Weak antilocalization in the topological semimetal candidate YbAuSb.

We report a study of the magnetic and magnetotransport properties of YbAuSb single crystals, which were grown using the bismuth flux. The x-ray diffraction data indicate that YbAuSb crystallizes in LiGaGe-type hexagonal structure with space groupP63mc. Our magnetic measurements revealed that YbAuSb is nonmagnetic with a divalent state of ytterbium ion. The temperature-dependent electrical resistivity exhibits a metallic behavior. A cusp-like feature in transverse and longitudinal magnetoresistance is observed at the low field regime. This cusp-like feature is attributed to the weak antilocalization (WAL) effect, which is more prominent at low temperatures. The transverse magnetoconductivity in low field region follows semiclassical model∼B, which is consistent with the presence of WAL phenomena. The WAL effect in transverse and longitudinal magnetoconductance is well explained using the modified Hikami-Larkin-Nagaoka and generalized Altshuler-Aronov model, respectively. The Hall resistivity shows a linear field dependence with a positive slope, suggesting hole charge carriers dominate in electrical transport. The calculated carrier density and mobility are in the order of 1020 cm-3and 102 cm2 V-1 s-1, respectively.

Evolution of ferrimagnetism against Griffiths singularity in calcium ruthenate.

The magnetism in the correlated metal CaRuO3is enigmatic as it is poised near a triple point among the ferromagnetic, antiferromagnetic, and paramagnetic ground states. Here we report a detailed work on structural, spectroscopic, magnetic, and transport properties in CaRu1-xCrxO3. We find that Cr doping reduces the orthorhombicity in CaRuO3. Surprisingly, a tiny (x= 0.01) amount of Cr-doping drives the magnetic ground state from 'paramagnetic-like' to ferrimagnetic. Slightly higher Cr-doping (x= 0.05) results formation of magnetic clusters which gives rise to Griffiths singularity and power law divergence in magnetic susceptibility. The magnetism in CaRu1-xCrxO3is explained in terms of 'seven atom' ferrimagnetic clusters. Electrical transport shows a gradual evolution of a non-metallic state upon Cr-doping. In particular, forx⩾0.1, the temperature-dependent resistivity follows Mott-VRH conduction. The XPS study also supports significant role of disorder and electron correlation which effectively reduces the itinerant character of electrons. Finally, a new T-x phase diagram is constructed depicting the evolution of electronic and magnetic state in CaRu1-xCrxO3.

Evidence of weak itinerant ferromagnetism and Griffiths like phase in MnFeGe.

Realizing the itinerant type of magnetic exchange in Mn-based alloys is quite unusual because of the weak hybridization between Mn-moments and conduction electrons. However, in the current study, we found MnFeGe to exhibit weak itinerant type magnetic character possibly arising due to the hybridization between Mn, Fe atoms with Ge atoms. Here, we present a comprehensive structural and magnetic study on polycrystalline MnFeGe. Rietveld refinement of the XRD pattern confirms that Mn and Fe atoms randomly (atomic disorder) occupy the2aand2dsites in MnFeGe. From the magnetic measurements, Curie temperature and saturation moment values are found to be 162 K and 1.58µB/f.u.at 2 K, respectively. The relative low values of Curie temperature, saturation magnetic moment, and a large value of Rhodes-Wohlfarth ratio (∼3.4) indicate the weak itinerant ferromagnetic character of the system. The Takahashi spin fluctuation theory analysis further supports the weak itinerant ferromagnetism in MnFeGe. Besides, we also observed Griffiths phase (GP) like behavior above the Curie temperature, which is attributed to the presence of atomic disorder in the system. The presence of GP is further confirmed by the zero spontaneous magnetization. Our findings demonstrate that MnFeGe is one of the very few Mn-based systems with weak itinerant magnetic behavior.

Decreased mortality in coronavirus disease 2019 associated mucormycosis with aspirin use: a retrospective cohort study.

