Additive manufacturing, also known as three-dimensional (3D) printing, relates to several rapid prototyping (RP) technologies, and has shown great potential in the manufacture of organoids and even ...complex bioartificial organs. A major challenge for 3D bioprinting complex org unit ans is the competitive requirements with respect to structural biomimeticability, material integrability, and functional manufacturability. Over the past several years, 3D bioprinting based on sacrificial templates has shown its unique advantages in building hierarchical vascular networks in complex organs. Sacrificial biomaterials as supporting structures have been used widely in the construction of tubular tissues. The advent of suspension printing has enabled the precise printing of some soft biomaterials (e.g., collagen and fibrinogen), which were previously considered unprintable singly with cells. In addition, the introduction of sacrificial biomaterials can improve the porosity of biomaterials, making the printed structures more favorable for cell proliferation, migration and connection. In this review, we mainly consider the latest developments and applications of 3D bioprinting based on the strategy of sacrificial biomaterials, discuss the basic principles of sacrificial templates, and look forward to the broad prospects of this approach for complex organ engineering or manufacturing.
Path planning technology is significant for planetary rovers that perform exploration missions in unfamiliar environments. In this work, we propose a novel global path planning algorithm, based on ...the value iteration network (VIN), which is embedded within a differentiable planning module, built on the value iteration (VI) algorithm, and has emerged as an effective method to learn to plan. Despite the capability of learning environment dynamics and performing long-range reasoning, the VIN suffers from several limitations, including sensitivity to initialization and poor performance in large-scale domains. We introduce the double value iteration network (dVIN), which decouples action selection and value estimation in the VI module, using the weighted double estimator method to approximate the maximum expected value, instead of maximizing over the estimated action value. We have devised a simple, yet effective, two-stage training strategy for VI-based models to address the problem of high computational cost and poor performance in large-size domains. We evaluate the dVIN on planning problems in grid-world domains and realistic datasets, generated from terrain images of a moon landscape. We show that our dVIN empirically outperforms the baseline methods and generalize better to large-scale environments.
Though previous research has examined how implicit meter can facilitate the processing of stress-timed languages, syllable-timed languages, such as Chinese, remain under studied. Past research has ...shown that among verb-noun combinations in Chinese, the processing of 2 + 2 (two disyllabic words) combination rhythmic pattern is easier than that of 2 + 1 (a disyllabic word and a monosyllabic word) pattern, though it is unclear whether this effect is modulated by the sentential position of the verb-noun combination. The present study uses eye-tracking to examine the influence of position on rhythmic pattern during silent reading. In Experiment 1, participants read sentences with 2 + 1 versus 2 + 2 VN phrases embedded in different sentential positions. Results show that the fixation duration of 2 + 1 VN phrases is significantly longer than that of 2 + 2 and that the fixation duration of VN phrases is shorter at the sentence-middle position than it is at the sentence-final position, suggesting that the rhythmic pattern effect at the sentence-middle position exhibits a reduced magnitude compared to the sentence-final position. In Experiment 2, participants read sentences with either mono- or disyllabic words after the VN phrases to further explore whether the reduction of the rhythmic pattern effect is related to the number of succeeding syllables. Results show that while the fixation duration of the 2 + 1 VN pattern is significantly longer than that of the 2 + 2 pattern, there is no significant difference between the monosyllabic versus the disyllabic conditions, nor is there a significant interaction between rhythmic pattern and syllable length post VN phrases, thus ruling out the rhythmic effect from succeeding context. Together, these patterns suggest that the reduction of the rhythmic pattern effect is caused by position rather than number of syllables after phrases.
Currently, biomimetic scaffold is one of the most promising strategies in the field of bone tissue engineering. Zirconia (ZrO
2
), as a kind of bioceramic material, has attracted much attention in ...biomimetic scaffolds due to its excellent biocompatibility, high mechanical strength and great chemical stability. A lot of work has been carried out to investigate the characteristics and applications of the zirconia-based biomimetic scaffolds. However, there is few work which can provide a systematic comparison and overview on the research progress of zirconia-based biomimetic scaffolds. This review focuses on the properties and preparations of ZrO
2
and its composite materials. In addition, the roles of ZrO
2
along with other materials as scaffolds for bone tissue repair applications are highlighted. Simultaneously, the limitations of materials and technology are discussed.
