Higher order gaps in the renormalized band structure of doubly aligned hBN/bilayer graphene moiré superlattice.

This paper presents our findings on the recursive band gap engineering of chiral fermions in bilayer graphene doubly aligned with hBN. Using two interfering moiré potentials, we generate a supermoiré pattern that renormalizes the electronic bands of the pristine bilayer graphene, resulting in higher order fractal gaps even at very low energies. These Bragg gaps can be mapped using a unique linear combination of periodic areas within the system. To validate our findings, we use electronic transport measurements to identify the position of these gaps as a function of the carrier density. We establish their agreement with the predicted carrier densities and corresponding quantum numbers obtained using the continuum model. Our study provides strong evidence of the quantization of the momentum-space area of quasi-Brillouin zones in a minimally incommensurate lattice. It fills important gaps in the understanding of band structure engineering of Dirac fermions with a doubly periodic superlattice spinor potential.

Controlling Umklapp Scattering in a Bilayer Graphene Moiré Superlattice.

We present experimental findings on electron-electron scattering in two-dimensional moiré heterostructures with a tunable Fermi wave vector, reciprocal lattice vector, and band gap. We achieve this in high-mobility aligned heterostructures of bilayer graphene (BLG) and hBN. Around the half-full point, the primary contribution to the resistance of these devices arises from Umklapp electron-electron (Uee) scattering, making the resistance of graphene/hBN moiré devices significantly larger than that of non-aligned devices (where Uee is forbidden). We find that the strength of Uee scattering follows a universal scaling with Fermi energy and is nonmonotonically dependent on the superlattice period. The Uee scattering can be tuned with the electric field and is affected by layer polarization of BLG. It has a strong particle-hole asymmetry; the resistance when the chemical potential is in the conduction band is significantly lower than when it is in the valence band, making the electron-doped regime more practical for potential applications.

Breakdown of semiclassical description of thermoelectricity in near-magic angle twisted bilayer graphene.

The planar assembly of twisted bilayer graphene (tBLG) hosts multitude of interaction-driven phases when the relative rotation is close to the magic angle (θm = 1.1∘). This includes correlation-induced ground states that reveal spontaneous symmetry breaking at low temperature, as well as possibility of non-Fermi liquid (NFL) excitations. However, experimentally, manifestation of NFL effects in transport properties of twisted bilayer graphene remains ambiguous. Here we report simultaneous measurements of electrical resistivity (ρ) and thermoelectric power (S) in tBLG for several twist angles between θ ~ 1.0 - 1.7∘. We observe an emergent violation of the semiclassical Mott relation in the form of excess S close to half-filling for θ ~ 1.6∘ that vanishes for θ ≳ 2∘. The excess S (≈2 µV/K at low temperatures T ~ 10 K at θ ≈ 1.6∘) persists upto ≈40 K, and is accompanied by metallic T-linear ρ with transport scattering rate (τ-1) of near-Planckian magnitude τ-1 ~ kBT/ℏ. Closer to θm, the excess S was also observed for fractional band filling (ν ≈ 0.5). The combination of non-trivial electrical transport and violation of Mott relation provides compelling evidence of NFL physics intrinsic to tBLG.

Molecular markers for early stratification of disease severity and progression in COVID-19

COVID-19 infections have imposed immense pressure on the healthcare system of most countries. While the initial studies have identified better therapeutic and diagnostic approaches, the disease severity is still assessed by close monitoring of symptoms by healthcare professionals due to the lack of biomarkers for disease stratification. In this study, we have probed the immune and molecular profiles of COVID-19 patients at 48-hour intervals after hospitalization to identify early markers, if any, of disease progression and severity. Our study reveals that the molecular profiles of patients likely to enter the host-immune response mediated moderate or severe disease progression are distinct even in the early phase of infection when severe symptoms are not yet apparent. Our data from 37 patients suggest that at hospitalization, IL6 (>300pg/ml) and IL8 levels (>200pg/ml) identify cytokine-dependent disease progression. Monitoring their levels will facilitate timely intervention using available immunomodulators or precision medicines in those likely to progress due to cytokine storm and help improve outcomes. Additionally, it will also help identify cytokine-independent progressive patients, not likely to benefit from immuno-modulators or precision drugs.

