Characterisation of Mg, Sr, and Zn containing fluoro-aluminosilicate glasses and their glass polyalkenoate cements

The glass polyalkenoate cements (GPCs) are formed by the acid-base reaction between fluoro-aluminosilicate glasses and polycarboxylic acid in the presence of water. Three series of glasses were produced by modifiying glass LG26 [32.1SiO2. 21.4Al2O3. 10.7P2O5. 21.4CaO. 14.3CaF2] (mole %). In the first series, calcium was substituted by magnesium, and in the second series, calcium in the first series was substituted by strontium. The last series were zinc substitution for calcium in LG26. These glasses were characterised by X-ray diffraction (XRD), magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy and differential scanning calorimetry (DSC). The gradual substitution of calcium by magnesium resulted in the formation of F-Mg(n) species and a disappearance of Al-F species on the 19F MAS-NMR. The 31P and 27Al MAS-NMR showed that all glasses contained Q1 pyrophosphate Al-O-PO3 3- species. In addition, the fully magnesium substituted glass showed the possible formation of magnesium pyrophosphate, Mg2P2O7. The fully zinc substituted glass, however, showed only Al-O-PO3 3- species charge balanced by Zn2+. An increase in Al(V) species was observed on the 27Al MAS-NMR with the fully magnesium and zinc substituted glasses. The presence of magnesium also increased the number of bridging oxygen on SiO4 tetrahedra, but the presence of zinc affected the Q structure of the aluminosilicate network less. GPCs with these glasses were formed with poly (acrylic acid) (PAA) and L-(+)-tartaric acid. The setting reaction of selected cements was studied by 19F, 31P and 27Al MAS-NMR spectroscopy. F-Ca(n) species were clearly shown to be consumed for cement formulation, and F-Mg(n) species were still present in the 19F MAS-NMR spectra of the magnesium containing cements. The Al-O-PO3 3- species were present in the cement. The conversion to Al(VI) from Al(IV) and Al(V) was observed by deconvoluting the 27Al MAS-NMR spectra. The experimental ratio of Al(VI):Al(IV)+Al(V) was higher than the theoretical ratio which may have resulted from the possibility of L-(+)-tartaric acid being involved in the Al conversion during the setting reaction. The working and setting times increased with magnesium substitution, but did not change with zinc substitution for calcium. The compressive strengths decreased with magnesium substitution, possibly resulting from the preferential crosslinking between Mg2+ and COO-. The highest release of fluoride was observed from the fully magnesium substituted cements. Another series of glasses [34.0SiO2. 22.6Al2O3. 5.7P2O5. (22.6-x)SrO. xZnO. 15.1SrF2] (mole %) was produced for formulating GPCs with poly (γ-glutamic acid), PgGA. All the glasses have Al-O-PO3 3- species with no change in the phosphorus environment with zinc substitution for strontium. Al(IV) was found to be the major aluminium species with a small presence of Al(V) and Al(VI). The Q structures of all the glasses were found to be a mixture of Q4(4Al) and Q3(3Al). Similarly, DSC showed a negligible change with zinc substitution for strontium. For cement formulations with PgGA, a co-polymer of PAA and poly (but-3-ene 1,2,4- tricarboxylic acid) was used due to the lower reactivity of PgGA than PAA, and cements with different proportions of PgGA and the co-polymer were formed. The working and setting times increased with PgGA content and zinc substitution. On the contrary, the compressive strengths decreased with PgGA content. The highest zinc containing cements in the series showed the highest compressive strength. A longterm fluoride release measurement showed the highest release from the highest PgGA containing cements, possibly resulting from the cements being less crosslinked. There was a slight increase in the adhesion to dentine

The effect of phosphate, fluorine, and soda content of the glass on the mechanical properties of the glass ionomer (polyalkenoate) cements

The authors would like to thank the Department of Trade and Industry, UK, under the project number of TP/5/REG/6/I/H0669A

Inhibitory Effects of Chlorella Extract on Airway Hyperresponsiveness and Airway Remodeling in a Murine Model of Asthma

Chlorella extract （CE） has been shown to induce production of T helper-1 cytokines, and regulate serum IgE levels in animal models of asthma. We aimed to evaluate whether CE could inhibit ovalbumin （OVA）-induced airway hyperresponsiveness （AHR） and airway remodeling in a murine model of asthma. Balb/c mice were allocated to four groups: a control group （no OVA exposure, not given CE）, a CE group （no OVA exposure, given CE）, an asthma group （sensitized/challenged with OVA, not given CE） and a CE＋asthma group （sensitized/challenged with OVA, given CE）. In the asthma and CE＋asthma groups, mice were sensitized with OVA on day 0 and day 12, and then challenged with OVA on three consecutive days. In the CE and CE＋asthma groups, the mice were given feed containing 2％ CE. We assessed AHR to methacholine, and analyzed bronchoalveolar lavage fluid （BALF）, serum, lung tissue and spleen cells. Administration of CE was associated with significantly lower AHR in OVA-sensitized and challenged mice. CE administration was also associated with marked reduction of total cells, eosinophils and T helper-2 cytokines （IL-4, IL-5 and IL-13） in BALF. In addition, administration of CE significantly decreased the numbers of periodic acid-Schiff （PAS）-positive cells in OVA-sensitized and challenged mice. Administration of CE also directly suppressed IL-4, IL-5 and IL-13 production in spleen cells of OVA-sensitized and challenged mice. These results indicate that CE can partly prevent AHR and airway remodeling in a murine model of asthma

Characterisation of Mg, Sr, and Zn containing fluoro-aluminosilicate glasses and their glass polyalkenoate cements

The glass polyalkenoate cements (GPCs) are formed by the acid-base reaction between fluoro-aluminosilicate glasses and polycarboxylic acid in the presence of water. Three series of glasses were produced by modifiying glass LG26 [32.1SiO2. 21.4Al2O3. 10.7P2O5. 21.4CaO. 14.3CaF2] (mole %). In the first series, calcium was substituted by magnesium, and in the second series, calcium in the first series was substituted by strontium. The last series were zinc substitution for calcium in LG26. These glasses were characterised by X-ray diffraction (XRD), magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy and differential scanning calorimetry (DSC). The gradual substitution of calcium by magnesium resulted in the formation of F-Mg(n) species and a disappearance of Al-F species on the 19F MAS-NMR. The 31P and 27Al MAS-NMR showed that all glasses contained Q1 pyrophosphate Al-O-PO3 3- species. In addition, the fully magnesium substituted glass showed the possible formation of magnesium pyrophosphate, Mg2P2O7. The fully zinc substituted glass, however, showed only Al-O-PO3 3- species charge balanced by Zn2+. An increase in Al(V) species was observed on the 27Al MAS-NMR with the fully magnesium and zinc substituted glasses. The presence of magnesium also increased the number of bridging oxygen on SiO4 tetrahedra, but the presence of zinc affected the Q structure of the aluminosilicate network less. GPCs with these glasses were formed with poly (acrylic acid) (PAA) and L-(+)-tartaric acid. The setting reaction of selected cements was studied by 19F, 31P and 27Al MAS-NMR spectroscopy. F-Ca(n) species were clearly shown to be consumed for cement formulation, and F-Mg(n) species were still present in the 19F MAS-NMR spectra of the magnesium containing cements. The Al-O-PO3 3- species were present in the cement. The conversion to Al(VI) from Al(IV) and Al(V) was observed by deconvoluting the 27Al MAS-NMR spectra. The experimental ratio of Al(VI):Al(IV)+Al(V) was higher than the theoretical ratio which may have resulted from the possibility of L-(+)-tartaric acid being involved in the Al conversion during the setting reaction. The working and setting times increased with magnesium substitution, but did not change with zinc substitution for calcium. The compressive strengths decreased with magnesium substitution, possibly resulting from the preferential crosslinking between Mg2+ and COO-. The highest release of fluoride was observed from the fully magnesium substituted cements. Another series of glasses [34.0SiO2. 22.6Al2O3. 5.7P2O5. (22.6-x)SrO. xZnO. 15.1SrF2] (mole %) was produced for formulating GPCs with poly (γ-glutamic acid), PgGA. All the glasses have Al-O-PO3 3- species with no change in the phosphorus environment with zinc substitution for strontium. Al(IV) was found to be the major aluminium species with a small presence of Al(V) and Al(VI). The Q structures of all the glasses were found to be a mixture of Q4(4Al) and Q3(3Al). Similarly, DSC showed a negligible change with zinc substitution for strontium. For cement formulations with PgGA, a co-polymer of PAA and poly (but-3-ene 1,2,4- tricarboxylic acid) was used due to the lower reactivity of PgGA than PAA, and cements with different proportions of PgGA and the co-polymer were formed. The working and setting times increased with PgGA content and zinc substitution. On the contrary, the compressive strengths decreased with PgGA content. The highest zinc containing cements in the series showed the highest compressive strength. A longterm fluoride release measurement showed the highest release from the highest PgGA containing cements, possibly resulting from the cements being less crosslinked. There was a slight increase in the adhesion to dentine.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A Comparison of Adverse Effect Profiles of Two Anti-IL-5 Therapies in Adults with Uncontrolled Asthma―A Network Meta-analysis of Phase 3 Trials―

The aim of this study was to compare the adverse effect profiles of mepolizumab（MPZ）and benralizumab（BRZ）in adults with uncontrolled asthma. A network meta-analysis of phase 3 trials was conducted to compare the adverse effects of MPZ and BRZ in patients with uncontrolled asthma. The MEDLINE-PubMed, Scopus and the Cochrane library databases were searched to identify any relevant articles. The outcome measures of fatal adverse events, headache, and injection site reaction are presented as odds ratios（ORs）with 95％ confidence intervals（CIs）. The surface under the cumulative curve（SUCRA）for each outcome was also compared among MPZ, BRZ, and placebo treatments. Four randomized controlled trials of MPZ（100mg s/c every four weeks）（100-MPZ）or BRZ（30mg s/c every eight weeks）（30-BRZ）met the criteria for inclusion in the study. The ORs and 95％ CIs of 100-MPZ compared with BRZ for fatal adverse events, headache, and injection site reaction were 0.26（0.01-4.90）, 0.79（0.40-1.54）, and 2.32（0.79-6.80）, respectively. SUCRAs for 100-MPZ, 30-BRZ, and placebo were 0.8, 0.3, and 0.4 for fatal adverse events, 0.5, 0.1, and 0.8 for headache, and 0.0, 0.6, and 0.8 for injection site reaction, respectively. There were no significant differences in the incidence of fatal adverse events, headache, and injection site reaction between MPZ and BRZ treatment. However, the SUCRA values indicate an association between administration of BRZ and the occurrence of fatal adverse event or headache, or between administration of MPZ and the occurrence of injection site reaction. Moreover, the incidence odds of injection site reaction were significantly higher in the MPZ group than in the placebo group. Further analysis will be needed to clarify the details of safety profiles of these anti-IL-5 therapies