Probing CP symmetry and weak phases with entangled double-strange baryons

Though immensely successful, the standard model of particle physics does not offer any explanation as to why our Universe contains so much more matter than antimatter. A key to a dynamically generated matter-antimatter asymmetry is the existence of processes that violate the combined charge conjugation and parity (CP) symmetry1. As such, precision tests of CP symmetry may be used to search for physics beyond the standard model. However, hadrons decay through an interplay of strong and weak processes, quantified in terms of relative phases between the amplitudes. Although previous experiments constructed CP observables that depend on both strong and weak phases, we present an approach where sequential two-body decays of entangled multi-strange baryon-antibaryon pairs provide a separation between these phases. Our method, exploiting spin entanglement between the double-strange Ξ- baryon and its antiparticle2 [Formula: see text], has enabled a direct determination of the weak-phase difference, (ξP - ξS) = (1.2 ± 3.4 ± 0.8) × 10-2 rad. Furthermore, three independent CP observables can be constructed from our measured parameters. The precision in the estimated parameters for a given data sample size is several orders of magnitude greater than achieved with previous methods3. Finally, we provide an independent measurement of the recently debated Λ decay parameter αΛ (refs. 4,5). The [Formula: see text] asymmetry is in agreement with and compatible in precision to the most precise previous measurement4.

Experimental Demonstration of the Thin-Film Liquid-Metal Jet as a Charge Stripper

For high-power heavy ion accelerators, the development of a suitable charge stripper, which can handle intense beams, is essential. This Letter describes the first experimental demonstration of a heavy ion liquid lithium charge stripper. A 10-20  μm thick liquid lithium jet flowing at >50  m/s was formed and confirmed stable when bombarded by various heavy ion beams, while increasing the charge state of the incoming beams to the desired charge state range. This demonstration proved the existing power limitation with the conventional strippers can be overcome by the liquid-metal stripper, opening completely new possibilities in high-power accelerator development.

[Rates and influencing factors of hospitalization after diagnosis among HIV infection cases in Yinzhou district of Ningbo, 2012-2020]

Objective: To understand the hospitalization rates and influencing factors after diagnosis among HIV infection cases, based on real-world data in Yinzhou district of Ningbo. Methods: A retrospective cohort study was conducted based on the databases of National AIDS Comprehensive Response Information Management System and Yinzhou Health Information Platform. The information about the following-up results, antiviral treatment data, electronic records of inpatient of the HIV cases reported during 2012-2020 were collected to analyze the rates, causes and influencing factors of hospitalization. Results: Among the 763 HIV infection cases reported in Yinzhou from 2012 to 2020, the hospitalization rate was 6.95% (53/763), and the number of inpatient was 2.59 per 100 person years. The hospitalization rate and the number of hospitalization per 100 person years in HIV infection cases were 3.16% (10/316) and 0.81 in those aged <30 years, 6.07% (15/247) and 1.59 in those aged >30 years, 7.86% (11/140) and 4.05 in those aged >45 years and 28.33% (17/60) and 17.40 in those aged ≥60 years respectively. Logistic multivariate regression analysis indicated that being aged ≥60 years was the influencing factor for hospitalizations in HIV infection cases (аOR=14.44, 95%CI:3.57-58.46). The hospitalization rates due to AIDS related diseases, cardiovascular diseases and metabolic diseases, and other diseases were 1.83% (14/763), 1.05% (8/763), and 3.93% (30/763), respectively. Conclusions: The hospitalization burden due to HIV infection was still mainly caused by those aged ≥60 years in Yinzhou, similar to that in general population and less proportion of hospitalizations were due to AIDS related diseases. The overall increase of hospitalizations due to AIDS was not obvious in Yinzhou.

Observation of the Singly Cabibbo Suppressed Decay Λ_{c}^{+}→nπ^{+}

The singly Cabibbo-suppressed decay Λ_{c}^{+}→nπ^{+} is observed for the first time with a statistical significance of 7.3σ by using 3.9  fb^{-1} of e^{+}e^{-} collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ_{c}^{+}→nπ^{+} is measured to be (6.6±1.2_{stat}±0.4_{syst})×10^{-4}. By taking the upper limit of branching fractions of Λ_{c}^{+}→pπ^{0} from the Belle experiment, the ratio of branching fractions between Λ_{c}^{+}→nπ^{+} and Λ_{c}^{+}→pπ^{0} is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with most predictions of the available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ_{c}^{+}→Λπ^{+} and Λ_{c}^{+}→Σ^{0}π^{+} are measured to be (1.31±0.08_{stat}±0.05_{syst})×10^{-2} and (1.22±0.08_{stat}±0.07_{syst})×10^{-2}, respectively, which are consistent with previous results.

