Performance analysis of the tight combination of GPS, BDS, GALILEO, and QzsS mixed frequencies signals

With the gradual development and modernization of satellite navigation systems,using observation information from multi-GNss has become one of the hot-spot issues in recent years.Multi-system loose combinations form double-difference observation equations within their respective systems,and the positioning effect is improved.However,the interchangeability and compatible interoperability between global navigation satellite systems(GNSS)cannot be truly realized.At the same time,when the number of visible satellites decreases abruptly,the positioning performance deteriorates sharply.This paper focuses on the GNsS multi-system tight combination relative positioning technique,gives a mathe-matical model of multi-system tight combination relative positioning considering differential inter-system bias(DISB),and analyzes the time-varying characteristics of DISB at overlapping and non-overlapping frequencies among GPS/Galileo,GPS/BDS,and GPS/QZSS in terms of receiver brand,tem-perature,and receiver restart.The GNsS tight combination relative positioning performance is verified by static data from Curtin University and dynamic data measured at Taiyuan University of Technology.The results show that compared with loose combination,the ambiguity-fixed rate increases from 62.18%to 97.60%for static data and from 74.97%to 99.53%for dynamic data when the elevation mask angle is 50°,resulting in a significant improvement in positioning performance.

Matrix stiffening promotes chondrocyte senescence and the osteoarthritis development through downregulating HDAC3

Extracellular matrix(ECM)stiffening is a typical characteristic of cartilage aging,which is a quintessential feature of knee osteoarthritis(KOA).However,little is known about how ECM stiffening affects chondrocytes and other molecules downstream.This study mimicked the physiological and pathological stiffness of human cartilage using polydimethylsiloxane(PDMS)substrates.It demonstrated that epigenetic Parkin regulation by histone deacetylase 3(HDAC3)represents a new mechanosensitive mechanism by which the stiffness matrix affected chondrocyte physiology.We found that ECM stiffening accelerated cultured chondrocyte senescence in vitro,while the stiffness ECM downregulated HDAC3,prompting Parkin acetylation to activate excessive mitophagy and accelerating chondrocyte senescence and osteoarthritis(OA)in mice.Contrarily,intra-articular injection with an HDAC3-expressing adeno-associated virus restored the young phenotype of the aged chondrocytes stimulated by ECM stiffening and alleviated OA in mice.The findings indicated that changes in the mechanical ECM properties initiated pathogenic mechanotransduction signals,promoted the Parkin acetylation and hyperactivated mitophagy,and damaged chondrocyte health.These results may provide new insights into chondrocyte regulation by the mechanical properties of ECM,suggesting that the modification of the physical ECM properties may be a potential OA treatment strategy.

Ginsenoside Rb1 attenuates activated microglia-induced neuronal damage

The microglia-mediated inflammatory reaction promotes neuronal damage under cerebral isch- emia/hypoxia conditions. We therefore speculated that inhibition of hypoxia-induced microglial activation may alleviate neuronal damage. To test this hypothesis, we co-cultured ginsenoside Rb 1, an active component of ginseng, and cortical neurons. Ginsenoside Rb l protected neuronal morphology and structure in a single hypoxic culture system and in a hypoxic co-culture system with microglia, and reduced neuronal apoptosis and caspase-3 production. The protective effect was observable prior to placing in co-culture. Additionally, ginsenoside Rbl inhibited levels of tumor necrosis factor-a in a co-culture system containing activated N9 microglial cells. Ginse-noside Rbl also significantly decreased nitric oxide and superoxide production induced by N9 microglia. Our findings indicate that ginsenoside Rbl attenuates damage to cerebral cortex neu-rons by downregulation of nitric oxide, superoxide, and tumor necrosis factor-a expression in hypoxia-activated microglia.

Chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor promotes sciatic nerve repair

A chemically extracted acellular allogeneic nerve graft can reduce postoperative immune rejection, similar to an autologous nerve graft, and can guide neural regeneration. However, it remains poorly understood whether a chemically extracted acellular allogeneic nerve graft combined with neurotrophic factors provides a good local environment for neural regeneration. This study investigated the repair of injured rat sciatic nerve using a chemically extracted acellular allogeneic nerve graft combined with ciliary neurotrophic factor. An autologous nerve anastomosis group and a chemical acellular allogeneic nerve bridging group were prepared as controls. At 8 weeks after repair, sciatic functional index, evoked potential amplitude of the soleus muscle, triceps wet weight recovery rate, total number of myelinated nerve fibers and myelin sheath thickness were measured. For these indices, values in the three groups showed the autologous nerve anastomosis group 〉 chemically extracted acellular nerve graft ＋ ciliary neurotrophic factor group 〉 chemical acellular allogeneic nerve bridging group. These results suggest that chemically extracted acellular nerve grafts combined with ciliary neurotrophic factor can repair sciatic nerve defects, and that this repair is inferior to autologous nerve anastomosis, but superior to chemically extracted acellular allogeneic nerve bridging alone.

