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Recycled steel fiber (RSF)-reinforced concrete is not only an innovative research trend in the field of civil engineering materials, but also a new type of civil engineering composites under the trend of low-carbon development. This article deals with the experimental study of applying waste steel fibers to form recycled steel fiber concrete (RSFC). The main materials in this study are RSF, coarse and fine aggregate, fly ash, silica fume, and water reducer agent formed by machining surplus materials as the main materials. Three types of concrete were prepared. They were normal concrete, primary steel fiber concrete (PSFC), and RSFC with six different volume contents. The slump and air content of the three types of concrete are compared and analyzed. Then, the effects of the volume content of RSF on the cube compressive strength, splitting tensile strength, flexural strength, and axial compressive strength of RSFC are studied. Finally, the toughness of RSFC is discussed. The test results show that with the increase in the volume content of RSF, the slump of RSFC is significantly reduced, the compressive strength, tensile strength, and flexural strength are enhanced, the increase in tensile strength and flexural strength is significantly higher than the cube compressive strength, and the RSF has an obvious inhibitory effect on the development of concrete cracks which can obviously enhance the ductility and toughness of the concrete.

We report the high-resolution radio observations of eight Fanaroff-Riley type 0 radio galaxies (FR 0s), selected from the published FR 0 sample. These observations were carried out with the Very Long Baseline Array (VLBA) and European VLBI Network (EVN) at frequencies of 5 and 8 GHz with a highest resolution of 0.6 mas. All eight sources show compact structures on projected physical sizes of 0.3-10 parsec. Six sources show a two-sided structure and two sources show a one-sided jet structure. J1025+1022 shows an X-shaped jet structure, which could result from a reorientation of the jet axis due to a restart of the central engine or a projection of a highly curved inner jet, but more studies are needed to examine these scenarios. Proper motions for 22 jet components of the eight sources are determined to be between -0.08 c and 0.51 c. Although most of the sources exhibit flat spectra, other observed characteristics, such as, low-amplitude flux density variations, low jet proper motion speeds, and symmetric two-sided jet structures, tend to support that the pc-scale FR 0 jets are mildly relativistic with lower bulk Lorentz factors and larger viewing angles., Comment: 15 pages, 2 figures, accepted for publication in MNRAS

Sustained release vaccine carriers can facilitate an increased interaction time between the antigen and immune system to strengthen immune responses, but their promotion on adaptive immune responses, especially cellular immunity, are still unfavorable. Herein, we report a sustained antigen delivery vector, which carries abundant antigens, a nucleic acid adjuvant and pathogen-associated molecular patterns to simulate a natural pathogen to reinforce immune responses. Specifically, murine colorectal cancer cells MC38 lysate and Toll-like receptor 9 agonist CpG are loaded into yeast derived β-glucan particles (GPs). After vaccination, these particles can form a vaccine depot that continuously release the antigen similar to the traditional aluminum hydroxide gel, but recruit more immune cells and induce more cytokine secretion at the injection site. Stronger antibody responses, Th1 and Th17 biased cellular immunity and immune memory are achieved compared with aluminum hydroxide gel. More importantly, treatment with these particles significantly suppress tumor growth in a therapeutic tumor model. This work shed light on the efficacy of combining sustained antigen release with pathogen-mimicking manner in vaccine design.

Human epidermal growth factor receptor2 (HER2) overexpression/amplification is associated with high malignancy, rapid disease progression and poor overall survival in breast cancer. The application of anti-HER2 drugs has greatly improved the survival of patients with HER2-positive breast cancer, but drug resistance issues affect the long-term efficacy. The HER2 mutation is considered to be one of the reasons for resistance to anti-HER2 therapy, and there is currently no standard treatment. We report for the first time the detection of HER2 amplification with R157W mutation by second-generation sequencing (NGS) in a 57-year-old hormone receptor-negative, HER2-positive woman with advanced breast cancer who was resistant to multi-line anti-HER2 therapies. She subsequently received pyrotinib combined with capecitabine treatment and achieved partial response. The small-molecule pan-HER family irreversible inhibitor pyrotinib combined with capecitabine has shown a promising effect in the treatment of HER2 mutation-induced resistance, but the molecular mechanism and efficacy need to be further verified.

