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51. The SOFIA Massive (SOMA) Star Formation Survey. IV. Isolated Protostars

Author

Rubén Fedriani, Jonathan C. Tan, Zoie Telkamp, Yichen Zhang, Yao-Lun Yang, Mengyao Liu, James M. De Buizer, Chi-Yan Law, Maria T. Beltran, Viviana Rosero, Kei E. I. Tanaka, Giuliana Cosentino, Prasanta Gorai, Juan Farias, Jan E. Staff, and Barbara Whitney

Subjects
Massive stars, Star formation, Interstellar medium, Jets, Infrared sources, Protostars, Astrophysics, QB460-466
Abstract

We present ∼10–40 μ m SOFIA-FORCAST images of 11 isolated protostars as part of the SOFIA Massive (SOMA) Star Formation Survey, with this morphological classification based on 37 μ m imaging. We develop an automated method to define source aperture size using the gradient of its background-subtracted enclosed flux and apply this to build spectral energy distributions (SEDs). We fit the SEDs with radiative transfer models, developed within the framework of turbulent core accretion (TCA) theory, to estimate key protostellar properties. Here, we release the sedcreator python package that carries out these methods. The SEDs are generally well fitted by the TCA models, from which we infer initial core masses M _c ranging from 20–430 M _⊙ , clump mass surface densities Σ _cl ∼ 0.3–1.7 g cm ^−2 , and current protostellar masses m _* ∼ 3–50 M _⊙ . From a uniform analysis of the 40 sources in the full SOMA survey to date, we find that massive protostars form across a wide range of clump mass surface density environments, placing constraints on theories that predict a minimum threshold Σ _cl for massive star formation. However, the upper end of the m _* −Σ _cl distribution follows trends predicted by models of internal protostellar feedback that find greater star formation efficiency in higher Σ _cl conditions. We also investigate protostellar far-IR variability by comparison with IRAS data, finding no significant variation over an ∼40 yr baseline.

Published
2022
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52. Establishment of a Suspension MDBK Cell Line in Serum-Free Medium for Production of Bovine Alphaherpesvirus-1

Author

Pengpeng Wang, Shulin Huang, Chengwu Hao, Zhanhui Wang, Haoran Zhao, Mengyao Liu, Xinrui Tian, Letu Ge, Wenxue Wu, and Chen Peng

Subjects
serum-free suspension adaptation process, suspended MDBK cells, serum-free medium, bovine alphaherpesvirus-1 (BoHV-1), virus production, ultrasonic treatment, Medicine
Abstract

The Madin–Darby bovine kidney (MDBK) cell line is currently used for the production of bovine alphaherpesvirus-1 (BoHV-1) vaccine. For the purpose of vaccine manufacturing, suspension cells are preferred over adherent ones due to simplified sub-cultivation and an easier scale-up process, both of which could significantly reduce production cost. This study aimed to establish a procedure for the culture of BoHV-1 in the suspended MDBK cell line in serum-free medium. We screened several commercially available serum-free media and chose ST503 for subsequent experiments. We successfully adapted the adherent MDBK cells to suspended growth in ST503 in the absence of serum. The maximum density of suspension-adapted MDBK cells could reach 2.5 × 107 cells/mL in ST503 medium with optimal conditions. The average size of suspension-adapted cells increased to 18 ± 1 µm from 16 ± 1 µm. Moreover, we examined tumorigenicity of the suspended cells and found no sign of tumorigenicity post adaptation. Next, we developed a protocol for the culture of BoHV-1 in the cell line described above and found that ultrasonic treatment could facilitate virus release and enhance virus yield by 11-fold, with the virus titer reaching 8.0 ± 0.2 log10TCID50/mL. Most importantly, the prototype inactivated BoHV-1 vaccine we generated using the suspension cultures of MDBK cells induced neutralizing antibodies to a titer comparable to that of the commercial inactivated BoHV-1 vaccine. Overall, we established and optimized a protocol for the production of inactivated BoHV-1 vaccine in MDBK cells adapted for suspension culture, which provides insights for future large-scale manufacturing of BoHV-1 vaccine.

Published
2021
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53. Induction of Robust and Specific Humoral and Cellular Immune Responses by Bovine Viral Diarrhea Virus Virus-Like Particles (BVDV-VLPs) Engineered with Baculovirus Expression Vector System

Author

Zhanhui Wang, Mengyao Liu, Haoran Zhao, Pengpeng Wang, Wenge Ma, Yunke Zhang, Wenxue Wu, and Chen Peng

Subjects
bovine viral diarrhea virus, virus-like particles, baculovirus expression vector system, Erns, E2, vaccine, Medicine
Abstract

Bovine viral diarrhea virus (BVDV) is an important animal pathogen that affects cattle. Infections caused by the virus have resulted in substantial economic losses and outbreaks of BVDV are reported globally. Virus-like particles (VLPs) are promising vaccine technology largely due to their safety and strong ability to elicit robust immune responses. In this study, we developed a strategy to generate BVDV-VLPs using a baculovirus expression vector system (BEVS). We were able to assemble BVDV-VLPs composed of dimerized viral proteins E2 and Erns, and the VLPs were spherical particles with the diameters of about 50 nm. Mice immunized with 15 μg of VLPs adjuvanted with ISA201 elicited higher levels of E2-specific IgG, IgG1, and IgG2a antibodies as well as higher BVDV-neutralizing activity in comparison with controls. Re-stimulation of the splenocytes collected from mice immunized with VLPs led to significantly increased levels of CD3+CD4+T cells and CD3+CD8+T cells. In addition, the splenocytes showed dramatically enhanced proliferation and the secretion of Th1-associated IFN-γ and Th2-associated IL-4 compared to that of the unstimulated control group. Taken together, our data indicate that BVDV-VLPs efficiently induced BVDV-specific humoral and cellular immune responses in mice, showing a promising potential of developing BVDV-VLP-based vaccines for the prevention of BVDV infections.