Combining acellular nerve allografts with brainderived neurotrophic factor transfected bone marrow mesenchymal stem cells restores sciatic nerve injury better than either intervention alone

In this study, we chemically extracted acellular nerve allografts from bilateral sciatic nerves, and repaired 10-mm sciatic nerve defects in rats using these grafts and brain-derived neurotrophic factor transfected bone marrow mesenchymal stem cells. Experiments were performed in three groups： the acellular nerve allograft bridging group, acellular nerve allograft ＋ bone marrow mesenchymal stem cells group, and the acellular nerve allograft ＋ brain-derived neurotrophic factor transfected bone marrow mesenchyrnal stem cells group. Results showed that at 8 weeks after bridging, sciatic functional index, triceps wet weight recovery rate, myelin thickness, and number of myelinated nerve fibers were significantly changed in the three groups. Variations were the largest in the acellular nerve allograft ＋ brain-derived neurotrophic factor transfected bone marrow mesenchymal stem cells group compared with the other two groups. Experimental findings suggest that chemically extracted acellular nerve allograft combined nerve factor and mesenchymal stem cells can promote the restoration of sciatic nerve defects. The repair effect seen is better than the single application of acellular nerve allograft or acellular nerve allograft combined mesenchymal stem cell transplantation.

A Meta-Analysis of Lymphatic Vessel Invasion Correlated with Pathologic Factors in Invasive Breast Cancer

Objectives: The invasive breast cancer is divided into four clinical subtypes: Luminal A-like, Luminal B-like, HER-2 positive, and triple-negative according to the expression status of estrogen receptor (ER), progesterone receptor(PR), human epidermal growth factor receptor-2 (HER-2) and Ki-67. The prognosis and treatment strategy vary with subtypes. The current studies have reported the relation between lymphatic vessel invasion (LVI) and the expression status of ER, PR, HER-2, Ki-67 in invasive breast cancer, but the results were debatable. So the meta-analysis was conducted to confirm the relation between LVI and the four factors. Methods: Literature was searched by entering the terms: breast AND (neoplasm OR cancer OR carcinoma) AND (lymphovascular OR “lymph vessel” OR “lymphatic vessel” invasion OR carcinoma embolus) AND (ER OR estrogen receptor OR PR OR progesterone receptor OR HER-2 OR human epidermal growth factor receptor-2 OR Ki-67 OR clinicopathological) in Pubmed. The merged odds ratio (OR) and 95% confidence interval (CI) were estimated using fixed-effect model. Review Manager 5.2 was used to analysis the relation between LVI and the expression status of ER, PR, HER-2, Ki-67 in invasive breast cancer respectively. The fail-safe number was used to estimate publication bias. Results: The analysis included 5 studies, LVI positive rate was significant lower in ER positive, PR positive, HER-2 negative, low Ki-67 expression group statistically. The OR and 95% CI were 0.6(0.44 - 0.81), 0.64(0.43 - 0.95), 1.52(1.03 - 2.24), 5.29(1.53 - 18.35) respectively.Conclusions:?LVI was significantly correlated with the expression status of ER, PR, HER-2 and Ki-67 in invasive breast cancer. Furthermore, LVI was consistent with poor prognostic expression status of the four factors.

An Efficient Quantum Key Distribution Protocol with Dense Coding on Single Photons

Combined with the dense coding mechanism and the bias-BB84 protocol,an efficient quantum key distribution protocol with dense coding on single photons(QDKD-SP)is proposed.Compared with the BB84 or bias-BB84 protocols based on single photons,our QDKD-SP protocol has a higher capacity without increasing the difficulty of its experiment implementation as each correlated photon can carry two bits of useful information.Compared with the quantum dense key distribution(QDKD)protocol based on entangled states,our protocol is more feasible as the preparation and the measurement of a single-photon quantum state is not difficult with current technology.In addition,our QDKD-SP protocol is theoretically proved to be secure against the intercept-resend attack.