Surprises in the t-J Model: Implications for Cuprates.

Many strongly correlated systems, such as the cuprate superconductors, have the interesting physics of low dimensionality and hence enhanced fluctuation effects. We perform an analysis of the t-J model in the slave boson formulation which accounts for strong correlations, focusing on fluctuation effects that have hitherto not received the attention they deserve. We find several interesting results including the instability of the d-wave superconducting state to internal phase fluctuations giving way to a time reversal broken d+is^{*} superconductor at low doping. This offers an explanation for some recent experimental findings in the cuprate superconductors, including the observation of nodeless superconductivity at low doping. We also suggest further experiments that can validate our claims. On a broader perspective, this work points to the importance of considering fluctuation effects in other two-dimensional strongly correlated systems opening up a plethora of possibilities.

Oestrogen Receptor-α binds the FOXP3 promoter and modulates regulatory T-cell function in human cervical cancer.

Oestrogen controls Foxp3 expression in regulatory T cells (Treg cells) via a mechanism thought to involve oestrogen receptor alpha (ERα), but the molecular basis and functional impact of ERα signalling in Treg cells remain unclear. We report that ERα ligand oestradiol (E2) is significantly increased in human cervical cancer (CxCa) tissues and tumour-infiltrating Treg cells (CD4+CD25hiCD127low), whereas blocking ERα with the antagonist ICI 182,780 abolishes FOXP3 expression and impairs the function of CxCa infiltrating Treg cells. Using a novel approach of co-immunoprecipitation with antibodies to E2 for capture, we identified binding of E2:ERα complexes to FOXP3 protein in CxCa-derived Treg cells. Chromatin immunoprecipitation analyses of male blood Treg cells revealed ERα occupancy at the FOXP3 promoter and conserved non-coding DNA elements 2 and 3. Accordingly, computational analyses of the enriched regions uncovered eight putative oestrogen response elements predicted to form a loop that can activate the FOXP3 promoter. Together, these data suggest that E2-mediated ERα signalling is critical for the sustenance of FOXP3 expression and Treg cell function in human CxCa via direct interaction of ERα with FOXP3 promoter. Overall, our work gives a molecular insight into ERα signalling and highlights a fundamental role of E2 in controlling human Treg cell physiology.

Erratum: Theoretical Description of time-Resolved Photoemission Spectroscopy: Application to Pump-Probe Experiments [Phys. Rev. Lett. 102, 136401 (2009)].

This corrects the article DOI: 10.1103/PhysRevLett.102.136401.

Seebeck Coefficient of a Single van der Waals Junction in Twisted Bilayer Graphene.

When two planar atomic membranes are placed within the van der Waals distance, the charge and heat transport across the interface are coupled by the rules of momentum conservation and structural commensurability, leading to outstanding thermoelectric properties. Here we show that an effective "interlayer phonon drag" determines the Seebeck coecient (S) across the van der Waals gap formed in twisted bilayer graphene (tBLG). The cross-plane thermovoltage, which is nonmonotonic in both temperature and density, is generated through scattering of electrons by the out-of-plane layer breathing (ZO'/ZA2) phonon modes and differs dramatically from the expected Landauer-Buttiker formalism in conventional tunnel junctions. The tunability of the cross-plane Seebeck effect in van der Waals junctions may be valuable in creating a new genre of versatile thermoelectric systems with layered solids.

Quantized edge modes in atomic-scale point contacts in graphene.

The zigzag edges of single- or few-layer graphene are perfect one-dimensional conductors owing to a set of gapless states that are topologically protected against backscattering. Direct experimental evidence of these states has been limited so far to their local thermodynamic and magnetic properties, determined by the competing effects of edge topology and electron-electron interaction. However, experimental signatures of edge-bound electrical conduction have remained elusive, primarily due to the lack of graphitic nanostructures with low structural and/or chemical edge disorder. Here, we report the experimental detection of edge-mode electrical transport in suspended atomic-scale constrictions of single and multilayer graphene created during nanomechanical exfoliation of highly oriented pyrolytic graphite. The edge-mode transport leads to the observed quantization of conductance close to multiples of G0 = 2e2/h. At the same time, conductance plateaux at G0/2 and a split zero-bias anomaly in non-equilibrium transport suggest conduction via spin-polarized states in the presence of an electron-electron interaction.

