Design and implementation of a low-cost CO2 monitoring and control system prototype to optimize ventilation levels in closed spaces

High concentrations of CO2 levels are significantly present in closed environments that do not have proper ventilation. Such high concentrations generate negative health consequences such as dizziness, headaches and various respiratory problems. For this reason, the design and implementation of a low-cost CO2 monitoring and control prototype is proposed to optimize ventilation levels in closed spaces. The parameters that the proposed device measures are concentration of carbon dioxide, humidity and temperature. A digital PID controller was implemented, with the use of C++ programming language and an exhaust fan to stabilize carbon dioxide levels within a closed space. The aforementioned parameters can be viewed in two ways: The first way is locally through a LCD screen and LED indicators, and the second one, remotely using the free Arduino IoT Cloud platform. The closed environment was emulated using a cardboard box and in the tests it was obtained that the prototype manages to keep the CO2 concentration levels below the established limit. However, this can be further improved by using more precise sensors for more accurate results. It is expected that this model can be successfully scaled to closed spaces such as classrooms and offices.Campus Lima Centr

Patellofemoral full-thickness chondral defects treated with hyalograft-C: A clinical, arthroscopic, and histologic review

BACKGROUND: Tissue engineering has emerged as a potential therapeutic option for cartilage regeneration. HYPOTHESIS: Hyaluronan-based scaffolds seeded with autologous chondrocytes are a viable treatment for damaged articular surface of the patellofemoral joint. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty-two chondral lesions with a mean size of 4.7 cm(2) were treated with Hyalograft-C. Twenty-two lesions were located in the patella and 10 in the trochlea. Sixteen patients had previous trauma, 3 had osteochondritis dissecans, and 13 had degenerative changes. Transplantations were carried out arthroscopically or through a miniarthrotomy incision. Eight patients had concomitant procedures, including patellar realignment (2), lateral release (3), and meniscectomy (3). Results were evaluated using the International Cartilage Repair Society-International Knee Documentation Committee scale, EuroQol EQ-5D form, and magnetic resonance imaging scans at 12 and 24 months. Six patients had second-look arthroscopy and biopsies. Statistical analysis was performed using the paired t test and Wilcoxon signed rank test. RESULTS: The International Cartilage Repair Society-International Knee Documentation Committee and EuroQol EQ-5D scores demonstrated a statistically significant improvement (P < .0001). Objective preoperative data improved from 6/32 (18.8%) with International Knee Documentation Committee A or B to 29/32 (90.7%) at 24 months after transplantation. Mean subjective scores improved from 43.2 points preoperatively to 73.6 points 24 months after implantation. Magnetic resonance imaging studies at 24 months revealed 71% to have an almost normal cartilage with positive correlation to clinical outcomes. Second-look arthroscopies in 6 cases revealed the repaired surface to be nearly normal with biopsy samples characterized as hyaline-like in appearance. CONCLUSION: Biodegradable scaffolds seeded with autologous chondrocytes can be a viable treatment for chondral lesions. The type of tissue repair achieved demonstrated histologic characteristics similar to normal articular cartilage. Long-term investigations are needed to determine the durability of the repair produced with this technique