Hetero-elements doping is an effective way to modify the composition and nanostructure of metal oxides. These modifications could lead to changes in physical and chemical properties correspondingly. In this study, Fe-doped MgO nanoparticles (NPs) were synthesized by simple calcination method in air. The antibacterial activity of MgO NPs against Escherichia coli (E. coli, ATCC 25922) was significantly improved as shown by the bactericidal efficacy test results. According to X-ray diffraction (XRD) results, Fe was successfully doped into MgO lattice and mainly adopted interstitial doping. The Fe-doping led to increased oxygen vacancies and OA content (from 13.5% to 41.3%) on MgO surface, which may have facilitated the reactive oxygen species (ROS) generation and bacteria death. The wrinkled and sunken E. coli surface after contact with Fe-doped MgO NPs also confirmed the existence of adsorption damage mechanism. Thus, the antibacterial activity enhancement against E. coli was originated from the synergistic effect of increased ROS concentration and the interaction with Fe-doped MgO NPs.

Acid treatment is one of the effective methods that directly modifies surface physical and chemical properties of inorganic materials, which improves the materials' application potential. In this work, the surface modified MgO nanoparticles (NPs) were prepared through a facile acid-treatment method at room temperature. Compared with the untreated sample, the surviving Escherichia coli (E. coli, ATCC 25922) colonies of the modified MgO NPs decreased from 120 to 54 (102 CFU mL−1). The enhanced antibacterial activity may be due to the improvement of oxygen vacancies and absorbed oxygen (OA) content (from 41.6% to 63.1%) as confirmed by electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS). These findings revealed that the acid treatment method could directly modify the surface of MgO NPs to expose more oxygen vacancies, which would promote reactive oxygen species (ROS) generation. The membrane tube and single ROS scavenging results further indicated that the increased antibacterial ability originated from the synergetic effect of ROS damage (especially ˙O2−) and direct contact between H-MgO NPs and E. coli.

ObjectiveVitreoretinal lymphoma (VRL) is a rare but aggressive masquerade syndrome, with challenging diagnosis. Since the tumor-related genetic mutation analysis based on cell-free DNA (cfDNA) are underutilized in ocular oncology, we aimed to test the VRL diagnostic value of cfDNA genetic mutation analysis using intraocular fluid (IOF) samples and to identify its mutation profile.SubjectsSeventeen VRL and 6 uveitis patients from Zhongshan Ophthalmic Centre were selected as training group, and 5 VRL and 5 uveitis patients from Beijing Chaoyang Hospital were selected as validation group.MethodsThe medical records and genetic mutation analysis using a panel containing 446 tumor-related genes of included patients were retrospectively reviewed. We analyzed the mutation profile, and identified the molecular subtypes and subdivisions of B-cell differentiation pathways of our VRL patients.Main outcomesThe cfDNA genetic mutations detected in IOF.ResultsThe VRL patients from the training group exhibited abundant cfDNA mutations in IOF (sensitivity 100%), while only 2 out of 6 uveitis patients were positive (specificity 67%). However, the number of cfDNA mutations observed in VRL patients was higher than that of uveitis patients. The mutation-positive patients from the validation group were diagnosed with VRL while the mutation-negative patients were diagnosed with uveitis (sensitivity and specificity 100%). VRL patients were characterized by the high mutation frequencies of PIM1, MYD88, CD79B, ETV6, and IRF4.ConclusionsThe genetic mutation analysis of IOF samples represents a feasible diagnosis method for VRL with 100% sensitivity; it could track genetic profiles; thus, revealing genetic heterogeneity of VRL.Statement of translational relevanceThe anterior chamber paracentesis and diagnostic vitrectomy have been widely used in ophthalmic clinics, as they are less invasive sampling techniques for liquid biopsies. Genetic mutation analysis of cell-free DNA (cfDNA) of intraocular fluid using a panel containing 446 targeted genes represents a feasible method with 100% sensitivity for vitreoretinal lymphoma (VRL) diagnosis. Furthermore, it can address cytological diagnostic issues including limited cellular yield, cell lysis associated with the fragile nature of lymphoma cells, and high risks associated with retinal tissue biopsies. Furthermore, it allows for genetic profile tracking, having the potential to reveal genetic heterogeneity and molecular characteristics of VRL in the future

