We report the magnetic and electrical characteristics of polycrystalline FeTiO_{3} synthesized at high pressure that is isostructural with acentric LiNbO_{3} (LBO). Piezoresponse force microscopy, ...optical second harmonic generation, and magnetometry demonstrate ferroelectricity at and below room temperature and weak ferromagnetism below approximately 120 K. These results validate symmetry-based criteria and first-principles calculations of the coexistence of ferroelectricity and weak ferromagnetism in a series of transition metal titanates crystallizing in the LBO structure.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Abstract Background and objectives Polymorphisms of the VEGF gene are known to affect the biological behaviour of cancers but have seldom been studied in thyroid cancer. The aim of the current study ...is to evaluate the prevalence and relevance of VEGF-A polymorphisms and mRNA expression in papillary thyroid carcinoma (PTC). Materials and methods Genomic DNA and total RNA were isolated from paraffin-embedded tissue from 91 PTC (51 conventional PTC and 40 follicular variant) and 78 control thyroid tissues. Three DNA polymorphisms (+936C > T , +405C > G and −141A > C ) in the 3′ and 5′ untranslated region (3′-UTR, 5′-UTR) of VEGF-A were studied using PCR and RFLP. Also, the mRNA expression of VEGF-A in these tissues was studied by real-time PCR. Results Distribution of polymorphisms in the 5′-UTR ( VEGF-VEGF -141 A > C and +405C > G ) and 3′-UTR ( VEGF +936C > T ) were all significantly different in PTC and benign thyroid tissue ( p = 0.0001, 0.001 and 0.028 respectively). The VEGF -141 C allele was more common in PTC with lymph node metastases ( p = 0.026). VEGF + 405 G alleles and VEGF +936 CC genotype were more common in PTC of advanced pathological staging ( p = 0.018 and 0.017 respectively). Also, increased expression of VEGF-A mRNA was noted in PTC compared to control ( p = 0.009). Within the group of patients with conventional PTC, those with lymph nodal metastases had a higher level of VEGF-A mRNA expression than other patients ( p = 0.0003). Conclusion These findings suggest that VEGF polymorphisms and mRNA expression may predict the aggressiveness behaviour of thyroid cancer.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
The 4d transition metal perovskites Ca
n+1
Ru
n
O
3n+1
have attracted interest for their strongly interacting electronic phases showing pronounced sensitivity to controllable stimuli like ...strain, temperature, and even electrical current. Through multi-messenger low-temperature nano-imaging, we reveal a spontaneous striped texture of coexisting insulating and metallic domains in single crystals of the bilayer ruthenate Ca
3
(Ti
x
Ru
1-x
)
2
O
7
across its first-order Mott transition at
$$T \approx 95$$
T
≈
95
K. We image on-demand anisotropic nucleation and growth of these domains under in situ applied uniaxial strain rationalized through control of a spontaneous Jahn-Teller distortion. Our scanning nano-susceptibility imaging resolves the detailed susceptibility of coexisting phases to strain and temperature at the transition threshold. Comparing these nano-imaging results to bulk-sensitive elastoresistance measurements, we uncover an emergent “domain susceptibility” sensitive to both the volumetric phase fractions and elasticity of the self-organized domain lattice. Our combined susceptibility probes afford nano-scale insights into strain-mediated control over the insulator-metal transition in 4d transition metal oxides.
The thermal conductivity of Si-doped thin films of indium phosphide grown via metalorganic vapour-phase epitaxy at different carrier concentrations and thicknesses was measured from 80 to 450 K using ...time domain thermoreflectance. Additionally, phonon gas modeling was conducted to characterize the various scattering mechanisms that contribute to the thermal transport in these materials. A sensitivity analysis based on the phonon gas model showed that while thickness has a greater influence on the thermal conductivity than carrier concentration at the micron-scale for all samples, point defects due to Si-dopant atoms at carrier concentrations of ∼1019 cm−3, as well as the presence of extended defects that are most likely present due to dopant saturation, have a significant impact on thermal transport as a result of increased phonon scattering, decreasing the thermal conductivity by 40% or more.
Designing novel multiferroic materials with simultaneous ferroelectric and magnetic orders has been one of the focal points over the last decade due to the promising applications and rich physics ...involved. In this study, using epitaxial strain (up to 3.8%) as tuning knob, we successfully introduce multiferroicity with prominent high-temperature ferroelectricity into the paraelectric SrMnO3. More interestingly, the experimental temperature-dependent ferroelectric and magnetic studies suggest that the emergent antiferromagnetic order below 100 K greatly enhances the ferroelectric polarization due to the spin-order-induced ionic displacements. We envision that the strain-mediated spin-phonon coupling can be utilized as a pathway to discover functionalities in a wide range of antiferromagnetic insulators with delicate epitaxial manipulations.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
A checklist of odonates of Kerala State is presented in this paper. Scientific binomen, vernacular names in Malayalam, IUCN Red List status, and endemism are also given. A total of 174 species of ...odonates have been recorded from Kerala till date, 65 of which are endemic to the Western Ghats, and 10 to India. Five species fall under various threatened categories of IUCN. None of the odonates occurring in Kerala is listed in the schedules of the Indian Wildlife (Protection) Act or the appendices of CITES.
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