Imaging the Meissner effect in hydride superconductors using quantum sensors.

By directly altering microscopic interactions, pressure provides a powerful tuning knob for the exploration of condensed phases and geophysical phenomena1. The megabar regime represents an interesting frontier, in which recent discoveries include high-temperature superconductors, as well as structural and valence phase transitions2-6. However, at such high pressures, many conventional measurement techniques fail. Here we demonstrate the ability to perform local magnetometry inside a diamond anvil cell with sub-micron spatial resolution at megabar pressures. Our approach uses a shallow layer of nitrogen-vacancy colour centres implanted directly within the anvil7-9; crucially, we choose a crystal cut compatible with the intrinsic symmetries of the nitrogen-vacancy centre to enable functionality at megabar pressures. We apply our technique to characterize a recently discovered hydride superconductor, CeH9 (ref. 10). By performing simultaneous magnetometry and electrical transport measurements, we observe the dual signatures of superconductivity: diamagnetism characteristic of the Meissner effect and a sharp drop of the resistance to near zero. By locally mapping both the diamagnetic response and flux trapping, we directly image the geometry of superconducting regions, showing marked inhomogeneities at the micron scale. Our work brings quantum sensing to the megabar frontier and enables the closed-loop optimization of superhydride materials synthesis.

[Expression of Mas1 receptor in human placenta and its effect on the function of trophoblast cells in pre-eclampsia patients].

Objective: To investigate the expression change of the Mas1 receptor in the placenta of healthy pregnant women during different gestation periods, analyze the expression level of the Mas1 receptor in the placenta of pre-eclampsia (PE) patients, and its biological function in trophoblast cells. Methods: Placental villous tissues were collected from normal pregnant women in early, mid and late pregnancy. Human trophoblast stem cells were isolated and cultured from early pregnancy villous tissues. The expression of the Mas1 receptor was detected by fluorescence immunoassay and real-time fluorescence quantitative PCR. In a case-control study, patients with full-term PE were selected as the case group and healthy women with full-term pregnancy were selected as the control group. Placental villus tissues were collected from both groups. Immunofluorescence chemistry and immunoprotein blotting were used to study the changes in Mas1 receptor expression in PE. Mas1 receptor agonists and blockers induced HTR8/Svneo cells and BeWo cells, and the effects of the Mas1 receptor on the proliferation and migration of trophoblast cells were detected by the CCK8 proliferation test and scratch test. Results: Eight cases were included in early pregnancy, seven cases in mid-pregnancy and six cases in late pregnancy. Mas1 receptors in normal placental villi tissue were mainly expressed in human trophoblast stem cell membranes and cytoplasm, and the expression of Mas1 receptor mRNA in villi tissue was significantly higher in late pregnancy than in mid-pregnancy. There were 24 cases included in the case group and 12 cases in the control group. Mas1 receptor expression in placental villi was significantly lower in the case group compared to the control group; Activation/inhibition of the Mas1 receptor had no significant effect on the proliferation of HTR8/Svneo cells and BeWo cells. Activated Mas1 receptor had no significant effect on the migration ability of HTR8/Svneo cells. Conclusion: Mas1 receptors are expressed in placental villous tissue and their expression varies with gestation. Mas1 receptor expression is reduced in PE patients, but it does not affect the value-added or migratory function of trophoblast cells.

[Optical quality with ocular aberrations in young myopic eyes with machine learning].