Published
2021
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54. Winners and losers of the Sino–US trade war from economic and environmental perspectives

Author

Mingxi Du, Lulu Chen, Jintai Lin, Yu Liu, Kuishuang Feng, Qiuyu Liu, Yawen Liu, Jingxu Wang, Ruijing Ni, Yu Zhao, Wei Si, Ying Li, Hao Kong, Hongjian Weng, Mengyao Liu, and Jamiu Adetayo Adeniran

Subjects
air pollution, atmospheric transport, international trade, Environmental technology. Sanitary engineering, TD1-1066, Environmental sciences, GE1-350, Science, Physics, QC1-999
Abstract

The ongoing trade war between the United States and China is having profound impacts on the global economy. As recent studies have found substantial amounts of carbon dioxide and air pollution embedded in the global supply chains, the Sino–US trade war may also affect emissions and health burdens worldwide, which remains poorly understood. Here, we estimate the potential changes in gross domestic product (GDP), anthropogenic emissions and particulate matter (PM _2.5 ) related premature deaths worldwide under two Sino–US trade war scenarios. We find that for the US and China, the trade war would reduce their GDP and, less significantly, emissions and mortality, suggesting that the trade war is not an effective means of environmental protection. The trade war would increase both GDP and mortality in many developing regions, because of their increased production of goods targeted in the Sino–US trade war. Surprisingly, Western Europe and Latin America and Caribbean would have higher GDP but lower emissions and mortality, an economic and environmental win-win outcome as a net result of the complex changes in the global supply chains. Neighbour regions of the US and China such as Canada, Japan and Korea would also have higher GDP but lower mortality, because of reduced atmospheric transboundary transport from the US and China overcompensating for increased local emissions of these neighbours. The complex consequences of the Sino–US trade war highlight the strong inter-regional and economic-environmental linkage in support of a global collaborative strategy to foster economic growth and environmental protection.

Published
2020
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55. Contemporary Pharyngeal and Invasive emm1 and Invasive emm12 Group A Streptococcus Isolates Exhibit Similar In Vivo Selection for CovRS Mutants in Mice.

Author

Wenchao Feng, Mengyao Liu, Daniel G Chen, Rossana Yiu, Ferric C Fang, and Benfang Lei

Subjects
Medicine, Science
Abstract

Group A Streptococcus (GAS) causes diverse infections ranging from common pharyngitis to rare severe invasive infections. Invasive GAS isolates can have natural mutations in the virulence regulator CovRS, which result in enhanced expression of multiple virulence genes, suppressed the expression of the protease SpeB, and increased virulence. It is believed that CovRS mutations arise during human infections with GAS carrying wild-type CovRS and are not transmissible. CovRS mutants of invasive GAS of the emm1 genotype arise readily during experimental infection in mice. It is possible that invasive GAS arises from pharyngeal GAS through rare genetic mutations that confer the capacity of mutated GAS to acquire covRS mutations during infection. The objective of this study was to determine whether contemporary pharyngeal emm1 GAS isolates have a reduced propensity to acquire CovRS mutations in vivo compared with invasive emm1 GAS and whether emm3, emm12, and emm28 GAS acquire CovRS mutants in mouse infection. The propensity of invasive and pharyngeal emm1 and invasive emm3, emm12, and emm28 SpeBA+ isolates to acquire variants with the SpeBA- phenotype was determined during subcutaneous infection of mice. The majority of both invasive and pharyngeal emm1 SpeBA+ isolates and two of three emm12 isolates, but not emm3 and emm28 isolates, were found to acquire SpeBA- variants during skin infection in mice. All analyzed SpeBA- variants of emm1 and emm12 GAS from the mouse infection acquired covRS mutations and produced more platelet-activating factor acetylhydrolase SsE. Thus, contemporary invasive and pharyngeal emm1 GAS isolates and emm12 GAS have a similar capacity to acquire covRS mutations in vivo. The rarity of severe invasive infections caused by GAS does not appear to be attributable to a reduced ability of pharyngeal isolates to acquire CovRS mutations.

Published
2016
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58. Serotype M3 and M28 Group A Streptococci Have Distinct Capacities to Evade Neutrophil and TNF-α Responses and to Invade Soft Tissues.

Author

Zachary W Stetzner, Dengfeng Li, Wenchao Feng, Mengyao Liu, Guanghui Liu, James Wiley, and Benfang Lei

Subjects
Medicine, Science
Abstract

The M3 Serotype of Group A Streptococcus (GAS) is one of the three most frequent serotypes associated with severe invasive GAS infections, such as necrotizing fasciitis, in the United States and other industrialized countries. The basis for this association and hypervirulence of invasive serotype M3 GAS is not fully understood. In this study, the sequenced serotype M3 strain, MGAS315, and serotype M28 strain, MGAS6180, were characterized in parallel to determine whether contemporary M3 GAS has a higher capacity to invade soft tissues than M28 GAS. In subcutaneous infection, MGAS315 invaded almost the whole skin, inhibited neutrophil recruitment and TNF-α production, and was lethal in subcutaneous infection of mice, whereas MGAS6180 did not invade skin, induced robust neutrophil infiltration and TNF-α production, and failed to kill mice. In contrast to MGAS6180, MGAS315 had covS G1370T mutation. Either replacement of the covS1370T gene with wild-type covS in MGAS315 chromosome or in trans expression of wild-type covS in MGAS315 reduced expression of CovRS-controlled virulence genes hasA, spyCEP, and sse by >10 fold. MGAS315 covSwt lost the capacity to extensively invade skin and to inhibit neutrophil recruitment and had attenuated virulence, indicating that the covS G1370T mutation critically contribute to the hypervirulence of MGAS315. Under the background of functional CovRS, MGAS315 covSwt still caused greater lesions than MGAS6180, and, consistently under the background of covS deletion, MGAS6180 ΔcovS caused smaller lesions than MGAS315 ΔcovS. Thus, contemporary invasive M3 GAS has a higher capacity to evade neutrophil and TNF-α responses and to invade soft tissue than M28 GAS and that this skin-invading capacity of M3 GAS is maximized by natural CovRS mutations. These findings enhance our understanding of the basis for the frequent association of M3 GAS with necrotizing fasciitis.

