NF membranes, Synder NFX and Vontron VNF1, with enhanced divalent over monovalent separation factors, in optimizing the extraction of magnesium hydroxide (Mg(OH)2) from seawater and seawater reverse osmosis (SWRO) brines. The research encompassed a thorough characterization of the membranes utilizing advanced physic-chemical analytical techniques, followed by rigorous experimental assessments using synthetic seawater and SWRO brine in concentration configuration. The findings highlighted the superior selectivity of NFX for magnesium recovery from SWRO brine and the promising concentration factors of VNF1 for seawater treatment. Cross-validation of experimental data with a mathematical model demonstrated the model's reliability as a process design tool in predicting membrane performance. A comprehensive techno-economic evaluation demonstrates the potential of NFX, operating optimally at 23 bar pressure and 70% permeate recovery rate, to yield an estimated annual revenue of 5.683 M€/yr through Mg(OH)2 production from SWRO brine for a plant with a nominal capacity of 0.8 Mm3/y. This research shed light on the promising role of NF membranes in enhancing mineral recovery taking benefit of their separation factors and emphasizes the economic viability of leveraging NF technology for maximizing magnesium recovery from seawater and SWRO brines.

Cell viability assessment and ion release profiles of GICs modified with TiO2- and Mg-doped hydroxyapatite nanoparticles.

OBJECTIVES: To assess and compare the cell viability and ion release profiles of two conventional glass ionomer cements (GICs), Fuji IX and Ketac Molar EasyMix, modified with TiO2 and Mg-doped-HAp nanoparticles (NPs). METHODS: TiO2 NPs, synthesized via a sol-gel method, and Mg-doped hydroxyapatite, synthesized via a hydrothermal process, were incorporated into GICs at a concentration of 5 wt.%. The biocompatibility of prepared materials was assessed by evaluating their effects on the viability of dental pulp stem cells (DPSCs), together with monitoring ion release profiles. Statistical analysis was performed using One-way analysis of variance, with significance level p < 0.05. RESULTS: The addition of NPs did not significantly affect the biocompatibility of GICs, as evidenced by comparable decreased levels in cell viability to their original formulations. Distinct variations in cell viability were observed among Fuji IX and Ketac Molar, including their respective modifications. FUJI IX and its modification with TiO2 exhibited moderate decrease in cell viability, while other groups exhibited severe negative effects. While slight differences in ion release profiles were observed among the groups, significant variations compared to original cements were not achieved. Fluoride release exhibited an initial "burst release" within the initial 24 h in all samples, stabilizing over subsequent days. CONCLUSIONS: The addition of NPs did not compromise biocompatibility, nor anticariogenic potential of tested GICs. However, observed differences among FUJI IX and Ketac Molar, including their respective modifications, as well as induced low viability of DPSC by all tested groups, suggest the need for careful consideration of cement composition in their biological assessments. CLINICAL SIGNIFICANCE: The findings contribute to understanding the complex interaction between NPs and GIC matrices. However, the results should be interpreted recognizing the inherent limitations associated with in vitro studies. Further research avenues could explore long-term effects, in vivo performance, and potential clinical applications.

Struvite crystallization by using active serpentine: An innovative application for the economical and efficient recovery of phosphorus from black water.

Recovery of phosphorus from wastewater through struvite crystallization is one of the most attractive methods. However, the cost of chemical consumption makes this technology is unattractive to some extent. In this work, highly active serpentine was prepared by one-step mechanical activation and then used to recover phosphate as struvite from the black water containing 132.8 mg/L phosphorus and 3144 mg/L ammonia nitrogen. The results indicated that the prepared active serpentine can release magnesium ions and hydroxide ions simultaneously into an aqueous solution and is an ideal raw material for struvite crystallization. The factors for phosphorus recovery in this process mainly include mechanical activation intensity, serpentine dosage, and contact time. For the actual black water, a high recovery rate of phosphorus (>98%) is achieved by using active serpentine as the magnesium and alkali source for struvite precipitation. The recovery product was identified as struvite with a median particle size of 32.96 µm. It was confirmed that the mechanical activation damaged the crystal structure of the raw serpentine, improving the activity of Mg2+ and OH-. The undissolved Si-containing particles act as crystal seeds, accelerating the struvite crystallization process. Furthermore, a pilot-scale test was conducted with a rural public toilet in Xiong'an New District, Hebei Province. The results showed that an acceptable phosphorus recovery (98%) could be achieved using active serpentine. Additionally, it was demonstrated that the serpentine process to recover phosphate as struvite reduced the cost by 54.4% in compared with an ordinary chemical process. The active serpentine is a promising dual source of magnesium and alkali for the phosphorus recovery by the struvite method. It has a potential prospect for the large-scale application in phosphorus recovery and struvite fertilizer production.

Assessment of protein adhesion behaviour and biocompatibility of magnesium/Co-substituted HA-based composites for orthopaedic application.

Protein adsorption has a great influence on Mg-based metallic implants, which affects cell attachment and cell growth. Adsorption of the proteins (via electrostatic interaction, hydrophobic/hydrophilic, and hydrogen-bonding) on the implant surface is greatly influenced by the surface chemistry of the implant. Hydroxyapatite (HA) is a class of CaP ceramic, beneficial for protein adsorption as it possesses Ca2+ and PO43- in it, which are believed to be the protein binding sites on the HA surface. Moreover, HA is the popular choice for reinforcement in the magnesium matrix owing to its similarity with bone mineral composition. However, negligible interaction between HA and Mg particles during sintering is the major limitation for frequent usage of Mg-HA implants. Doping of HA with Mg2+ and Zn2+ (CoHA) ions leads to its chemistry similar to natural apatite in human bone and facilitates comparatively better bonding with the MgZn matrix. This study mainly aims to delve into the protein adsorption behaviour of Magnesium/Co-substituted HA-based Composites (M3Z-CoHA) along with their biocompatibility. Qualitative and quantitative protein adsorption analysis shows that the addition of 15 wt% CoHA to Mg matrix enhanced protein adsorption by ~60% and renders cell viability >90% after day 1, supporting cellular growth and proliferation. The implants also initiated osteogenic differentiation of the cells after day 7. The leached-out products from all the composites showed no toxicity. The morphology of the cells in all the composites was found as healthy as the control cells. Overall, the composite with 15 wt% HA reinforcement (M3Z-15CoHA) has shown favourable protein adsorption behaviour and cytocompatibility.

Low-Cost Biobased Coatings for AM60 Magnesium Alloys for Food Contact and Harsh Environment Applications.

Low-cost, environmentally friendly and easily applicable coating for Mg alloys, able to resist in real world conditions, are studied. Coatings already used for other metals (aluminum, steel) and never tested on Mg alloy for its different surface and reactivity were deposited on AM60 magnesium alloys to facilitate their technological applications, also in presence of chemically aggressive conditions. A biobased PA11 powder coating was compared to synthetic silicon-based and polyester coatings, producing lab scale samples, probed by drop deposition tests and dipping in increasingly aggressive, salty, basic and acid solutions, at RT and at higher temperatures. Coatings were analyzed by SEM/EDX to assess their morphology and compositions, by optical and IR-ATR microscopy analyses, before and after the drop tests. Migration analyses from the samples were performed by immersion tests using food simulants followed by ICP-OES analysis of the recovered simulant to explore applications also in the food contact field. A 30 µm thick white lacquer and a 120 µm PA11 coating resulted the best solutions. The thinner siliconic and lacquer coatings, appearing brittle and thin in the SEM analysis, failed some drop and/or dipping test, with damages especially at the edges. The larger thickness is thus the unique solution for edgy or pointy samples. Finally, coffee cups in AM60 alloy were produced, as real word prototypes, with the best performing coatings and tested for both migration by dipping, simulating also real world aging (2 h in acetic acid at 70° and 24 h in hot coffee at 60 °C): PA11 resulted stable in all the tests and no migration of toxic metals was observed, resulting a promising candidate for many real world application in chemically aggressive environments and also food and beverage related applications.

Osmoregulatory power influences tissue ionic composition after salinity acclimation in aquatic decapods.