OBJECTIVE: Rhino-orbito-cerebral mucormycosis is a rapidly progressive disease with high mortality rates of about 60 per cent. The increasing incidence of rhino-orbito-cerebral mucormycosis in coronavirus disease 2019 patients in India and worldwide has become a matter of concern owing to the case fatality rate. This study explored the use of low dose aspirin in decreasing the mortality rate of coronavirus disease 2019 associated mucormycosis. METHOD: This was a retrospective observational study. Patients suffering from post-coronavirus disease 2019 mucormycosis were included in the study. Each patient was treated with surgical debridement and systemic amphotericin B. Low dose aspirin was added, and mortality rates were compared with the patients who did not receive aspirin. RESULTS: The demographic data and rhino-orbito-cerebral mucormycosis staging between the two groups were not significantly different. There was a statistically significant difference in mortality outcomes between the two groups (p = 0.029) and a 1.77 times higher risk of dying for patients not receiving aspirin. Kaplan-Meier survival indicated that patients receiving aspirin had better survival rates (p = 0.04). CONCLUSION: Low dose aspirin improves survival rates in coronavirus disease 2019 associated mucormycosis.

Oncologic safety of submental island flap reconstruction in clinically node-negative oral cancer patients: a prospective comparative study.

The purpose of this study was to evaluate the oncologic safety of submental island flap (SIF) reconstruction in clinically node-negative oral cancer patients. Forty-four clinically node-negative oral cancer patients with tumour size T1-T3 were divided into two groups. The Submental group consisted of 21 patients, who underwent submental island flap reconstruction whereas the control group consisted of 23 patients who underwent reconstruction with other locoregional or free flaps. The locoregional recurrence rate (LRR) and recurrence-free survival (RFS) in these two groups were assessed and compared. The follow-up period in the two groups ranged from six to 28 months, with a median follow-up period of 15 months and 21 months, respectively. Results showed that the LRR in the control and the submental group was 21.7% and 19%, respectively (p = 0.825). Kaplan-Meier curve showed that the difference in recurrence-free survival in the two groups was not statistically significant (p = 0.749). Multivariate and bivariate analyses did not establish any relationship between the predictive parameters and locoregional recurrence. Thus, the Submental island flap is a reliable and versatile locoregional flap for the reconstruction of post-resection defects in oral cancer. It has no predictive influence on locoregional recurrence in clinically node-negative oral cancer patients.

Tailoring magnetism in spinel vanadate CoV2O4epitaxial thin films.

Near itinerant cubic bulk CoV2O4is at variance with other spinel vanadates by not showing orbital ordering down to low temperature, albeit it displays fragile anomalies related to spin, and lattice structure, signaling a spin/orbital glass transition around 95 K. We investigate tetragonal-like epitaxial CoV2O4films on SrTiO3and (La0.3Sr0.7)(Al0.65Ta0.35)O3substrates that exhibit pronounced signature of spin reorientation transition from toa/bplane around 90 K unlike its bulk counterpart. Using in-plane and out-of-plane magnetic measurements, we demonstrate the intricate link between Co2+and V3+sublattice magnetizations that give rise to anisotropic magnetic switching. In-plane magnetic measurements reveal a wasp-waist shapedM(H) loop below reorientation transition temperature, while the out-of-plane follows antiferromagnet-likeM(H) response. The wasp-waist shaped feature could be linked to in-plane spin-canted (anti)ferromagnetism induced by canting away of V-spins away from antiferromagnetically coupled Co-spin direction below reorientation transition temperature. Further, we uncover the evidence for slow relaxation over a period of ∼104 s at 20 K and memory effect that indicates the possible existence for magnetic glassy phase in the low temperature regime. Using epitaxial strain as a control knob, our results inspire future study to manipulate orbital states, spin texture and itinerant electron character in tailored CoV2O4films away from cubic lattice symmetry.

Electronic and topological properties of group-10 transition metal dichalcogenides.

