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Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded. Nevertheless, they have a number of drawbacks including the insufficient level of mechanical properties and low degradation rate. Struvite (MgNH4PO4) -based cements, which grew in popularity in recent years, despite their neutral pH and acceptable mechanical performance, release undesirable NH4+ ions during their resorption. This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium, however, such cements have a pH values of 9–10, leading to cytotoxicity.Thus, the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties: neutral pH, sufficient mechanical properties, and the absence of cytotoxicity, applying Na2HPO4-based cement liquid. For this purpose, cement powders precursors in the CaO–MgO–P2O5 system were synthesized by one-pot process in a wide composition range, and their properties were investigated.The optimal performance was observed for the cements with (Ca + Mg)/P ratio of 1.67, which are characterized by newberyite phase formation during setting reaction, pH values close to 7, sufficient compressive strength up to 22 ± 3 MPa (for 20 mol.% of Mg), dense microstructure and adequate matrix properties of the surface. This set of features make those materials promising candidates for medical applications.

Al-substituted hydroxyapatite (Al-HA) powders with apatite structure and particle size of 30–70 nm were obtained via precipitation method. The effect of Al content on specific surface area and morphology of powders was studied, and a formation of highly anisotropic phase due to Al doping was observed. The influence of heat treatment in 300–1400 °C range on the phase composition, lattice parameters, Fourier-transform infrared spectroscopy (FTIR) spectra and mass loss of powders was investigated. Introduction of Al in the hydroxyapatite (HA) lattice in the range 0.5–1.0 mol.% resulted in the improvement in thermal stability, which had not been reported previously. Incorporation of 5–10 mol.% of Al resulted in the formation of biphasic materials based on HA and whitlockite-like structure at 900 °C and apatite and α- tricalcium phosphate (α-TCP) phases at 1200–1400 °C. Introduction of 20 mol.% of Al resulted in the formation of isomorphic Al-substituted whitlockite phase Ca9Al(PO4)7. We have estimated the onset of Ca9Al(PO4)7 transformation into α-TCP phase at 1400 °C. Keywords: Al-substituted hydroxyapatite, Phase transformation, Thermal stability

Increased planting of hard mast oak species in the Lower Missouri River floodplain is critical as natural regeneration of oak along the Upper Mississippi and Lower Missouri Rivers has been limited following major flood events in 1993 and 1995. Traditional planting methods have limited success due to frequent flood events, competition from faster growing vegetation and white-tailed deer herbivory. Results of early growth response of swamp white oak (Quercus bicolor Willd.) seedlings in relation to initial acorn mass and size, and early rapid shoot growth for seedlings produced by containerized root production method (RPM™), are presented. Containerized RPM™ seedlings grown in the greenhouse under optimal conditions demonstrate that seed size had no discernable impact on first-year root or shoot size. Seedling survival for the first two years and acorn production for the first three years after outplanting are presented, comparing use of containerized RPM™ swamp white oak seedlings to nursery stock. Flood tolerant precocious RPM™ oak seedlings in the floodplain provide a source of food for acorn-consuming wildlife ten to fifteen years sooner than oaks originating from natural regeneration, direct seeding or traditional bare root planting. Compared to bare root nursery stock that produced no acorns, some RPM™ swamp white oak seedlings averaged 4.3, 5.2, and 6.3 acorns/seedling in the first three years after fall outplanting. [ABSTRACT FROM AUTHOR]

Background: Delayed cerebral ischemia and vasospasm are the most common causes of late morbidity following aneurysmal SAH, but their diagnosis remains challenging., Purpose: This systematic review and meta-analysis investigated the diagnostic performance of CTP for detection of delayed cerebral ischemia and vasospasm in the setting of aneurysmal SAH., Data Sources: Studies evaluating the diagnostic performance of CTP in the setting of aneurysmal SAH were searched on the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Clinical Answers, Cochrane Methodology Register, Ovid MEDLINE, EMBASE, American College of Physicians Journal Club, Database of Abstracts of Reviews of Effects, Health Technology Assessment, National Health Service Economic Evaluation Database, PubMed, and Google Scholar from their inception to September 2023., Study Selection: Thirty studies were included, encompassing 1786 patients with aneurysmal SAH and 2302 CTP studies. Studies were included if they compared the diagnostic accuracy of CTP with a reference standard (clinical or radiologic delayed cerebral ischemia, angiographic spasm) for the detection of delayed cerebral ischemia or vasospasm in patients with aneurysmal SAH. The primary outcome was accuracy for the detection of delayed cerebral ischemia or vasospasm., Data Analysis: Bivariate random effects models were used to pool outcomes for sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. Subgroup analyses for individual CTP parameters and early-versus-late study timing were performed. Bias and applicability were assessed using the modified QUADAS-2 tool., Data Synthesis: For assessment of delayed cerebral ischemia, CTP demonstrated a pooled sensitivity of 82.1% (95% CI, 74.5%-87.8%), specificity of 79.6% (95% CI, 73.0%-84.9%), positive likelihood ratio of 4.01 (95% CI, 2.94-5.47), and negative likelihood ratio of 0.23 (95% CI, 0.12-0.33). For assessment of vasospasm, CTP showed a pooled sensitivity of 85.6% (95% CI, 74.2%-92.5%), specificity of 87.9% (95% CI, 79.2%-93.3%), positive likelihood ratio of 7.10 (95% CI, 3.87-13.04), and negative likelihood ratio of 0.16 (95% CI, 0.09-0.31)., Limitations: QUADAS-2 assessment identified 12 articles with low risk, 11 with moderate risk, and 7 with a high risk of bias., Conclusions: For delayed cerebral ischemia, CTP had a sensitivity of >80%, specificity of >75%, and a low negative likelihood ratio of 0.23. CTP had better performance for the detection of vasospasm, with sensitivity and specificity of >85% and a low negative likelihood ratio of 0.16. Although the accuracy offers the potential for CTP to be used in limited clinical contexts, standardization of CTP techniques and high-quality randomized trials evaluating its impact are required., (© 2024 by American Journal of Neuroradiology.)