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.

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.

[Research progress on the influence of nanoparticles on intestinal flora]

Nanoparticle is a kind of material with at least one dimension in Nanometer scale, which has unique physical and chemical properties and is widely used in the fields of food and engineering. Intestinal Flora is involved in the regulation of human circulation and metabolism. The disturbance of Intestinal Flora may cause inflammatory reaction and chronic metabolic diseases. Nano titanium dioxide, Nano silver, Nano zinc oxide, Nano carbon nanoparticles and other nanoparticles have been proven to have good antibacterial properties, and can affect the intestinal flora of experimental animals. In this paper, the effects and mechanisms of various nanoparticles on intestinal microflora are summarized, which is helpful to provide a new idea for the safety study of nanoparticles.

[Correlational verification of drug-induced liver injury with HLA-B*35:01 allele due to Polygonum multiflorum]

In order to verify the correlation between Polygonum multiflorum-induced liver injury and HLA-B*35 : 01 alleles, six hospitalized patients diagnosed with Polygonum multiflorum-induced liver injury (PM-DILI) were selected, and their clinicopathological data were collected. Simultaneously, blood HLA-B* 35 : 01 allele detection was performed. Among the six PM-DILI cases, 4 were male, aged 38.83 ± 10.13 years old. The types of liver injury were hepatocellular injury types in all, and the severity of liver injury in five cases was grade 3. The histological presentations were acute hepatitis and acute cholestatic hepatitis. PM-DILI cases were all HLA-B*35:01 carriers, with a carrier rate of 100%. This finding indicates that PM-DILI is significantly correlated with HLA-B*35:01 alleles. Therefore, HLA-B*35 : 01 alleles can be used as an important predictive indicator for PM-DILI.

[Comparison of single incision robot-assisted laparoscopic radical prostatectomy with and without extraperitoneal special channel device]

Objective: To compare the clinical effects of single-incision robot-assisted laparoscopic radical prostatectomy (RARP) with and without extraperitoneal special channel device. Methods: The clinical data of 70 patients who had undergone RARP in the Robotic Minimally Invasive Surgery Center of Sichuan Provincial People's Hospital from September 2020 to February 2021 were analyzed retrospectively, including 29 cases who were operated on without special channel device (group A) and 41 cases with special channel device (group B). All operations were performed by robot-assisted single-incision retrograde bladder neck exfoliation via extraperitoneal approach in patients by the same operator. The operation time, intraoperative blood loss, the bladder neck urethral anastomosis time, postoperative hospital stay, postoperative exhaust time, positive rate of incisal margin, indwelling time of urinary catheter, retention rate of postoperative erectile function, satisfaction rate of immediate postoperative urine control, positive rate of postoperative lymph node pathology, incision length, treatment cost and the rate of prostate specific antigen (PSA)lower than 0.2 μg/L at 6 weeks after operation were compared between the two groups. Results: All 70 cases were operated successfully. The difference of age[ (68.9±3.9) vs (69.4±5.4) years], preoperative PSA level[14.1(6.3, 19.8)vs13.7(5.8, 18.1)μg/L], prostate volume[44.8(30.7,172.6)vs 56.3(40.9,163.4)ml ] of the two groups was not statistically significant(all P>0.05). The difference of operation time [ (59.1±18.5) vs (59.6±18.0) min ], intraoperative blood loss [93(66,198)vs 95(68,203) ml ], bladder neck urethral anastomosis time [ (12.6±1.3) vs (13.7±2.8) min ], postoperative hospital stay [ (8.1±2.3) vs (9.1±1.3) d], postoperative exhaust time [ (1.4±0.6) vs (1.3±0.6) d], positive rate of incisal margin (20.7% vs 19.5%), indwelling time of the urinary catheter after operation [ (6.8±1.5) vs (7.1±2.0) d ], the retention rate of postoperative erectile function (31.0% vs 27.0%), the satisfaction rate of immediate postoperative urine control (79.3% vs 75.6%), the positive rate of postoperative lymph node pathology (17.2% vs 14.6%), the length of incision [ (5.1±0.5) vs (6.1±0.4) cm ], the rate of PSA lower than 0.2 μg/L at 6 weeks after operation (86.2% vs 83.0%) of the two groups was not statistically significant(all P>0.05). The operation cost of group A[(62 000±4 000) yuan]was lower than group B[(68 000±4 000) yuan] (P<0.05). Conclusion: Extraperitoneal non-special channel device single-incision RARP is safe and feasible.