Objective: The objective of this retrospective study was to employ machine learning techniques to examine age-related traits of ocular aberrations in a substantial population with myopia and myopic astigmatism. Methods: This was a cross-sectional study. Data from a population of myopic and myopic astigmatism patients who underwent wavefront aberration examinations at the Refractive Surgery Center of Tianjin Eye Hospital in Tianjin, China, were collected continuously from January 2013 to July 2017. The data from the right eye of each individual were collected for analysis. Each eye had 32 outcome data points, including age, best-corrected visual acuity (BCVA), lower-order aberrations (spherical diopter, cylindrical diopter, and astigmatic axis), and higher-order aberrations [Zernike coefficients and root mean square (RMS) of the third to sixth order aberrations] were analyzed. Higher-order aberrations were measured by Hartmann-Shack aberrometer. Results: The study included 1 507 subjects (1 507 eyes), comprising of 694 males and 813 females, with a mean age of (23.28±5.45) years. The findings demonstrated a decrease followed by an increase in most of the higher-order aberrations with age between 15-40 years. The minimum value points were observed in the age group of 25-30 years for RMS of total higher-order aberrations, 3rd RMS (with a confidence of 47.74% for range 1), 4th RMS (with a confidence of 86.01% for range 1), and trefoil aberrations (with a confidence of 56.38% for C33 and 73.25% for C3-3). The minimum value points were also observed in the age group of 30-35 years for primary spherical aberration (with a confidence of 56.10% for C40) and vertical coma-like aberration (with a confidence of 56.91% for C3-1). In contrast, astigmatism with the rule tended to decrease with age, while astigmatism against the rule and oblique astigmatism tended to increase (with a confidence of 88.66%, 84.71%, 81.07%, 79.67%, and 66.35% for astigmatism with the rule in different age groups). Conclusions: As age increases, the population with with-the-rule astigmatism decreases while the population with against-the-rule astigmatism increases. The high-order aberrations are the lowest in the 25-35 age group.

An investigation of the PM2.5 concentrations and cumulative inhaled dose during subway commutes in Changchun, China.

Air quality in subway systems is crucial as it affects the health of passengers and staff. Although most tests of PM2.5 concentrations in subway stations have taken place in public areas, PM2.5 is less understood in workplaces. Few studies have estimated the cumulative inhaled dose of passengers based on real-time changes in PM2.5 concentrations as they commute. To clarify the above issues, this study first measured PM2.5 concentrations in four subway stations in Changchun, China, where measuring points included five workrooms. Then, passengers' exposure to PM2.5 during the whole subway commute (20-30 min) was measured and segmented inhalation was calculated. The results showed that PM2.5 concentration in public places ranged from 50 to 180 µg/m3, and was strongly correlated with outdoors. While the PM2.5 average concentration in workplaces was 60 µg/m3, and it was less affected by outdoor PM2.5 concentration. Passenger's cumulative inhalations in single commuting were about 42 µg and 100 µg when the outdoor PM2.5 concentrations were 20-30 µg/m3 and 120-180 µg/m3, respectively. The PM2.5 inhalation in carriages accounted for the largest proportion of the entire commuting, about 25-40%, because of the longer exposure time and higher PM2.5 concentrations. It is recommended to improve the tightness of the carriage and filter the fresh air to improve the air quality inside. The average daily PM2.5 inhaled by staff was 513.53 µg, which was 5-12 times higher than that of passengers. Installing air purification devices in workplaces and reminding staff to take personal protection can positively protect their health.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission.

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

[Related environmental factors of refractive parameters in children and adolescents aged 6-14].

