Observation of the non-linear Meissner effect.

A long-standing theoretical prediction is that in clean, nodal unconventional superconductors the magnetic penetration depth λ, at zero temperature, varies linearly with magnetic field. This non-linear Meissner effect is an equally important manifestation of the nodal state as the well studied linear-in-T dependence of λ, but has never been convincingly experimentally observed. Here we present measurements of the nodal superconductors CeCoIn5 and LaFePO which clearly show this non-linear Meissner effect. We further show how the effect of a small dc magnetic field on λ(T) can be used to distinguish gap nodes from non-nodal deep gap minima. Our measurements of KFe2As2 suggest that this material has such a non-nodal state.

[Clinical significance and pathogenesis analysis of heterogeneous nuclear ribonucleoprotein U in acute myeloid leukemia].

Objective: To investigate the clinical significance and pathogenesis of heterogeneous nuclear ribonucleoprotein U (hnRNP U) in acute myeloid leukemia (AML) . Methods: The expression of hnRNP U, an RNA binding protein, in patients with AML and healthy controls was compared based on the Gene Expression Profiling Interactive Analysis database and the data of the center. The Beat AML Dataset (n=158) was downloaded from the cBioPortal database. The hnRNP U expression level was divided into the high-expression group (n=89) and low-expression group (n=69) , and patients' clinical characteristics were compared. The effect of hnRNP U on the biological behavior of human AML cell lines was studied by Cell Counting Kit-8 assay to detect cell proliferation. Annexin Ⅴ-APC/7-AAD antibodies were used to detect cell apoptosis. DNA content (PI staining) was quantitatively analyzed to detect cell cycle changes, and colony formation experiments were performed to detect cell cloning formation ability after hnRNP U knockdown in Kasumi-1 and MOLM-13 cells. To study the effect of hnRNP U knockdown on the DNA damage response (DDR) pathway proteins of cleaved-PARP, immunoblot analysis using p-H2A.X was conducted. Results: ①Pan-cancer analysis showed that hnRNP U was highly expressed in patients with AML, and the expression level of hnRNP U mRNA in peripheral blood mononuclear cells was significantly higher in patients with AML than in healthy controls (0.0315±0.0042 vs 0.0195±0.0006, respectively, P<0.01) . ②The age of onset was 56 (2-87) years in the high-expression group and 65 (8-85) years in the low-expression group (t=-2.681, P=0.007) . Moreover, the high-expression group had a higher proportion of combined FLT3 mutations than the low-expression group (χ(2)=4.069, P=0.044) . ③Compared with the negative control, hnRNP U knockdown inhibited the proliferation (P<0.001 and P<0.001) , promoted the apoptosis (P<0.01 and P<0.001) , decreased the colony formation ability (P<0.001 and P<0.001) , and arrested the cell cycles in the G(2)/M phase (P<0.05 and P<0.01) of Kasumi-1 and MOLM-13 cells, respectively. ④hnRNP U knockdown could increase the protein expression of cleaved-PARP and p-H2A.X on the DDR pathway. Conclusion: hnRNP U is highly expressed in AML, and hnRNP U knockdown can inhibit the occurrence and development of AML possibly through the activation of the DDR pathway.

[Multicenter clinical study on the diagnosis and treatment of childhood renal tumor].

