Observation of Double Weyl Phonons in Parity-Breaking FeSi

Condensed matter systems have now become a fertile ground to discover emerging topological quasiparticles with symmetry protected modes. While many studies have focused on fermionic excitations, the same conceptual framework can also be applied to bosons yielding new types of topological states. Motivated by Zhang et al.'s recent theoretical prediction of double Weyl phonons in transition metal monosilicides [Phys. Rev. Lett. 120, 016401 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.016401], we directly measure the phonon dispersion in parity-breaking FeSi using inelastic x-ray scattering. By comparing the experimental data with theoretical calculations, we make the first observation of double Weyl points in FeSi, which will be an ideal material to explore emerging bosonic excitations and its topologically nontrivial properties.

Visual preconditioning reduces emergence delirium in children undergoing ophthalmic surgery: a randomised controlled trial

BACKGROUND

Emergence delirium is a common complication in children, especially in preschool children undergoing ophthalmic surgery. The aim of the study was to investigate the effects of visual preconditioning (application of an eyepatch over the eye to be operated for ≥3 h the day before surgery) on emergence delirium after ophthalmic surgery under sevoflurane anaesthesia.

METHODS

One hundred and seventy-nine children undergoing unilateral cataract surgery, aged 3-7 yr, were involved in this prospective, blinded, randomised study. Subjects were randomised to receive visual preconditioning (Group P, n=89) or to receive programmed explanation the day before surgery (Group C, n=90). The primary outcome was incidence of emergence delirium evaluated by the paediatric anaesthesia emergence delirium (PAED) scale. The secondary outcomes included emergence time and post-anaesthesia care unit (PACU) stay time.

RESULTS

Children in Group P had a significantly lower incidence of emergence delirium than those in Group C [16.9% vs 44.4%, odds ratio (OR) 4.0, 95% confidence interval (CI) 2.0 to 8.0]. The maximal PAED score was lower in Group P than in Group C [4 (0-20) vs 9 (0-20), median difference -3.0, 95% CI -5.0 to -1.0]. Visual preconditioning prolonged emergence time (P<0.001) and PACU stay time (P=0.002).

CONCLUSION

Visual disturbance contributes to emergence delirium in preschool children undergoing ophthalmic surgery with sevoflurane, and prophylactic eyepatch treatment can reduce emergence delirium.

CLINICAL TRIALS REGISTRATION

NCT02590744.

ROCK Inhibitor Y-27632 Promotes Human Retinal Pigment Epithelium Survival by Altering Cellular Biomechanical Properties

Purpose:

Dysfunction or death of retinal pigment epithelial (RPE) cells is a common pathogenesis of various types of retinal degenerative diseases. Recent reports indicated that ROCK pathway inhibitors regulate cell proliferation or apoptosis in a cell-type-dependent manner. Here, we aim to investigate the effect of ROCK inhibitor Y-27632 on the human retinal pigment epithelium (RPE) in vitro.

Methods:

Cell proliferation and apoptosis were analyzed by CCK-8 and flow cytometry respectively. Cell proliferation markers were detected by immunofluorescence and western blot. Cell morphology was evaluated using scanning electron microscopy. The topography and biomechanical properties of living cells were assessed using atomic force microscope (AFM). In addition, cytoskeleton and epithelial-mesenchymal transition (EMT) markers were detected by western blot and immunofluorescence.

Results:

30μM Y-27632 significantly promoted cell proliferation and decreased apoptosis. Compared with control group, human retinal pigment epithelial cell line ARPE-19 cells treated with 30μM Y-27632 exhibited significantly decreased cytomembrane roughness (Ra: 41.04±1.63nm vs. 24.41±0.75nm, P<0.01; Rq: 51.56±2.03nm vs. 30.81±0.95nm, P<0.01) and increased elasticity modulus (16.66±0.83KPa vs. 32.55±1.48KPa, P<0.01). In addition, the inhibition of ROCK activity by Y-27632 caused cell elongation and reorganization of microfilaments and microtubules of cytoskeletons.

Conclusion:

Taken together, our data demonstrated that Y-27632 could alter biomechanical properties and reorganized cytoskeletons to promote RPE cell survival. These results are an important step toward the future application of Y-27632 in retinal degenerative diseases.