The group 10 transition metal dichalcogenides (TMDs) (MX 2: M = Ni, Pd, Pt; X = S, Se, Te) have attracted much attention in the last few decades because of observation of exotic phases and phenomena such as superconductivity (SC), topological surface states (TSSs), type II Dirac fermions, helical spin texture, Rashba effect, 3D Dirac plasmons, metal-insulator transitions, charge density waves (CDW) etc. In this review, we cover the experimental and theoretical progress on the physical phenomena influenced by the strong electron-electron correlation of the group-10 TMDs from the past to the present. We have especially emphasized on the SC and topological phases in the bulk as well as in atomically thin materials.

Robust weak antilocalization due to spin-orbital entanglement in Dirac material Sr3SnO.

The presence of both inversion (P) and time-reversal (T) symmetries in solids leads to a double degeneracy of the electronic bands (Kramers degeneracy). By lifting the degeneracy, spin textures manifest themselves in momentum space, as in topological insulators or in strong Rashba materials. The existence of spin textures with Kramers degeneracy, however, is difficult to observe directly. Here, we use quantum interference measurements to provide evidence for the existence of hidden entanglement between spin and momentum in the antiperovskite-type Dirac material Sr3SnO. We find robust weak antilocalization (WAL) independent of the position of EF. The observed WAL is fitted using a single interference channel at low doping, which implies that the different Dirac valleys are mixed by disorder. Notably, this mixing does not suppress WAL, suggesting contrasting interference physics compared to graphene. We identify scattering among axially spin-momentum locked states as a key process that leads to a spin-orbital entanglement.

Bilateral blindness following anterior nasal packing in a case of nasopharyngeal angiofibroma.

BACKGROUND: Epistaxis is the most common ENT emergency encountered in the Emergency Department. Most cases can be managed by simple anterior nasal packing. This is usually a safe and very effective option in an emergency situation, requiring minimal expertise and infrastructure. This paper describes a rare instance of a serious complication following anterior nasal packing in a case of nasopharyngeal angiofibroma. CASE REPORT: A 27-year-old man diagnosed with nasopharyngeal angiofibroma presented to the Emergency Department with bilateral epistaxis. The patient was stabilised and anterior nasal packing was performed, which controlled the bleeding. Three hours later, the patient developed complete blindness in both eyes. Aggressive medical management was initiated immediately, but failed to restore the patient's vision. CONCLUSION: Anterior nasal packing is a simple and minimally invasive procedure practised regularly in an Emergency Department setting. However, it can occasionally lead to serious complications such as blindness. Thus, obtaining informed consent is essential to avoid medico-legal consequences in high-risk cases.

Quenched Magnon excitations by oxygen sublattice reconstruction in (SrCuO2)n/(SrTiO3)2 superlattices.

The recently discovered structural reconstruction in the cuprate superlattice (SrCuO2)n/(SrTiO3)2 has been investigated across the critical value of n = 5 using resonant inelastic x-ray scattering (RIXS). We find that at the critical value of n, the cuprate layer remains largely in the bulk-like two-dimensional structure with a minority of Cu plaquettes being reconstructed. The partial reconstruction leads to quenching of the magnons starting at the Γ-point due to the minority plaquettes acting as scattering points. Although comparable in relative abundance, the doped charge impurities in electron-doped cuprate superconductors do not show this quenching of magnetic excitations.

Reliability of assessing lifestyle and trigger factors in patients with migraine--findings from the PAMINA study.