Objective: To summarize the effect of Chinese Children's Cancer Group (CCCG) Wilms tumor (WT)-2015 protocol. Methods: This was a prospective study. CCCG-WT-2015 protocol was revised on the basis of the CCCG-WT-2009 protocol. Clinical data of 288 children diagnosed with newly diagnosed kidney neoplasms in fourteen pediatric centers between September 2015 to December 2018 were summarized. The age of onset, distribution of pathological subtypes, staging, curative effect and prognostic factors of these children were analyzed. Kaplan-Meier method was used for survival curve and Log-Rank method was used for univariate analysis. Results: Among 288 cases with kidney neoplasms, there were 261 cases of WT, including 254 cases (97.3%) with favorable histology (FH) WT and 7 cases (2.7%) with unfavorable histology WT (UFHWT). The 3 year events free survival (EFS) rate for FHWT and UFHWT were (88.9±2.1)% and (80.0±17.9)%, which were better than that in WT-2009 (81.2% and 71.7%). In the 96 cases of stage Ⅲ/Ⅳ FHWT with indications for radiotherapy, 76 cases received radiation, another 20 cases received M protocol chemotherapy (cyclophosphamide, etoposide, gentamycin, vincristine and adriamycin) instead of radiation. The 3 year EFS rate for these two groups were (84.7±4.3)% and (84.7±8.1)%(χ2=0.015, P=0.902). There were 22 renal clear cell sarcoma and 5 malignant rhabdoid tumor, 3 year EFS rate of them was (94.4±5.4)% and (20.0±17.9)%. Univariate analysis was performed for age, gender, pathological type, stage, whether rupture occurred during operation, whether complete remission (CR) occurred at the end of treatment and radiotherapy. Pathological types (χ2=44.329,P<0.01) and failure to achieve CR at the end of the treatment (χ2=49.459,P<0.01) were independent factor for predicting survival. Conclusion: Compared with CCCG-WT-2009, treatment of renal tumors in CCCG-WT-2015 study yielded good survival outcome, which can be further applied.

LncRNA TRERNA1 promotes malignant progression of NSCLC through targeting FOXL1.

OBJECTIVE: Previous studies have shown the carcinogenic role of long-chain non-coding RNAs (lncRNA) TRERNA1. However, the role of TRERNA1 in non-small cell lung cancer (NSCLC) has not been reported. This research aims to explore the regulatory effect of TRERNA1/FOXL1 axis on the malignant progression of NSCLC. PATIENTS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine the expression levels of TRERNA1 and FOXL1 in 39 pairs of tumor tissues and paracancerous ones collected from NSCLC patients. The potential relation between TRERNA1 expression and clinical indicators of NSCLC patients was analyzed. Meanwhile, expression levels of TRERNA1 and FOXL1 in NSCLC cell lines were also detected by qRT-PCR. In addition, TRERNA1 knockdown model was constructed in H358 and SPC-A1 cells. Cell counting kit-8 (CCK-8), cell colony formation assay, and flow cytometry were applied to analyze the influence of TRERNA1 on NSCLC cell biological functions. Finally, Dual-Luciferase reporter gene assay and cell reverse recovery experiments were performed to figure out the underlying mechanisms of TRERNA1 in regulating NSCLC progression. RESULTS: QRT-PCR results indicated that the expression level of lncRNA TRERNA1 in tumor tissue samples of NSCLC patients was remarkably higher than that in adjacent tissues. Compared with NSCLC patients with low expression of TRERNA1, patients with high TRERNA1 expression had a worse pathological stage and overall survival. Similarly, compared with cells in sh-NC group, the proliferation ability of cells in sh-TRERNA1 group was remarkably attenuated. In addition, cell ratio in the G1 phase increased after knockdown of TRERNA1, suggesting the arrested G1/S cell cycle. Subsequently, FOXL1 was downregulated in NSCLC cell lines and tumor tissues. Meanwhile, FOXL1 level was verified to be negatively correlated with TRERNA1 level. Additionally, the binding between TRERNA1 and FOXL1 was confirmed by Dual-Luciferase reporter gene assay. Cell reverse investigation indicated the involvement of FOXL1 in TRERNA1-regulated malignant progression of NSCLC. CONCLUSIONS: LncRNA TRERNA1 was up-regulated both in NSCLC tissues and cell lines. Its level was associated with pathological stage and poor prognosis in NSCLC. In addition, lncRNA TRERNA1 could promote the malignant progression of NSCLC via modulating FOXL1.

MUC1 inhibition leads to decrease in PD-L1 levels via upregulation of miRNAs.