AT2019wey is a transient discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey in December of 2019. Follow-up optical, radio, and X-ray observations led to classification of this source as a Galactic black hole X-ray binary. We carried out one-epoch 6.7 GHz European VLBI (Very Long Baseline Interferometry) Network (EVN) and two-epoch multiple-frequency (1.6, 4.5, 6.7 GHz) Very Long Baseline Array (VLBA) observations within a year after its discovery. These observations reveal a fading and flat-spectrum radio source with no discernible motion. These features suggest the detection of a compact jet. The source appears resolved at milliarcsecond scales, and the source angular size versus frequency trend is consistent with scatter broadening. This allows us to constrain the lower limit of the source distance to 6 kpc, if the scattering medium is in a Galactic spiral arm. For a source location larger than 3 kpc, the estimated upper limit of the peculiar velocity, relative to the local standard of rest, suggests the asymmetric natal kick may have occurred during the black hole formation stage., Comment: pages 9, 4 figures, A&A accepted for publication

Metal-organic frameworks (MOFs) have high surface area, tunable pore size, and high loading capacity, making them promising for drug delivery. However, their synthesis requires organic solvents, high temperature and high pressure that are incompatible with biomacromolecules. Zeolitic imidazole frameworks (ZIF-8) which forms through coordination between zinc ions and 2-methylimidazole (MeIM) have emerged as an advanced functional material for drug delivery due to its unique features such as high loading and pH-sensitive degradation. In this study, we took advantage of a natural biomineralization process to create aluminum-containing nanoZIF-8 particles for antigen delivery. Without organic solvents or stabilizing agent, nanoparticles (ZANPs) were synthesized by a mild and facile method with aluminum, model antigen ovalbumin (OVA) and ZIF-8 integrated. A high antigen loading capacity (%) of 30.6% and a pH dependent antigen release were achieved. A Toll-like receptor 9 agonist cytosine-phosphate-guanine oligodeoxynucleotides (CpG) was adsorbed on the surface of ZANPs (hereafter CpG/ZANPs) to boost the immune response. After subcutaneous injection in vivo, CpG/ZANPs targeted lymph nodes (LNs), where their cargo was efficiently internalized by LN-resident antigen-presenting cells (APCs). ZANPs decomposition in lysosomes released antigen into the cytoplasm and enhanced cross-presentation. Moreover, CpG/ZANPs induced strong antigen-specific humoral and cytotoxic T lymphocyte responses that significantly inhibited the growth of EG7-OVA tumors while showing minimal cytotoxicity. We demonstrate that ZANPs may be a safe and effective vehicle for the development of cancer vaccines.

Super-critical accretion is the most powerful episode in nursing the black hole growth and works in several types of objects. Given that the inverse correlation between radio loudness and Eddington ratio, the super-Eddington active galactic nuclei (AGNs) hold the extremely radio-quiet end of AGNs. Regarding the existence of jet in super-Eddington or radio-quiet AGNs, it’s still unclear. Years of studies indicate nearly all types of super-Eddington accreting systems can launch a jet with one exception: no clear evidence to show jet in super-Eddington AGNs. Observations and theoretical works suggest that super-Eddington accretion can drive high-speed wind-like outflows, therefore produce radio emission through synchrotron (shocked wind) and bremsstrahlung mechanisms. However, such a radio-emitting wind has not been observed in super-Eddington systems except for the Galactic micro-quasar SS 433. In principle, high resolution very long baseline interferometry (VLBI) observation can directly map the inner structure of super-Eddington AGNs. Here, we report the discovery of the coupling of jet and radio-emitting winds in a nearby super-Eddington AGN, I Zw1. Its parsec-scale jet exhibits a wiggling, we interpret this as a jet precession. All the features make IZw1 act as a scaled-up version of SS 433. The observations favour that jet can be launched in extremely radio-quiet AGNs and ubiquitous in super-Eddington accreting systems. The jet wiggling or precession can produce a large aperture-angle shock, which emphasises the jet’s contribution to gas feedback. As the jet precession was also discovered in other super-Eddington systems such as SS 433 and V404 Cygni, it is possible that there is a correlation with each other.