Published
2015
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59. Non-heme-binding domains and segments of the Staphylococcus aureus IsdB protein critically contribute to the kinetics and equilibrium of heme acquisition from methemoglobin.

Author

Hui Zhu, Dengfeng Li, Mengyao Liu, Valerie Copié, and Benfang Lei

Subjects
Medicine, Science
Abstract

The hemoglobin receptor IsdB rapidly acquires heme from methemoglobin (metHb) in the heme acquisition pathway of Staphylococcus aureus. IsdB consists of N-terminal segment (NS), NEAT1 (N1), middle (MD), and heme binding NEAT2 (N2) domains, and C-terminal segment (CS). This study aims to elucidate the roles of these domains or segments in the metHb/IsdB reaction. Deletion of CS does not alter the kinetics and equilibrium of the reaction. Sequential deletions of NS and N1 in NS-N1-MD-N2 progressively reduce heme transfer rates and change the kinetic pattern from one to two phases, but have no effect on the equilibrium of the heme transfer reaction, whereas further deletion of MD reduces the percentage of transferred metHb heme. MD-N2 has higher affinity for heme than N2. MD in trans reduces rates of heme dissociation from holo-N2 and increases the percentage of metHb heme captured by N2 by 4.5 fold. NS-N1-MD and N2, but not NS-N1, MD, and N2, reconstitute the rapid metHb/IsdB reaction. NS-N1-MD-NIsdC, a fusion protein of NS-N1-MD and the NEAT domain of IsdC, slowly acquires heme from metHb by itself but together with N2 results in rapid heme loss from metHb. Thus, NS-N1 and MD domains specifically and critically contribute to the kinetics and equilibrium of the metHb/IsdB reaction, respectively. These findings support a mechanism of direct heme acquisition by IsdB in which MD enhances the affinity of N2 for heme to thermodynamically drive heme transfer from metHb to IsdB and in which NS is required for the rapid and single phase kinetics of the metHb/IsdB reaction.

Published
2014
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60. Direct heme transfer reactions in the Group A Streptococcus heme acquisition pathway.

Author

Chunmei Lu, Gang Xie, Mengyao Liu, Hui Zhu, and Benfang Lei

Subjects
Medicine, Science
Abstract

The heme acquisition machinery in Group A Streptococcus (GAS) consists of the surface proteins Shr and Shp and ATP-binding cassette transporter HtsABC. Shp cannot directly acquire heme from methemoglobin (metHb) but directly transfers its heme to HtsA. It has not been previously determined whether Shr directly relays heme from metHb to Shp. Thus, the complete pathway for heme acquisition from metHb by the GAS heme acquisition machinery has remained unclear. In this study, the metHb-to-Shr and Shr-to-Shp heme transfer reactions were characterized by spectroscopy, kinetics and protein-protein interaction analyses. Heme is efficiently transferred from the β and α subunits of metHb to Shr with rates that are 7 and 60 times greater than those of the passive heme release from metHb, indicating that Shr directly acquires heme from metHb. The rapid heme transfer from Shr to Shp involves an initial heme donor/acceptor complex and a spectrally and kinetically detectable transfer intermediate, implying that heme is directly channeled from Shr to Shp. The present results show that Shr speeds up heme transfer from metHb to Shp, whereas Shp speeds up heme transfer from Shr to HtsA. Furthermore, the findings demonstrate that Shr can interact with metHb and Shp but not HtsA. Taken together with our published results on the Shp/HtsA reaction, these findings establish a model of the heme acquisition pathway in GAS in which Shr directly extracts heme from metHb and Shp relays it from Shr to HtsA.

Published
2012
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61. Group A Streptococcus secreted esterase hydrolyzes platelet-activating factor to impede neutrophil recruitment and facilitate innate immune evasion.

Author

Mengyao Liu, Hui Zhu, Jinquan Li, Cristiana C Garcia, Wenchao Feng, Liliya N Kirpotina, Jonathan Hilmer, Luciana P Tavares, Arthur W Layton, Mark T Quinn, Brian Bothner, Mauro M Teixeira, and Benfang Lei

Subjects
Immunologic diseases. Allergy, RC581-607, Biology (General), QH301-705.5
Abstract

The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a null covS mutation enhances neutrophil ingress to infection sites in the skin of mice. In trans expression of SsE in MGAS2221 reduces neutrophil recruitment and enhances skin invasion. The sse deletion mutant of MGAS5005 (Δsse(MGAS5005)) is more efficiently cleared from skin than the parent strain. SsE hydrolyzes the sn-2 ester bond of platelet-activating factor (PAF), converting biologically active PAF into inactive lyso-PAF. K(M) and k(cat) of SsE for hydrolysis of 2-thio-PAF were similar to those of the human plasma PAF acetylhydrolase. Treatment of PAF with SsE abolishes the capacity of PAF to induce activation and chemotaxis of human neutrophils. More importantly, PAF receptor-deficient mice significantly reduce neutrophil infiltration to the site of Δsse(MGAS5005) infection. These findings identify the first secreted PAF acetylhydrolase of bacterial pathogens and support a novel GAS evasion mechanism that reduces phagocyte recruitment to sites of infection by inactivating PAF, providing a new paradigm for bacterial evasion of neutrophil responses.

Published
2012
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68. Research on Fine-Grained Recognition Method for Sensitive Information in Social Networks Based on CLIP.