Objective: To explore the relationship between environmental factors and refractive parameters of children and adolescents aged 6 to 14 years old. Methods: A total of 566 students aged 6 to 14 years old were selected by using random cluster sampling method in Nankai District and Hongqiao District of Tianjin from September to December 2016. Questionnaires were conducted and refractive parameters were measured including axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD) and lens thickness (LT). Vitreous chamber depth (VCD), corneal radius (CR), the ratio of axial length to corneal radius (AL/CR) and equivalent spherical diopter (SER) were calculated. Multivariate generalized linear model was used to analyze the related factors of refractive parameters. Results: The average age of the subjects was (9.8±2.5) years old, including 302 male students (53.4%). The overall SER, AL, CCT, ACD, LT, VCD, CR and AL/CR ratios were (-1.31±1.85) D, (23.67±1.16) mm, (23.67±1.16) mm, (546.60±31.98) µm, (3.06±0.27) mm, (3.48±0.21) mm, (17.12±1.13) mm, (7.78±0.25) mm and 3.04±0.14, respectively. Multivariate generalized linear model analysis showed that after adjusting for age, gender, height, weight, education level of parents, occupation of parents and family income, compared with those whose daily reading and writing time>6 hours, the AL and VCD of students with daily reading and writing time ≤ 2 hours, 3-4 hours or 5-6 hours were smaller, and the AL/CR ratio of students with daily reading and writing time ≤ 2 hours or 3-4 hours were also smaller (all P<0.05). Compared with those having daily sleep time>9 hours, the students with daily sleep time of 8 hours or 9 hours had higher AL, while the students with daily sleep time of 8 hours had higher CCT, and the students with daily sleep time ≤ 7 hours had higher CR (all P<0.05). Compared with those whose daily electronic screen usage time>1.5 hours, the AL, VCD and CR of students who used electronic screen ≤1.5 hours per day were lower (all P<0.05). Conclusions: Daily reading and writing time, daily electronic screen use time and daily sleep time are the main environmental factors related to eye refractive parameters.

Graphene-based temperature sensors suspended by anodic aluminum oxide.

In this paper, we investigate the substrate effect in graphene temperature sensors. Recently, there have been many research studies done on temperature sensors using the nanofabrication technique. However, the sensitivity and response time need to be improved. In this study, we propose a new type of temperature sensor that consists of graphene and Anodic Aluminum Oxide (AAO). In this device, graphene and AAO are used as the sensing material and the substrate, respectively. We characterize the sensitivity and the response time using the experimental results and simulation data. The real-time resistance change of graphene is monitored depending on the temperature, and the response time is also analyzed by COMSOL Multiphysics. To confirm the porous substrate effect, we compare the device performance of the AAO substrate to the performance of the glass substrate. From these results, the suspended graphene on the AAO substrate shows about two times higher sensitivity and a much faster response time than the glass substrate.

[Clinical observation on corneal transparency after small incision lenticule extraction surgery].

Objective: To evaluate the changes of corneal transparency over the 1-year period after small incision lenticule extraction (SMILE) according to corneal Scheimpflug densitometry. Methods: Prospective cohort study. Fifty-five patients (100 eyes) with myopia (19 male and 36 female, aged 18 to 39 years with average of 24) who underwent SMILE and regular follow-up for at least 1 year at Tianjin Eye Hospital were enrolled. Examinations took place before SMILE and postoperatively at 1 day, 1 week, and 1, 3, 6, and 12 months. The preoperative spherical equivalent of surgical refractive correction was (-5.75±1.64) D. Corneal densitometry (CD) data were calculated automatically by the Pentacam Scheimpflug system and expressed in gray scale units (GSU), from 0 (completely transparent) to 100 (completely opaque). During the analysis of corneal densitometry, the average corneal optical density of three concentric radial zones centered on the apex of the cornea ≤2 mm, >2 mm and ≤6 mm, >6 mm and ≤10 mm diameter) were applied, and three layers were defined according to different corneal depths (the anterior 120 µm as 1st layer, and the posterior 60 µm as 3rd layer, and the center part between them of the cornea as 2nd layer). The automatic release mode was applied in order to avoid operator-induced errors. The preoperative and postoperative values in different corneal layers and different concentric radial zones were compared using Kruskal-Wallis. Results: Ninty-three eyes(93%) of all eyes achieved uncorrected distance visual acuity (UCVA) of 0.8 or better on the first day postoperatively, and 96% (96 of 100 eyes) achieved UCVA of 0.8 or better in the first week postoperatevely, and all eyes 100% (100 of 100 eyes) achieved UCVA 0.8 or better until the end of our follow-up (in 1 year postoperatively). In general, the difference preoperative and postoperative corneal average optical density is of no statistical significance (χ(2)=8.446, P=0.207), specifically, the overall postoperative CD increased in the first week after surgery (1 day to 15.90, 1 week to 15.65), and then decreased to the equivalent of baseline levels and maintained such level until 6 months after surgery (1 month to 15.60; 3 month to 15.50, 6 month to 15.55), though at the 12-month follow-up, densitometry values had spiked significantly again (12 month, 15.90). The difference between the preoperative and postoperative CD values in the central two zones (≤2 mm, >2 mm and ≤6 mm), but not the outer (>6 mm and ≤10 mm), were of statistical significance (χ(2)=61.961, 52.397, P<0.000). When subdivided by corneal layer, significant changes in CD were detected in the anterior 120 µm layer (χ(2)=27.774, P<0.000). The CD increased significantly (i.e., corneal transparency decreased) as compared to the preoperative baseline on the first postoperative day, and lasted through the first week. There were no significant changes in the CD of the central layer (χ(2)=0.918, P=0.986). Significant increases in the posterior 60 µm of the cornea after surgery were found only at the 6-month and 1-year follow-up examinations (χ(2)=17.469, P=0.008). No correlation was found in the preoperative refractive error, ablation depth, postoperative UCVA and the CD. The CD at 6 months was found negatively correlated with SE at 6 months (r=-0.219, P=0.028). Conclusions: SMILE reduced corneal transparency temporarily and primarily within the surgically altered area, however such change has no significant correlation with the ablation depth, SE, and the postoperative UCVA. Transparency recovered within a month, but patients should be monitored for at least 1 year. (Chin J Ophthalmol, 2018, 54: 27-32).

