Higgs-mode radiance and charge-density-wave order in 2H-NbSe2_2

Despite being usually considered two competing phenomena, charge-density-wave and superconductivity coexist in few systems, the most emblematic one being the transition metal dichalcogenide 2H-NbSe$_2$. This unusual condition is responsible for specific Raman signatures across the two phase transitions in this compound. While the appearance of a soft phonon mode is a well-established fingerprint of the charge-density-wave order, the nature of the sharp sub-gap mode emerging below the superconducting temperature is still under debate. In this work we use the external pressure as a knob to unveil the delicate interplay between the two orders, and consequently the nature of the superconducting mode. Thanks to an advanced extreme-conditions Raman technique we are able to follow the pressure evolution and the simultaneous collapse of the two intertwined charge density wave and superconducting modes. The comparison with microscopic calculations in a model system supports the Higgs-type nature of the superconducting mode and suggests that charge-density-wave and superconductivity in 2H-NbSe$_2$ involve mutual electronic degrees of freedom. These findings fill knowledge gap on the electronic mechanisms at play in transition metal dichalcogenides, a crucial step to fully exploit their properties in few-layers systems optimized for devices applications

Sorriso gengival: etiologias e diagnóstico

O sorriso gengival é o termo usado para descrever uma exposição gengival excessiva ao nível do maxilar superior durante o sorriso. Esta condição atinge mais as mulheres que os homens, os indivíduos entre 20 e 30 anos e tem uma prevalência perto de 10 % na população. A noção de sorriso gengival estético ou inestético é dependente da cultura, da localização geográfica, das opinões pessoais, a moda, do ambiente sociale da profissão dos indivíduos. Para escolher o tratamento adequado para a correção do sorriso gengival, o médico dentista deve conhecer e distinguir as diferentes etiologias que podem ser combinadas ou não, eo reconhecimento da etiologia ou das etiologias permite que o diagnóstico seja correcto. As etiologias possíveis são; ação de factores externos, esquelética, dento-alveolar, gengival e muscular.Gummy smile is the terminology used to describe excessive gingival exposure to the upper jaw when smiling. This condition reaches more women than men, individuals between 20 and 30 years and has a prevalence close to 10% in the population. The notion of aesthetic or non-aesthetic gummy smile depends on the culture, geographical location, personal opinions, fashion, social environment and the profession of individuals. In order to choose the appropriate treatment for the correction of the gummy smile, the dentist must know and distinguish the different etiologies that can be combined or not, and recognition of the etiology or etiologies enables the diagnosis to be correct. The possible etiologies are; action of external factors, skeletal, dento-alveolar, gingival and muscular

Sorriso gengival: etiologias e diagnóstico

O sorriso gengival é o termo usado para descrever uma exposição gengival excessiva ao nível do maxilar superior durante o sorriso. Esta condição atinge mais as mulheres que os homens, os indivíduos entre 20 e 30 anos e tem uma prevalência perto de 10 % na população. A noção de sorriso gengival estético ou inestético é dependente da cultura, da localização geográfica, das opinões pessoais, a moda, do ambiente sociale da profissão dos indivíduos. Para escolher o tratamento adequado para a correção do sorriso gengival, o médico dentista deve conhecer e distinguir as diferentes etiologias que podem ser combinadas ou não, eo reconhecimento da etiologia ou das etiologias permite que o diagnóstico seja correcto. As etiologias possíveis são; ação de factores externos, esquelética, dento-alveolar, gengival e muscular.Gummy smile is the terminology used to describe excessive gingival exposure to the upper jaw when smiling. This condition reaches more women than men, individuals between 20 and 30 years and has a prevalence close to 10% in the population. The notion of aesthetic or non-aesthetic gummy smile depends on the culture, geographical location, personal opinions, fashion, social environment and the profession of individuals. In order to choose the appropriate treatment for the correction of the gummy smile, the dentist must know and distinguish the different etiologies that can be combined or not, and recognition of the etiology or etiologies enables the diagnosis to be correct. The possible etiologies are; action of external factors, skeletal, dento-alveolar, gingival and muscular