Author

Menghan Zhang, Fangfang Shan, Mengyao Liu, and Zhenyu Wang

Subjects
DIGITAL technology, SOCIAL networks, INFORMATION networks, DEEP learning, DISCLOSURE
Abstract

With the emergence and development of social networks, people can stay in touch with friends, family, and colleagues more quickly and conveniently, regardless of their location. This ubiquitous digital internet environment has also led to large-scale disclosure of personal privacy. Due to the complexity and subtlety of sensitive information, traditional sensitive information identification technologies cannot thoroughly address the characteristics of each piece of data, thus weakening the deep connections between text and images. In this context, this paper adopts the CLIP model as a modality discriminator. By using comparative learning between sensitive image descriptions and images, the similarity between the images and the sensitive descriptions is obtained to determine whether the images contain sensitive information. This provides the basis for identifying sensitive information using different modalities. Specifically, if the original data does not contain sensitive information, only single-modality text-sensitive information identification is performed; if the original data contains sensitive information, multimodality sensitive information identification is conducted. This approach allows for differentiated processing of each piece of data, thereby achieving more accurate sensitive information identification. The aforementioned modality discriminator can address the limitations of existing sensitive information identification technologies, making the identification of sensitive information from the original data more appropriate and precise. [ABSTRACT FROM AUTHOR]

Published
2024
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76. Therapeutic efficacy and safety of JAK inhibitors in treating polymyositis/ dermatomyositis: a single-arm systemic meta-analysis.

Author

Chenhang Ma, Mengyao Liu, Yang Cheng, Xinchang Wang, Yu Zhao, Kailu Wang, and Weijie Wang

Subjects
DERMATOMYOSITIS, TREATMENT effectiveness, SKIN diseases, CREATINE kinase, POLYMYOSITIS
Abstract

Introduction: We performed a single-arm meta-analysis to evaluate the efficacy and safety of JAK inhibitors in the treatment of dermatomyositis (DM)/ polymyositis (PM). Methods: Relevant studies from four databases were systematically searched until April 25, 2023. The primary endpoint was Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) and other outcomes were Manual Muscle Testing (MMT) and Creatine Kinase (CK). According to the type of JAK and medication regimen, we conducted subgroup analyses. The registration number in PROSPERO was CRD42023416493. Results: According to the selection criteria, we identified 7 publications with a total of 91 patients. Regarding skin lesions, the CDASI decreased by 17.67 (95% CI: -20.94 ~ -14.41). The CK increased by 8.64 U (95% CI: -28.25 ~ 45.53). About muscle lesions, MMT increased by 10.31 (95% CI: -2.83 ~ 23.46). Subgroup analysis revealed that different types of JAK inhibitors had various degrees of reduction. CDASI in patients treated with RUX had the lowest one [-20.00 (95% CI: -34.9 ~ -5.1)], followed by TOF [-18.29 (95% CI: -21.8 ~ -14.78)] and BAR [-11.2 (95% CI: -21.51 ~ -0.89)]. Additionally, the mean reduction in CDASI in patients treated with TOF alone was 16.16 (95% CI: -21.21 ~ -11.11), in combination with other immunosuppressants was 18.59 (95% CI: -22.74 ~ -14.45). For safety evaluation, one patient developed Orolabial HSV, and two patients developed thromboembolism events. Discussion: In summary, this meta-analysis demonstrated that JAK inhibitors can potentially treat DM/PM without severe adverse reactions. [ABSTRACT FROM AUTHOR]

Published
2024
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77. GPR43 protects human A16 cardiomyocytes against hypoxia/reoxygenation injury by regulating nesfatin1.

Author

Jie Yu, Qingquan Li, Chang Guan, Ming Yuan, Ding Yu, Yaqin Wang, Mengyao Liu, and Ying Lv

Abstract

Background: The purpose of this study was to investigate the regulatory role of G coupled-protein receptor 43 (GPR43) during myocardial ischaemia/reperfusion (I/R) injury and to explore the relevant molecular mechanism. Materials and methods: AC16 hypoxia/reoxygenation (H/R) model was established to simulate I/R injury in vitro. Gain- and loss-of-function experiments were conducted to regulate GPR43 or nesfatin1 expression. Cell viability and apoptosis was examined adopting CCK-8 and TUNEL assays. Commercial kits were applied for detecting ROS and inflammatory cytokines. Quantitative real-time PCR (qRT-PCR) and western blotting were conducted to measure the expression level of critical genes and proteins. Results: GPR43 was downregulated in H/R-mediated AC16 cells. GPR43 over-expression or the GPR43 agonist greatly inhibited H/R-induced cell viability loss, cell apoptosis, and excessive production of ROS and pro-inflammatory cytokines in AC16 cardiomyocytes. Co-immunoprecipitation (Co-IP) assay identified an interaction between GPR43 and nesfatin1, and GPR43 could positively regulate nesfatin1. In addition, the protective role of GPR43 against H/R injury was partly abolished upon nesfatin1 knockdown. Eventually, GPR43 could inhibit H/R-stimulated JNK/P38 MAPK signalling in AC16 cells, which was also hindered by nesfatin1 knockdown. Conclusions: Our findings demonstrated the protective role of GPR43 against H/R-mediated cardiomyocytes injury through up-regulating nesfatin1, providing a novel target for the prevention and treatment of myocardial I/R injury. [ABSTRACT FROM AUTHOR]

Published
2024
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78. Prognostic Analysis on Different Tumor Sizes for 14634 Hepatocellular Carcinoma Patients

Author

Zilin Chen, He Zheng, Wen Zeng, Mengyao Liu, and Yong Chen

Subjects
Oncology
Abstract

Aim. This study investigated the effect of tumor size and other factors on the survival and prognosis of hepatocellular carcinoma (HCC). Methods. All HCC populations based on the National Cancer Institute’s SEER database to receive from 2010 to 2016 were employed in the study. Results. This study enrolled a total of 14,634 HCC. Among them, 1,686 patients had tumors ≤ 2 cm, 6,169 patients had tumors 2–5 cm, and 6,779 patients had tumors > 5 cm. The results using univariate analysis showed that all factors were significant prognostic factors for overall survival and specific survival. Patients with tumor size ≤ 2 cm were more likely to survive, while patients with tumor size > 5 cm had a lower survival rate. Patients who had surgery or surgery plus chemotherapy had a higher chance of survival in stages I-II, and the survival rate declined smoothly during the 80 months. The change rate of the mortality rate increased rapidly during the period of 1–12 cm; afterwards, the mortality rate’s HR was basically and smoothly maintained at a high level. Conclusions. Tumor size was positively correlated with the mortality rate of HCC. Survival rates were greater in patients with tumors ≤ 2 cm who underwent surgery or surgery plus chemotherapy. Patients with HCC in the early stage had a higher survival probability particularly when they had experienced surgery or surgery plus chemotherapy.

