Case report: Right ventricular outflow tract obstruction caused by multicomponent mesenchymal tumor.

Right ventricular outflow tract obstruction (RVOTO) is a cause of hemodynamic instability that can lead to right ventricular dysfunction. Cardiac tumors located in the right ventricle or surrounding structures can cause RVOTO. Herein, we present a rare case of a 21-year-old male with palpitations due to RVOTO caused by a cardiac multicomponent mesenchymal tumor. The tumor was localized in the right ventricular outflow tract, resulting in right side heart enlargement, tricuspid regurgitation, and RVOTO. Hence, tumor resection was performed. The patient was in a stable condition and discharged home on the 6th post-operative day. However, histopathological examination of the tumor specimen suggested a three-component mesenchymal tumor containing mucinous components, formed blood vessels, and fibrous tissue, which is like an atypical capillary hemangioma. After seven years of follow-up, the patient had no right heart enlargement, tricuspid regurgitation, and tumor recurrence. We believe surgical treatment is effective, and this case will provide a reference for clinicians to treat and evaluate the prognosis of similar three-component mesenchymal cardiac tumor cases in the future.

Dynamics of Topological Polarization Singularity in Momentum Space.

The polarization singularity in momentum space has recently been discovered as a new class of topological signatures of Bloch modes in photonic crystal slabs concerning the far-field radiations, beyond its near-field description with widely explored topological band theory. Bound states in the continuum (BICs) in photonic crystal slabs are demonstrated as vortex eigenpolarization singularities in momentum space and the circular polarization points (C points) are also obtained based on BICs, opening up more possibilities for exotic light scattering and various topological phenomena of singular optics. Here, focusing on the nondegenerate bands, we report the generation to annihilation of two pairs of C points in momentum space in the photonic crystal slabs with inversion symmetry but broken up-down mirror symmetry. Interestingly, as the C points evolve with the structure parameter, we find two merging processes of C points, where an accidental at-Γ BIC and unidirectional radiative resonances with leaky channels of drastically different radiative lifetime emerge. The whole evolution is governed by the global charge conservation and the sum of topological charges equals to zero. Our findings suggest a novel recipe for dynamic generation and manipulation of various polarization singularities in momentum space and might shed new light to control the resonant and topological properties of light-matter interactions.

Multiple endocrine neoplasia 2A with RET mutation p.Cys611Tyr: A case report.

RATIONALE: Multiple endocrine neoplasia 2A (MEN2A) is a rare autosomal-dominant genetic syndrome, frequently misdiagnosed or neglected clinically, resulting in delayed therapy to patients. PATIENT CONCERNS: A 47-year-old Chinese male patient underwent laparoscopic right adrenal tumorectomy, and postoperative pathology confirmed the tumor as pheochromocytoma (PHEO). He was readmitted to the department of endocrinology and metabolism due to constant increase in carcinoembryonic antigen (CEA) at 5 months after the operation. DIAGNOSIS: The patient was confirmed with medullary thyroid carcinoma (MTC), multiple neck lymph node metastasis, and pituitary microadenoma. The p.Cys611Tyr (c.1832G>A, C611Y) mutation was detected. Therefore, he was diagnosed with MEN2A. INTERVENTIONS: He underwent total thyroidectomy. The gene-sequencing analysis of his family was conducted, and the C611Y mutation was detected in his daughter. OUTCOMES: The level of carcinoembryonic antigen decreased significantly after thyroidectomy in this patient. Long-term follow-up management was conducted. Elevated serum calcitonin and bilateral thyroid nodules were found in his 13-year-old daughter. Thus, MEN2A was highly suspected and she was suggested to undergo total thyroidectomy. CONCLUSION: Patients with MEN2A should be screened regularly and managed by a multidisciplinary team.

Three-Dimensional-Stacked Gold Nanoparticles with Sub-5 nm Gaps on Vertically Aligned TiO2 Nanosheets for Surface-Enhanced Raman Scattering Detection Down to 10 fM Scale.

Seeking for ultrasensitive and low-cost substrates is highly demandable for practical applications of surface-enhanced Raman scattering (SERS) technology. In this work, we report an ultrasensitive SERS-active substrate based on wet-chemistry-synthesized vertically aligned large-area TiO2 nanosheets (NSs) decorated by densely packed gold nanoparticles (Au NPs) with sub-5 nm gaps. Via a multistep successive deposition process, three-dimensional-stacked Au NPs sandwiched by a 3 nm SiO2 layer were assembled onto the TiO2 NS, enabling numerous hotspots due to the formation of both ultratiny plasmonic gaps and semiconductor/metal interfaces. Experimental results show that the fabricated substrate displays a detection limit down to 10 fM (10-14 M) without involving any condensation process by using the crystal violet as probe molecules. Control experiments and electromagnetic simulations indicate that the nanogaps defined by the 3 nm spacer are essential for the obtained excellent SERS performance. With its ultrasensitive detection capability, we demonstrate that the fabricated SERS substrate can be used for the trace analysis of melamine in milk.