Measurement of the Absolute Branching Fraction of D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}

Using a dataset of 6.32  fb^{-1} of e^{+}e^{-} annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}, and find B_{D_{s}^{+}→τ^{+}ν_{τ}}=(5.27±0.10±0.12)×10^{-2}, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with f_{D_{s}^{+}} from lattice quantum chromodynamics calculations or the |V_{cs}| from the CKMfitter group, we extract |V_{cs}|=0.978±0.009±0.012 and f_{D_{s}^{+}}=(251.1±2.4±3.0)  MeV, respectively. Combining our result with the world averages of B_{D_{s}^{+}→τ^{+}ν_{τ}} and B_{D_{s}^{+}→μ^{+}ν_{μ}}, we obtain the ratio of the branching fractions B_{D_{s}^{+}→τ^{+}ν_{τ}}/B_{D_{s}^{+}→μ^{+}ν_{μ}}=9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.

Observation of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e}

Using 2.93  fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time to be 0.50±0.19_{stat}±0.08_{syst}.

First Measurement of the Absolute Branching Fraction of Λ→pμ^{-}ν[over ¯]_{μ}

The absolute branching fraction of Λ→pμ^{-}ν[over ¯]_{μ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9}  J/ψ events collected with the BESIII detector at sqrt[s]=3.097  GeV. The branching fraction is determined to be B(Λ→pμ^{-}ν[over ¯]_{μ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]_{e}), we obtain the ratio {[Γ(Λ→pμ^{-}ν[over ¯]_{μ})]/[Γ(Λ→pe^{-}ν[over ¯]_{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pμ^{-}ν[over ¯]_{μ} and Λ[over ¯]→p[over ¯]μ^{+}ν_{μ} is also determined, and no evidence for CP violation is found.

Three-Dimensional Dirac Phonons with Inversion Symmetry

Dirac semimetals associated with bulk Dirac fermions are well known in topological electronic systems. In sharp contrast, three-dimensional (3D) Dirac phonons in crystalline solids are still unavailable. Here we perform symmetry arguments and first-principles calculations to systematically investigate 3D Dirac phonons in all space groups with inversion symmetry. The results show that there are two categories of 3D Dirac phonons depending on their protection mechanisms and positions in momentum space. The first category originates from the four-dimensional irreducible representations at the high symmetry points. The second category arises from the phonon branch inversion, and the symmetry guarantees Dirac points to be located along the high symmetry lines. Furthermore, we reveal that nonsymmorphic symmetries and the combination of inversion and time-reversal symmetries play essential roles in the emergence of 3D Dirac phonons. Our work not only offers a comprehensive understanding of 3D Dirac phonons but also provides significant guidance for exploring Dirac bosons in both phononic and photonic systems.

Pathogenicity and transmissibility of a novel respirovirus isolated from a Malayan pangolin

The identification of SARS-CoV-2-like viruses in Malayan pangolins (Manis javanica) has focused attention on these endangered animals and the viruses they carry. We successfully isolated a novel respirovirus from the lungs of a dead Malayan pangolin. Similar to murine respirovirus, the full-length genome of this novel virus was 15 384 nucleotides comprising six genes in the order 3'-(leader)-NP-P-M-F-HN-l-(trailer)-5'. Phylogenetic analysis revealed that this virus belongs to the genus Respirovirus and is most closely related to murine respirovirus. Notably, animal infection experiments indicated that the pangolin virus is highly pathogenic and transmissible in mice, with inoculated mice having variable clinical symptoms and a fatality rate of 70.37 %. The virus was found to replicate in most tissues with the exception of muscle and heart. Contact transmission of the virus was 100 % efficient, although the mice in the contact group displayed milder symptoms, with the virus mainly being detected in the trachea and lungs. The isolation of a novel respirovirus from the Malayan pangolin provides new insight into the evolution and distribution of this important group of viruses and again demonstrates the potential infectious disease threats faced by endangered pangolins.

