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In this paper, the wasted PET bottles were analyzed. With the experiment analysis and the related literature, we determine the feasibility of the wasted PET plastic bottles as 3D printing materials. We design and introduced the principle of the 3D print nozzle of using the positive and negative screw to extrude material. The feasibility of the design is demonstrated by three - dimensional modeling, physical experiment analysis and ANSYS simulation analysis.

In this paper, development of virtual reality-based rock climbing system is demonstrated. As virtual reality possesses immersive, synchronous and interactive characteristics, the VR technology has been widely used in many engineering areas. Through the combination of multi-path variable amplitude rock climbing machine and the virtual reality technology, the users can do the rock climbing sports in room environment with immersive experience. The virtual rock climbing scene is developed based on the Unity3D engine to achieve the interaction among the user, the rock climbing machine and the virtual reality environment. The system utilizes virtual reality technologies such as HTC Vive, Leap Motion and Unity3D game engine in an attempt to simulate an immersive rock climbing experience. The rock climbing machine is designed that capable of changing the path or amplitude automatically, which overcomes the defects of indoor climbing machine with fixed route. With the VR technology, it greatly improves the indoor climbing experience.

To investigate the protective effect of retinoic acid (RA) on hyperoxic lung injury and the role of RA as a modulator on mitogen-activated protein kinases (MAPKs), gastation 21 d Sprague-Dawley (SD) fetuses (term = 22 d) were delivered by hysterotomy. Within 12-24 h of birth, premature rat pups were randomly divided into 4 groups (n=12 each): air-exposed control group (group I); hyperoxia-exposed group (group II), air-exposed plus RA group (group III), hyperoxia-exposed plus RA group (group IV). Group I, III were kept in room air, and group II, IV were placed in 85 % oxygen. The pups in groups III and IV were intraperitoneally injected with RA (500 microg/kg every day). All lung tissues of premature rat pups were collected at the 4th day after birth. Terminal transferase d-UTP nick end labeling (TUNEL) staining was used for the detection of cell apoptosis. The expression of PCNA was immunohistochemically detected. Western blot analysis was employed for the determination of phosphorylated and total nonphosphorylated ERKs, JNKs or p38. Our results showed that lungs from the pups exposed to hyperoxia for 4 d exhibited TUNEL-positive nuclei increased markedly throughout the parenchyma (P0.01), and decreased significantly after RA treatment (P0.01). The index of PCNA-positive cells was significantly decreased (P0.01), and was significantly increased by RA treatment (P0.01). The air-space size was significantly enlarged, secondary crests were markedly decreased in hyperoxia-exposed animals. RA treatment improved lung air spaces and secondary crests in air-exposed pups, but had no effect on hyperoxia-exposure pups. Western blotting showed that the amounts of JNK, p38 and ERK proteins in hyperoxia-exposure or RA-treated lung tissues were same as those in untreated lung tissues (P0.05), whereas activation of these MAPKs was markedly altered by hyperoxia and RA. After hyperoxia exposure, p-ERK1/2, p-JNK1/2 and p-p38 were dramatically increased (P0.01), whereas p-JNK1/2 and p-p38 were markedly declined and p-ERK1/2 was further elevated by RA treatment (P0.01). It is concluded that RA could decrease cell apoptosis and stimulate cell proliferation under hyperoxic condition. The protection of RA on hyperoxia-induced lung injury was related to the regulation of MAP kinase activation.

To investigate whether treatment with retinoic acid (RA) could improve level of lung alveolarization and influence lung collagen in newborn rats exposed to hyperoxia, newborn Sprague-Dawley rats aged 2 days were randomly assigned to 8 groups: (1) air, (2) O2, (3) air+NS, (4) O2+NS, (5) air+dex, (6) O2+dex, (7) air+RA and (8) O2+RA. Group 2, 4 6 and 8 were kept in chambers containing 85% oxygen, the values were checked 3 times a day. The other 4 groups were exposed to room air. Level of alveolarization and lung collagen were analyzed at age of 14 or 21 days through radial alveolar counts, alveolar airspace measurements, type I, II collagen immunohistochemical methods (SP method) and image processing system. Transforming growth factor-β receptors and procollagen mRNA accumulation were examined at age of 14 days through immunohistochemical methods andin situ hybridization. Our results showed that radial alveolar counts were increased and distal airspace was enlarged in group 8. Type I collagen was markedly increased, and transforming growth factor-β receptors and procollagen mRNA were decreased by retinoic acid in bronchial epithelial cells, alveolar epithelial cells and alveolar intersitium. It is concluded that retinoic acid can partially reverse lung development arrest during exposure to hyperoxia by increasing lung collagen.

To assess the efficacy and the optimum dose of recombinant human erythropoietin (rhEpo) on the anemia of premature, 45 preterm infants with a gestational age of less than 35 weeks and birth weight of less 1,800 g were randomly assigned to treatment group 1 (n = 15, receiving subcutaneous rhEpo 150 U/kg.time), treatment group 2 (n = 15, receiving 250 U/kg.time), three times a week for 6 weeks, and control group (n = 15, no treatment was given). All preterm infants received supplements of vitamin E (20 IU) and iron (20 mg) each day. Our results showed that postnatal decline of hemoglobin (Hb) and hematocrit (Hct) were lessened in the treatment groups, particularly in the group 2 and the differences were very significant (P0.0001 for all). Treated infants had significantly higher reticulocyte counts (Ret) (P0.0001 for all), but there was no significant difference between the two treatment groups (P0.05). Serum iron dropped significantly in the treatment groups as compared with control group (P0.01 for all), but no dose-dependent relationship was observed in treated infants (P0.05). After treatment, serum levels of erythropoietin was higher in group 2 than those in group 1 and control group (P0.0001, P0.01 and P0.05, respectively). There was no significant difference between group 1 and control group (P0.05). No side effects related to rhEpo therapy were observed. Our study suggested that rhEpo therapy stimulates endogenous erythropoiesis and enhances Ret, Hct and level of Hb in a dose-dependent manner in premature infants. The therapy is more efficient when given in higher dosages.

To explore the mechanism of Notch in hyperoxia-induced preterm rat lung injury, 2-days-old preterm SD rats were randomized into control and hyperoxia group (FiO2or = 0.85). On day 1, 7, 14 and 21, 8 rat pups of each time point were used to assess histopathological changes of lung with HE staining and to evaluate the expression of Notch1 and Notch3 with immunohistochemistry. Notch1, Notch3, Aquaprin5 (AQP5) and surfactant protein C (SP-C) mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). The results showed that the lung injury in the hyperoxia group was characterized by retarded lung alveolization and differentiation of alveolar epithelial type II cells (AEC II). Positive staining of Notch1 in hyperoxia group was weaker than controls at every time point (except for day 7), while positive staining of Notch3 was much stronger (P0.05, P0.01). Notch1, Notch3 mRNA level showed similar change as protein level. AQP5, SP-C mRNA decreased significantly as compared with that of the controls (P0.01). We are led to conclude that hyperoxia results in abnormal expression of Notch, which is likely to contribute to the pathogenesis of lung injury through regulating proliferation and transdifferentiation of alveolar epithelial cells.