Decapod crustaceans show variable degrees of euryhalinity and osmoregulatory capacity, by responding to salinity changes through anisosmotic extracellular regulation and/or cell volume regulation. Cell volume regulatory mechanisms involve exchange of inorganic ions between extra- and intra-cellular (tissue) compartments. Here, this interplay of inorganic ions between both compartments has been evaluated in four decapod species with distinct habitats and osmoregulatory strategies. The marine/estuarine species Litopenaeus vannamei (Lv) and Callinectes danae (Cd) were submitted to reduced salinity (15‰), after acclimation to 25 and 30‰, respectively. The freshwater Macrobrachium acanthurus (Ma) and Aegla schmitti (As) were submitted to increased salinity (25‰). The four species were salinity-challenged for both 5 and 10 days. Hemolymph osmolality, sodium, chloride, potassium, and magnesium were assayed. The same inorganic ions were quantified in muscle samples. Muscle hydration (MH) and ninhydrin-positive substances (NPS) were also determined. Lv showed slight hemolymph dilution, increased MH and no osmotically-relevant decreases in muscle osmolytes; Cd displayed hemolymph dilution, decreased muscular NaCl and stable MH; Ma showed hypo-regulation and steady MH, with no change in muscle ions; As conformed hemolymph sodium but hypo-regulated chloride, had stable MH and increased muscle NPS and ion levels. Hemolymph and muscle ions (especially chloride) of As were highly correlated (Pearson, +0.83). Significant exchanges between hemolymph and muscle ionic pools were more evident in the two species with comparatively less AER regulatory power, C. danae and A. schmitti. Our findings endorse that the interplay between extracellular and tissue ionic pools is especially detectable in euryhaline species with relatively lower osmoregulatory strength.

Assessment of bone healing using (Ti,Mg)N thin film coated plates and screws: Rabbit femur model.

Magnesium (Mg) based implants such as plates and screws are often preferred to treat bone defects because of the positive effects of magnesium in bone growth and healing. Their low corrosion resistance, however, leads to fast degradation and consequently failure before healing was completed. Previously, we developed Mg doped titanium nitrate (TiN) thin film coatings to address these limitations and demonstrated that <10 at% Mg doping led to enhanced mineralization in vitro. In the present study, in vivo performance of (Ti,Mg)N coated Ti6Al4V based plates and screws were studied in the rabbit model. Bone fractures were formed on femurs of 16 rabbits and then fixed with either (Ti,Mg)N coated (n = 8) or standard TiN coated (n = 8) plates and screws. X-ray imaging and µCT analyses showed enhanced bone regeneration on fracture sites fixed with (Ti,Mg)N coated plates in comparison with the Mg free ones. Bone mineral density, bone volume, and callus volume were also found to be 11.4, 23.4, and 42.8% higher, respectively, in accordance with µCT results. Furthermore, while TiN coatings promoted only primary bone regeneration, (Ti,Mg)N led to secondary bone regeneration in 6 weeks. These results indicated that Mg presence in the coatings accelerated bone regeneration in the fracture site. (Ti,Mg)N coating can be used as a practical method to increase the efficiency of existing bone fixation devices of varying geometry.

Mechanical performance and biocompatibility assessment of Zn-0.05wt%Mg-(0.5, 1 wt%) Ag alloys.

Zn alloys are emerging as promising degradable biomedical materials due to their tailorable mechanical properties and moderate biodegradable rate, compared with conventional biodegradable metallic materials. Ag, as an effective antibacterial and reinforcing element, was incorporated into Zn-0.05Mg alloys. In the present work, the effects of the Ag addition on mechanical, cytotoxic, hemolytic, pyrogenic, histological behaviors of the animal were investigated. The compressive yielding strength is enhanced from 198 MPa for Zn-0.05Mg alloy up to 224 and 234 MPa for Zn-0.05Mg-0.5Ag and Zn-0.05Mg-1Ag alloys, respectively. When the compressive strain was 65%, the strength of the Zn-0.05Mg-1.0Ag alloy reached 833 MPa, which was much higher than that of 721 MPa for Zn-0.05Mg alloy. The relative growth rate (RGR) for the extracts of Zn-0.05Mg-1Ag alloy with the concentrations of 10, 50, and 100% after 5 days incubation reaches 98.5, 95.2, and 94.2%, which are higher than those in extracts of Zn-0.05Mg-0.5Ag alloy (98.2, 93.9, 92.1%). The hemolysis rate of the Zn-0.05Mg alloys with 0.5 and 1 wt% Ag is 2.46 and 2.28%, respectively. The variations of body weight and temperature, postinjection symptoms, pathological morphologies of the visceral organs demonstrate that the alloys are nontoxic according to the toxicity rating standards. Zn-0.05wt%Mg-(0.5, 1 wt%) Ag alloys are experimentally safe materials and promising for the future application as biodegradable medical devices.

Crystallization kinetics and growth of struvite crystals by seawater versus magnesium chloride as magnesium source: towards enhancing sustainability and economics of struvite crystallization.