Fast-Running Tools for Personalized Monitoring of Blast Exposure in Military Training and Operations

INTRODUCTION

During training and combat operations, military personnel may be exposed to repetitive low-level blast while using explosives to gain entry or by firing heavy weapon systems such as recoilless weapons and high-caliber sniper rifles. This repeated exposure, even within allowable limits, has been associated with cognitive deficits similar to that of accidental and sports concussion such as delayed verbal memory, visual-spatial memory, and executive function. This article presents a novel framework for accurate calculation of the human body blast exposure in military heavy weapon training scenarios using data from the free-field and warfighter wearable pressure sensors.

MATERIALS AND METHODS

The CoBi human body model generator tools were used to reconstruct multiple training scenes with different weapon systems. The CoBi Blast tools were used to develop the weapon signature and estimate blast overpressure exposure. The authors have used data from the free-field and wearable pressure sensors to evaluate the framework.

RESULTS

Carl-Gustav and 0.50 caliber sniper training scenarios were used to demonstrate and validate the developed framework. These simulations can calculate spatially and temporally resolved blast loads on the whole human body and on specific organs vulnerable to blast loads, such as head, face, and lungs.

CONCLUSIONS

This framework has numerous advantages including easier model setup and shorter simulation times. The framework is an important step towards developing an advanced field-applicable technology to monitor low-level blast exposure during heavy weapon military training and combat scenarios.

Observation of a Near-Threshold Structure in the K^{+} Recoil-Mass Spectra in e^{+}e^{-}→K^{+}(D_{s}^{-}D^{*0}+D_{s}^{*-}D^{0})

We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7  fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrt[s]=4.681  GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1)  MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0)  MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3  σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.

Observation of the Doubly Cabibbo-Suppressed Decay D^{+}→K^{+}π^{+}π^{-}π^{0} and Evidence for D^{+}→K^{+}ω

Using 2.93  fb^{-1} of e^{+}e^{-} collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, the first observation of the doubly Cabibbo-suppressed decay D^{+}→K^{+}π^{+}π^{-}π^{0} is reported. After removing decays that contain narrow intermediate resonances, including D^{+}→K^{+}η, D^{+}→K^{+}ω, and D^{+}→K^{+}ϕ, the branching fraction of the decay D^{+}→K^{+}π^{+}π^{-}π^{0} is measured to be (1.13±0.08_{stat}±0.03_{syst})×10^{-3}. The ratio of branching fractions of D^{+}→K^{+}π^{+}π^{-}π^{0} over D^{+}→K^{-}π^{+}π^{+}π^{0} is found to be (1.81±0.15)%, which corresponds to (6.28±0.52)tan^{4}θ_{C}, where θ_{C} is the Cabibbo mixing angle. This ratio is significantly larger than the corresponding ratios for other doubly Cabibbo-suppressed decays. The asymmetry of the branching fractions of charge-conjugated decays D^{±}→K^{±}π^{±}π^{∓}π^{0} is also determined, and no evidence for CP violation is found. In addition, the first evidence for the D^{+}→K^{+}ω decay, with a statistical significance of 3.3σ, is presented and the branching fraction is measured to be B(D^{+}→K^{+}ω)=(5.7_{-2.1}^{+2.5}_{stat}±0.2_{syst})×10^{-5}.