A dual-label time-resolved fluorescence immunoassay for the simultaneous determination of cystatin C and ß2-microglobulin in urine.

BACKGROUND: Contrast media is widely used in clinical diagnostic and interventional procedures, but may cause damage to the kidney, that is, contrast-induced nephropathy. This study was to establish a dual-label time-resolved fluorescence immunoassay (TRFIA) for the simultaneous determination of renal function markers cystatin-C (Cys-C) and ß2-microglobulin (ß2-MG) for the early diagnosis and follow-up surveillance of contrast-induced nephropathy. METHODS: A sandwich immunoassay was used to detect the concentration of Cys-C, and the competitive immunoassay was used to detect the concentration of ß2-MG in 50 samples of urine. The performance of this dual-label TRFIA was evaluated and compared with commercial assays. RESULTS: The sensitivity for Cys-C detection was 1.26 ng/ml, the average recovery was 99.36%; The sensitivity for ß2-MG detection was 2.13 ng/ml, the average recovery was 100.18%. Bland-Altman analysis showed that the dual-label TRFIA method and the commercial kits had a good agreement, suggesting they can be used interchangeably in clinical urine analysis. CONCLUSION: The present dual-label TRFIA has high sensitivity, specificity and accuracy in clinical sample analysis. This method can be used for the early diagnosis and follow-up surveillance of the contrast-induced nephropathy.

Myoglobin A79G polymorphism association with exercise-induced skeletal muscle damage.

We assessed the role of A79G, a polymorphism of the myoglobin gene (MB), in susceptibility to exercise-induced skeletal muscle damage. Between January 2012 and December 2014, a total of 166 cases with exercise-induced skeletal muscle damage and 166 controls were recruited into our study. Genotyping of MB A79G was carried out using polymerase chain reaction coupled with restriction fragment length polymorphism. Using unconditional logistic regression analysis, we found that the GG genotype of MB A79G was associated with higher risk of exercise-induced muscle damage compared with the wild-type genotype, and the OR (95%CI) was 2.91 (1.20-7.59). Compared with the AA genotype, the AG+GG genotype was associated with a significantly increased risk of exercise-induced muscle damage for those with blood lactic acid ≥1.80 mM (OR = 2.05; 95%CI = 1.09-3.88). In conclusion, we found that the A79G polymorphism of the MB gene plays an important role in influencing the development of exercise-induced skeletal muscle damage.