Membrane complement regulatory protein reduces the damage of transplanting autologous bone marrow mesenchymal stem cells by suppressing the activation of complement

There are few studies on the interaction of transplanting autologous bone marrow mesenchymal stem cells (BMSCs) and complement. In order to further explore the effect of complement on BMSCs, BMSCs were obtained from bone marrow of 20 cases clinical patients, and then experimented in vitro. The cytotoxicity of complement on the mesenchymal stem cells in autologous human serum (AHS) was measured by Europium cytotoxicity assay. The complement membrane attack complex (MAC) deposited on the membrane surface was detected by flow cytometry. Finally, the cytotoxicity on BMSCs was measured after mCRPs overexpression or knockdown. We found that more than 90% of cells derived from bone marrow were identified to be mesenchymal stem cells through detection of cell membrane surface markers by flow cytometry. BMSCs harvested from the 20 patients all had cytotoxicity after incubated with AHS, and the cytotoxicity was significant higher than that incubated with complement inactivated autologous human serum (iAHS). Complement attack complex (MAC) could be detected on the BMSCs incubated with AHS, which implied the complement activation. We also found that mCRPs CD55 and CD59 overexpressions can resist the cytotoxicity induced by complement activation, while mCRPs CD55 and CD59 knockdown can enhance the cytotoxicity. Thus, the results indicated that mCRPs could effectively protect BMSCs from attacking by complement by suppressing the activation of complement.

Association of endothelin-1 gene polymorphisms with essential hypertension in a Chinese population

Endothelin-1 (ET-1) is the most potent endogenous vasoconstrictor and is involved in several vascular disorders such as hypertension. Its strong interaction with other vasoactive hormone systems suggests that the ET-1 gene (EDN1) is a potential candidate molecule that influences the risk of developing hypertension. Recently, two single nucleotide polymorphisms in EDN1 have been reported to be associated with hypertension: Lys198Asn and 3A/4A (-134delA) located in the 5'-untranslated region. To determine the association of these two polymorphisms with hypertension, we genotyped patients and controls (N = 537) and compared the allele and genotype frequencies between groups. There was no significant difference in the genotype frequencies of these two polymorphisms between healthy controls and hypertension patients. Although previous reports have revealed a significant interaction between the END1 Lys198Asn (G/T) polymorphism and body mass index in association with hypertension, no such relationship was observed in the present study. Further, we compared blood pressure among hypertensive subjects and observed that neither systolic nor diastolic blood pressure was significantly associated with variations in the genotypes of the two single nucleotide polymorphisms. In summary, these two END1 polymorphisms do not appear to affect the development of hypertension in the Chinese population.

A SAR-based mechanistic study on the combined toxicities of sulfonamides and quorum sensing inhibitors on Escherichia coli

Quorum sensing inhibitors (QSIs) are promising alternatives to antibiotics, but they are discharged into the environment after their use cycle. This poses joint effects on the organisms in the environment. Therefore, it is of great importance to study the combined toxicities of QSIs and antibiotics. In this study, we investigated the single and combined toxicities of four potential QSIs and 11 sulfonamides (SAs) on Escherichia coli. The results revealed that the single toxicities of SAs were greater than those of QSIs, and the toxicities were found positively related to the binding energies (E_bind) with their target proteins, for both antibiotics and QSIs. The combined toxicities of the binary mixtures were observed to be either antagonism or addition. The antagonism could be explained by the phenomenon that QSIs changed SAs molecules into ionic forms, preventing the SA molecules entering the bacteria. Furthermore, it was found that the ratios of the effective concentration (the actual concentration involved in the interaction with the proteins) in the antagonistic cases were higher than those in the additive cases. This study would benefit both rational use of the drug combination and ecological risk assessment of antibiotics and QSIs in the real environment.

