717 research outputs found
Fault diagnosis of rotating machinery under time-varying speed based on order tracking and deep learning
Due to the disadvantages that rely on prior knowledge and expert experience in traditional order analysis methods and deep learning cannot accurately extract the features in time-varying conditions. A fault diagnosis method for rotating machinery under time-varying conditions based on tacholess order tracking (TOT) and deep learning is proposed in this paper. Firstly, frequency domain periodic signals and estimated speed information are obtained by order tracking. Secondly, the frequency domain periodic signal is speed normalized using the estimated speed information. Finally, normalized features are extracted by deep learning network to form feature vector. The feature vector is fed into a softmax layer to complete fault diagnosis of the gearbox. The fault diagnosis of the gearbox results are compared with other traditional methods and show that the proposed fault diagnosis method can effectively identify the faults and obtain higher fault diagnosis accuracy under time-varying speed
The M-T hook structure increases the potency of HIV-1 fusion inhibitor sifuvirtide and overcomes drug resistance
Objectives Peptides derived from the C-terminal heptad repeat (CHR) of HIV-1 gp41 are potent fusion inhibitors. We have recently demonstrated that the unique M-T hook structure preceding the pocket-binding motif of CHR peptide-based inhibitors can greatly improve their antiviral activity. In this study, we applied the M-T hook structure to optimize sifuvirtide (SFT), a potent CHR-derived inhibitor currently under Phase III clinical trials in China. Methods The peptide MT-SFT was generated by incorporating two M-T hook residues (Met-Thr) into the N-terminus of sifuvirtide. Multiple structural and functional approaches were used to determine the biophysical properties and antiviral activity of MT-SFT. Results The high-resolution crystal structure of MT-SFT reveals a highly conserved M-T hook conformation. Compared with sifuvirtide, MT-SFT exhibited a significant improvement in the ability to bind to the N-terminal heptad repeat, to block the formation of the six helix bundle and to inhibit HIV-1 Env-mediated cell fusion, viral entry and infection. Importantly, MT-SFT was fully active against sifuvirtide- and enfuvirtide (T20)-resistant HIV-1 variants and displayed a high genetic barrier to developing drug resistance. Conclusions Our studies have verified that the M-T hook structure offers a general strategy for designing novel HIV-1 fusion inhibitors and provide new insights into viral entry and inhibitio
Prickly Ash Seeds improve immunity of Hu sheep by changing the diversity and structure of gut microbiota
Prickly Ash Seeds (PAS), as a traditional Chinese medicinal herb, have pharmacological effects such as anti-asthma, anti-thrombotic, and anti-bacterial, but their impact on gut microbiota is still unclear. This study used a full-length 16 s rRNA gene sequencing technique to determine the effect of adding PAS to the diet on the structure and distribution of gut microbiota in Hu sheep. All lambs were randomly divided into two groups, the CK group was fed with a basal ration, and the LZS group was given a basal diet with 3% of PAS added to the ration. The levels of inflammatory factors (IL-10, IL-1β, and TNF-α) in intestinal tissues were measured by enzyme-linked immunosorbent assay (ELISA) for Hu sheep in the CK and LZS group. The results indicate that PAS can increase the diversity and richness of gut microbiota, and can affect the community composition of gut microbiota. LEfSe analysis revealed that Verrucomicrobiota, Kiritimatiella, WCHB 41, and uncultured_rumen_bacterium were significantly enriched in the LZS group. KEGG pathway analysis found that LZS was significantly higher than the CK group in the Excretory system, Folding, sorting and degradation, and Immune system pathways (p < 0.05). The results of ELISA assay showed that the level of IL-10 was significantly higher in the LZS group than in the CK group (p < 0.05), and the levels of TNF-α and IL-1β were significantly higher in the CK group than in the LZS group (p < 0.05). LEfSe analysis revealed that the dominant flora in the large intestine segment changed from Bacteroidota and Gammaproteobacteria to Akkermansiaceae and Verrucomicrobiae after PAS addition to Hu sheep lambs; the dominant flora in the small intestine segment changed from Lactobacillales and Aeriscardovia to Kiritimatiellae and WCHB1 41. In conclusion, the addition of PAS to sheep diets can increase the number and types of beneficial bacteria in the intestinal tract, improve lamb immunity, and reduce intestinal inflammation. It provides new insights into healthy sheep production
