With the preeminent features of polyurethane (PU) panels such as sound insulation, heat insulation, fireproof, high load capacity, lightweight, high aesthetics, especially using simple and easy assembly construction and move, so new PU panel is now the first choice for construction projects. In this work, the authors study the new generation physical foaming agent cyclopentane that is environmentally friendly and completely does not destroy the ozone layer. Study investigating and evaluating the effect of content of physical foam cyclopentane on free expansion density, reaction time of rigid polyurethane foam (R-PUF), and reaction time values ​​(cream time, gel time, tack-free time, and rise time). The morphology and size of the closed-cell of the R-PUF samples with cyclopentane concentrations increasing from 0% to 20% are observed by the optical microscope image and the closed-cell size distribution chart is determined by IT3 software. In addition, the physical and mechanical properties of dimensional stability and compressive strength were analyzed to evaluate the quality of the expanded R-PUF insulation in the mold using a cyclopentane physical foaming agent. Experimental procedures according to Taguchi's analysis on the continuous production line are aimed at giving optimal parameters for the industrial PU panel manufacturing process. The research results provide an excellent reference value for manufacturers to further improve the performance and quality of PU panels.

Osteonecrosis of the femoral head (ONFH) develops when the bone in the head of the femur dies and gradually collapses due to the disruption of its blood supply. Total hip arthroplasty (THA) is the standard treatment for patients with late-stage ONFH. However, there is uncertainty about the type of prosthesis design that provides the best outcome. During the last decade, despite the increasing number of researches on short-stem prostheses, it is still questionable whether they represents a risk factor for failure after implantation. The aim of this study was to review researches comparing the outcome of short-stem and conventional-stem arthroplasty in ONFH and to present the pros and cons of short-stem hip arthroplasty in osteonecrosis of the femoral head. The short- to medium-term results showed predominantly good outcomes. However, due to differences in the design of short stems and their fixation, it is hard to draw a general conclusion. Short stems with primary diaphyseal fixation do not reveal a high increased risk of failed integration or loosening. For designs with a primary metaphyseal anchorage, an MRI should be conducted to exclude that the necrosis exceeds the femoral neck.

Objective: To give initial results in the restoration of some important anatomical parameters (femoral neck angle, distance from the center of the crest to the femoral axis (offset), and limb deviation) in the standard cementless total hip replacement in the treatment of aseptic necrosis of the femoral head. Subject and method: In studies in the period from 2/2021 to 6/2021, the authors used the Medi-CAD software integrated on the computer to determine the femoral neck angle, the distance from the center of the crest to the femoral axis (offset), the limb deviation of 24 hip joints was surveyed on 20 patients at the time preoperative and postoperative with standard Zimmer hip joints. The method used in this study is a cross-sectional, prospective study. Result: The results show that the mean postoperative femoral neck angle was 131.1 ± 3.2º while the preoperative size was 129.8 ± 3.4º. The average postoperative offset size was 35.6 ± 4.8mm and higher than before surgery was 32.5 ± 5.4mm. Postoperative limb deviation was 3.2 ± 2.7mm and lower than preoperative was 12.3 ± 4.5mm, the difference was insignificant statistically. Conclusion: Research results show that the closer the femoral neck angle and the offset is to the original value, the better the limb balance.

Objective: we perform this study with the following objective: Studying the initial stability of a new type of hip replacement-spiron short stem. Subjects and methods: Experiments to determine the deformability, elasticity and force capacity of the femur were used for the short stem and the long stem replacement corresponds to the original femur without the prosthesis. Along with that, we were evaluated  short-term results of treatment for 70 patients with 92 Spiron hips replacement  in the Institute of Trauma and Orthopedic-108 Military Central Hospital, from 2012 to 2016. Results: The analysis results showed that the Spiron short stem prosthetic had a significantly smaller displacement in the mid-frost bond than the Zweymuller long stem prosthesis. Clinical research: Harris’s score was 45.2 (± 2.4) before surgery. At the final examination time Harris’s score was 91.4 (± 2.5). The rate: very good (75.0%), good (17.4%), average (3.3%), poor (4.3%). There are 02 cases early stem loosening had to stem revision surgery (2.2%). Conclusion: These results show the good initial fixed ability as well as stability when replaced by the Spiron stem.