Published
2023

79. Research on kinematics of 3-dof connecting rod manipulator based on 5R kinematic chain

Author

LiHua Li, Hong Zhang, LingXia Hou, Jie Yuan, MengYao Liu, Xin Liu, HongYe Yan, and YuBo Jiang

Subjects
General Medicine
Abstract

Based on the flexibility of the neck manipulator of the bionic pelican fishing device, the demand for carrying capacity and the consideration of economic benefits, a 3-DOF connecting rod manipulator based on the 5R kinematic chain was designed, and the kinematic characteristics of the 5R five-bar mechanism in two-dimensional space and the mobility of the mechanism under the constraint of the bar length were studied. Through the application of matlab simulation, the movable range of the mechanism is obtained and the data analysis of the predetermined track is realized within the movable range, and the angle change curve chart required for the motor to achieve the predetermined track is obtained. The predetermined movement track is simulated by using the corresponding data and motion characteristics of the curve chart, which verifies the feasibility of achieving the target tracksetting within the movable range of the track.

Published
2023

80. Structural design and mechanics research of a bionic pelican floating object fishing device

Author

Jie Yuan, Hong Zhang, LingXia Hou, LiHua Li, MengYao Liu, Xin Liu, HongYe Yan, and YuBo Jiang

Subjects
General Medicine
Abstract

In order to meet the needs of surface floating objects fishing operations in small areas such as lakes and rivers, a fishing device is developed that can be used for high-intensity operations and is highly adaptable to the environment. In this paper, a water and land type bionic pelican surface floating object fishing device is developed based on the MeArm robotic arm combined with a three-degree-of-freedom linkage robotic arm using bionic principles. In order to meet the needs of the fishing function, the overall structure of the surface floating object fishing device was bionically designed by combining the large beak and flexible neck of the pelican, The innovative design of the mouth lower beak opening and closing mechanism, the lower beak gear rack lever slide mechanism, the mouth throat pouch bottom release mechanism and the neck structure are mainly carried out.The structural strength of the device under the most dangerous operating conditions was simulated using finite element analysis software for statics and dynamics simulation. The research results show that the structure of this design is reliable, and the experimental test of the prototype model verifies the validity and reliability of this design scheme, which provides the theoretical and experimental basis for the further development of the subsequent products.

Published
2023

85. Preparation and mechanism of lightweight wood fiber/poly(lactic acid) composites

Author

Baiwang, Wang, Zhongyu, Qi, Xiaojian, Chen, Ce, Sun, Wenrui, Yao, Hao, Zheng, Mengyao, Liu, Wenlong, Li, Aihang, Qin, Haiyan, Tan, and Yanhua, Zhang

Subjects
Construction Materials, Structural Biology, Polyesters, Temperature, General Medicine, Wood, Molecular Biology, Biochemistry
Abstract

The high density and poor thermal insulation of traditional wood-plastic composites limited the application in the field of building materials. In this paper, wood fiber (WF) and PLA were used as raw materials and azodicarbonamide was used as the foaming agent. Lightweight WF/PLA composites were prepared by the hot-pressing foaming method, aiming to obtain renewable, low-density material with high strength-to-weight ratio and thermal insulation performance. The results showed that after adding 20 % WF into PLA, the cell morphology was excellent and the cell size was uniform. The magnification reached the minimum value of 0.36 g/cm

Published
2022

86. The Energy-Saving Effect of E-Commerce Development—A Quasi-Natural Experiment in China

Author

Jiang, Mengyao Liu, Yan Hou, and Hongli

Subjects
national e-commerce demonstration cities (NEDC) policy, energy saving, low-energy transformation, difference-in-difference (DID) model
Abstract

This study provides a viable path to save energy by means of e-commerce development. Taking the national e-commerce demonstration cities (NEDC) pilots policy implemented in China as a quasi-natural experiment, based on the city panel data from 2006 to 2019, this study applies the multi-period difference-in-difference (DID) method to evaluate the effect of NEDC on energy saving in pilot cities. The empirical results suggest that the NEDC policy obviously contributes to energy conservation. The treated cities reduced energy consumption by 14.2% as a result of the implementation of NEDC, relative to the untreated cities. The conclusions remain valid after conducting robustness tests such as placebo test, instrumental variables regression, propensity score matching-difference-in-difference (PSM-DID), and synthetic difference-in-difference (SDID). The NEDC achieves energy-saving effects through technological innovation, industrial restructuring, and economic agglomeration. Furthermore, the heterogeneity analysis indicates that, in cities with high levels of human capital, well-developed information infrastructure, non-resource-based cities, and favorable business environments, the impact of NEDC on energy saving is more significant. Analysis of spatial effects shows that the implementation of NEDC has negative externalities, increasing energy consumption in the surrounding area. In the context of the digital economy, this paper presents new insights on the relationship between e-commerce and energy consumption and provides policy direction for countries looking for energy-saving solutions.