Two-Dimensional Dirac Semimetals without Inversion Symmetry

Realizing stable two-dimensional (2D) Dirac points against spin-orbit coupling (SOC) has attracted much attention because it provides a platform to study the unique transport properties. In previous work, Young and Kane [Phys. Rev. Lett. 115, 126803 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.126803 proposed stable 2D Dirac points with SOC, in which the Berry curvature and edge states vanish due to the coexistence of inversion and time-reversal symmetries. Herein, using the tight-binding model and k·p effective Hamiltonian, we present that 2D Dirac points can survive in the presence of SOC without inversion symmetry. Such 2D Dirac semimetals possess nonzero Berry curvature near the crossing nodes, and two edge states are terminated at one pair of Dirac points. In addition, according to symmetry arguments and high-throughput first-principles calculations, we identify a family of ideal 2D Dirac semimetals, which has nonzero Berry curvature in the vicinity of Dirac points and visible edge states, thus facilitating the experimental observations. Our work shows that 2D Dirac points can emerge without inversion symmetry, which not only enriches the classification of 2D topological semimetals but also provides a promising avenue to observe exotic transport phenomena beyond graphene, e.g., nonlinear Hall effect.

[Effects of titanium dioxide nanoparticles on fecal metabolome in rats after oral administration for 90 days]

OBJECTIVE

To explore the effects and related mechanisms of oral exposure titanium dioxide nanoparticles (TiO₂ NPs) for 90 days on the intestinal and the gut microbiota of rats, through fecal metabolomics.

METHODS

Twelve 4-week-old clean-grade Sprague Dawley (SD) rats were randomly de-vided into 2 groups by body weight, treated with TiO₂ NPs at dose of 0 or 50 mg/kg body weight everyday respectively for 90 days. The solution of each infection was freshly prepared and shocked fully by ultrasonic. Characterization of the particle size, crystal form, purity, and specific surface area of TiO₂ NPs was conducted. And the fresh feces of the rats were collected on the 90th day. After lyophilized and hydrophilic phase extraction, ultra performance liquid chromatography-Q-exactive orbitrap-high-resolution mass spectrometry system (UPLC-QEMS) was utilized for non-targeted determination of fecal meta-bolites. The metabolites were identified and labeled through Compound Discoverer 3.0 software, and used for subsequent metabolomics analysis. Bioinformatics analysis was carried out including unsupervised principal component analysis and supervised orthogonal projection to latent structure discriminant analysis for the differential metabolites between the two groups. The differential metabolites were followed-up for Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

RESULTS

Compared with the control group, the body weight of the rats was significantly reduced (P<0.05) in the treatment group. A total of 22 metabolites in fecal metabolomics showed significant changes. Among them, xanthine, 1-methyladenine, 3-hydroxypyridine, methionine sulfoxide, pyridoxine, 1,5-isoquinolinediol, N-acetylornithine, N-acetyl-D-galactosamine, L-citrulline, L-methionine, leucine, DL-tryptophan, L-ornithine, 4-methyl-5-thiazoleethanol, and L-glutamic acid totaled 15 metabolites increased significantly. N-acetylhistamine, D-pipecolinic acid, imidazolelactic acid, L-valine, 2,3,4,6-tetramethylpyrazine, caprolactam, and histamine totaled 7 metabolites decreased significantly. N-acetylhistamine, L-valine and methionine sulfoxide were changed more than 16 times. Analysis of KEGG pathway revealed that the two metabolic pathways arginine biosynthesis and aminoacyl-tRNA biosynthesis were significantly changed (false discover rate < 0.05, pathway impact > 0.1).

CONCLUSION

Oral exposure to TiO₂ NPs for 90 days could disrupt the metabolism of the intestine and gut microbiota, causing significant changes in metabolites and metabolic pathways which were related to inflammatory response, oxidative stress, glucose homeostasis, blood system and amino acid homeostasis in rat feces. It is suggested that the toxic effect of TiO₂ NPs on rats may be closely related to intestinal and gut microbiota metabolism.