Dietary supplementation with tributyrin prevented weaned pigs from growth retardation and lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation

Weanling pigs, with an underdeveloped intestine and immature immune system, are usually subjected to depressed feed intake, growth retardation, and postweaning diarrhea. The aim of this study was to determine 1) the growth response of weaned pigs to supplemental tributyrin (TB) and 2) the potential effects and mechanisms of TB in modulating immune responses of lipopolysaccharide (LPS)-challenged piglets. A total of 240 piglets (Duroc × Large White × Landrace) were weaned at 21 d of age to a control (basal diet), supplemented with antibiotics (AB; +AB), supplemented with TB (+TB), or with supplemental AB and TB (+AB+TB) diets, with 10 replicate pens (6 piglets/pen) per diet. At 49 d of age, male pigs from the control and +TB groups were intraperitoneally injected with LPS (25 μg/kg BW) or saline ( = 6) and sacrificed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis. There were higher ( < 0.05) feed intake and lower ( < 0.05) percentage of negative growth piglets in the +TB groups than in the control group during the first week after weaning. For piglets without LPS challenge, there were higher ( < 0.05) ileal fibroblast growth factor 19 () mRNA abundance and total bile acid concentrations in the +TB groups than in the control group, whereas downregulated ( < 0.05) expression was observed in the +TB groups after LPS challenge. Lipopolysaccharide challenge in the control group increased ( < 0.05) plasma tumor necrosis factor α and IL-6 concentrations and colonic amount and decreased ( < 0.05) colonic goblet cells and colonic and cecal acetate concentrations, with no differences ( > 0.05) observed between +TB groups following LPS challenge. Taken together, dietary supplementation with TB prevented growth retardation through stimulating the appetite of weaned pigs and protected piglets against lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation.

Superconductivity in HfTe5 across weak to strong topological insulator transition induced via pressures

Recently, theoretical studies show that layered HfTe₅ is at the boundary of weak & strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe₅ are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic & crystal structures for HfTe₅ with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI. The HfTe₅ crystal becomes superconductive above ~5.5 GPa where the Tp reaches maximum. The highest superconducting transition temperature (Tc) around 5 K was achieved at 20 GPa. Crystal structure studies indicate that HfTe₅ transforms from a Cmcm phase across a monoclinic C2/m phase then to a P-1 phase with increasing pressure. Based on transport, structure studies a comprehensive phase diagram of HfTe₅ is constructed as function of pressure. The work provides valuable experimental insights into the evolution on how to proceed from a weak TI precursor across a strong TI to superconductors.

Topologically Entangled Rashba-Split Shockley States on the Surface of Grey Arsenic

We discover a pair of spin-polarized surface bands on the (111) face of grey arsenic by using angle-resolved photoemission spectroscopy (ARPES). In the occupied side, the pair resembles typical nearly-free-electron Shockley states observed on noble-metal surfaces. However, pump-probe ARPES reveals that the spin-polarized pair traverses the bulk band gap and that the crossing of the pair at Γ[over ¯] is topologically unavoidable. First-principles calculations well reproduce the bands and their nontrivial topology; the calculations also support that the surface states are of Shockley type because they arise from a band inversion caused by crystal field. The results provide compelling evidence that topological Shockley states are realized on As(111).

PKR2 and β-catenin genes regulates pancreatic cancer chemosensitivity

OBJECTIVE

Pancreas is a well developed glandular organ lying behind the stomach. Cancer arises in this organ are difficult to identify in the initial stages, even in advanced stages it shows non-specific symptoms, and it is difficult to prognosis. Since they are identified and treated in the last stage, they are less responsive to chemotherapy. Therefore, it is important to study the proteins that are involved in regulating chemosensitivity and chemoresistance.

MATERIALS AND METHODS

Initially, using KRAS mutant mice, we developed initial and advanced stage of pancreatic cancer. And we analyzed the expression of PKR2 and β-catenin in different pathological stages of pancreatic cancer using Immunohistology and Western blotting.

RESULTS

The histology of the tissue nature confirms and helps to categorize cancer, which shows enlarged nucleus in initial stages and shows clustering of cells in advanced stages. Immunohistological and Western blotting analyzes show prominent increasing in the expression of PKR2 and β-catenin as the tumor develops to the next stages. On the course of initial treatment with cisplatin we find out that PKR2 and β-catenin regulate the chemosensitivity with under-expression when compared with respective controls. In the advanced stages of pancreatic cancer with cisplatin treatment, we observed chemoresistance behavior with overexpression, especially for β-catenin.

CONCLUSIONS

The results conclude that using PKR2 and β-catenin we are able to assess the chemosensitivity and chemoresistance nature of pancreatic cancer.

Fabrication of HA/PEI-functionalized carbon dots for tumor targeting, intracellular imaging and gene delivery

Carbon quantum dots (CDs) as emerging carbon nano-materials have attracted tremendous attention in biomedical fields due to unique properties.