The PD-L1/PD-1 pathway is a critical component of the immunosuppressive tumor microenvironment in acute myeloid leukemia (AML), but little is known about its regulation. We investigated the role of the MUC1 oncoprotein in modulating PD-L1 expression in AML. Silencing of MUC1 in AML cell lines suppressed PD-L1 expression without a decrease in PD-L1 mRNA levels, suggesting a post-transcriptional mechanism of regulation. We identified the microRNAs miR-200c and miR-34a as key regulators of PD-L1 expression in AML. Silencing of MUC1 in AML cells led to a marked increase in miR-200c and miR-34a levels, without changes in precursor microRNA, suggesting that MUC1 might regulate microRNA-processing. MUC1 signaling decreased the expression of the microRNA-processing protein DICER, via the suppression of c-Jun activity. NanoString (Seattle, WA, USA) array of MUC1-silenced AML cells demonstrated an increase in the majority of probed microRNAs. In an immunocompetent murine AML model, targeting of MUC1 led to a significant increase in leukemia-specific T cells. In concert, targeting MUC1 signaling in human AML cells resulted in enhanced sensitivity to T-cell-mediated lysis. These findings suggest MUC1 is a critical regulator of PD-L1 expression via its effects on microRNA levels and represents a potential therapeutic target to enhance anti-tumor immunity.

Tunnel electroresistance through organic ferroelectrics.

Organic electronics is emerging for large-area applications such as photovoltaic cells, rollable displays or electronic paper. Its future development and integration will require a simple, low-power organic memory, that can be written, erased and readout electrically. Here we demonstrate a non-volatile memory in which the ferroelectric polarisation state of an organic tunnel barrier encodes the stored information and sets the readout tunnel current. We use high-sensitivity piezoresponse force microscopy to show that films as thin as one or two layers of ferroelectric poly(vinylidene fluoride) remain switchable with low voltages. Submicron junctions based on these films display tunnel electroresistance reaching 1,000% at room temperature that is driven by ferroelectric switching and explained by electrostatic effects in a direct tunnelling regime. Our findings provide a path to develop low-cost, large-scale arrays of organic ferroelectric tunnel junctions on silicon or flexible substrates.

NMR Evidence for Inhomogeneous Nematic Fluctuations in BaFe_{2}(As_{1-x}P_{x})_{2}.

We present evidence for nuclear spin-lattice relaxation driven by glassy nematic fluctuations in isovalent P-doped BaFe_{2}As_{2} single crystals. Both the ^{75}As and ^{31}P sites exhibit a stretched-exponential relaxation similar to the electron-doped systems. By comparing the hyperfine fields and the relaxation rates at these sites we find that the As relaxation cannot be explained solely in terms of magnetic spin fluctuations. We demonstrate that nematic fluctuations couple to the As nuclear quadrupolar moment and can explain the excess relaxation. These results suggest that glassy nematic dynamics are a common phenomenon in the iron-based superconductors.

Persistent order due to transiently enhanced nesting in an electronically excited charge density wave.

Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time- and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of the dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. Our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order.

Origin of the Resistive Anisotropy in the Electronic Nematic Phase of BaFe(2)As(2) Revealed by Optical Spectroscopy.

We perform, as a function of uniaxial stress, an optical-reflectivity investigation of the representative "parent" ferropnictide BaFe(2)As(2) in a broad spectral range, across the tetragonal-to-orthorhombic phase transition and the onset of the long-range antiferromagnetic (AFM) order. The infrared response reveals that the dc transport anisotropy in the orthorhombic AFM state is determined by the interplay between the Drude spectral weight and the scattering rate, but that the dominant effect is clearly associated with the metallic spectral weight. In the paramagnetic tetragonal phase, though, the dc resistivity anisotropy of strained samples is almost exclusively due to stress-induced changes in the Drude weight rather than in the scattering rate, definitively establishing the anisotropy of the Fermi surface parameters as the primary effect driving the dc transport properties in the electronic nematic state.

Observation of universal strong orbital-dependent correlation effects in iron chalcogenides.

Establishing the appropriate theoretical framework for unconventional superconductivity in the iron-based materials requires correct understanding of both the electron correlation strength and the role of Fermi surfaces. This fundamental issue becomes especially relevant with the discovery of the iron chalcogenide superconductors. Here, we use angle-resolved photoemission spectroscopy to measure three representative iron chalcogenides, FeTe0.56Se0.44, monolayer FeSe grown on SrTiO3 and K0.76Fe1.72Se2. We show that these superconductors are all strongly correlated, with an orbital-selective strong renormalization in the dxy bands despite having drastically different Fermi surface topologies. Furthermore, raising temperature brings all three compounds from a metallic state to a phase where the dxy orbital loses all spectral weight while other orbitals remain itinerant. These observations establish that iron chalcogenides display universal orbital-selective strong correlations that are insensitive to the Fermi surface topology, and are close to an orbital-selective Mott phase, hence placing strong constraints for theoretical understanding of iron-based superconductors.