CRISPR-Cas12a based fluorescence assay for organophosphorus pesticides in agricultural products

Herein, we propose a sensitive fluorescent assay for organophosphorus pesticides (OPs) detection based on a novel strategy of activating the CRISPR-Cas12a system. Specifically, acetylcholinesterase (AChE) hydrolyzes acetylthiocholine into thiocholine (TCh). Subsequently, TCh induces the degradation of MnO₂ nanosheets and generates sufficient Mn²⁺ ions to activate the Mn²⁺-dependent DNAzyme. Then, as the catalytic product of activated DNAzyme, the short DNA strand activates the CRISPR-Cas12a system to cleave the fluorophore-quencher-labeled DNA reporter (FQ) probe effectively; thus, increasing the fluorescence intensity (FI) in the solution. However, in the presence of OPs, the activity of AChE is suppressed, resulting in a decrease in FI. Under optimized conditions, the limits of detection for paraoxon, dichlorvos, and demeton were 270, 406, and 218 pg/mL, respectively. Benefiting from the outstanding MnO₂ nanosheets properties and three rounds of enzymatic signal amplification, the proposed fluorescence assay holds great potential for the detection of OPs in agricultural products.

[Construction of spvD gene deletion mutant and compensation strains in Salmonella enteritidis and its effects on Caco-2 cells]

Objective: To analyze the effects of spvD gene on invasion and intracellular proliferation of Caco-2 cells and in order to provide insight into the function of that gene and the underlying mechanism of Salmonella caused infection. Methods: Functional verification of spvD gene deletion mutant and compensation strain. The deletion mutant strain was constructed through a suicide plasmid-mediated homologous recombination. The compensation plasmid constructed by cloning the coding sequence of spvD by PCR into plasmid pBAD33 was mobilized into the deletion mutant by conjugation and the pBAD33 was introduced into wild strains and deleted mutant strains as control. The relative expression of spvD mRNA was detected by quantitative reverse transcription PCR. In order to analyze the virulence of spvD against Caco-2 cells, Caco-2 cells was cocultured with wild type Salmonella enteritidis carrying spvD gene, the deletion mutant strain and compensation strain respectively. The expression level of spvD mRNA and the the number of Salmonella enteritidis after Caco-2 cells intervention were compared between the three groups by LSD-t test, and the invasion rate was compared by χ² test. Results: The expression level of spvD mRNA in wild type Salmonella enteritidis was set as unit "1", the deletion mutant strain was "0.00", and the compensation strain was "2.60" (LSD-t_{wild, deleted}=1.11, P=0.31; LSD-t_{wild, compensation}=-1.77, P=0.13; LSD-t _{deleted, compensation}=-2.88, P=0.03), which confirmed the successful construction of the deletion mutant strain and the compensation strain. The invasion experiment results of the above three Salmonella enteritidis strains on Caco-2 cells showed that the invasion rate of wild strain was 0.23%, the invasion rate of deleted mutant strain was 0.16%, and the invasion rate of compensation strain was 0.16%, with no statistical significance (χ²=1.13, P=0.570). By comparing the number of Salmonella enteritidis at different time points after Caco-2 cells intervention, it was discovered that the number of Salmonella enteritidis in wild strains (6.50×10⁶ CFU/ml) and compensation strains (7.25×10⁶ CFU/ml) was significantly increased than that in deletion mutant strain (1.90×10⁶ CFU/ml) after 16 h coculture (LSD-t_{wild, deleted}=7.95, P=0.00; LSD-t_{wild, compensation}=-1.27, P=0.25; LSD-t _{deleted, compensation}=-9.22, P=0.00). Conclusion: It is not considered that spvD gene can affect the invasion of Salmonella enteritidis on Caco-2 cells, but the gene can promote the reproduction of Salmonella enteritidis in Caco-2 cells.

N(6)-methyladenosine RNA methyltransferase like 3 inhibits extracellular matrix synthesis of endplate chondrocytes by downregulating sex-determining region Y-Box transcription factor 9 expression under tension

OBJECTIVE

Tension stimulation is an important inducer of endplate cartilage degeneration, but the specific regulatory mechanism remains unclear. This study was the first to reveal the mechanism by which methyltransferase-like 3 (METTL3)-mediated N(6)-methyladenosine (m6A) modification affected the extracellular matrix anabolism by tension-induced endplate chondrocytes.

METHOD

We examined the differences in METTL3 expression and m6A methylation levels in human endplate chondrocytes and human cartilage endplate tissues under in vitro tension. The effect on endplate cartilage degeneration was evaluated by manipulating m6A methylation mediated by METTL3 in vivo and in vitro. The effect of METTL3-mediated m6A methylation on the stability of sex-determining region Y-box transcription factor 9 (SOX9) gene expression was determined experimentally.

RESULTS

METTL3 expression and m6A methylation levels were significantly increased in degenerative human endplate cartilage tissue. Similarly, tension stimulation inhibited the ability of human endplate chondrocytes to synthesize extracellular matrix, which was accompanied by an increase in METTL3-mediated m6A methylation. The ability of endplate chondrocytes to resist tension was significantly enhanced by inhibiting METTL3 expression and subsequently downregulating m6A methylation in vitro and in vivo, thereby reducing intervertebral disc degeneration. Furthermore, METTL3 mediated SOX9 RNA methylation and disrupted SOX9 mRNA stability, thereby inhibiting the gene expression of the downstream collagen type II alpha 1 chain.

CONCLUSION

Tension stimulation downregulated SOX9 expression through METTL3-mediated m6A methylation, thereby inhibiting the synthesis of extracellular matrix in endplate chondrocytes.

Identification of Dental Stem Cells Similar to Skeletal Stem Cells

Stem and progenitor cells play important roles in the development and maintenance of teeth and bone. Surface markers expressed in bone marrow–derived mesenchymal stem cells are also expressed in dental tissue–derived stem cells. Mouse skeletal stem cells (mSSCs, CD45−Ter119−Tie2−CD51+Thy−6C3−CD105−CD200+) and human skeletal stem cells (hSSCs, CD45−CD235a−TIE2−CD31−CD146−PDPN+CD73+CD164+) have been identified in bone and shown to play important roles in skeletal development and regeneration. However, it is unclear whether dental tissues also harbor mSSC or hSSC populations. Here, we employed rainbow tracers and found that clonal expansion occurred in mouse dental tissues similar to that in bone. We sorted the mSSC population from mouse periodontal ligament (mPDL) tissue and mouse dental pulp (mDP) tissue in the lower incisors by fluorescence-activated cell sorting (FACS). In addition, we demonstrated that mPDL-derived skeletal stem cells (mPDL-SSCs) and mDP-derived skeletal stem cells (mDP-SSCs) have similar clonogenic capacity, as well as cementogenic and odontogenic potential, but not adipogenic potential, similar to the characteristics of mSSCs. Moreover, we found that the dental tissue–derived mSSC population plays an important role in repairing clipped incisors. Importantly, we sorted the hSSC population from human periodontal ligament (hPDL) and human dental pulp (hDP) tissue in molars and identified its stem cell characteristics. Finally, hPDL-like and hDP-like structures were generated after transplanting hPDL-SSCs and hDP-SSCs beneath the renal capsules. In conclusion, we demonstrated that mouse and human PDL and DP tissues harbor dental stem cells similar to mSSCs and hSSCs, respectively, providing a precise stem cell population for the exploration of dental diseases.

Measurement of the Cross Section for e^{+}e^{-}→Hadrons at Energies from 2.2324 to 3.6710 GeV

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.

First Measurement of Polarizations in the Decay D^{0}→ωφ

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy sqrt[s]=3.773  GeV by the BESIII detector, the decay D^{0}→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.40)×10^{-4} with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D^{0}→ωϕ decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.

Limonitum Ameliorates Castor Oil-Induced Diarrhoea in Mice by Modulating Gut Microbiota

Diarrhoea is a common clinical condition; its pathogenesis is strongly associated with gut microbiota dysbiosis. Limonitum is a well-known traditional Chinese medicine that exerts appreciable benefits regarding the amelioration of diarrhoea. However, the mechanism through which Limonitum ameliorates diarrhoea remains unclear. Here, the efficacy and underlying mechanism of Limonitum decoction (LD) regarding diarrhoea were explored from the aspect of gut microbiota. Castor oil (CO) was used to induce diarrhoea in mice, which were then used to evaluate the effects of LD regarding the timing of the first defecation, diarrhoea stool rate, degree of diarrhoea, diarrhoea score, intestinal propulsive rate, and weight of intestinal contents. The concentrations of short-chain fatty acids (SCFAs), including acetic, propionic, isobutyric, butyric and valeric acids, were analysed by gas chromatography-mass spectrometry (GC-MS). The 16S rRNA high-throughput sequencing technology was applied to evaluate changes in the gut microbiota under exposure to LD. LD was found to effectively ameliorate the symptoms of diarrhoea, and the diversity and relative abundance of gut microbiota were restored to normal levels following LD treatment. Additionally, LD significantly restored the observed reductions in SCFAs. These results provide strong evidence that LD can sufficiently ameliorate diarrhoea in mice by regulating their gut microbiota. The findings presented here highlight that Limonitum may constitute a prospective remedy for diarrhoea.

Analysis of microbial diversity in the root of Astragalus mongholicus

Abstract The dry root of Astragalus mongholicus has therapeutic effects such as tonifing the middle - jiao, replenishing qi, solidifing the surface, promoting diuresis, dispelling sepsis outwards and nourishing muscle. There are some slices having black spots after slicing the root of astragalus. The diversity of endophytic fungi between slices with black spots and normal slices was analysed in this paper. The endophytic fungal sequences obtained by high-throughput sequencing were 298,044 and 297,396, and the 116 OTU subsets obtained after clustering belonged to 3 phyla, 9 classes, 22 orders, 38 families and 46 genera. The dominant classes were Eurotiomycetes and Leotiomycetes. The dominant order is Eurotiales and Helotiales. The dominant families are Helotiales_fam_Incertae_sedis and Aspergillaceae. The dominant genera are Cadophora and Aspergillus. There are some peculiar fungal flora in both normal slices and spotted slices. The study on endophytic fungi diversity of astragalus slices will provide some help for drug development of this plant.