[Analysis on the efficacy and safety of fibrinolytic therapy in patients with acute ST-segment elevation myocardial infarction during the COVID-19 epidemic]

Objective: To evaluate the efficacy and safety of fibrinolysis strategy in patients with acute ST-segment elevation myocardial infarction (STEMI) during the COVID-19 epidemic, and to provide reference value for optimization of fibrinolytic process on the premise of prevention and control of COVID-19 transmission, including self-protection of medical staff. Methods: The efficacy and safety of fibrinolysis were retrospectively analyzed in 7 patients with acute STEM, who hospitalized from February 29, 2020 to April 3, 2020 in the Department of Cardiology, Wuhan Union Hospital of Tongji Medical College, Huazhong University of Science and Technology. To optimize the fibrinolytic process on the premise of prevention and control of COVID-19 transmission, including self-protection of medical staff, a full-time medical team in charge of fibrinolysis under third-grade protection was established. The acute STEMI patients were treated immediately in a fixed and isolated area in emergency department before receiving green channel fibrinolysis. Blood samples for complete blood count, COVID-19 antibody test and nasopharyngeal swab samples for COVID-19 nucleic acid test were made before fibrinolysis, while the chest CT examination was accomplished after fibrinolysis. By comparing differences of time from the first electrocardiogram (ECG) to fibrinolysis before and after the improvement of fibrinolytic process, the effect of optimization of the fibrinolytic process was evaluated. Results: In the present study, seven patients with acute STEMI received fibrinolysis therapy, 6 of them achieved reperfusion and no bleeding was observed in all of the patients. Five out of the 7 patients were hospitalized after fibrinolysis, and the hospitalization days were 19.6 days on average. By following up to April 14, 2020, none of the 7 patients died. The first 2 patients were treated according to the routine medical procedure and the time from the first ECG to fibrinolysis were 201 and 106 minutes, respectively. After the optimization of the fibrinolytic process, the time from the first ECG to fibrinolysis of the last 5 patients were 42, 46, 51, 43 and 54 minutes, respectively，which was significantly shorter than that before optimization. Conclusions: During the COVID-19 epidemic, fibrinolysis in patients with acute STEMI is safe, effective and easy to implement. Therefore, it is recommended as the top priority for the patients with acute STEMI with indications for fibrinolysis. On the premise of prevention and control of COVID-19 transmission, including self-protection of medical staff, the duration of myocardial ischemia can be shortened by optimization of the fibrinolytic process.

[Effect of subchronic combined oral exposure of titanium dioxide nanoparticles and glucose on levels of serum folate and vitamin B12 in young SD rats]

OBJECTIVE

To explore the effect of subchronic combined oral exposure of titanium dioxide nanoparticles and glucose on levels of serum folate and vitamin B₁₂ in young SD rats.

METHODS

At first, the physical and chemical properties of titanium dioxide nanoparticles, such as particle size, shape, crystal form and agglomeration degree in solution system, were characterized in detail. Eighty 4-week-old young SD rats were randomly divided into 8 groups (10 rats in each group, half male and half female). The rats were exposed to titanium dioxide nanoparticles through intragastric administration at 0, 2, 10 and 50 mg/kg body weight with or without 1.8 g/kg glucose daily for 90 days. At last, the concentrations of serum folate and vitamin B₁₂ were detected.

RESULTS

Titanium dioxide nanoparticles were anatase crystals, closely spherical shape, with an average particle size of (24±5) nm. In male young rats, compared with the control group, the serum folate concentration was significantly increased when exposed to titanium dioxide nanoparticles (10 mg/kg) and glucose. The difference was statistically significant (P<0.05). However, in female and male young rats, compared with glucose (1.8 g/kg) exposure group, titanium dioxide nanoparticles (50 mg/kg) and glucose significantly reduced the serum folate concentration. The difference was statistically significant (P<0.05). Through statistical analysis of factorial design and calculation of interaction, obvious antagonistic effect was observed between titanium dioxide nanoparticles and glucose on the serum folate concentration in the young female SD rats. The combined oral exposure of titanium dioxide nanoparticles and glucose had little effect on the concentration of serum vitamin B₁₂ in the young SD rats, with no significant interaction between the two substances. It was only found that titanium dioxide nanoparticles (2 mg/kg) and glucose significantly increased the serum vitamin B₁₂ concentration, compared with glucose (1.8 g/kg) exposure group. The difference was statistically significant (P<0.05).