Hetero-elements doping is an effective way to modify the composition and nanostructure of metal oxides. These modifications could lead to changes in physical and chemical properties correspondingly. In this study, Fe-doped MgO nanoparticles (NPs) were synthesized by simple calcination method in air. The antibacterial activity of MgO NPs against

Structure of SARS-CoV-2 spike in complex with ACE2 reveals the mechanism of ACE2 induced spike conformational transitions., The recent outbreaks of SARS-CoV-2 pose a global health emergency. The SARS-CoV-2 trimeric spike (S) glycoprotein interacts with the human ACE2 receptor to mediate viral entry into host cells. We report the cryo-EM structures of a tightly closed SARS-CoV-2 S trimer with packed fusion peptide and an ACE2-bound S trimer at 2.7- and 3.8-Å resolution, respectively. Accompanying ACE2 binding to the up receptor-binding domain (RBD), the associated ACE2-RBD exhibits continuous swing motions. Notably, the SARS-CoV-2 S trimer appears much more sensitive to the ACE2 receptor than the SARS-CoV S trimer regarding receptor-triggered transformation from the closed prefusion state to the fusion-prone open state, potentially contributing to the superior infectivity of SARS-CoV-2. We defined the RBD T470-T478 loop and Y505 as viral determinants for specific recognition of SARS-CoV-2 RBD by ACE2. Our findings depict the mechanism of ACE2-induced S trimer conformational transitions from the ground prefusion state toward the postfusion state, facilitating development of anti–SARS-CoV-2 vaccines and therapeutics.

The strength of humoral and cellular immune responses is regulated by the properties of mesoporous silica., Subunit vaccines generally proceed through a 4-step in vivo cascade—the DUMP cascade—to generate potent cell-mediated immune responses: (1) drainage to lymph nodes; (2) uptake by dendritic cells (DCs); (3) maturation of DCs; and (4) Presentation of peptide-MHC I complexes to CD8+ T cells. How the physical properties of vaccine carriers such as mesoporous silica nanoparticles (MSNs) influence this cascade is unclear. We fabricated 80-nm MSNs with different pore sizes (7.8 nm, 10.3 nm, and 12.9 nm) and loaded them with ovalbumin antigen. Results demonstrated these MSNs with different pore sizes were equally effective in the first three steps of the DUMP cascade, but those with larger pores showed higher cross-presentation efficiency (step 4). Consistently, large-pore MSNs loaded with B16F10 tumor antigens yielded the strongest antitumor effects. These results demonstrate the promise of our lymph node-targeting large-pore MSNs as vaccine-delivery vehicles for immune activation and cancer vaccination.

The application of circulating tumor DNA (ctDNA) monitoring after resection in pathologic(p) stage I lung adenocarcinoma (LUAD) patients remains controversial and it is of great clinical interest to decipher the difference of genetic features between ground-glass opacity (GGO) and solid nodules (non-GGO) subgroups. We aim to assess the utility of ctDNA in tracking early recurrence or metastasis following surgery and reveal the genetic differences between GGO and non-GGO.Tumor tissues and matched postoperative plasma samples were collected from a total of 82 (p)stage I LUAD patients. Comprehensive genomic profiling was performed using capture-based hybrid next generation sequencing by targeting 422 cancer relevant genes.EGFR and TP53 represent commonly mutated genes in this cohort of (p)stage I lung adenocarcinoma, followed by alterations in ALK, PIK3CA, STK11 and MYC. For a median follow-up period of 22.83 months after surgery, 65 out of 67 ctDNA-negative patients remained progression-free, while 3 out of 15 ctDNA-positive patients progressed [P = 0.040; positive predictive value = 0.20, 95 % confidence interval (CI), 0.04-0.48; negative predictive value = 0.97, 95 % CI, 0.9-1]. With time-dependent Cox regression analysis, we observed that ctDNA positivity significantly correlated with increased probability of early tumor recurrence or metastasis (P = 0.02, HR=8.5). Further comparison between GGO and non-GGO subgroups indicated the frequency of TP53 mutations in non-GGO was markedly higher than that in GGO (47 % vs 21 %, P 0.05). Pathway analysis showed the epigenetic regulation pathway was more frequently affected in GGO subgroup, while impaired apoptosis/cell cycle pathway was more enriched in non-GGO LUADs.Our longitudinal ctDNA monitoring data showed that undetectable ctDNA may predict low risk of tumor recurrence or metastasis in postoperative (p)stage I LUAD patients, while it requires further investigation on how robust the positive ctDNA results could predict tumor relapse in these patients.NCT03172156.