Post-marketing safety monitoring of Shenqifuzheng injection: a solution made of Dangshen(Radix Codonopsis)and Huangqi(Radix Astragali Mongolici)

OBJECTIVE:Toidentify the potential risk factors associated with Shenqifuzheng injection(SFI), a solution made of Dangshen(Radix Codonopsis) and Huangqi(Radix Astragali Mongolici), for the timely provision of information to regulatory authorities.METHODS: A comprehensive analysis of the production process, quality standards, pharmacology,post-marketing clinical studies, and safety evaluation using the primary literature of adverse reactions(ADR), case analyses, and systematic reviews,intensive hospital safety monitoring of post-marketing drugs, and data provided by the hospital in-formationsystem(HIS).RESULTS: Sub-acute toxicity tests suggesting that a dose of 15 mL/kg(concentrated solution) had specific biological effects, whereas a smaller dose engendered no observable effects. Long-term toxicity testing in domestic rabbits showed that after SFI was administered for 90 days, the animals in each dosing group showed no chronic toxic reactions. Among 20 100 cases observed, the incidence of an ADR was 1.85‰. From March to November 2013,of the leading institutions and 22 sub-centers involved in the post-marketing clinical safety intensive hospital monitoring, 21 units completed 8484 cases of monitoring, and reported 23 cases of adverse reactions. No damage to renal function was found using SFI ata dosageanda treatment course larger and longer than that recommended for the adjuvant treatment of tumors. This could reduce the mortality rate of admitted patients based on the analysis of the data provided by the HIS. A total of 16 clinical case reports of adverse reactions related to SFI in 1999-2012 were obtained through literature retrieval. These reports contained information concerning 17 cases, with adverse reaction symptoms including thrombocytopenia, rash,chills,feeling cold,palpitation,dyspnea,edemaofa lower extremity, palpebral edema, and superficial vein in flammation,among others.CONCLUSION: This study introduces "get full access" to the flow of information on medicines regarding their ADR incidence rate and characteristics and factors.It supports the safety of SFI for clinical, research, and production uses based on objec-tive, reliable, and scientific information to provide safe medication.

北京地区四个豹猫亚种群肠道菌群的组成

野生动物的肠道微生物组成受食物资源和遗传属性的影响较大,为了解北京地区小型猫科动物肠道菌群组成特点及其影响因素,本研究通过扩增细菌16S rRNA的V3‒V4高变区进行高通量测序,对云蒙山、云峰山、松山、百花山4个区域的豹猫(Prionailurus bengalensis)亚种群进行肠道菌群组成分析。结果表明,在门水平上,豹猫的肠道优势菌群主要由厚壁菌门(相对多度52.40%)、变形菌门(25.18%)、放线菌门(9.07%)、拟杆菌门(8.17%)和梭杆菌门(4.74%)组成。在属水平上,相对多度最高的前5个属为假单胞菌属(Pseudomonas,13.37%)、布劳特氏菌属(Blautia,11.20%)、梭菌属(Clostridium_sensu_stricto_1,9.10%)、消化梭菌属(Peptoclostridium,8.62%)、乳杆菌属(Lactobacillus,6.08%),共约占总多度的50%。各区域豹猫亚种群的肠道菌群β多样性不存在显著差异,松山区域的ACE指数和Chao 1指数与云蒙山和云峰山存在显著差异。鉴于松山亚种群的遗传结构与其他区域有所不同,而4个区域的气候类型和豹猫食物构成相似性高,推测该亚种群的肠道菌群主要受遗传结构分化的影响,对此还需进一步研究。

Study on the promotion of lymphocytes in patients with COVID-19 by broad-spectrum chemokine receptor inhibitor vMIP-Ⅱ and its Mechanism of signal transmission in vitro

Dear Editor,COVID-19 cases showed a significant decrease in the number of peripheral CD4^(+) and CD8^(+)T cells accompanied by overactivation of cells.1 HHV8-derived viral macrophage inflammatory protein vMIP-Ⅱ is the only broad-spectrum chemokine receptor inhibitor that binds to three subtribes of chemokine receptors,which can significantly increase the specific cell immune response in infected organisms and have an effect of reducing plasma viral load on the viremia period.24 Here we report the effect of vMIP-Ⅱ in COVID-19.

Theoretical analysis of a quasi-Bessel beam for laser ablation

A quasi-Bessel beam(QBB)is suitable for laser ablation because it possesses a micrometer-sized focal spot and long depth of focus simultaneously.In this paper,the characterizations of QBBs formed by the ideal axicon and oblate-tip axicon are described.Strong on-axis intensity oscillations occur due to interference between the QBB and the refracted beam by the oblate tip.Using the axicon for laser ablation was theoretically investigated.Simple analytical formulas can be used to predict the required laser parameters,including the laser pulse energy,the generated fluence distributions,and the beam diameters.