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Viruses are the main infectious agents of acute respiratory infections in children. We aim to describe the epidemiological characteristics of viral pathogens of acute respiratory tract infections in ...outpatient children.
From April 2018 to March 2019, the results of viral detection using oral pharyngeal swabs from 103,210 children with acute respiratory tract infection in the outpatient department of the Children's Hospital, Zhejiang University School of Medicine, were retrospectively analyzed. Viral antigens, including adenovirus (ADV), influenza A (FLUA), influenza B (FLUB) and respiratory syncytial virus (RSV), were detected by the colloidal gold method.
At least one virus was detected in 38,355 cases; the positivity rate was 37.2%. A total of 1910 cases of mixed infection with two or more viruses were detected, and the positivity rate of multiple infection was 1.9%. The ADV positivity rate was highest in the 3-6-year-old group (18.7%), the FLUA positivity rate was highest in the > 6-year-old group (21.6%), the FLUB positivity rate was highest in the > 6-year-old group (6.6%), and the RSV positivity rate was highest in the < 1-year-old group (10.6%). There was a significant difference in the positivity rate of viral infection among different age groups (χ
= 1280.7, P < 0.001). The rate of positive viral infection was highest in winter (47.1%). The ADV infection rate was highest in spring (18.2%). The rates of FLUA and FLUB positivity were highest in winter (28.8% and 3.6%, respectively). The rate of RSV positivity was highest in autumn (17.4%). The rate of positive viral infection in different seasons was significantly different (χ
= 6459.1, P < 0.001).
Viral infection rates in children differ for different ages and seasons. The positivity rate of ADV is highest in the preschool period and that of RSV is highest in infants; that of FLU increases with age. The total positive rate of viral infection in different seasons is highest in winter, as is the rate of FLU positivity.
In this paper, through the application research of underwater gliders, it is found that ocean currents are the major influencing factor in the practical application of gliders. The objective of this ...study is to solve the path planning of glider formation in time-varying ocean currents. Using the existing glider model, energy consumption model and time-varying ocean current model are established based on the existing data, and a model close to the practical application of glider formation is established as well. The existing RRT algorithms are improved to be OCi-RRT (Ocean current improved RRT) algorithms based on environmental ocean currents. the algorithms are used to solve the path planning problems encountered in the practical application of gliders. Through simulations that are close to the restrictions of reality and the ideal communication state, it indicates that the improved RRT algorithms are suitable for path planning of glider formation in real ocean current environments. Then, a large number of simulation experiments are conducted, the results show that OCi-RRT* can reduce the number of cycles and path length by up to 14%, and the unit energy utilization can increase by up to 25% comparing with the RRT algorithm.
It is well known that lead-induced neurotoxicity is closely related to oxidative stress. According to previous reports, wheat germ peptides (WGPs) isolated from wheat germ have been shown to have ...potent antioxidant capacity. This study hypothesized that WGPs could protect PC12 cells from lead-induced oxidative stress. Here, the protecting-efficacies of WGPs were investigated in PC12 cells that were pretreated with WGPs (200 μM, 4 h) and exposed to lead (10 μM, 24 h). The antioxidant capacity was assessed by cell viability, ROS, MDA, SOD, CAT, GR, GPx, GSH, and GSSG. The experimental results showed that WGP3, WGP8, and WGP9 could reverse the reduction of cell viability caused by lead exposure. Lead exposure causes oxidative stress by increasing the levels of ROS and MDA. Moreover, the decrease in the levels of SOD, CAT, GPx, GR, and GSH/GSSG could be observed. However, WGP3, WGP8, and WGP9 can protect PC12 cells against lead-induced oxidative stress by reversing these phenomena. The protein expression of TXNIP, Keap1, and Nrf2 was characterized by western blotting, and the results illustrated that lead exposure up-regulated the expression of TXNIP and Keap1 and down-regulated the expression of Nrf2, and WGP3, WGP8, and WGP9 could improve the antioxidant capacity of PC12 cells by reversing this phenomenon. Therefore, the present study demonstrated that WGP3, WGP8, and WGP9 may protect against lead-induced oxidative stress in PC12 cells by regulating the TXNIP/Keap1/Nrf2 pathway.