BACKGROUND AND PURPOSE: Numerous lifestyle factors are blamed for triggering migraine attacks. The reliability of assessing these factors retrospectively is unknown. Therefore, retrospective and prospective assessments of lifestyle in general and of migraine triggers in particular were compared in patients with migraine. METHODS: At baseline, the patients filled in two questionnaires covering the previous 90 days. Thereafter they kept a prospective 90-day diary. Questionnaires and diary included the same set of 45 factors. In the first questionnaire the patients assessed their lifestyle, in the second they rated for each factor the likelihood of triggering a migraine attack, and in the diary they recorded the daily presence of these factors irrespective of headache. Five categories were used for comparing frequencies in questionnaire and diary, defining agreement as identical categories in diary and questionnaire, minor disagreement and major disagreement as overestimation or underestimation by one category and two or more categories, respectively. RESULTS: In all, 327 patients (283 women, age 41.9 ± 12.1 years) who recorded 28,325 patient days were included. Calculating for each factor the percentage of patients with major disagreement the mean proportion was larger for trigger factors than for lifestyle (38.7% ± 6.6% vs. 16.9% ± 6.4%, P < 0.001). The proportion of factors showing major disagreement in more than 20% of the patients was 8.8% for lifestyle but 94.1% for trigger factors (P < 0.001). CONCLUSION: Comparing questionnaire and diary assessments of lifestyle and trigger factors in patients with migraine shows that questionnaire assessment of lifestyle is reliable, whereas trigger factors are overestimated and/or underestimated in retrospective questionnaires.

High-Resolution Ultrasound for Diagnostic Assessment of the Great Auricular Nerve--Normal and First Pathologic Findings.

PURPOSE: The great auricular nerve (GAN) is a sensory branch of the superficial cervical plexus. While its blockade is an established procedure, little is known about the ultrasound appearance of pathologic conditions of the GAN itself. We, therefore, aimed to evaluate the possibility of the visualization and diagnostic assessment of the GAN along its entire course by means of high-resolution ultrasound (HRUS). MATERIALS AND METHODS: To assess the feasibility of visualization, we performed HRUS with an 18 MHz probe, HRUS-guided, fine-needle ink markings and consecutive dissection in six anatomical specimens. Then, we measured the diameter of the GAN in healthy volunteers and finally performed a retrospective review of patients referred for HRUS examinations because of pain within GAN territory between August 1, 2012 and August 1, 2013. RESULTS: The GAN was clearly visible with HRUS from its formation to the final branches, and was marked successfully on both sides in all anatomical specimens (n = 12). The mean average in-vivo was 0.14 cm ± 0.03 (range 0.08-0.2). Seven cases of patients with GAN pathologies of various origins (idiopathic, traumatic, tumorous and iatrogenic) were identified, of which 6 were visible on HRUS and all of which could be confirmed by complete resolution of symptoms after selective HRUS-guided GAN block. CONCLUSION: This study confirms the reliable ability to visualize the GAN with HRUS throughout its course, both in anatomical specimens and in vivo. The provided cases show that pathologies of the GAN seem to have a variety of causes and may not be rare. We, therefore, encourage the use of HRUS in patients with unclear pain in the auricular, periauricular and posterior-lateral head.

Visualization of the Long Thoracic Nerve using High-Resolution Sonography.

PURPOSE: The long thoracic nerve (LTN) innervates the serratus anterior muscle (SA) which plays an important role in shoulder function. Evaluation of the LTN has so far been restricted to clinical assessment and partly electromyography and neurography. Progress of high-resolution ultrasound (HRUS) increasingly enables visualization of small peripheral nerves and their pathologies. We therefore aimed at (a) clarifying the possibility of visualization of the LTN from its origin to the most distal point in the supraclavicular region visible and (b) developing an ultrasound protocol for routine use. We further present two cases of patients with LTN pathology. METHODS: The study consisted of two parts: Part 1 included 4 non-enbalmed human bodies in whom the LTN (n = 8) was located and then marked by ink injection. Correct identification was confirmed by anatomical dissection. Part 2 included 20 healthy volunteers whose LTN (n = 40) was assessed independently by two radiologists. Identification of the LTN was defined as consensus in recorded images. RESULTS: LTN was clearly visible in all anatomical specimens and volunteers using HRUS and could be followed until the second slip of the serratus anterior muscle from the supraclavicular region. In anatomical specimens, dissection confirmed HRUS findings. For all volunteers, consensus was obtained. The mean nerve diameter was 1.6 mm ±â€Š0.3 (range 1.1 - 2.1 mm) after the formation of the main trunk. DISCUSSION: We hereby confirm a reliable possibility of visualization of the LTN in anatomical specimens as well as in volunteers. We encourage HRUS of the LTN to be part of the diagnostic work-up in patients presenting with scapular winging, shoulder weakness or pain of unknown origin.