FAM89A and IFI44L for distinguishing between viral and bacterial infections in children with febrile illness

Importance: The current lack of reliable rapid tests for distinguishing between bacterial and viral infections has contributed to antibiotic misuse.Objective: This study aimed to develop a novel biomarker assay that integratesFAM89A andIFI44L measurements to assist in differentiating between bacterial and viral infections.Methods: This prospective study recruited children with febrile illness from two hospitals between July 1, 2018, and June 30, 2019. A panel of three experienced pediatricians performed reference standard diagnoses of all patients (i.e., bacterial or viral infection) using available clinical and laboratory data, including a 28-day follow-up assessment. Assay operators were blinded to the reference standard diagnoses. The expression levels ofFAM89A andIFI44L were determined by quantitative real-time polymerase chain reaction assessment.Results: Of 133 potentially eligible patients with suspected bacterial or viral infection, 35 were excluded after the application of exclusion criteria. The resulting cohort included 98 patients: 59 with viral diagnoses and 39 with bacterial diagnoses. The areas under the curve (AUCs) of diagnoses usingFAM89A andIFI44L were 0.694 [95% confidence interval (CI): 0.583-0.804] and 0.751 (95%CI: 0.651-0.851), respectively. The disease risk score (DRS) [log2(FAM89A expression) - log2(IFI44L expression)] signature achieved an improved area under the receiver operating characteristic curve (AUC, 0.825;95%CI: 0.735-0.915), compared with the AUC generated from individual host RNA. A combination of the DRS and the C-reactive protein (CRP) level achieved an AUC of 0.896 (95%CI: 0.825-0.966). Optimal cutoffs for the DRS and CRP level were -3.18 and 19.80 mg/L, respectively.Interpretation: The DRS was significantly more accurate than the CRP level in distinguishing between bacterial and viral infections;the combination of these two parameters exhibited greater sensitivity and specificity. This study provides information that could be useful for the clinical application ofFAM89A andIFI44L in terms of distinguishing between viral and bacterial infections.

Simultaneous acquisition of CT angiography and whole brain CT perfusion images by using multiphase dynamic helical scan on 16 MDCT

We implemented a new protocol—multiphase dynamic helical scan to acquire CT angiography(CTA)and whole brain CT perfusion(CTP)images simulta-neously with single scan on 16 multidetector CT(MDCT).A total of 90 patients who were randomly assigned into 3 groups were included in our study.Each group underwent CT scan by using the new protocol,traditional CTA and CTP protocol,respectively.The image quality of CTA,the CTP parameter values and the X-ray doses were measured and compared between the new protocol and the traditional protocols.There was no statistically significant difference in the CTA image quality between the above methods(P=0.55).For CTP parameters,the new protocol tended to overestimate the blood volume(BV)and bloodflow(BF)value,and to underestimate the mean transit time(MTT)value compared with the traditional method.However,there was no statistically significant difference in BV,BF,and MTT value between the two methods except permeability surface(PS)(P>0.05).The volume CT dose index(CTDIvol)and dose length product(DLP)of our protocol were lower than the traditional one.The new protocol can obtain valuable diagnostic information in a shorter time without significant compromise in image quality.In addition,it reduces the radiation dose as well as contrast medium usage on the patient.

3D Printing-Electrospinning Hybrid Nanofibrous Scaffold as LEGO-Like Bricks for Modular Assembling Skeletal Muscle-on-a-Chip Functional Platform

Organ-on-a-chip stands as a pivotal platform for skeletal muscle research while constructing 3D skeletal muscle tissues that possess both macroscopic and microscopic structures remains a considerable challenge.This study draws inspiration from LEGO-like assembly,employing a modular approach to construct muscle tissue that integrates biomimetic macroscopic and microscopic structures.Modular LEGO-like hybrid nanofibrous scaffold bricks were fabricated by the combination of 3D printing and electrospinning techniques.Skeletal muscle cells cultured on these modular scaffold bricks exhibited a highly orientated nanofibrous structure.A variety of construction of skeletal muscle tissues further enabled development by various assembling processes.Moreover,skeletal muscle-on-a-chip(SMoC)was further assembled as a functional platform for electrical or perfusion stimuli investigation.The electrical stimulus was conveniently applied and tuned in such a SMoC platform to significantly enhance the differentiation of skeletal muscle tissues.Additionally,the effect of perfusion stimulation on skeletal muscle vascularization within the SMoC platform was also demonstrated.These findings highlight the potential of these assembled SMoCs as functional ex vivo platforms for skeletal tissue engineering and drug research applications,and such a LEGO-like assembly strategy could also be applied to the other engineering organ-on-chips fabrication,which facilitates the development of bionic functional platforms for various biomedical research applications.