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•WGP3, WGP8, and WGP9 improved the reduction in cell viability caused by lead exposure.•WGP3, WGP8, and WGP9 reduced the elevation of ROS and MDA due to lead exposure. They increased the reduction of SOD, CAT, GR, GPx, and GSH/GSSG due to lead exposure.•WGP3, WGP8, and WGP9 alleviated oxidative stress due to lead exposure by regulating Nrf2, Keap1, and TXNIP.
This study aimed to investigate the anxiety levels of healthcare workers and to provide guidance on potential accurate social and psychological interventions for healthcare workers during the ...epidemic of COVID-19 in Zhejiang Province, China.
Healthcare workers from five hospitals in Zhejiang Province were randomly selected into this study. Zung Self-Assessment Scale for Anxiety (SAS) was used to evaluate the anxiety status of the included 1637 healthcare workers.
The total anxiety score of healthcare workers in Zhejiang Province was 30.85 ± 6.89. The univariate analysis showed that the anxiety level of healthcare workers was related to gender, education, occupation, physical condition, job risk coefficient, and with family members on the first-line combating COVID-19 (P <0.05). The multivariate analysis showed that physical condition and job risk coefficient were predictors of anxiety levels of healthcare workers.
During the epidemic of COVID-19, 1637 healthcare workers generally had an increased tendency to have anxiety. Individualized assessment of the anxiety level of healthcare workers should be provided, and different interventions should be given based on the evaluation results.
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•An improved efficient decellularization protocol was identified, and this decellularized matrix could form hydrogels derived from human umbilical cord within 24 h.•HUVECs exhibited ...abundant cellular behavior in the hydrogels, including efficient adhesion, rapid proliferation, and vascularization.•The hydrogel showed good injectability and in situ molding ability, as well as excellent biocompatibility in vivo.
Refractory wounds are frequent and protracted diabetes or postoperative complications that greatly affect the quality of life and mental health of patients. As a result of repeated dressing replacements and local debridement of the existing therapeutic therapies, freshly formed granulation is once more infiltrated by inflammation and eliminated, which delays the healing process. Herein, the improved Fryetes' method, which retained most of the active factors in the extracellular matrix, was developed to prepare injectable decellularized extracellular matrix hydrogels (dECMH) from human umbilical cord tissue. The physical, biochemical, in vivo and in vitro biological properties were analysed in detail. The results showed that the pre-gel exhibited good injectability and could form the hydrogel within 30 min. Biochemical analysis indicated that the prepared decellularized extracellular matrix retained abundant structural proteins and wound healing-related growth factors. In vitro and in vivo experiments confirmed the excellent biocompatibility of dECMH and the extremely high migration and proliferation capacities of human umbilical vein endothelial cells in the hydrogels. Thus, the injectability, gel-forming ability, and excellent biological characteristics of the hydrogel are highly compatible with refractory wounds with various irregular shapes, showing great potential for clinical application in wound repair.
Infants must develop both flexibility and constraint in their interpretation of acceptable word forms. The current experiments examined the development of infants' lexical interpretation of ...non-native variations in pitch contour. Fourteen-, 17-, and 19-month-olds (Experiments 1 and 2, N = 72) heard labels for two novel objects; labels contained the same syllable produced with distinct pitch contours (Mandarin lexical tones). The youngest infants learned the label–object mappings, but the older groups did not, despite being able to discriminate pitch differences in an object-free task (Experiment 3, N = 14). Results indicate that 14-month-olds remain flexible regarding what sounds make meaningful distinctions between words. By 17–19 months, experience with a nontonal native language constrains infants' interpretation of lexical tone.
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