The recycling of nutrients from wastewater and their recovery in the form of valuable products is an effective strategy to accelerate the circular economy concept. Phosphorus recovery from wastewater by struvite crystallization (MgNH4PO4·6H2O) is one of the most applied techniques to compensate for the increasing demand and to slow down the depletion rate of phosphate rocks. Using low-cost magnesium sources, such as seawater, improves the financial sustainability of struvite production. In this study, the potential of seawater for struvite crystallization versus the commonly used magnesium source, MgCl2, was tested by crystal growth and kinetic experiments. The impact of ammonium concentration, magnesium concentration and pH on the growth kinetics of struvite in synthetic and real reject water were studied. The results showed that simultaneous precipitation of calcium phosphate was insignificant when using seawater, while presence of struvite seeds diminished it further. Among the supersaturation regulators, pH had the most significant effect on the struvite growth with both MgCl2 and seawater, while high N:P molar ratios further improved the struvite crystal growth by seawater. The N:P molar ratios higher than 6 and Mg:P molar ratios higher than 0.2 are recommended to improve the crystal growth kinetics. It was concluded that seawater is a promising alternative magnesium source and the control of supersaturation regulators (i.e., Mg:P, N:P and pH) is an effective strategy to control the reaction kinetics and product properties.

Biochemical and genotoxic biomarkers and cell cycle assessment in the zebrafish liver (ZF-L) cell line exposed to the novel metal-insecticide magnesium-hespiridin complex.

The flavonoid metal-insecticide magnesium-hesperidin complex (MgHP) has recently been considered as a novel insecticide to replace some persistent pesticides. However, it is important to evaluate its action on non-target species, mainly those living in an aquatic environment, as these ecosystems are the final receptors of most chemicals. Reactive oxygen species, antioxidant and oxidative stress biomarkers, genotoxicity as well as cell cycle was evaluated in the liver cell line from zebrafish (Danio rerio; ZF-L) exposed to 0, 0.1, 1, 10, 100 and 1000 ng mL-1 MgHP. MgHP affected cell stability by increasing reactive oxygen species (ROS) in both exposure times (24 and 96 h) at high concentrations. Catalase (CAT) activity decreased after 24 h exposure, and glutathione and metallothionein values increased, avoiding the lipid peroxidation. Genotoxicity increased as MgHP concentration increased, after 24 h exposure, exhibiting nuclear abnormalities; it was recovered after 96 h exposure, evidencing possible stimulation of DNA repair mechanisms. The alteration in the cell cycle (increasing in the Sub-G1 phase and decreasing in the S-phase) was associated with chromosomal instability. In conclusion, the responses of ROS and the antioxidant defense system depended on MgHP concentration and time exposure, while DNA exhibited some instability after 24 h exposure, which was recovered after 96 h.

Characterization and preparation of Fe3O4 nanoparticles loaded bioglass-chitosan nanocomposite coating on Mg alloy and in vitro bioactivity assessment.

In this study, bioglass (BG)­iron oxide (Fe3O4) nanocomposite coating was developed to produce bioactive and antibacterial coatings. The nanocomposite coating was embedded in chitosan (CS) matrix and coating was fabricated by electrophoretic deposition (EPD) method. The coating was characterized by using SEM/EDX and XRD respectively. The experiment was performed with three varying concentrations (1, 3, 5 (wt%)) of Fe3O4 nanoparticles prepared by the co- precipitation method in the bioactive glass coating. The antibacterial activity was examined in Escherichia coli and Staphylococcus aureus bacteria which determine that the growth of microorganisms was inhibited with the progressive increment of Fe3O4 nanoparticles. The bioactivity assessment was done in PBS for 7 days and it was detected that the composite coatings improve the bone-bonding ability which was again confirmed by SEM-EDX. The corrosion behavior was evaluated in Ringer's solution by electrochemical test. The corrosion analysis revealed that the BG-1% Fe3O4 nanocomposite coating has superior corrosion resistance as compared to the other coatings. The findings of the research have shown that the BG-Fe3O4-CS nanocomposite coating can be widely used as a suitable material for orthopedic applications.

Absorbed dose measurements from a 90Y radionuclide liquid solution using LiF:Mg,Cu,P thermoluminescent dosimeters.