Enhanced magnetic anisotropies of single transition-metal adatoms on a defective MoS2 monolayer.

Single magnetic atoms absorbed on an atomically thin layer represent the ultimate limit of bit miniaturization for data storage. To approach the limit, a critical step is to find an appropriate material system with high chemical stability and large magnetic anisotropic energy. Here, on the basis of first-principles calculations and the spin-orbit coupling theory, it is elucidated that the transition-metal Mn and Fe atoms absorbed on disulfur vacancies of MoS2 monolayers are very promising candidates. It is analysed that these absorption systems are of not only high chemical stabilities but also much enhanced magnetic anisotropies and particularly the easy magnetization axis is changed from the in-plane one for Mn to the out-of-plane one for Fe by a symmetry-lowering Jahn-Teller distortion. The results point out a promising direction to achieve the ultimate goal of single adatomic magnets with utilizing the defective atomically thin layers.

Coherent dynamics of the charge density wave gap in tritellurides.

The dynamics of the transient electronic structure in the charge density wave (CDW) system RTe3 (R = rare-earth element) is studied using time- and angle-resolved photoemission spectroscopy (trARPES). Employing a three-pulse pump-probe scheme we investigate the effect of the amplitude mode oscillations on the electronic band structure and, in particular, on the CDW energy gap. We observe coherent oscillations in both lower and upper CDW band with opposite phases, whereby two dominating frequencies are modulating the CDW order parameter. This demonstrates the existence of more than one collective amplitude mode, in contrast to a simple Peierls model. Coherent control experiments of the two amplitude modes, which are strongly coupled in equilibrium, demonstrate independent control of the modes suggesting a decoupling of both modes in the transient photoexcited state.

Photoluminescence study on polar nanoregions and structural variations in Pb(Mg1/3Nb2/3)O3 ₋ PbTiO3 single crystals.

We report polar nanostructure and electronic transitions in relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 ₋ PbTiO (PMN-PT) single crystals around morphotropic phase boundary (MPB) region by variable-temperature (80-800 K) photoluminescence (PL) spectra and low-wavenumber Raman scattering (LWRS). The discontinuous evolution from peak positions and intensity of luminescence emissions can be corresponding to formation of polar nanoclusters and phase transitions. Six emissions have been derived from PL spectra and show obvious characteristics near phase transition temperatures, which indicates that PL spectral measurement is promising in understanding the microcosmic mechanism. The Raman mode at 1145 cm(-1) indicates that temperature dependent luminescence phenomena can be modulated by thermal quenching.

Generic Feature Selection with Short Fat Data.

Consider a regression problem in which there are many more explanatory variables than data points, i.e., p ≫ n. Essentially, without reducing the number of variables inference is impossible. So, we group the p explanatory variables into blocks by clustering, evaluate statistics on the blocks and then regress the response on these statistics under a penalized error criterion to obtain estimates of the regression coefficients. We examine the performance of this approach for a variety of choices of n, p, classes of statistics, clustering algorithms, penalty terms, and data types. When n is not large, the discrimination over number of statistics is weak, but computations suggest regressing on approximately [n/K] statistics where K is the number of blocks formed by a clustering algorithm. Small deviations from this are observed when the blocks of variables are of very different sizes. Larger deviations are observed when the penalty term is an Lq norm with high enough q.

Anisotropic magnetoresistance in an antiferromagnetic semiconductor.

Recent studies in devices comprising metal antiferromagnets have demonstrated the feasibility of a novel spintronic concept in which spin-dependent phenomena are governed by an antiferromagnet instead of a ferromagnet. Here we report experimental observation of the anisotropic magnetoresistance in an antiferromagnetic semiconductor Sr2IrO4. Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure. The antiferromagnet film is exchange coupled to a ferromagnet, which allows us to reorient the antiferromagnet spin-axis in applied magnetic fields via the exchange spring effect. We demonstrate that the semiconducting nature of our AFM electrode allows us to perform anisotropic magnetoresistance measurements in the current-perpendicular-to-plane geometry without introducing a tunnel barrier into the stack. Temperature-dependent measurements of the resistance and anisotropic magnetoresistance highlight the large, entangled tunabilities of the ordinary charge and spin-dependent transport in a spintronic device utilizing the antiferromagnet semiconductor.