Simulation of inhomogeneous distributions of ultracold atoms in an optical lattice via a massively parallel implementation of nonequilibrium strong-coupling perturbation theory.

We present a nonequilibrium strong-coupling approach to inhomogeneous systems of ultracold atoms in optical lattices. We demonstrate its application to the Mott-insulating phase of a two-dimensional Fermi-Hubbard model in the presence of a trap potential. Since the theory is formulated self-consistently, the numerical implementation relies on a massively parallel evaluation of the self-energy and the Green's function at each lattice site, employing thousands of CPUs. While the computation of the self-energy is straightforward to parallelize, the evaluation of the Green's function requires the inversion of a large sparse 10(d) × 10(d) matrix, with d > 6. As a crucial ingredient, our solution heavily relies on the smallness of the hopping as compared to the interaction strength and yields a widely scalable realization of a rapidly converging iterative algorithm which evaluates all elements of the Green's function. Results are validated by comparing with the homogeneous case via the local-density approximation. These calculations also show that the local-density approximation is valid in nonequilibrium setups without mass transport.

CD66+ cells in cervical precancers are partially differentiated progenitors with neoplastic traits.

Cervical cancers, a malignancy associated with oncogenic papilloma viruses, remain a major disease burden in the absence of effective implementation of preventive strategies. CD66(+) cells have previously been identified as a tumor-propagating subset in cervical cancers. We investigated the existence, differentiation state, and neoplastic potential of CD66(+) cells in a precancer cell line harboring HPV31b episomes. The gene expression profile of CD66(high) cells overlaps with differentiated keratinocytes, neoplastic mesenchymal transition, cells of the squamocolumnar junction, and cervical cancer cell line-derived spheroids. There is elevated expression of DNMT1, Notch1, and the viral gene product E1⁁E4 in CD66(high) cells. Thus, CD66(high) cells, in the absence of differentiating signals, express higher levels of key regulators of keratinocytes stemness, differentiation, and the viral life cycle, respectively. We also find a striking association of neoplastic traits, including migration, invasion, and colony formation, in soft agar with CD66(high) cells. These properties and a distinct G2-M-enriched cell-cycle profile are conserved in cells from cervical cancers. Principally, using a precancerous cell line, we propose that CD66(high) cells have an intermediate differentiation state, with a cellular milieu connected with both viral replication and neoplastic potential, and validate some key features in precancer lesions. Such pathophysiologically relevant systems for defining cellular changes in the early phases of the disease process provide both mechanistic insight and potential therapeutic strategies. Collectively, our data provide a rationale for exploring novel therapeutic targets in CD66(+) subsets during cancer progression.

Nonequilibrium "melting" of a charge density wave insulator via an ultrafast laser pulse.

We employ an exact solution of the simplest model for pump-probe time-resolved photoemission spectroscopy in charge-density-wave systems to show how, in nonequilibrium, the gap in the density of states disappears while the charge density remains modulated, and then the gap reforms after the pulse has passed. This nonequilibrium scenario qualitatively describes the common short-time experimental features in TaS(2) and TbTe(3), indicating a quasiuniversality for nonequilibrium "melting" with qualitative features that can be easily understood within a simple picture.

Doping a correlated band insulator: a new route to half-metallic behavior.

We demonstrate in a simple model the surprising result that turning on an on-site Coulomb interaction U in a doped band insulator leads to the formation of a half-metallic state. In the undoped system, we show that increasing U leads to a first order transition at a finite value UAF between a paramagnetic band insulator and an antiferomagnetic Mott insulator. Upon doping, the system exhibits half-metallic ferrimagnetism over a wide range of doping and interaction strengths on either side of UAF. Our results, based on dynamical mean field theory, suggest a new route to half metallicity, and will hopefully motivate searches for new materials for spintronics.

Toll-like receptors 7, 8, and 9 expression and function in primary human cervical cancer Langerhans cells: evidence of anergy.