Collapse of critical nematic fluctuations in FeSe under pressure

We report the evolution of the electronic nematic susceptibility in FeSe via Raman scattering as a function of hydrostatic pressure up to 5.8 GPa where the superconducting transition temperature $T_{c}$ reaches its maximum. The critical nematic fluctuations observed at low pressure vanish above 1.6 GPa, indicating they play a marginal role in the four-fold enhancement of $T_{c}$ at higher pressures. The collapse of nematic fluctuations appears to be linked to a suppression of low energy electronic excitations which manifests itself by optical phonon anomalies at around 2 GPa, in agreement with lattice dynamical and electronic structure calculations using local density approximation combined with dynamical mean field theory. Our results reveal two different regimes of nematicity in the phase diagram of FeSe under pressure: a d-wave Pomeranchuk instability of the Fermi surface at low pressure and a magnetic driven orthorhombic distortion at higher pressure.Comment: 7 pages, 4 figures. Supplementary Material available upon reques

Pressure-Induced Collapse of the Charge Density Wave and Higgs Mode Visibility in 2H−TaS2

The pressure evolution of the Raman active electronic excitations of the transition metal dichalcogenides 2H-TaS2 is followed through the pressure phase diagram embedding incommensurate charge-density-wave and superconducting states. At high pressure, the charge-density wave is found to collapse at 8.5 GPa. In the coexisting charge-density-wave and superconducting orders, we unravel a strong in-gap superconducting mode, attributed to a Higgs mode, coexisting with the expected incoherent Cooper-pair breaking signature. The latter remains in the pure superconducting state reached above 8.5 GPa. Our report constitutes a new observation of such Raman active Higgs mode since the long-standing unique case 2H-NbSe2

Antibody response against Trichinella spiralis in experimentally infected rats is dose dependent

Domestic pigs are the main representatives of the domestic cycle of Trichinella spiralis that play a role in transmission to humans. In Europe, backyard pigs of small household farms are the most important risks for humans to obtain trichinellosis. Rats might play a role in the transmission of Trichinella spiralis from domestic to sylvatic animals and vice versa. In order to be able to investigate the role of wild rats in the epidemiology of T. spiralis in The Netherlands, we studied the dynamics of antibody response after T. spiralis infections in experimental rats, using infection doses ranging from very low (10 muscle larvae, ML, per rat) to very high (16 000 ML per rat). To evaluate the feasibility of rats surviving high infection doses with T. spiralis, clinical and pathological parameters were quantified. Serological tools for detecting T. spiralis in rats were developed to quantitatively study the correlation between parasite load and immunological response. The results show that an infection dose-dependent antibody response was developed in rats after infection with as low as 10 ML up to a level of 10 000 ML. A positive correlation was found between the number of recovered ML and serum antibody levels, although specific measured antibody levels correspond to a wide range of LPG values. Serum antibodies of rats that were infected even with 10 or 25 ML could readily be detected by use of the T. spiralis western blot 2 weeks post infection. We conclude that based on these low infection doses, serologic tests are a useful tool to survey T. spiralis in wild rats

Flt3(+) macrophage precursors commit sequentially to osteoclasts, dendritic cells and microglia

BACKGROUND: Macrophages, osteoclasts, dendritic cells, and microglia are highly specialized cells that belong to the mononuclear phagocyte system. Functional and phenotypic heterogeneity within the mononuclear phagocyte system may reveal differentiation plasticity of a common progenitor, but developmental pathways leading to such diversity are still unclear. RESULTS: Mouse bone marrow cells were expanded in vitro in the presence of Flt3-ligand (FL), yielding high numbers of non-adherent cells exhibiting immature monocyte characteristics. Cells expanded for 6 days, 8 days, or 11 days (day 6-FL, day 8-FL, and day 11-FL cells, respectively) exhibited constitutive potential towards macrophage differentiation. In contrast, they showed time-dependent potential towards osteoclast, dendritic, and microglia differentiation that was detected in day 6-, day 8-, and day 11-FL cells, in response to M-CSF and receptor activator of NFκB ligand (RANKL), granulocyte-macrophage colony stimulating-factor (GM-CSF) and tumor necrosis factor-α (TNFα), and glial cell-conditioned medium (GCCM), respectively. Analysis of cell proliferation using the vital dye CFSE revealed homogenous growth in FL-stimulated cultures of bone marrow cells, demonstrating that changes in differential potential did not result from sequential outgrowth of specific precursors. CONCLUSIONS: We propose that macrophages, osteoclasts, dendritic cells, and microglia may arise from expansion of common progenitors undergoing sequential differentiation commitment. This study also emphasizes differentiation plasticity within the mononuclear phagocyte system. Furthermore, selective massive cell production, as shown here, would greatly facilitate investigation of the clinical potential of dendritic cells and microglia

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease