Microrobot Path Planning Based on the Multi-Module DWA Method in Crossing Dense Obstacle Scenario.

A hard issue in the field of microrobots is path planning in complicated situations with dense obstacle distribution. Although the Dynamic Window Approach (DWA) is a good obstacle avoidance planning algorithm, it struggles to adapt to complex situations and has a low success rate when planning in densely populated obstacle locations. This paper suggests a multi-module enhanced DWA (MEDWA) obstacle avoidance planning algorithm to address the aforementioned issues. An obstacle-dense area judgment approach is initially presented by combining Mahalanobis distance, Frobenius norm, and covariance matrix on the basis of a multi-obstacle coverage model. Second, MEDWA is a hybrid of enhanced DWA (EDWA) algorithms in non-dense areas with a class of two-dimensional analytic vector field methods developed in dense areas. The vector field methods are used instead of the DWA algorithms with poor planning performance in dense areas, which greatly improves the passing ability of microrobots over dense obstacles. The core of EDWA is to extend the new navigation function by modifying the original evaluation function and dynamically adjusting the weights of the trajectory evaluation function in different modules using the improved immune algorithm (IIA), thus improving the adaptability of the algorithm to different scenarios and achieving trajectory optimization. Finally, two scenarios with different obstacle-dense area locations were constructed to test the proposed method 1000 times, and the performance of the algorithm was verified in terms of step number, trajectory length, heading angle deviation, and path deviation. The findings indicate that the method has a smaller planning deviation and that the length of the trajectory and the number of steps can both be reduced by about 15%. This improves the ability of the microrobot to pass through obstacle-dense areas while successfully preventing the phenomenon of microrobots going around or even colliding with obstacles outside of dense areas.

First donor haemovigilance system at a national level in China: Establishment and improvement.

BACKGROUND AND OBJECTIVES: No systematic study has measured the incidence of adverse reactions (ARs) to blood donation at the national level in China before 2019. The objective of this study was to establish an effective reporting system to collect information on ARs to blood donation in China. MATERIALS AND METHODS: The status of donor haemovigilance (DHV) in blood collection facilities in China was evaluated, and an online DHV system was established to collect data on ARs to blood donation in July 2019. The definitions of ARs were based on the International Society of Blood Transfusion (ISBT) standards. The prevalence and data quality of ARs from 2019 to 2021 were analysed. RESULTS: A standard online reporting system has been established for ARs to blood donation. In total, 61, 62 and 81 participating sites were included in this pilot study in 2019, 2020 and 2021, respectively. From July 2019 to December 2021, 21,502 cases of whole-blood-related ARs and 1114 cases of apheresis platelet-related ARs were reported, with an incidence of 3.8‰ and 2.2‰, respectively. Data completeness for key reporting elements improved from 41.7% (15/36) in 2019 to 74.4% (29/39) in 2020. Data quality analysis for the year 2021 yielded similar results as for 2020. CONCLUSION: The construction and continuous improvement of the blood donor safety monitoring system prompted the establishment of the DHV system. Improvements have been made to the DHV system in China, with a significant increase in sentinels and higher data quality.

Challenges and Research in Managing Blood Supply in China.

Although considerable progress has been made in improving the blood service system in China over the last 2 decades, many challenges remain. A number of issues have received public attentions; however, others continue to be underacknowledged and controversial. This article describes 3 of these important and less emphasized issues: first, the ambiguity of the definition of voluntary nonremunerated blood donation and its relationship to an adequate blood supply; second, the current inadequacies of cost recovery from the blood service system; and third, the lack of a universally implemented program of hemovigilance. Currently, there is controversy regarding these challenges. Open recognition and discussion offers the prospect of bringing solutions closer to reality.

A potential role for the homeoprotein Hhex in hepatocellular carcinoma progression.

Hepatocellular carcinoma (HCC), the most common primary malignant tumor of the liver, often associated with the dysregulation of transcriptional pathways involved in cell growth and differentiation. The hematopoietically expressed homeobox protein (Hhex) is an important transcription factor throughout liver development and is essential to liver bud formation and hepatoblast differentiation. Here, we report a relationship between Hhex expression and HCC. First, adenovirus-mediated Hhex delivery into the hepatoma cell line, Hepa1-6, resulted in decreased expression of several proto-oncogenes (c-Jun and Bcl2), increased expression of some tumor suppressor genes (P53 and Rb), and enhanced expression of a cluster of hepatocytic and bile ductular markers. Second, Hhex expression significantly attenuated Hepa1-6 tumorigenicity in nude mice. Third, we report a correlation between Hhex expression and the differentiation state of human HCC. In 24 cases of clinical specimens, there was a significant difference in Hhex expression between poorly differentiated HCC and well-differentiated HCC (P < 0.001). Taken together, these results indicate that Hhex is a potential candidate molecular marker for HCC pathological evaluation, suggesting a need to evaluate Hhex as a potential target for therapeutic intervention.

Liver xeno-repopulation with human hepatocytes in Fah-/-Rag2-/- mice after pharmacological immunosuppression.

Functional human hepatocytes xeno-engrafted in mouse liver can be used as a model system to study hepatitis virus infection and vaccine efficacy. Significant liver xeno-repopulation has been reported in two kinds of genetically modified mice that have both immune deficiency and liver injury-induced donor hepatocyte selection: the uPA/SCID mice and Fah(-/-) Rag2(-/-)Il2rg(-/-) mice. The lack of hardy breeding and the overly elaborated technique in these two models may hinder the potential future application of these models to hepatitis virus infection and vaccination studies. Improving the transplantation protocol for liver xeno-repopulation from human hepatocytes will increase the model efficiency and application. In this study, we successfully apply immunosuppressive drug treatments of anti-asialo GM1 and FK506 in Fah(-/-)Rag2(-/-) mice, resulting in significant liver xeno-repopulation from human hepatocytes and human fetal liver cells. This methodology decreases the risk of animal mortality during breeding and surgery. When infected with hepatitis B virus (HBV) sera, Fah(-/-)Rag2(-/-) mice with liver xeno-repopulation from human hepatocytes accumulate significant levels of HBV DNA and HBV proteins. Our new protocol for humanized liver could be applied in the study of human hepatitis virus infection in vivo, as well as the pharmacokinetics and efficacy of potential vaccines.

Oncoprotein BMI-1 induces the malignant transformation of HaCaT cells.

BMI-1 (B-cell-specific Moloney murine leukemia virus integration site 1), a novel oncogene, has attracted much attention in recent years for its involvement in the initiation of a variety of tumors. Recent evidence showed that BMI-1 was highly expressed in neoplastic skin lesions. However, whether dysregulated BMI-1 expression is causal for the transformation of skin cells remains unknown. In this study, we stably expressed BMI-1 in a human keratinocyte cell line, HaCaT. The expression of wild-type BMI-1 induced the malignant transformation of HaCaT cells in vitro. More importantly, we found that expression of BMI-1 promoted formation of squamous cell carcinomas in vivo. Furthermore, we showed that BMI-1 expression led to the downregulation of tumor suppressors, such as p16INK4a and p14ARF, cell adhesion molecules, such as E-Cadherin, and differentiation related factor, such as KRT6. Therefore, our findings demonstrated that dysregulated BMI-1 could indeed lead to keratinocytes transformation and tumorigenesis, potentially through promoting cell cycle progression and increasing cell mobility.