[Evaluate the prevalence of trachoma in high risk area of China].

OBJECTIVE: To determine the prevalence of trachoma in urban and rural area in China. To provide the data evidence for the strategies of eliminating trachoma in China. METHODS: Survey was conducted in 13 suspect trachoma high prevalence provinces according to the World Health Organization trachoma grading system and Trachoma Rapid Assessment(TRA). RESULTS: From 2004 to 2007, a total number of examined children which were younger than 10 years old was 59 630. The prevalence of TF was 0.94%. To sum up the data of 2004 and 2005, the prevalence of active trachoma was 1.71% for children.TT and CO was not reported. The results for subjects older than 50 years old showed that the prevalence of TT was 0.34%. We examined 26 857 adults in both 2004 and 2005.The prevalence of TF, TI, TS and CO was 0.03%,0.08%,0.88% and 0.05% respectively. CONCLUSIONS: The prevalence of active trachoma of younger children was under 5%. However,the prevalence of TT of the adults was not reached the target.

Proteomic analysis revealed the altered kidney protein profile of a Cyld knockout mouse model.

The aim of this study was to compare the proteomics pattern of the kidneys from Cyld knockout mice with that from normal mouse kidneys and establish a preliminary understanding of the role of Cyld in the kidney. Proteins from the kidneys of knockout Cyld mice and wild-type mice were extracted, isobaric tags for relative and absolute quantitation (iTRAQ) was performed, and the proteomics patterns of the two groups were compared. The genotypes of the mice were verified by polymerase chain reaction. A total of 1748 proteins with a local false discovery rate of ≤5% were identified, among which 1437 proteins were reliably recognized and quantified. The expression of two dysregulated proteins was confirmed by Western blotting. Gene ontology and pathway analyses indicated that the proteins identified were involved in biological processes, cell components, and molecular functions, and participated in different pathways. Some of the proteins identified were relevant to renal function or kidney diseases. The difference between the proteomics profiles of kidneys from Cyld knockout mice and wild-type mice was prominent, which correlates to kidney dysfunction and the development of renal diseases.

Transjugular Intrahepatic Portosystemic Shunt Combined with Haemoperfusion in an End-stage Renal Disease Patient with Liver Cirrhosis-related Refractory Portal Hypertensive Variceal Bleeding: A Case Report.

Transjugular intrahepatic portosystemic shunt (TIPS) is recommended as the second-line option for variceal bleeding in liver cirrhosis patients when the bleeding is not well controlled by medical and/or endoscopic therapy. However, due to a high incidence of post-TIPS hepatic encephalopathy, particularly in patients with end-stage renal disease (ESRD), TIPS is rarely used in such cases. We report a case involving the successful and safe use of TIPS combined with haemoperfusion to treat an ESRD patient with liver cirrhosis-related refractory portal hypertensive variceal bleeding. Our case suggests the possibility of inserting TIPS to stop recurrent variceal bleeding in ESRD patients with liver cirrhosis. Haemoperfusion may be used to reduce the risk of post-TIPS hepatic encephalopathy.

Optically controlled background-free terahertz switching in chiral metamaterial.

We demonstrate a multiband background-free terahertz (THz) switch in photoactive chiral metamaterial using polarization conversion. Orthogonal arrangement of two asymmetrical split-ring apertures allows a high polarization conversion efficiency and low copolarization transmission. The chiral metamaterial embedded with photoactive silicon promises a dynamic control on cross-polarization transmission and thus enables an efficient background-free THz switch. The on/off state of THz metamaterial switching can be efficiently controlled by an optical pump. The realization of a cross-polarization THz switch provides a new mechanism of mode switching to control THz wave propagation and will be a promising candidate for polarization devices.

DNA methylation promotes the expression of PPARγ transcript 1 at least in part by preventing NRF1 binding to the promoter P1 of chicken PPARγ gene.

