Search

Introduction: Diabetes mellitus is one of the most important health issues worldwide. The rising incidence of the disease has resulted in a parallel increase of complications such as diabetic foot ulcers (DFU). It is estimated that 25% of patients with diabetes will develop foot ulcers over a lifetime. In Mexico, this lifetime incidence is about 40% to 50%, and 20% of the cases will require amputations. DFU can result in staggering financial burdens for the healthcare system and the patient. Therapies that promote rapid and complete healing and reduce the need for expensive surgical procedures would impact these costs substantially. Methods: Cu/TiO2–SiO2 nanoparticles were synthesized by T. López et al. sol-gel patented method. After synthesis, they were characterized using transmission electron microscopy (TEM) and X-ray diffraction. Then, they were embedded in a polymeric gel matrix. The Cu/TiO2–SiO2 nanogel was used as conservative therapy for a chronic non-healing DFU on a 62-year old female with several comorbidities and chronic complications of diabetes. Wound debridement was performed prior to nanogel administration. The nanogel was applied over the ulcer on alternate days for an initial period of 2 weeks and then continued for 10 months. Results: Significant improvement was observed in the wound healing process since the first applications. The infection was limited and tissue regeneration was enhanced until complete healing of the ulcer. Conclusion: Cu/TiO2–SiO2 nanogel therapy enhanced reepithelialization and healing of the DFU. The successful outcome allowed to avoid the amputation that was proposed for the patient.

Spacecraft hatch needs to be tested for leakage in various environments. Hatch Quick Leak Detector (HQLD) leak testing method is a convenient and effective method for the orbital hatch. Vacuum Chamber leak testing (VCLT) method is a proper integral leakage rate method for the hatch. We performed the testing in the “CMK2000” vacuum vessel. The detection principles and steps are described in detail. Leak testing was performed on all of the hatch seals using helium mass spectrometer leak detectors and special apparatus under the Thermal Vacuum testing. We performed leak testing after finishing operating the hatch in the Thermal Vacuum environment. The relative uncertainty of the total leakage rate value of the hatch is 23.6% (k = 2). The total leakage rate testing was a successful example of complex quantitative leakage rate testing in a middle vacuum chamber.

BaO–CaO–Al 2 O 3 –B 2 O 3 –SiO 2 (BCAS) glass–ceramics can be used as sealant for large size planar anode-supported solid oxide fuel cells (SOFCs). BCAS glass–ceramics after heat treatment for different times were characterized by means of thermal dilatometer, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the coefficients of thermal expansion (CTE) of BCAS glass–ceramics are 11.4×10 −6 K −1 , 11.3×10 −6 K −1 and 11.2×10 −6 K −1 after heated at 750 °C for 0 h, 50 h, and 100 h, respectively. The CTE of BCAS matches that of YSZ, Ni–YSZ and the interconnection of SOFC. Needle-like barium silicate, barium calcium silicate and hexacelsian are crystallized in the BCAS glass after heat-treatment for above 50 h at 750 °C. The glass–ceramics green tape prepared by aqueous tape casting can be directly applied in sealing the cell of SOFCs with 10 cm×10 cm. The open circuit voltage (OCV) of the cell keeps 1.19 V after running for 280 h at 750 °C and thermal cycling 10 times from 750 °C to room temperature. The maximum power density is 0.42 W/cm 2 using pure H 2 as fuel and air as oxidation gas. SEM images show no cracks or pores exist in the interface of BCAS glass–ceramics and the cell.

A series of nano-crystalline ceria-based solid solution electrolyte, Ce0.8La0.2−x MgxO2−δ (x = 0.0, 0.05, 0.10, 0.15, and 0.2), were synthesized via the polyvinyl alcohol (PVA) assisted combustion method, and then characterized to the crystalline structure, powder morphology, sintering micro-structure, and electrical properties. Present study showed that Ce0.8La0.2−x Mg x O2−δ was exceedingly stable as a cubic phase in all temperature range and exhibited fine crystals ranging from 15 to 20 nm. After sintering at 1,400 °C, the as-prepared pellets exhibited a dense micro-structure with 96 % of theoretical density. The electrical conductivity was studied using AC impedance spectroscopy and it was observed that the composition Ce0.8La0.1 Mg0.1O2−δ showed higher electrical conductivity of 0.020 S cm−1 at 700 °C. The thermal expansion was measured using dilatometer technique in the temperature range 30–1,000 °C. The average thermal expansion coefficient of Ce0.8La0.1 Mg0.1O2−δ was 12.37 × 10−6 K−1, which was higher than that of the commonly used SOFC electrolyte YSZ (~10.8 × 10−6 K−1).