In the last few years there has been an increasing interest in the measurement of the absorbed dose from radionuclides, with special attention devoted to molecular radiotherapy treatments. In particular, the determination of the absorbed dose from beta emitting radionuclides in liquid solution poses a number of issues when dose measurements are performed using thermoluminescent dosimeters (TLD). Finite volume effect, i.e. the exclusion of radioactivity from the volume occupied by the TLD is one of these. Furthermore, TLDs need to be encapsulated into some kind of waterproof envelope that unavoidably contributes to beta particle attenuation during the measurement. The purpose of this study is twofold: I) to measure the absorbed dose to water, Dw, using LiF:Mg,Cu,P chips inside a PMMA cylindrical phantom filled with a homogenous 90YCl3 aqueous solution II) to assess the uncertainty budget related to Dw measurements. To this purpose, six cylindrical PMMA phantoms were manufactured at ENEA. Each phantom can host a waterproof PMMA stick containing 3 TLD chips encapsulated by a polystyrene envelope. The cylindrical phantoms were manufactured so that the radioactive liquid environment surrounds the whole stick. Finally, Dw measurements were compared with Monte Carlo (MC) calculations. The measurement of absorbed dose to water from 90YCl3 radionuclide solution using LiF:Mg,Cu,P TLDs turned out to be a viable technique, provided that all necessary correction factors are applied. Using this method, a relative combined standard uncertainty in the range 3.1-3.7% was obtained on each Dw measurement. The major source of uncertainty was shown to be TLDs calibration, with associated uncertainties in the range 0.7-2.2%. Comparison of measured and MC-calculated absorbed dose per emitted beta particle provided good results, with the two quantities being in the ratio 1.08.

In vitro toxicity assessment of hydrogel patches obtained by cation-induced cross-linking of rod-like cellulose nanocrystals.

With the purpose of designing active patches for photodynamic therapy of melanoma, transparent and soft hydrogel membranes (HMs) have been fabricated by cation-induced gelation of rod-like cellulose nanocrystals (CNCs) bearing negatively charged carboxylic groups. Na+ , Ca2+ , Mg2+ have been used as cross-linkers of cellulose nanocrystal (CNC). The biosafety of this material and of its precursors has been evaluated in vitro in cell cultures. Morphological changes, cell organelles integrity, and cell survival with the tetrazolium salt reduction (MTT) assay were utilized as tests of cytotoxicity. Preliminary investigation was performed by addition of the hydrogel components to the cell culture medium and by incubations of the CNC-HM in direct and indirect contact with a confluent monolayer of A375 melanoma cells. Direct contact assays suffered from interference of physical stress. Careful evaluation of cytotoxicity was obtained considering the overall picture provided by microscopy and biochemical tests performed with the CNC-HM in indirect contact with two melanoma cell lines (A375, M14) and human fibroblasts. CNCs have been demonstrated to be a safe precursor material and CNC-HMs have a good biocompatibility provided that the excess of cations, in particular of Ca2+ is removed. These results indicate that CNC and can be safely used to fabricate biomedical devices such as transparent hydrogel patches, although attention must be paid to the fabrication procedure.

Assessment of magnesium-based biomaterials: from bench to clinic.

Despite the high potential of biodegradable magnesium (Mg) alloys as a new generation of biomaterials for orthopaedic and cardiovascular implantation, their high corrosion rate in body fluid limits their suitability for clinical applications. Extensive research has been performed to improve the corrosion resistance of Mg-based biomaterials. Researchers have also been working to develop new testing and assessment techniques to evaluate the corrosion performance and other in vitro and in vivo properties of their modified Mg alloys. The objective of this review is to present the principles and operation procedures of commonly used standard methods for assessment of Mg-based biomaterials from bench to clinic. The pros and cons of each of these methods are discussed, together with factors for consideration to choose the right methodology. This review also presents the current state and challenges in understanding the testing of Mg-based biomaterials.

On uranium 234U and 238U radionuclides in calcium and magnesium supplements and the potential effective radiation dose assessment to the consumers.

In this survey the concentrations of the radioactive nuclides uranium 234U and 238U were determined in the most popular calcium and magnesium supplements for adults in Poland. It was also investigated whether the supplements contain uranium isotopes and could be a potential source in the human diet and have an influence on the value of effective radiation doses to the consumers. The analyzed calcium and magnesium pharmaceuticals contained organic or inorganic compounds, several of natural origin as mussel's shells, fish extracts, or sedimentary rocks. As results showed, 234U and 238U concentrations in natural origin calcium and magnesium supplements were significantly higher than in other, synthetic ones. The highest 234U and 238U activity concentrations were determined in tablets from mussel's shells. The radiochemical hazard was assessed and the highest annual radiation dose was found in 234U and 238U present in supplements produced from shells or dolomite rock.