Peroxisome proliferator-activated receptor gamma (PPARγ) is a master regulator of adipogenesis. Our previous study revealed that chicken PPARγ has 3 alternative promoters named as P1, P2, and P3, and the DNA methylation of promoter P3 was negatively associated with PPARγ mRNA expression in abdominal adipose tissue (AAT). However, the methylation status of promoters P1 and P2 is unclear. Here we assessed promoter P1 methylation status in AAT of Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF). The results showed that promoter P1 methylation differed in AAT between the lean and fat lines of NEAUHLF at 7 wk of age (p < 0.05), and AAT expression of PPARγ transcript 1 (PPARγ1), which was derived from the promoter P1, was greatly higher in fat line than in lean line at 2 and 7 wk of age. The results of the correlation analysis showed that P1 methylation was positively correlated with PPARγ1 expression at 7 wk of age (Pearson's r = 0.356, p = 0.0242), suggesting P1 methylation promotes PPARγ1 expression. To explore the underlying molecular mechanism of P1 methylation on PPARγ1 expression, bioinformatics analysis, dual-luciferase reporter assay, pyrosequencing, and electrophoresis mobility shift assay (EMSA) were performed. The results showed that transcription factor NRF1 repressed the promoter activity of the unmethylated P1, but not the methylated P1. Of all the 4 CpGs (CpG48, CpG49, CpG50, and CpG51), which reside within or nearby the NRF1 binding sites of the P1, only CpG49 methylation in AAT was remarkably higher in the fat line than in lean line at 7 wk of age (3.18 to 0.57, p < 0.05), and CpG49 methylation was positively correlated with PPARγ1 expression (Pearson's r = 0.3716, p = 0.0432). Furthermore, EMSA showed that CpG49 methylation reduced the binding of NRF1 to the P1. Taken together, our findings illustrate that P1 methylation promotes PPARγ1 expression at least in part by preventing NRF1 from binding to the promoter P1.

Improving Bond Strength of Translucent Zirconia Through Surface Treatment With SiO2-ZrO2 Coatings.

BACKGROUND: Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bonding with resin composite increases the fracture resistance of ceramic restorations. However, zirconia is a chemically stable material that is difficult to adhesively bond with resin. OBJECTIVES: To investigate the influences of SiO2-ZrO2 coatings on adhesive bonding of zirconia and the surface characterization of those coatings. METHODS AND MATERIALS: Translucent zirconia discs were classified into groups based on surface treatments: CT (control), SB (sandblasting), C21(SiO2:ZrO2=2:1), C11(SiO2:ZrO2=1:1), and C12 (SiO2:ZrO2=1:2) (n=10). Surface characterization of coatings on zirconia were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness assessment (Ra), X-ray diffraction (XRD), water contact angle (WCA), translucency parameter (TP), and shear bond strength (SBS). Two-way ANOVA for shear bond strength results and ANOVA for Ra and WCA were performed. RESULTS: SEM images revealed SiO2 islands on zirconia disks coated with SiO2-ZrO2. Surface roughness of C12, C11, and C21 groups was significantly larger than those of groups SB and CT (p<0.05). XRD results showed that phase transformation of zirconia disks was detected only in the SB group. In addition, SiO2-ZrO2 coatings reduced WCA. The translucency decreased only in group C21. Group C11 showed the highest shear bond strength under both aging conditions. CONCLUSION: SiO2-ZrO2 coating is a promising method to enhance the adhesive resin bonding of translucent zirconia without causing phase transformation of translucent zirconia.

Torsional electromechanical systems based on carbon nanotubes.

Carbon nanotubes (CNTs) are among the most highly studied nanomaterials due to their unique (and intertwined) mechanical and electrical properties. Recent advances in fabrication have allowed devices to be fabricated that are capable of applying a twisting force to individual CNTs while measuring mechanical and electrical response. Here, we review major results from this emerging field of study, revealing new properties of the material itself and opening possibilities for advances in future devices.