Correspondence between neutron depolarization and higher order magnetic susceptibility to investigate ferromagnetic clusters in phase separated systems.

It is a tough task to distinguish a short-range ferromagnetically correlated cluster-glass phase from a canonical spin-glass-like phase in many magnetic oxide systems using conventional magnetometry measurements. As a case study, we investigate the magnetic ground state of La0.85Sr0.15CoO3, which is often debated based on phase separation issues. We report the results of two samples of La0.85Sr0.15CoO3 (S-1 and S-2) prepared under different conditions. Neutron depolarization, higher harmonic ac susceptibility and magnetic relaxation studies were carried out along with conventional magnetometry measurements to differentiate subtle changes at the microscopic level. There is no evidence of ferromagnetic correlation in the sample S-2 attributed to a spin-glass phase, and this is compounded by the lack of existence of a second order component of higher harmonic ac susceptibility and neutron depolarization. A magnetic relaxation experiment at different temperatures complements the spin glass characteristic in S-2. All these signal a sharp variance when we consider the cluster-glass-like phase (phase separated) in S-1, especially when prepared from an improper chemical synthesis process. This shows that the nonlinear ac susceptibility is a viable tool to detect ferromagnetic clusters such as those the neutron depolarization study can reveal.

Experimental evidence for oxygen sublattice control in polar infinite layer SrCuO2.

A recent theoretical study [Phys. Rev. B 85, 121411(R) (2012)] predicted a thickness limit below which ideal polar cuprates turn nonpolar driven by the associated electrostatic instability. Here we demonstrate this possibility by inducing a structural transformation from the bulk planar to chainlike structure upon reducing the SrCuO2 repeat thickness in SrCuO2/SrTiO3 superlattices with unit-cell precision. Our results, based on structural investigation by x-ray diffraction and high resolution scanning transmission electron microscopy, demonstrate that the oxygen sublattice can essentially be built by design. In addition, the electronic structure of the chainlike structure, as studied by x-ray absorption spectroscopy, shows the signature for preferential hole occupation in the Cu 3d(3z2-r2) orbital, which is different from the planar case.

A critical re-examination and a revised phase diagram of La(1 - x)Sr(x)CoO3.

We report the results of a comprehensive study on dc magnetization, ac susceptibility, and the magnetotransport properties of the La(1 - x)Sr(x)CoO3(0 ≤ x ≤ 0.5) system. At higher Sr doping (x ≥ 0.18), the system exhibits Brillouin-like field cooled magnetization (M(FC)). However, for x < 0.18, the system exhibits a kink in the M(FC), a peak at the intermediate field in the thermoremnant magnetization and a non-saturating tendency in the M-H plot that all point towards the characteristic of spin glass behavior. More interestingly, dc magnetization studies for x < 0.18 do not suggest the existence of ferromagnetic correlation that can give rise to an irreversible line in the spin glass regime. The ac susceptibility study for x > 0.2 exhibits apparently no frequency dependent peak shift around the ferromagnetic transition region. However, a feeble signature of glassiness is verified by studying the frequency dependent shoulder position in χ('')(T) and the memory effect below the Curie temperature. But, for x < 0.18, the ac susceptibility study exhibits a considerable frequency dependent peak shift, time dependent memory effect, and the characteristic spin relaxation time scale τ(o) approximately 10(- 13) s. The reciprocal susceptibility versus temperature plot adheres to Curie-Weiss behavior and does not provide any signature of preformed ferromagnetic clusters well above the Curie temperature. The magnetotransport study reveals a cross over from metallic to semiconducting-like behavior for x ≤ 0.18. On the semiconducting side, the system exhibits a large value of magnetoresistance (upto 75%) towards low temperature and it is strongly connected to the spin dependent part of the random potential distribution in the spin glass phase. Based on the above observations, we have reconstructed a new magnetic phase diagram and characterized each phase with associated properties.