Sensitive Surface-Enhanced Raman Scattering Detection Using On-Demand Postassembled Particle-on-Film Structure.

Highly sensitive and low-cost surface-enhanced Raman scattering (SERS) substrates are essential for practical applications of SERS. In this work, we report an extremely simple but effective approach to achieve sensitive SERS detection of molecules (down to 10-10 M) by using a particle/molecule/film sandwich configuration. Compared to conventional SERS substrates which are preprepared to absorb analyte molecules for detection, the proposed sandwich configuration is achieved by postassembling a flexible transparent gel tape embedded with plasmonic nanoparticles onto an Au film decorated with to-be-detected analyte molecules. In such a configuration, the individual plasmonic gel tape and Au film have low or no SERS activity but the final assembled sandwich structure shows strong SERS signal due to the formation of numerous hot spots at the particle-film interface, where the analyte molecules themselves serve as both spacer and signal probes. Because of its simple configuration, we demonstrate that the proposed SERS substrate can be obtained over a large area with extremely low cost. Particularly, because of the on-demand nature and the flexibility, such a postassembly strategy provides an ideal solution to detect the pesticide residue on fruit surfaces with significantly enhanced sensitivity.

Physical mechanisms for tuning the nonlinear effects in photonic crystals.

By simultaneously taking field localization and slow light effects into account, in this paper we make use of a field averaging method to calculate the effective nonlinear refractive index coefficient (n2) of Kerr photonic crystals (PhCs) in the first band. Although the nonlinear PhC is beyond the traditional long-wavelength limit, interestingly, the theoretically calculated effective n2 agrees well with one numerically measured via the self-phase-modulation induced spectral broadening. Moreover, due to the cooperative influence of field localization and slow light effects, the effective n2 of the PhC decreases slowly at first and then goes up quickly with increasing frequency. This kind of dispersive nonlinearity is purely induced by the periodic nanostructures because the optical parameters of both components of the PhC we took are frequency-independent. Our results may pave the way for enhancing or limiting nonlinear effects and provide a method for producing the dispersive nonlinearity.

Multiple hot images from an obscuration in an intense laser beam through cascaded Kerr medium disks.

We present a theoretical investigation on the formation of hot images in an intense laser beam through cascaded Kerr medium disks, to disclose the distribution and intensity of hot images in high-power disk amplifiers. It is shown that multiple hot images from an obscuration may be formed, instead of one hot image as reported previously in the literature. This gives a clear explanation for the curious damage pattern of hot images, namely, damage sites appearing on alternating optics in periodic trains. Further analysis demonstrates that the distribution and intensity of hot images depend closely on the number of Kerr medium disks, the distance from the obscuration to the front of the first disk downstream, the space between two neighboring disks, and the thickness and B integral of each disk. Moreover, we take two cascaded Kerr medium disks for example to detail multiple hot images from an obscuration and confirm the theoretical results by numerical simulations.

Optical properties of a square-lattice photonic crystal within the partial bandgap.

Optical properties of a two-dimensional square-lattice photonic crystal are systematically investigated within the partial bandgap through anisotropic characteristics analysis and numerical simulation of field pattern. Using the plane-wave expansion method and Hellmann-Feynman theorem, the relationships between the incident and refracted angles for both phase and group velocities are calculated to analyze light propagation from air to photonic crystals. Three kinds of flat slab focusing are summarized and demonstrated by numerical simulations using the multiple scattering method.

Field and dispersion properties of subwavelength-diameter hollow optical fiber.

We have investigated the basic properties of subwavelength- diameter hollow optical fiber with exact solutions of Maxwell's equations. The characteristics of modal field and waveguide dispersion have been studied. It shows that the subwavelength-diameter hollow optical fibers have interesting properties, such as enhanced evanescent field, local enhanced intensity in the hollow core and large waveguide dispersion that are very promising for many miniaturized high performance and novel photonic devices.

Transverse intensity distributions of a broadband laser modulated by a hard-edged aperture.

By means of the Huygens-Fresnel diffraction integral, the field representation of a laser beam modulated by a hard-edged aperture is derived. The near-field and far-field transverse intensity distributions of the beams with different bandwidths are analyzed by using the representation. The numerical calculation results indicate that the amplitudes and numbers of the intensity spikes decrease with increasing bandwidth, and beam smoothing is achieved when the bandwidth takes a certain value in the near field. In the far field, the radius of the transverse intensity distribution decreases as the bandwidth increases, and the physical explanation of this fact is also given.

Absolute left-handed behaviors in a triangular elliptical-rod photonic crystal.

In this paper we theoretically study the left-handed behaviors in a two-dimensional triangular photonic crystal made of elliptical rods in air. An absolute left-handed region is found in the second photonic band by using the plane wave expansion method to analyze the photonic band structure and equifrequency contours. Typical left-handed behaviors such as negative refraction, flat superlensing and plano-concave lensing are demonstrated by the finite-difference time-domain simulations. These behaviors are also compared with the quasi-negative refraction and the resulted focusing effects in a square-lattice two-dimensional photonic crystal.