Published
2023
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88. Unique Electrochemiluminescent Behavior of two Quinolones, Enoxacin and Nadifloxacin, and their Sensing Application

Author

Xu Panpan, Yue Wang, Mengyao Liu, Xu Tingting, Sufan Wang, and Zhu Yinggui

Subjects
Renewable Energy, Sustainability and the Environment, Materials Chemistry, Electrochemistry, Condensed Matter Physics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials
Abstract

We looked at the electrochemiluminescence (ECL) signals of two quinolones, Enoxacin (Enox) and Nadifloxacin (Nadf), which were investigated in H3BO3-Na2B4O7 buffered solutions containing the co-reactant K2S2O8. Based on the fluorescence (FL) spectra, ECL spectra, and corresponding ECL experiments, a possible mechanism of the ECL reaction was proposed. The effect of experimental conditions on quinolone ECL behavior was studied and optimized, so we revealed the value of organic molecules as ECL luminophores. According to calculations, Nadifloxacin has a smaller LUMO-HOMO band gap than Enoxacin, making it more suitable for use as a luminophore. Furthermore, we discovered a quenching effect of lead ion (Pb2+) on the ECL signal of Nadifloxacin, and we focused on the Pb2+ quenching mechanism in this system and made reasonable guesses. We invented a novel technique for ECL detection of Pb2+ with high sensitivity and selectivity. This method demonstrates the potential application of ECL in pollution management.

Published
2023

89. Current potential of CH4 emission estimates using TROPOMI in the Middle East

Author

Mengyao Liu, Ronald van der A, Michiel van Weele, Henk Eskes, Pepijn Veefkind, Xin Zhang, Hanqing Kang, and Jieying Ding

Abstract

Methane (CH4) is the second most important greenhouse gas after CO2. The TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel 5 Precursor (S5-P) satellite measures CH4 at a high horizontal resolution of 7 × 7 km2, showing the capability on identifying and quantifying the sources at a local to regional scale. The Middle East is one of the strong CH4-emitting regions in the world. However, it is difficult to estimate the emissions here because of the uncertainties caused by bright surfaces and high aerosol loadings. Furthermore, several sources are located near the coast or in places with complex topography, where satellite observations are often of reduced quality. We use the product from the University of Bremen, WMF-DOAS XCH4 v1.8 product, which has good spatial coverage over the ocean and mountains, to estimate the emissions in the Middle East. The Aerosol Optical Depth (AOD) data from the MODIS/Aqua satellite instrument, which has a similar overpass time as TROPOMI, was adopted to filter potential unreliable XCH4 in the product.For the inversion, we use the divergence method of Liu et al., (2021), which has been proven to be a fast and efficient way to estimate CH4 emissions from satellite observations. We have improved our method by comparing the fluxes in different directions for better background corrections over areas with complicated topographies. The temporal filter was established to further filter false emissions caused by surface albedos. We derived CH4 emissions on a grid of 0.2° from 2018 to 2021 and compared them to the latest bottom-up inventory EDGAR v7.0 in the same years. We found significantly lower emissions than EDGAR for the locations that are mainly determined by observed gas-flaring from satellites. Apart from sources of oil/gas production, the emissions from livestock in Saudi Arabia's irrigation zones, which have been reported neither in EDGAR nor other previous studies, are identified and quantified by using our divergence method. Another unexpected finding is that emissions from landfills are fairly stable and strong in some cities like Tehran.

Published
2023

90. CD133-Targeted Hybrid Nanovesicles for Fluorescent/Ultrasonic Imaging-Guided HIFU Pancreatic Cancer Therapy

Author

Rui Wang, Yijing Yao, Yihui Gao, Mengyao Liu, Qian Yu, Xuejiao Song, Xiao Han, Dechao Niu, and Lixin Jiang

Subjects
Biomaterials, International Journal of Nanomedicine, Organic Chemistry, Drug Discovery, Biophysics, Pharmaceutical Science, Bioengineering, General Medicine
Abstract

Rui Wang,1,* Yijing Yao,1,2,* Yihui Gao,1 Mengyao Liu,1 Qian Yu,3 Xuejiao Song,4 Xiao Han,5 Dechao Niu,6 Lixin Jiang1,2 1Department of Ultrasound, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200127, People’s Republic of China; 2Shanghai Institute of Ultrasound in Medicine, Shanghai, 200233, People’s Republic of China; 3Department of Ultrasonography, Shanghai Jiao Tong University Affiliated No. 6 Hospital, Shanghai, 200233, People’s Republic of China; 4School of Physical and Mathematical Sciences, Nanjing Tech University (NanjingTech), Nanjing, 211800, People’s Republic of China; 5Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu, 215123, People’s Republic of China; 6Lab of Low-Dimensional Materials Chemistry, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, People’s Republic of China*These authors contributed equally to this workCorrespondence: Lixin Jiang; Dechao Niu, Email jinger_28@sina.com; dcniu@ecust.edu.cnBackground: Pancreatic cancer is regarded as one of the most lethal types of tumor in the world, and optional way to treat the tumor are urgently needed. Cancer stem cells (CSCs) play a key role in the occurrence and development of pancreatic tumors. CD133 is a specific antigen for targeting the pancreatic CSCs subpopulation. Previous studies have shown that CSC-targeted therapy is effective in inhibiting tumorigenesis and transmission. However, CD133 targeted therapy combined with HIFU for pancreatic cancer is absent.Purpose: To improve therapeutic efficiency and minimize side effects, we carry a potent combination of CSCs antibody with synergist by an effective and visualized delivery nanocarrier to pancreatic cancer.Materials and Methods: Multifunctional CD133-targeted nanovesicles (CD133-grafted Cy5.5/PFOB@P-HVs) with encapsulated perfluorooctyl bromide (PFOB) in a 3-mercaptopropyltrimethoxysilane (MPTMS) shell modified with poly ethylene glycol (PEG) and superficially modified with CD133 and Cy 5.5 were constructed following the prescribed order. The nanovesicles were characterized for the biological and chemical characteristics feature. We explored the specific targeting capacity in vitro and the therapeutic effect in vivo.Results: The in vitro targeting experiment and in vivo FL and ultrasonic experiments showed the aggregation of CD133-grafted Cy5.5/PFOB@P-HVs around CSCs. In vivo FL imaging experiments demonstrated that the nanovesicles assemble for the highest concentration in the tumor at 24 h after administration. Under HIFU irradiation, the synergistic efficacy of the combination of the CD133-targeting carrier and HIFU for tumor treatment was obvious.Conclusion: CD133-grafted Cy5.5/PFOB@P-HVs combined with HIFU irradiation could enhance the tumor treatment effect not only by improving the delivery of nanovesicles but also by enhancing the HIFU thermal and mechanical effects in the tumor microenvironment, which is a highly effective targeted therapy for treating pancreatic cancer.Keywords: multifunctional nanovesicles, cancer stem cells, high-intensity focused ultrasound, in vivo fluorescent imaging, ultrasonic imaging

Published
2023

91. Multi-omics blood atlas reveals unique features of immune and platelet responses to SARS-CoV-2 Omicron breakthrough infection

Author

Hong Wang, Cuicui Liu, Xiaowei Xie, Mingming Niu, Yingrui Wang, Xuelian Cheng, Biao Zhang, Dong Zhang, Mengyao Liu, Rui Sun, Yezi Ma, Shihui Ma, Huijun Wang, Guoqing Zhu, Yang Lu, Baiming Huang, Pei Su, Xiaoyuan Chen, Jingjing Zhao, Hongtao Wang, Long Shen, Lixia Fu, Qianqian Huang, Yang Yang, He Wang, Chunlong Wu, Weigang Ge, Chen Chen, Qianyu Huo, Qingping Wang, Ying Wang, Li Geng, Yan Xie, Yi Xie, Lijun Liu, Jianwei Qi, Huaiyong Chen, Junping Wu, Erlie Jiang, Wentao Jiang, Ximo Wang, Zhongyang Shen, Tiannan Guo, Jiaxi Zhou, Ping Zhu, and Tao Cheng

Subjects
Infectious Diseases, Immunology, Immunology and Allergy
Published
2023

95. POMINO-GEMS: A Research Product for Tropospheric NO2 Columns from Geostationary Environment Monitoring Spectrometer

Author

Yuhang Zhang, Jintai Lin, Jhoon Kim, Hanlim Lee, Junsung Park, Hyunkee Hong, Michel Van Roozendael, Francois Hendrick, Ting Wang, Pucai Wang, Qin He, Kai Qin, Yongjoo Choi, Yugo Kanaya, Jin Xu, Pinhua Xie, Xin Tian, Sanbao Zhang, Shanshan Wang, Robert Spurr, Lulu Chen, Hao Kong, and Mengyao Liu

Abstract

Nitrogen dioxide (NO2) is a major air pollutant. Tropospheric NO2 vertical column densities (VCDs) retrieved from sun-synchronous satellite instruments have provided abundant NO2 data for environmental studies, but such data are limited by insufficient temporal sampling (e.g., once a day). The Geostationary Environment Monitoring Spectrometer (GEMS) launched in February 2020 monitors NO2 at an unprecedented high temporal resolution. Here we present a research product for tropospheric NO2 VCDs, referred to as POMINO-GEMS. We develop a hybrid retrieval method combining GEMS and TROPOMI observations as well as GEOS-Chem simulations to generate hourly tropospheric NO2 slant column densities (SCDs). We then derive tropospheric NO2 air mass factors (AMFs) with explicit corrections for the anisotropy of surface reflectance and aerosol optical effects, through pixel-by-pixel radiative transfer calculations. Prerequisite cloud parameters are retrieved with the O2-O2 algorithm by using ancillary parameters consistent with those used in NO2 AMF calculations. Initial retrieval of POMINO-GEMS tropospheric NO2 VCDs for June–August 2021 reveals strong hotspot signals over megacities and distinctive diurnal variations over polluted and clean areas. POMINO-GEMS NO2 VCDs agree well with our POMINO-TROPOMI v1.2.2 product (R = 0.97, and NMB = 3.6 %) over Asia. Comparison with ground-based MAX-DOAS VCD data at nine sites shows a small bias of POMINO-GEMS (NMB = –15.7 %); however, the correlation for diurnal variation varies from -0.66 to 0.90, suggesting location-dependent performance. Surface NO2 concentrations estimated from POMINO-GEMS VCDs are consistent with measurements from the Ministry of Ecology and Environment of China at 855 sites (NMB = –24.1 %, and R = 0.95 for diurnal correlation averaged over all sites). POMINO-GEMS data will be made freely available for users to study the spatiotemporal variations, sources and impacts of NO2.

Published
2023

96. A survey and antibody test following the surge of SARS-CoV-2 Omicron infection in China

Author

Yichuan Yao, Yunru Yang, Qiqin Wu, Mengyao Liu, Wei Bao, Qiutong Wang, Meijun Cheng, Yunuo Chen, Yuan Cai, Mei Zhang, Jingxue Yao, Hongliang He, Changjiang Jin, Tian Xue, Changcheng Zheng, Tengchuan Jin, and Dali Tong

Abstract

The surge of SARS-CoV-2 Omicron infection in most Chinese residents at the end of 2022 provided a unique opportunity to understand how the immune system responds to the Omicron infection in a population with limited contact to prior SARS-CoV-2 variants. Moreover, whether the prototype SARS-CoV-2 booster vaccination could help induce the antibody against Omicron variants? Here, we tested the level of IgG, IgA, and IgM specific to the prototype SARS-CoV-2 spike RBD (Receptor Binding Domain) from the collected blood samples from 636 individuals. Sequential inoculation of different vaccines showed higher IgG levels after infection. As the antibody level against Omicron BA.5, BF.7, and XBB 1.5 of the individuals has highly positive correlation with the antibody level against prototype SARS-CoV2, the IgG level specific to the prototype SARS-CoV-2 spike RBD could also represent the IgG level against Omicron variants. Furthermore, the 4thbooster vaccination could induce a comparable antibody level against prototype, Omicron BA.5, BF.7, and XBB 1.5 variants in the patients with 2 or 3-dose vaccination and protect people from being infected. In conclusion, these data suggest that the prototype SARS-CoV-2 booster vaccination helps induce a high level of antibody against prototype, BA.5, BF.7, and XBB 1.5 variants after Omicron infection.