OBJECTIVE: Human papillomavirus oncoproteins E6 and E7 down modulate Toll-like receptor (TLR) 9 expression in infected keratinocytes. We explored the status of expression and function of TLR7, TLR8, and TLR9 in primary human Langerhans cells (LCs) isolated from cervical tumors. METHODOLOGY: Single-cell suspensions were made from fresh tissues of squamous cell carcinoma (International Federation of Gynecology and Obstetrics stage IB2); myeloid dendritic cells were purified using CD1c magnetic activated cell separation kits. Langerhans cells were further flow sorted into CD1a*CD207* cells. Acute monocytic leukemia cell line THP-1-derived LCs (moLCs) formed the controls. mRNA from flow-sorted LCs was reverse transcribed to cDNA and TLR7, TLR8, and TLR9 amplified. Monocyte-derived Langerhans cells and cervical tumor LCs were stimulated with TLR7, TLR8, and TLR9 ligands. Culture supernatants were assayed for interleukin (IL) 1ß, IL-6, IL-10, IL-12p70, interferon (IFN) α, interferon γ, and tumor necrosis factor (TNF) α by Luminex multiplex bead array. Human papillomavirus was genotyped. RESULTS: We have for the first time demonstrated that the acute monocytic leukemia cell line THP-1 can be differentiated into LCs in vitro. Although these moLCs expressed all the 3 TLRs, tumor LCs expressed TLR7 and TLR8, but uniformly lacked TLR9. Also, moLCs secreted IL-6, IL-1ß, and tumor necrosis factor α to TLR8 ligand and interferon α in response to TLR9 ligand; in contrast, tumor LCs did not express any cytokine to any of the 3 TLR ligands. Human papillomavirus type 16 was one of the common human papillomavirus types in all cases. CONCLUSIONS: Cervical tumor LCs lacked TLR9 expression and were functionally anergic to all the 3: TLR7, TLR8, and TLR9 ligands, which may play a crucial role in immune tolerance. The exact location of block(s) in TLR7 and TLR8 signaling needs to be investigated, which would have important immunotherapeutic implications.

Successful endodontic management of hypo, meso and hypertaurodontism: Two case reports.

Taurodontism is a morphoanatomical developmental anomaly rarely seen in teeth. Permanent mandibular molars are most commonly affected. Endodontic treatment of a taurodont tooth is challenging and requires special handling because of proximity and apical displacement of roots. This paper presents a successful endodontic therapy of all three types of taurodonism with two case reports - the first case with mesotaurodontism of mandibular left first molar and hypotaurodontism of mandibular left second molar and the second case with hyper taurodontism of mandibular left second molar.

Functional tumor infiltrating TH1 and TH2 effectors in large early-stage cervical cancer are suppressed by regulatory T cells.

OBJECTIVE: Analysis of tumor-infiltrating lymphocytes (TILs) is one of the cornerstones for the understanding of immune responses prevailing in the tumor microenvironment. We studied TILs from squamous cell carcinoma of the cervix ex vivo without proliferating them in vitro before analysis. METHODS: Whereas TILs were magnetic activated cell separation enriched and flow sorted into CD4 CD25 (regulatory T cells [Tregs]), CD4 CD25 (effector T cells [Teffs]) were directly purified by flow cytometry, and both these subsets were characterized phenotypically and functionally. Tissue sections were probed for interleukin 4 (IL-4) and interferon γ. RESULTS: Effector T cells constitutively expressed both interferon γ and IL-4 prototypical cytokines of TH1 and TH2, respectively, and were able to proliferate and secrete higher quantities of both cytokines in response to anti-CD3/anti-CD28 and autologous tumor lysates. Only 53% of cervical cancer Tregs were FOXP3, elaborated transforming growth factor ß1, and IL-10 and were able to inhibit both T helper subsets. CONCLUSIONS: Intratumoral Teffs represented functionally active subsets of both TH1 and TH2 that were not anergic but were suppressed by multiple Treg subsets, which comprised FOXP3 + Tregs and Tregs secreting transforming growth factor ß1 and IL-10. These results imply that the microenvironment of cervical carcinomas harbored both TH1 and TH2 subsets of CD4 Teffs that were functionally active but were perhaps unable to perform because of the overpowering effect of Tregs.

Poor sperm quality and advancing age are associated with increased sperm DNA damage in infertile men.