Dynamic competition between spin-density wave order and superconductivity in underdoped Ba(1-x)K(x)Fe2As2.

An intriguing aspect of unconventional superconductivity is that it always appears in the vicinity of other competing phases, whose suppression brings the full emergence of superconductivity. In the iron pnictides, these competing phases are marked by a tetragonal-to-orthorhombic structural transition and a collinear spin-density wave (SDW) transition. There has been macroscopic evidence for competition between these phases and superconductivity as the magnitude of both the orthorhombicity and magnetic moment are suppressed in the superconducting state. Here, using angle-resolved photoemission spectroscopy on detwinned underdoped Ba(1-x)K(x)Fe2As2, we observe a coexistence of both the SDW gap and superconducting gap in the same electronic structure. Furthermore, our data reveal that following the onset of superconductivity, the SDW gap decreases in magnitude and shifts in a direction consistent with a reduction of the orbital anisotropy. This observation provides direct spectroscopic evidence for the dynamic competition between superconductivity and both SDW and electronic nematic orders in these materials.

Room-temperature antiferromagnetic memory resistor.

The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.

Copy number variation prevalence in known asthma genes and their impact on asthma susceptibility.

BACKGROUND: Genetic studies have identified numerous genes reproducibly associated with asthma, yet these studies have focussed almost entirely on single nucleotide polymorphisms (SNPs), and virtually ignored another highly prevalent form of genetic variation: Copy Number Variants (CNVs). OBJECTIVE: To survey the prevalence of CNVs in genes previously associated with asthma, and to assess whether CNVs represent the functional asthma-susceptibility variants at these loci. METHODS: We genotyped 383 asthmatic trios participating in the Childhood Asthma Management Program (CAMP) using a competitive genomic hybridization (CGH) array designed to interrogate 20 092 CNVs. To ensure comprehensive assessment of all potential asthma candidate genes, we purposely used liberal asthma gene inclusion criteria, resulting in consideration of 270 candidate genes previously implicated in asthma. We performed statistical testing using FBAT-CNV. RESULTS: Copy number variation in asthma candidate genes was prevalent, with 21% of tested genes residing near or within one of 69 CNVs. In six instances, the complete candidate gene sequence resides within the CNV boundaries. On average, asthmatic probands carried six asthma-candidate CNVs (range 1-29). However, the vast majority of identified CNVs were of rare frequency (< 5%) and were not statistically associated with asthma. Modest evidence for association with asthma was observed for 2 CNVs near NOS1 and SERPINA3. Linkage disequilibrium analysis suggests that CNV effects are unlikely to explain previously detected SNP associations with asthma. CONCLUSIONS AND CLINICAL RELEVANCE: Although a substantial proportion of asthma-susceptibility genes harbour polymorphic CNVs, the majority of these variants do not confer increased asthma risk. The lack of linkage disequilibrium (LD) between CNVs and asthma-associated SNPs suggests that these CNVs are unlikely to represent the functional variant responsible for most known asthma associations.

Observation of temperature-induced crossover to an orbital-selective Mott phase in A(x)Fe(2-y)Se2 (A=K, Rb) superconductors.

Using angle-resolved photoemission spectroscopy, we observe the low-temperature state of the A(x)Fe(2-y)Se(2) (A=K, Rb) superconductors to exhibit an orbital-dependent renormalization of the bands near the Fermi level-the d(xy) bands heavily renormalized compared to the d(xz)/d(yz) bands. Upon raising the temperature to above 150 K, the system evolves into a state in which the d(xy) bands have depleted spectral weight while the d(xz)/d(yz) bands remain metallic. Combined with theoretical calculations, our observations can be consistently understood as a temperature-induced crossover from a metallic state at low temperatures to an orbital-selective Mott phase at high temperatures. Moreover, the fact that the superconducting state of A(x)Fe(2-y)Se(2) is near the boundary of such an orbital-selective Mott phase constrains the system to have sufficiently strong on-site Coulomb interactions and Hund's coupling, highlighting the nontrivial role of electron correlation in this family of iron-based superconductors.