Biomarkers are routinely discovered by comparing the signal intensity of mixture samples from healthy and disease, which defaults to the most obvious difference between the two groups are associated with the disease. Actually, there also may be huge differences among healthy individual samples, so elucidation of individual differences of healthy samples can help to determine the screening criteria for biomarkers. The urine sample of a 12 healthy people and 3 mixed urine samples were analyzed by using nano-liquid chromatography-high-resolution tandem mass spectrometry. The number of identified peptides and proteins as well as peptide sequence was compared to explore the compositional features and inter-individual differences in the urine peptidome. The numbers of peptides detected ranged from 80 to 1715 per sample, with the number of proteins of origin ranging from 18 to 146. Despite this very large variance, some peptides were detected in all 15 samples, includes peptides from uromodulin, hemoglobin, fibrinogen, and collagen alpha-2(I) chain. We have found that the results of peptidomics were more stable at protein level, peptides from proteins such as uromodulin, hemoglobin and fibrinogen were detected with high frequency and huge difference of signal intensity in urine of health person, which suggested that selecting these peptides as disease biomarkers may be compromised by insufficient specificity.

BL Lac objects are known to have compact jets inclined to our line of sight at a small angle, showing prominent radio emission. Two radio-weak BL Lac candidates with no counterparts in current radio surveys were recently reported by Massaro et al. (2017). Both sources were selected as candidate low-energy counterparts of unassociated Fermi {\gamma}-ray sources. We carried out very long baseline interferometry (VLBI) observations with the European VLBI Network (EVN) at 5 GHz to explore their radio properties at milli-arcsecond (mas) scale. One target, J1410+7405, is clearly detected with the EVN. Its measured 5-GHz flux density, 2.4 mJy, is consistent with recent interferometric measurements with the Karl G. Jansky Very Large Array, suggesting that the radio emission is confined to the inner < ~10 mas region. J1410+7405 is therefore identified as a radio-loud jetted active galactic nucleus, and its brightness temperature exceeds ~10^9 K. Its properties are similar to those of other {\gamma}-ray detected BL Lac objects. On the other hand, the second target, J0644+6031, remains undetected with the EVN with a 6-{\sigma} brightness upper limit of 0.12 mJy/beam. This source is thus radio-quiet, confirming its peculiarity, or possibly questioning its BL Lac nature., Comment: 6 pages, 2 figures, MNRAS Letter accepted

Alzheimer's disease (AD) is a chronic neurodegenerative disorder contributing to nearly 70% of dementia cases. However, no diagnostic protein biomarkers are available in urine. In this study, we combined computational and experimental methods to identify urinary biomarkers for AD. First, by analyzing brain tissue-based gene expression data of AD, 2,754 differentially expressed genes were identified, 559 of which were predicted to encode urine-excretory proteins that might act as candidate protein biomarkers of AD. GO enrichment analyses implied that they were mainly involved in microtubule-based process, myelin sheath, and calcium ion binding, suggesting that they might be associated with AD pathogenesis. In order to verify these proteins in urine, an iTRAQ experiment was carried out to analyze urine samples from AD patients and healthy controls, and 15 proteins were detected. Based on the expression changes of these proteins, 4 proteins were chosen for further validation by ELISA experiment, and SPP1, GSN, and IGFBP7 were found to be differentially expressed in the urine of AD patients. After a literature survey, we found that they were involved in AD pathophysiology and might serve as new urine biomarkers for AD. To our knowledge, this is the first time that urine biomarkers for AD were identified by combining computational and experimental methods. Furthermore, this is the first time SPP1, GSN, and IGFBP7 have been reported as potential urine protein biomarkers for AD. Therefore, our findings might provide significant guidance for finding early biomarkers of AD in urine.

Background Next-generation sequencing (NGS) based on liquid biopsy has been an emerging technology to identify tumor-specific genetic aberrations in adult lymphoma. However, there were few studies on the genomic profiling of plasma circulating tumor-derived DNA (ctDNA) in pediatric mature B-NHL. Methods Paraffin-embedded tissue (FFPE) and plasma samples from the newly diagnosed patients were collected and sequenced by 475 genes panel before, during and post of treatment. Clinical stage system, risk stratification and treatment of pediatric mature B-NHL followed a the modified BFM-95 protocol. Results A total of 53 pediatric mature B-NHLs were enrolled，including 35 Burkitt lymphoma, 18 diffused large B cell lymphoma/high-grade B cell lymphoma (DLBCL/HGBCL). We collected 38 tissue and 124 plasma samples for somatic mutation testing. The number of somatic mutations and the TOP 5 genes detected in the 38 tissues and 31 baseline plasma samples, were 416 vs 496, and MYC(71%), DDX3X(45%)，ID3 (42%), TP53(40%), SMARCA4(29%) (Fig1. A)vs MYC(52%), DDX3X(45%)，ID3(42%), TP53(36%), GNA13(23%) (Fig1. B), respectively. The median allele frequency of mutations in plasma was 3%(ranged from 0.2% to 96.6%) and MYC, DDX3X, ID3, TP53, SMARCA4,ARID1A shows higher max somatic allele frequency (MSAF), indicated that was the early events in tumor genesis. The sensitivity of plasma ctDNA to detecting tissue mutations was 63.4% in the 19 matched samples (11 samples from BL and 8 samples from DLBCL/HGBCL) and the sensitivity in BL and DLBCL/HGBCL were 64.1% and 62%, respectively. All genomic alteration types, including single nucleotide variants (SNVs), indels, and gene fusions were detected in similar proportions in each sample type and the gene mutation rate of every gene detected in paired tissue and ctDNA samples. Among the 37 mature B-NHL patients, 6 patients were collected plasma samples after resection of tumor, of which 4 patients was not detected the somatic gene mutations in plasma (Fig. 2). The abundance of ctDNA in patients with stage IV (N=10) was significantly higher than that of stage I-II (N=6) (P=0.0002) and stage III patients(N=15)(P With a median follow-up of 182 Days, 33 patients have completed anti-tumor treatment, 27 patients completed post-treatment PET-CT, and 20 patients have done ctDNA testing synchronously. PET-CT showed tumor residue in 4 patients, of which 2 patients showed no tumor residue in pathology and ctDNA, 1 patient showed tumor residue in pathology but not in ctDNA and with tumor progression 6 months after treatment, 1 patient unable to take biopsy showed no tumor residue in ctDNA and was no tumor reccourence with regular follow-up. At the last follow-up, 1 patient was disease progression, and all of the 53 patients survived. Conclusion Plasma ctDNA testing by NGS was practicable in pediatric mature B-NHL. The abundance of ctDNA is significantly related to tumor burden. CtDNA testing may be more sensitive than PET-CT for residual disease assessment. Nevertheless, sample size expansion is required to verify such conclusions. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Cancer immunotherapy appears to have a promising future, but it can be thwarted by secretion of immunosuppressive factors, such as transforming growth factor-β (TGF-β), which inhibits local immune responses to tumors. To weaken immune resistance of tumors and simultaneously strengthen immune responses, we developed a multifunctional polymer that could co-deliver hydrophobic TGF-β inhibitor and an adenovirus gene vector to tumor sites. This co-delivery system sustainably released TGF-β inhibitor SB-505124 and effectively transferred the adenovirus vector carrying the interleukin-12 gene. In addition, it significantly delayed growth of B16 melanoma xenografts in mice and increased animal survival. Mechanistic studies showed that this combination therapy enhanced anti-tumor immune response by activating CD4+ and CD8+ T cells, natural killer cells and interferon-γ secretion in the tumor microenvironment. Statement of Significance To weaken immune resistance of tumors and simultaneously strengthen tumors' immune responses, we synthesized a structurally simple, low-toxic but functional polymer β-cyclodextrin-PEI to encapsulate a hydrophobic TGF-β inhibitor SB-505124 and to complex adenovirus vectors expressing IL-12. This is the first report demonstrating that combining TGF-β inhibitor with IL-12 could provide effective immunotherapy against melanoma by the sustainable release of SB-505124 and the effectible transduction of IL-12 gene in tumor cells. The rational delivery system presented a comprehensive and valued platform to be a candidate vector for co-delivering hydrophobic small-molecule drugs and therapeutic genes for treating cancer, providing a new approach for cancer immunotherapy.

