Evaluation of the Flexural Strength,Water Sorption,and Solubility of a Glass Ionomer Dental Cement Modified Using Phytomedicine

Objectives: Various medicinal plant parts and extracts have been proven to be sources of biologically active compounds, many of which have been incorporated in the production of new pharmaceutical compounds. Thus, the aim of this study was to increase the antimicrobial properties of a glass ionomer cement (GIC) through its modification with a mixture of plant extracts, which were evaluated along with a 0.5% chlorohexidine-modified GIC (CHX-GIC) with regard to the water sorption, solubility, and flexural strength. Methods: Salvadora persica, Olea europaea, and Ficus carcia leaves were prepared for extraction with ethyll alcohol using a Soxhlet extractor for 12 h. The plant extract mixture (PE) was added in three different concentrations to the water used for preparation of a conventional freeze-dried GIC (groups 1:1, 2:1, and 1:2). Specimens were then mixed according to the manufacturer’s instructions and tested against the unmodified GIC (control) and a GIC modified with 0.5% chlorhexidine. Water sorption and solubility were evaluated after 7 days of immersion in distilled water. Flexural strength was evaluated in a three-point bending test after 24 h using a universal material testing machine at a crosshead speed of 1 mm/min. One-way analysis of variance (ANOVA) was used for comparison between the groups. Tukey’s post hoc test was used for pairwise comparison when the ANOVA test was significant. Results: There were no statistically significant differences between the control (M = 20.5%), CHX-GIC (M = 19.6%), 1:1 (M = 20.0%), 1:2 (M = 19.5%), and 2:1 (19.7%) groups with regard to the percentage of water sorption, while for water solubility the 2:1 (M = −0.39%) plant-modified group was significantly different from all of the other groups. Flexural strength test results showed that the 2:1 group (M = 26.1 MPa) recorded significantly higher mean values compared to all other tested groups. Conclusion and clinical relevance: The plant extracts did not negatively affect the water sorption and solubility of the GIC, while the flexural strength was improved by the addition of the plant extract at higher concentrations.     

Joining of Hypereutectic Al-50Si Alloys Using Lead-Free Brazing Filler Glass in Air

Hypereutectic Al-Si alloys are attractive materials in the fields of electronic packaging and aerospace. A Bi₂O₃-ZnO-B₂O₃ system lead-free brazing filler glass was employed to braze hypereutectic Al-50Si alloys in air. The hypereutectic Al-50Si alloys were pre-oxidized and the low-temperature glass powder was flake-shaped in the brazing process. The effects of brazing temperature and time on joints microstructure evolution, resulting mechanical strength, and air tightness were systematically investigated. The results indicated that the maximum shear strength of the joint was 34.49 MPa and leakage rate was 1.0 × 10⁻¹⁰ Pa m³/s at a temperature of 495 °C for 30 min. Crystalline phases, including Bi₂₄B₂O₃₉ and Bi₂O₃, were generated in the glass joint. The formation of a diffusion transition layer with a thickness of 3 μm, including elements of Al, Si, Zn, Bi, Na, and B, was the key to form an effective joint. The elements of Al, Si, and Bi had a short diffusion distance while the elements of Zn, Na, and B diffused in a long way under brazing condition.     

Surgical therapy of ground-glass opacities

Ground glass opacities, also known as GGOs, are detected on computed tomography (CT) scans as hazy areas if increased attenuation in the lung, and my represent a variety of pulmonary processes. Natural history of GGOs and their clinical implications are not yet fully understood. Controversies associated with the management of GGOs surround their histological classification, malignant potential, indications, timing, and type of intervention. Herein we discuss the principles and role of surgical therapy for ground glass opacities.     

Does the Glass Transition of Polymers Change Upon 3D Confinement?

The calorimetric trace of polymer spheres shows an increase of the glass‐transition temperature (T_g), with respect to its bulk value. This increase is evaluated by means of an entropy model, where the 3D confinement leads to a limiting number of repeating polymer units in the sphere, and thus to a reduction of the possible configuration states of the polymer chains. This is ultimately related to variations in the bulk value of the T_g. Also, the way the polymer nature affects how confinement takes place and how restrictions imposed affect the way a polymer forms cooperative rearranging regions at T_g are presented.

     

Image-guided bronchoscopy for histopathologic diagnosis of pure ground glass opacity: a case report

Guided bronchoscopy has been found to be useful for the diagnosis of solid peripheral pulmonary lesions (PPLs) but more evidence on ground glass opacities (GGOs), especially those without a solid component, are lacking. A 69-year-old male, asymptomatic, heavy smoker was referred to our department for non-surgical diagnosis of a focal pure GGO in the right upper lobe that was found incidentally on computed tomography (CT). Transbronchial biopsy (TBB) with the aide of endobronchial ultrasound with a guide sheath (EBUS-GS), virtual bronchoscopic navigation (VBN), and fluoroscopy was performed for sampling. There were no complications after the procedure. The diagnosis of adenocarcinoma with lepidic growth pattern was established from the fourth and fifth TBB specimens and was confirmed on subsequent surgical resection. Image-guided bronchoscopy with TBB was successful for the diagnosis of a pure GGO. Use of a larger biopsy device may be helpful for the histopathologic diagnosis of lung adenocarcinoma with lepidic growth.     

Silicone Oil-Free Polymer Syringes for the Storage of Therapeutic Proteins

Prefilled syringes are a popular choice for the delivery of biopharmaceuticals. However, glass syringes might not be the optimal primary packaging material for all biopharmaceuticals. There is evidence that the necessary lubricant silicone oil in glass syringes can interact with proteins and can be shed from the surface into the product solution. In recent years, silicone oil-free polymer syringes were developed. Despite several advantages, however, a major shortcoming of these polymer systems is their relatively high gas permeability, which might be a limitation for the storage of oxygen sensitive biopharmaceuticals. So far, no long-term protein stability studies regarding such polymer systems have been published. In this study, 2 therapeutic proteins were stored in glass syringes and in silicone oil-free polymer syringes. In addition, polymer syringes stored in nitrogen-filled aluminum pouches or covered with oxygen-tight labels were included. Similar chemical protein stability was achieved at 4°C for all syringes. However, in contrast to the polymer syringes, high particle counts were observed in the glass syringes. Polymer syringes stored in nitrogen-filled aluminum pouches presented a promising alternative for the storage of biopharmaceuticals as they do not expose patients to silicone oil and silicone oil-protein aggregates.     

Physical Stability of an Amorphous Sugar Matrix Dried From Methanol as an Amorphous Solid Dispersion Carrier and the Influence of Heat Treatment

An amorphous sugar matrix, after drying from an organic solvent, was investigated for use as a method for dispersing hydrophobic drugs (solid dispersion). However, the amorphous sugar, originally contained in the organic solvent, had a significantly low glass transition temperature (T_g), thus rendering it physically unstable. In this study, we examined the physicochemical properties of a sugar in a dried matrix and in an organic solvent, using α-maltose and methanol as a representative sugar and organic solvent. The apparent molar volume of α-maltose was ∼30% smaller in methanol than in water. The methanol-originated amorphous α-maltose exhibited a much greater degree of hydrogen bonding than the water-originated one. Considering these findings, we conclude that the α-maltose maintained its compact conformation in the dried state and consequently caused the markedly low T_g. Second, it was found that heating under appropriate conditions resulted in an increase in the T_g of the methanol-originated amorphous α-maltose as well as a decrease in the level of hydrogen bonding. The aqueous dissolution of 2 model hydrophobic drugs (indomethacin and ibuprofen) from the solid dispersion was also improved as the result of the heat treatment, whereas, to the contrary, the dissolution of another model drug (curcumin) was lowered.     

New Insight Into Thermodynamical Stability of Carbamazepine

Carbamazepine (CBZ)—an antiepileptic drug—belongs to Biopharmaceutics Classification System II Class. It has low solubility and consequently limited bioavailability. One of the ways to improve drugs solubility is amorphization of their structure. Herein, cooling CBZ—at different cooling rates—was investigated as a way to obtain glassy, better soluble form. During preliminary differential scanning calorimetry experiments, some peculiar behavior of the examined material, different from those stated in the literature, was observed. Further investigations using differential scanning calorimetry, thermogravimetric analysis, and polarizing optical microscope revealed that decomposition temperature of CBZ is about 30°C lower than previously assumed. Moreover, high-resolution thermogravimetric measurements indicate that some decomposition processes could start even below the temperature reported as the melting point of the form I of CBZ.