Published
2023

97. Muscle-Derived Beige Adipose Precursors Secrete Promyogenic Exosomes That Treat Rotator Cuff Muscle Degeneration in Mice and Are Identified in Humans by Single-Cell RNA Sequencing

Author

Michael R. Davies, Steven Garcia, Mengyao Liu, Hannah Chi, Hubert T. Kim, Robert L. Raffai, Xuhui Liu, and Brian T. Feeley

Subjects
Mice, Muscular Atrophy, Rotator Cuff, Sequence Analysis, RNA, Animals, Humans, Physical Therapy, Sports Therapy and Rehabilitation, Orthopedics and Sports Medicine, Fibroblasts, Exosomes, Fibrosis, Rotator Cuff Injuries
Abstract

Background: Muscle atrophy, fibrosis, and fatty infiltration are common to a variety of sports-related and degenerative conditions and are thought to be irreversible. Fibroadipogenic progenitors (FAPs) are multipotent resident muscle stem cells with the capacity to differentiate into fibrogenic as well as white and beige adipose tissue (BAT). FAPs that have assumed a BAT differentiation state (FAP-BAT) have proven efficacious in treating muscle degeneration in numerous injury models. Purpose: To characterize the subpopulation of murine FAPs with FAP-BAT activity, determine whether their promyogenic effect is mediated via exosomes, and analyze human FAPs for an analogous promyogenic exosome-rich subpopulation. Study Design: Controlled laboratory study. Methods: FAPs from UCP1 reporter mice were isolated via fluorescence-activated cell sorting and sorted according to the differential intensity of the UCP1 signal observed: negative for UCP1 (UCP1–), intermediate intensity (UCP1+), and high intensity (UCP1++). Bulk RNA sequencing was performed on UCP1–, UCP1+, and UCP1++ FAPs to evaluate distinct characteristics of each population. Exosomes were harvested from UCP1++ FAP-BAT exosomes (Exo-FB) as well as UCP1– non–FAP-BAT exosomes (Exo-nFB) cells using cushioned-density gradient ultracentrifugation and used to treat C2C12 cells and mouse embryonic fibroblasts in vitro, and the myotube fusion index was assessed. Exo-FB and Exo-nFB were then used to treat wild type C57B/L6J mice that had undergone a massive rotator cuff tear. At 6 weeks mice were sacrificed, and supraspinatus muscles were harvested and analyzed for muscle atrophy, fibrosis, fatty infiltration, and UCP1 expression. Single-cell RNA sequencing was then performed on FAPs isolated from human muscle that were treated with the beta-agonist formoterol or standard media to assess for the presence of a parallel promyogenic subpopulation of FAP-BAT cells in humans. Results: Flow cytometry analysis of sorted UCP1 reporter mouse FAPs revealed a trimodal distribution of UCP1 signal intensity, which correlated with 3 distinct transcriptomic profiles characterized with bulk RNA sequencing. UCP1++ cells were marked by high mitochondrial gene expression, BAT markers, and exosome surface makers; UCP1– cells were marked by fibrogenic markers; and UCP1+ cells were characterized differential enrichment of white adipose tissue markers. Exo-FB treatment of C2C12 cells resulted in robust myotube fusion, while treatment of mouse embryonic fibroblasts resulted in differentiation into myotubes. Treatment of cells with Exo-nFB resulted in poor myotube formation. Mice that were treated with Exo-FB at the time of rotator cuff injury demonstrated markedly reduced muscle atrophy and fatty infiltration as compared with treatment with Exo-nFB or phosphate-buffered saline. Single-cell RNA sequencing of human FAPs from the rotator cuff revealed 6 distinct subpopulations of human FAPs, with one subpopulation demonstrating the presence of UCP1+ beige adipocytes with a distinct profile of BAT, mitochondrial, and extracellular vesicle–associated markers. Conclusion: FAP-BAT cells form a subpopulation of FAPs with upregulated beige gene expression and exosome production that mediate promyogenic effects in vitro and in vivo, and they are present as a transcriptomically similar subpopulation of FAPs in humans. Clinical Relevance: FAP-BAT cells and their exosomes represent a potential therapeutic avenue for treating rotator cuff muscle degeneration.

Published
2022

100. A novel mouse model of hindlimb joint contracture with 3D‐printed casts

Author

Laura K. Moore, Carlin S. Lee, Obiajulu Agha, Mengyao Liu, He Zhang, Alan B. C. Dang, Alexis Dang, Xuhui Liu, and Brian T. Feeley

Subjects
Range of Motion, Contracture, Knee Joint, Clinical Sciences, Joint Dislocations, Biomedical Engineering, stiff joint, Article, Mice, arthrofibrosis, Animals, Orthopedics and Sports Medicine, Range of Motion, Articular, Gait, mouse, Mammals, Animal, Human Movement and Sports Sciences, Hindlimb, Disease Models, Animal, Orthopedics, Musculoskeletal, Printing, Three-Dimensional, Disease Models, Three-Dimensional, gait analysis, Printing, Female, Joint Diseases, Ankle Joint, Articular
Abstract

Stiff joints formed after trauma, surgery or immobilization are frustrating for surgeons, therapists and patients alike. Unfortunately, the study of contracture is limited by available animal model systems, which focus on the utilization of larger mammals and joint trauma. Here we describe a novel mouse-based model system for the generation of joint contracture using 3D-printed clamshell casts. With this model system we are able to generate both reversible and irreversible contractures of the knee and ankle. Four- or 8-month-old female mice were casted for either 2 or 3 weeks before liberation. All groups formed measurable contractures of the knee and ankle. Younger mice immobilized for less time formed reversible contractures of the knee and ankle. We were able to generate irreversible contracture with either longer immobilization time or the utilization of older mice. The contracture formation translated into differences in gait, which were detectable using the DigiGait(®) analysis system. This novel model system provides a higher throughput, lower cost and more powerful tool in studying the molecular and cellular mechanisms considering the large existing pool of transgenic/knockout murine strains.

Published
2022

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