Observation of reduced activation energy and the possible existence of decoupled pancake vortices in superconductor/ferromagnet bilayers.

Investigations of different superconducting (S)/ferromagnetic (F) heterostructures grown by pulsed laser deposition reveal that the activation energy (U) for the vortex motion in a high T(c) superconductor is reduced remarkably by the presence of F layers. The U exhibits a logarithmic dependence on the applied magnetic field in the S/F bilayers suggesting the existence of decoupled two-dimensional (2D) pancake vortices. This result is discussed in terms of the reduction in the effective S layer thickness and the weakening of the S coherence length due to the presence of F layers. In addition, the U and the superconducting T(c) in Y Ba(2)Cu(3)O(7 - δ)/La(0.5)Sr(0.5)CoO(3) bilayers are observed to be much lower than in the Y Ba(2)Cu(3)O(7 - δ)/La(0.7)Sr(0.3)MnO(3) ones. This in turn suggests that the degree of spin polarization of the F layer might not play a crucial role for the suppression of superconductivity due to a spin polarized induced pair-breaking effect in S/F bilayers.

The course of migraine-a diary study in unselected patients.

The course of disease and the predictive value of depression and anxiety in patients with migraine were prospectively examined. We recruited 393 migraineurs through articles in newspapers and performed a follow-up examination 30 months later. At baseline and follow-up, patients underwent a semistructured interview, filled out the Headache Impact Test (HIT-6), Self-rating Depression Scale (SDS) and Self-rating Anxiety Scale (SAS) and they kept a headache diary for 30 days. One hundred and fifty-one patients (38.6%) were seen at follow-up. The baseline data of patients with and without follow-up were comparable. At follow-up the number of headache days per month had decreased from 9.6 +/- 5.8 to 8.1 +/- 6.3 (P < 0.001) and the proportion of patients with chronic headache (15.4%) and medication overuse (13%) had remained stable. SDS and SAS scores were associated with a high migraine frequency and high initial SDS scores predicted high migraine frequency at follow-up. This longitudinal study in unselected patients with migraine not excluding subjects with chronic headache, medication overuse, depression or anxiety does not point towards migraine as a progressive disease in the vast majority of patients and confirms the importance of psychiatric comorbidity.

Observation of the intense de-pairing effect in YBa(2)Cu(3)O(7-δ) due to the spin injection from La(0.5)Sr(0.5)CoO(3).

We report experimental evidence for a huge pair breaking effect induced by spin polarized quasiparticles in a YBa(2)Cu(3)O(7-δ)/La(0.5)Sr(0.5)CoO(3) bi-layer fabricated by pulsed laser deposition. The temperature dependent magnetization measurements show evidence for the presence of both ferromagnetic and diamagnetic phases in the bi-layer. The current dependent electrical transport studies in the bi-layer exhibit a significant reduction in the superconducting transition temperature with the increase in applied current as compared to a single YBa(2)Cu(3)O(7-δ) layer and it follows a I(2/3) dependence in accordance with the pair breaking effect. Here, we find that the current driven from a ferromagnetic electrode with low spin polarization, such as La(0.5)Sr(0.5)CoO(3) (-11%), into the superconductor can act as a strong pair breaker. This indicates that the spin polarization of the injecting electrode is not the only criterion in determining the pair breaking effect, rather the transparency of the interface for the spin polarization may also be significant. More interestingly, the spin diffusion length for YBa(2)Cu(3)O(7-δ) has a much longer length scale than that reported earlier in the study of ferromagnetic/superconducting heterostructures.