A novel trifunctional IgG-like bispecific antibody to inhibit HIV-1 infection and enhance lysis of HIV by targeting activation of complement
BACKGROUND: The complement system is not only a key component of innate immunity but also provides a first line of defense against invading pathogens, especially for viral pathogens. Human immunodeficiency virus (HIV), however, possesses several mechanisms to evade complement-mediated lysis (CoML) and exploit the complement system to enhance viral infectivity. Responsible for this intrinsic resistance against complement-mediated virolysis are complement regulatory membrane proteins derived from the host cell that inherently downregulates complement activation at several stages of the cascade. In addition, HIV is protected from complement-mediated lysis by binding soluble factor H (fH) through the viral envelope proteins, gp120 and gp41. Whereas inhibition of complement activity is the desired outcome in the vast majority of therapeutic approaches, there is a broader potential for complement-mediated inhibition of HIV by complement local stimulation. PRESENTATION OF THE HYPOTHESIS: Our previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that another new activator of complement, consisting of two dsFv (against gp120 and against C3d respectively) linked to a complement-activating human IgG1 Fc domain ((anti-gp120 × anti-C3d)-Fc), can not only target and amplify complement activation on HIV virions for enhancing the efficiency of HIV lysis, but also reduce the infectivity of HIV through blocking the gp120 and C3d on the surface of HIV. TESTING THE HYPOTHESIS: Our hypothesis was tested using cell-free HIV-1 virions cultivated in vitro and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified (anti-gp120 × anti-C3d)-Fc proteins. As a control group, viruses were incubated with normal human serum under the same conditions. Virus neutralization assays were used to estimate the degree of (anti-gp120 × anti-C3d)-Fc lysis of HIV compared to untreated virus. IMPLICATIONS OF THE HYPOTHESIS: The targeted complement activator, (anti-gp120 × anti-C3d)-Fc, can be used as a novel approach to HIV therapy by abrogating the complement-enhanced HIV infection of cells
Pulmonary Toxicity and Adjuvant Effect of Di-(2-exylhexyl) Phthalate in Ovalbumin-Immunized BALB/c Mice
BACKGROUND: Asthma is a complex pulmonary inflammatory disease, which is characterized by airway hyperresponsiveness, variable airflow obstruction and inflammation in the airways. The majority of asthma is allergic asthma, which is a disease caused by type I hypersensitivity mediated by IgE. Exposures to a number of environmental chemicals are suspected to lead to asthma, one such pollutant is di-(2-ethylheyl) phthalate (DEHP). DEHP is a manufactured chemical that is commonly added in plastic products to make them flexible. Epidemiological studies have revealed a positive association between DEHP exposure and asthma prevalence. METHODOLOGY/PRINCIPAL FINDINGS: The present study was aimed to determine the underlying role of DEHP exposure in airway reactivity, especially when combined with allergen exposure. The biomarkers include pulmonary histopathology, airway hyperresponsiveness (lung function), IgE, IL-4, IFN-γ and eosinophils. Healthy balb/c mice were randomly divided into eight exposure groups (n = 8 each): (1) saline control, (2) 30 µg/(kg•d) DEHP, (3) 300 µg/(kg•d) DEHP, (4) 3000 µg/(kg•d) DEHP, and (5) ovalbumin (OVA)-sensitized group, (6) OVA-combined with 30 µg/(kg•d) DEHP, (7) OVA-combined with 300 µg/(kg•d) DEHP, and (8) OVA-combined with 3000 µg/(kg•d) DEHP. Experimental tests were conducted after 52-day DEHP exposure and subsequently one week of challenge with aerosolized OVA. The principal findings include: (1) Strong postive associations exist between OVA-combined DEHP exposure and serum total IgE (T-IgE), as well as histological findings. These positive associations show a dose-dependent low dose sensitive effect of DEHP. (2) IL-4, eosinophil recruitment and lung function are also indicators for adjuvant effect of DEHP. CONCLUSIONS/SIGNIFICANCE: Our results suggest that except the significant changes of immunological and inflammatory biomarkers (T-IgE, IL-4, IFN-γ and eosinophils), the pulmonary histological (histopathological examination) and physiological (lung function) data also support that DEHP may promote and aggravate allergic asthma by adjuvant effect
Observation of in
Using a sample of events recorded with
the BESIII detector at the symmetric electron positron collider BEPCII, we
report the observation of the decay of the charmonium state
into a pair of mesons in the process
. The branching fraction is measured for the first
time to be , where the first uncertainty is
statistical, the second systematic and the third is from the uncertainty of
. The mass and width of the are
determined as MeV/ and
MeV.Comment: 13 pages, 6 figure
Observation and study of the decay
We report the observation and study of the decay
using events
collected with the BESIII detector. Its branching fraction, including all
possible intermediate states, is measured to be
. We also report evidence for a structure,
denoted as , in the mass spectrum in the GeV/
region. Using two decay modes of the meson ( and
), a simultaneous fit to the mass spectra is
performed. Assuming the quantum numbers of the to be , its
significance is found to be 4.4, with a mass and width of MeV/ and MeV, respectively, and a
product branching fraction
. Alternatively, assuming , the
significance is 3.8, with a mass and width of MeV/ and MeV, respectively, and a product
branching fraction
. The angular distribution of
is studied and the two assumptions of the
cannot be clearly distinguished due to the limited statistics. In all
measurements the first uncertainties are statistical and the second systematic.Comment: 10 pages, 6 figures and 4 table
Evidence of a resonant structure in the cross section between 4.05 and 4.60 GeV
The cross section of the process for
center-of-mass energies from 4.05 to 4.60~GeV is measured precisely using data
samples collected with the BESIII detector operating at the BEPCII storage
ring.
Two enhancements are clearly visible in the cross section around 4.23 and
4.40~GeV.
Using several models to describe the dressed cross section yields stable
parameters for the first enhancement, which has a mass of 4228.6 \pm 4.1 \pm
6.3 \un{MeV}/c^2 and a width of 77.0 \pm 6.8 \pm 6.3 \un{MeV}, where the
first uncertainties are statistical and the second ones are systematic.
Our resonant mass is consistent with previous observations of the
state and the theoretical prediction of a molecule.
This result is the first observation of associated with an
open-charm final state.
Fits with three resonance functions with additional , ,
, , or a new resonance, do not show significant
contributions from either of these resonances. The second enhancement is not
from a single known resonance. It could contain contributions from
and other resonances, and a detailed amplitude analysis is required to better
understand this enhancement
Observation of and confirmation of its large branching fraction
The baryonic decay is observed, and the
corresponding branching fraction is measured to be
, where the first uncertainty is statistical
and second systematic. The data sample used in this analysis was collected with
the BESIII detector operating at the BEPCII double-ring collider with
a center-of-mass energy of 4.178~GeV and an integrated luminosity of
3.19~fb. The result confirms the previous measurement by the CLEO
Collaboration and is of greatly improved precision, which may deepen our
understanding of the dynamical enhancement of the W-annihilation topology in
the charmed meson decays
Search for the decay
We search for radiative decays into a weakly interacting neutral
particle, namely an invisible particle, using the produced through the
process in a data sample of
decays collected by the BESIII detector
at BEPCII. No significant signal is observed. Using a modified frequentist
method, upper limits on the branching fractions are set under different
assumptions of invisible particle masses up to 1.2 . The upper limit corresponding to an invisible particle with zero mass
is 7.0 at the 90\% confidence level
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