With increasing evidence for faulty paternal contribution to reproduction, there has been a steady increase in studies highlighting an association between sperm DNA damage, failed/delayed fertilisation and aberrant embryo development. Owing to prevailing ambiguity, the aims of the study were to analyse the genetic integrity of the male gamete and then to understand its association with age, standard semen parameters, lifestyle and occupational factors. The study included 504 subjects, attending university infertility clinic for fertility evaluation and treatment. Semen characteristics were analysed by standard criteria; terminal deoxynucelotidyl transferase-mediated nick end-labelling assay was employed for DNA damage assessment. The average incidence of sperm DNA damage in patients with normozoospermic semen parameters was <10%. Patients with oligozoospermia, severe oligozoospermia, oligoasthenoteratospermia, asthenoteratozoospermia and necrozoospermia had significantly higher level of sperm DNA damage (P < 0.001). Patients above 40 years of age had significantly high levels of DNA damage (P < 0.001) compared with their counterparts. Patients with varicocele and a history of alcohol consumption had higher incidence of spermatozoa with DNA damage (P < 0.01). Poor sperm characteristics in the ejaculate are associated with increased sperm DNA damage. Age-related increase in sperm DNA damage and association of the same with varicocele and alcohol consumption are also demonstrated.

Quasiuniversal transient behavior of a nonequilibrium Mott insulator driven by an electric field.

We use a self-consistent strong-coupling expansion for the self-energy (perturbation theory in the hopping) to describe the nonequilibrium dynamics of strongly correlated lattice fermions. We study the three-dimensional homogeneous Fermi-Hubbard model driven by an external electric field showing that the damping of the ensuing Bloch oscillations depends on the direction of the field and that for a broad range of field strengths a long-lived transient prethermalized state emerges. This long-lived transient regime implies that thermal equilibrium may be out of reach of the time scales accessible in present cold atom experiments but shows that an interesting new quasiuniversal transient state exists in nonequilibrium governed by a thermalized kinetic energy but not a thermalized potential energy. In addition, when the field strength is equal in magnitude to the interaction between atoms, the system undergoes a rapid thermalization, characterized by a different quasiuniversal behavior of the current and spectral function for different values of the hopping.

Notch signaling in CD66+ cells drives the progression of human cervical cancers.

Human epithelial tumor progression and metastasis involve cellular invasion, dissemination in the vasculature, and regrowth at metastatic sites. Notch signaling has been implicated in metastatic progression but its roles have yet to be fully understood. Here we report the important role of Notch signaling in maintaining cells expressing the carcinoembryonic antigen cell adhesion molecule CEACAM (CD66), a known mediator of metastasis. CD66 and Notch1 were studied in clinical specimens and explants of human cervical cancer, including specimens grown in a pathophysiologically relevant murine model. Gene expression profiling of CD66(+) cells from primary tumors showed enhanced features of Notch signaling, metastasis, and stemness. Significant differences were also seen in invasion, colony formation, and tumor forming efficiency between CD66(+) and CD66(-) cancer cells. Notably, CD66(+) cells showed a marked sensitivity to a Notch small molecule inhibitor. In support of studies in established cell lines, we documented the emergence of a tumorigenic CD66(+) cell subset within a metastatic lesion-derived cervical-cancer cell line. Similar to primary cancers, CD66 expression in the cell line was blocked by chemical and genetic inhibitors of ligand-dependent nuclear Notch signaling. Collectively, our work on the oncogenic properties of CD66(+) cells in epithelial cancers provides insights into the nature of tumor progression and offers a mechanistic rationale to inhibit the Notch signaling pathway as a generalized therapeutic strategy to treat metastatic cancers.

Avulsion and storage media.

Avulsion of a tooth caused by trauma, and its successful treatment is a challenging situation that a dentist encounters in clinical practice. There is a definitive treatment for the avulsed tooth, which depends on many factors. The immediate replacement and replantation of the avulsed tooth is necessary, but it cannot always be accomplished for a number of reasons. Thus, the tooth should be transported in a suitable medium to maintain the cell viability. The storage medium is one of the important factors that will help the dentist in rendering successful treatment for the avulsed tooth. There is a continuing search for an ideal storage medium. This review paper focuses on the various storage media, with special reference to coconut water.