CONCLUSION

Subchronic combined oral exposure of titanium dioxide nanoparticles and glucose had an obvious antagonistic effect on serum folate concentrations in young SD rats.

Anthropometry-based generation of personalized and population-specific human airway models

Understanding aerosol deposition in the human lung is of great significance in pulmonary toxicology and inhalation pharmacology. Adverse effects of inhaled environmental aerosols and pharmacological efficacy of inhaled therapeutics are dependent on aerosol properties as well as person-specific respiratory tract anatomy and physiology. Anatomical geometry and physiological function of human airways depend on age, gender, weight, fitness, health, and disease status. Tools for the generation of the population- and subject-specific virtual airway anatomical geometry based on anthropometric data and physiological vitals are invaluable in respiratory diagnostics, personalized pulmonary pharmacology, and model-based management of chronic respiratory diseases. Here we present a novel protocol and software framework for the generation of subject-specific airways based on anthropometric measurements of the subject's body, using the anatomical input, and the conventional spirometry, providing the functional (physiological) data. This model can be used for subject-specific simulations of respiration physiology, gas exchange, and aerosol inhalation and deposition.

Symmetry-Protected Topological Triangular Weyl Complex

Weyl points are often believed to appear in pairs with opposite chirality. In this work, we show by first-principles calculations and symmetry analysis that single Weyl phonons with linear dispersion and double Weyl phonons with quadratic dispersion are simultaneously present between two specific phonon branches in realistic materials with trigonal or hexagonal lattices. These phonon Weyl points are guaranteed to locate at high-symmetry points due to the screw rotational symmetry, forming a unique triangular Weyl complex. In sharp contrast to conventional Weyl systems with surface arcs terminated at the projections of a pair of Weyl points with opposite chirality, the phonon surface arcs of the unconventional triangular Weyl complex connect the projections of one double Weyl point and two single Weyl points. Importantly, the phonon surface arcs originating from the triangular Weyl complex are extremely long and span the entire surface Brillouin zone. Furthermore, there are only nontrivial phonon surface states across the isofrequency surface, which facilitates their detection in experiments and further applications. Our work not only offers the promising triangular phonon Weyl complex but also provides guidance for exploring triangular Weyl bosons in both phononic and photonic systems.

[Texture analysis of diffusion-weighted magnetic resonance imaging to identify atypically enhanced small hepatocellular carcinoma and dysplastic nodules under the background of cirrhosis]

Objective: To investigate the value of texture analysis based on diffusion-weighted magnetic resonance imaging (DWI) in the differential diagnosis of atypically enhanced small hepatocellular carcinoma (sHCC) and dysplastic nodules (DNs) in liver cirrhosis. Methods: Data of 59 cases with atypical enhancement and solitary cirrhotic nodule (≤2 cm) confirmed by dynamic contrast enhanced MRI and surgical pathology specimen were analyzed retrospectively. Among them, 37 cases were of atypically enhanced sHCC and 22 cases of DNS. The DWI signal characteristics of the lesions were analyzed to measure the average apparent diffusion coefficient (ADC) value of the lesions, and the ADC ratio of the lesion to the liver parenchyma. MaZda software was used to manually draw the region of interest to extract the texture parameters of DWI lesions. The three sets (combination of Fisher coefficient, classification of error probability combined with average correlation coefficient and interactive information) were used to select the thirty optimal texture parameters. Raw data analysis (RDA), principal component analysis (PCA), linear discriminant analysis (LDA) and non-linear discriminant analysis (NDA) were performed for texture classification. The difference of ADC value and ADC ratio between sHCC and DNS group was compared by independent sample t-test, and χ2 test was used to compare the count data (or rate). ROC curve analysis was used to evaluate the diagnostic efficiency. Results: The sensitivity, specificity and accuracy of DWI high-signal in the identification of atypically enhanced sHCC and DNs were 94.6% (35/37), 68.2% (15/22), and 84.7% (50/59), respectively. The ADC ratio of atypically enhanced sHCC was significantly lower than DNs, and the difference was statistically significant (t = 2.99, P = 0.002). The sensitivity, specificity, and accuracy for the diagnosis of atypically enhanced sHCC were 73.0% (27/37), 72.7% (16/22) and 72.9% (43/59), respectively. The sensitivity, specificity and accuracy of DWI texture analysis in diagnosing atypically enhanced sHCC were 94.6% (35/37), 95.5% (21/22) and 94.9% (56/59).The diagnostic efficiency of DWI texture analysis (AUC = 0.94) was significantly higher than DWI high-signal (AUC = 0.81) and ADC ratio (AUC = 0.72). Conclusion: The texture analysis based on DWI can identify atypically enhanced sHCC and dysplastic nodules under the background of cirrhosis, and its efficacy is better than qualitative and quantitative DWI.