Improved In Vitro Test Procedure for Full Assessment of the Cytocompatibility of Degradable Magnesium Based on ISO 10993-5/-12.

Magnesium (Mg)-based biomaterials are promising candidates for bone and tissue regeneration. Alloying and surface modifications provide effective strategies for optimizing and tailoring their degradation kinetics. Nevertheless, biocompatibility analyses of Mg-based materials are challenging due to its special degradation mechanism with continuous hydrogen release. In this context, the hydrogen release and the related (micro-) milieu conditions pretend to strictly follow in vitro standards based on ISO 10993-5/-12. Thus, special adaptions for the testing of Mg materials are necessary, which have been described in a previous study from our group. Based on these adaptions, further developments of a test procedure allowing rapid and effective in vitro cytocompatibility analyses of Mg-based materials based on ISO 10993-5/-12 are necessary. The following study introduces a new two-step test scheme for rapid and effective testing of Mg. Specimens with different surface characteristics were produced by means of plasma electrolytic oxidation (PEO) using silicate-based and phosphate-based electrolytes. The test samples were evaluated for corrosion behavior, cytocompatibility and their mechanical and osteogenic properties. Thereby, two PEO ceramics could be identified for further in vivo evaluations.

MICRODOSIMETRIC MODELING OF THE RELATIVE LUMINESCENCE EFFICIENCY OF LiF:Mg,Cu,P (MCP) DETECTORS EXPOSED TO CHARGED PARTICLES.

Using a recently developed microdosimetric model based on the Monte Carlo code PHITS, the relative luminescence efficiency of LiF:Mg,Cu,P (MCP) thermoluminescent detectors to charged particles from 1H to 132Xe with energies from 3 to 1000 MeV/u has been assessed. The results have been compared with literature data showing very good agreement for particles from 12C to 132Xe in case of model calculations performed in a site size of 40 nm. For 1H and 4He ions, the model overestimates the experimental values by ~10%. An explanation of this deviation as a consequence of fading effects has been included.

Bayesian analysis of isothermal titration calorimetry for binding thermodynamics.

Isothermal titration calorimetry (ITC) is the only technique able to determine both the enthalpy and entropy of noncovalent association in a single experiment. The standard data analysis method based on nonlinear regression, however, provides unrealistically small uncertainty estimates due to its neglect of dominant sources of error. Here, we present a Bayesian framework for sampling from the posterior distribution of all thermodynamic parameters and other quantities of interest from one or more ITC experiments, allowing uncertainties and correlations to be quantitatively assessed. For a series of ITC measurements on metal:chelator and protein:ligand systems, the Bayesian approach yields uncertainties which represent the variability from experiment to experiment more accurately than the standard data analysis. In some datasets, the median enthalpy of binding is shifted by as much as 1.5 kcal/mol. A Python implementation suitable for analysis of data generated by MicroCal instruments (and adaptable to other calorimeters) is freely available online.

Assessment of the degradation rates and effectiveness of different coated Mg-Zn-Ca alloy scaffolds for in vivo repair of critical-size bone defects.

Surgical repair of bone defects remains challenging, and the search for alternative procedures is ongoing. Devices made of Mg for bone repair have received much attention owing to their good biocompatibility and mechanical properties. We developed a new type of scaffold made of a Mg-Zn-Ca alloy with a shape that mimics cortical bone and can be filled with morselized bone. We evaluated its durability and efficacy in a rabbit ulna-defect model. Three types of scaffold-surface coating were evaluated: group A, no coating; group B, a 10-µm microarc oxidation coating; group C, a hydrothermal duplex composite coating; and group D, an empty-defect control. X-ray and micro-computed tomography(micro-CT) images were acquired over 12 weeks to assess ulnar repair. A mechanical stress test indicated that bone repair within each group improved significantly over time (P < 0.01). The degradation behavior of the different scaffolds was assessed by micro-CT and quantified according to the amount of hydrogen gas generated; these measurements indicated that the group C scaffold better resisted corrosion than did the other scaffold types (P < 0.05). Calcein fluorescence and histology revealed that greater mineral densities and better bone responses were achieved for groups B and C than for group A, with group C providing the best response. In conclusion, our Mg-Zn-Ca-alloy scaffold effectively aided bone repair. The group C scaffold exhibited the best corrosion resistance and osteogenesis properties, making it a candidate scaffold for repair of bone defects.