PKS 1155+251 is a radio-loud quasar source at z=0.203. Observations using very long baseline interferometry (VLBI) at ~2, 5, 8 and 15 GHz show that the structure of the radio source is quite complicated on parsec scales and that the outer hot spots are apparently undergoing a significant contraction. Because these results cannot be fully explained based on the compact symmetric object (CSO) scenario with a radio core located between the northern and southern complexes, we made observations with the Very Long Baseline Array (VLBA) at 24 and 43 GHz to search for compact substructures and alternative interpretations. The results show that the radio core revealed in the previous VLBI observations remains compact with a flat spectrum in our sub-milli-arcsecond--resolution images; the northern lobe emission becomes faint at 24 GHz and is mostly resolving out at 43 GHz; the southern complex is more bright but has been resolved into the brightest southern-end (S1) and jet or tail alike components westwards. Explaining the southern components aligned westward with a standard CSO scenario alone remains a challenge. As for the flatter spectral index of the southern-end component S1 between 24 and 43 GHz in our observations and the significant 15 GHz VLBA flux variability of S1, an alternative scenario is that the southern complex may be powered by a secondary black hole residing at S1. But more sensitive and high-resolution VLBI monitoring is required to discriminate the CSO and the binary black hole scenarios., 7 pages, 3 figures, accepted by MNRAS

We present the observational results from the 43-GHz Very Long Baseline Array (VLBA) observations of 124 compact radio-loud active galactic nuclei (AGNs) that were conducted between 2014 November and 2016 May. The typical dimensions of the restoring beam in each image are about 0.5 mas $\times$ 0.2 mas. The highest resolution of 0.2 mas corresponds to a physical size of 0.02 pc for the lowest redshift source in the sample. The 43-GHz very long baseline interferometry (VLBI) images of 97 AGNs are presented for the first time. We study the source compactness on milli-arcsec (mas) and sub-mas scales, and suggest that 95 sources in our sample are suitable for future space VLBI observations. By analyzing our data supplemented with other VLBA AGN surveys from literature, we find that the core brightness temperature increases with increasing frequency below a break frequency ~ 7 GHz, and decreases between ~7--240~GHz but increases again above~240 GHz in the rest frame of the sources. This indicates that the synchrotron opacity changes from optically thick to thin. We also find a strong statistical correlation between radio and $\gamma$-ray flux densities. Our correlation is tighter than those in literature derived from lower-frequency VLBI data, suggesting that the $\gamma$-ray emission is produced more co-spatially with the 43-GHz VLBA core emission. This correlation can also be extrapolated to the un-beamed AGN population, implying that a universal $\gamma$-ray production mechanism might be at work for all types of AGNs., Comment: Accepted for publication in ApJS

M87 is one of the best available source for studying the AGN jet-launching region. To enrich our knowledge of this region, with quasi-simultaneous observations using VLBA at 22, 43 and 86 GHz, we capture the images of the radio jet in M87 on a scale within several thousand R s . Based on the images, we analyze the transverse jet structure and obtain the most accurate spectral-index maps of the jet in M87 so far, then for the first time, we compare the results of the two analyses and find a spatial association between the jet collimations and the local enhancement of the density of external medium in the jet-launching region. We also find the external medium is not uniform, and greatly contributes to the free-free absorption in this region. In addition, we find for the jet in M87, its temporal morphology in the launching region may be largely affected by the local, short-lived kink instability growing in itself., Accepted by Galaxies