[Interference research of umbilical cord mesenchymal stem cells on the pulmonary fibrosis in silicosis rats]

Objective: To explore the effect of the umbilical cord mesenchymal stem cells(UC-MSCs) on the pulmonary fibrosis in silicosis rats. Methods: SPF male Sprague Dawley rats were randomly divided into control group, silica model group and UC-MSCs treatment group with 12 rats each group. SiO(2) intra-tracheal injection(0.5 ml of 50 mg/ml/rat) were applied to silica model group and UC-MSCs treatment groups. After that UC-MSCs treatment group received 1 ml UC-MSCs suspension (3×10(6) cells/ml) by tail vein injection on the 29th, 36th, 43th and 50th day after exposure to the first silica suspension. On the 60th and 75th day after exposure to silica suspension, all animals were examed for pulmonary CT. Then the rats were euthanized on 75th day after the first exposure to silica.Lung's histopathological examination of the rats from all the groups were carried out. The content of hydroxyproline in lungs, TGF-β1 and IL-6 in serum were examined. Results: The lung's histopathological examination showed no obvious inflammatory cell and no fibrosis in the lung tissue of the control group, there were a lot of inflammatory cell aggregation and collagen fiber deposition in silica model group, while in the UC-MSCs intervention group and treatment group, there were less inflammatory cells and collagen fiber. The rats from silica model groups had higher HYP, TGF-β1 and IL-6 than the rats from UC-MSCs treatment group and control group. Lung fields of rats in the control group were clear and no obvious high-density shadow. Different-sized granular high-density shadows or reticular fibrous shadows were found diffusely distributed in the lungs of the rats in silica model group. Lung field of rats in UC-MSCs intervention group and treatment group were less high density shadows, and more clear. Conclusion: UC-MSCs can alleviate the pulmonary fibrosis in silica model rats through regulating the secretion of some fibrosis related cytokines.

Symmetry-Protected Ideal Type-II Weyl Phonons in CdTe

Nontrivial low-energy excitations of crystalline solids have insightfully strengthened understanding of elementary particles in quantum field theory. Usually, topological quasiparticles are mainly focused on fermions in topological semimetals. We alternatively show by first-principles calculations and symmetry analysis that ideal type-II Weyl phonons are present in zinc-blende cadmium telluride, a well-known II-VI semiconductor. Importantly, these type-II Weyl phonons originate from the inversion between the longitudinal acoustic and transverse optical branches. Symmetry guarantees that the type-II Weyl points lie along the high-symmetry lines at the boundaries of the Brillouin zone even with a breaking of inversion symmetry, exhibiting the robustness of protected phonon features. The nontrivial phonon surface states and surface arcs projected on the semifinite (001) and (111) surfaces are investigated. The phonon surface arcs connecting the Weyl points with opposite chirality, guaranteed to be very long, are clearly visible. We not only offer a promising candidate for studying type-II Weyl phonons but also provide a route to realize symmetry-protected nontrivial phonons and related applications in realistic materials.