Broadband enhancement of thermal radiation.

Broadband thermal radiation sources are critical for various applications including spectroscopy and electricity generation. However, due to the difficulty in simultaneously achieving high absorptivity and low thermal mass these sources are inefficient. We show a platform that enables one to obtain enhanced emission by coupling a thermal emitter to an optical cavity. We experimentally demonstrate broadband enhancement of thermal emission between λ ~2 ̶ 4.2 µm using an inherently poor thermal emitter consisting of tens of nanometers thick SiC film with 10% emissivity (εSiC ~0.1). We measure over twofold enhancement of total emission power over the entire spectral band and threefold enhancement of thermal emission over 3 to 3.4 µm. Our platform has the potential to enable development of ideal blackbody sources operating at substantially lower heating powers.

ANATOMICAL VARIATIONS OF THE CELIAC TRUNK: A SYSTEMATIC REVIEW.

INTRODUCTION: The celiac trunk (CT) is one of the abdominal portion branches of the aortic artery and, together with the superior mesenteric and inferior mesenteric arteries, participates in the abdominal viscera vascularization through a series of anastomoses. Absence of CT or variation in the number of terminal branches implies in varied abdominal arteries origins, which may have implication in surgical approaches. OBJECTIVE: To analyze the anatomical variations of the celiac trunk and possible associated surgical clinical implications. METHODS: It is a systematic review of articles indexed in the PubMed, Lilacs, SciELO, Springerlink, Scienc Direct and Latindex databases from August to September 2017. Original articles involving the anatomical variations of the celiac trunk in humans were included. The presence/absence of the celiac trunk, the number of terminal branches and the place of origin of its branches in variant cases of the normal anatomical pattern, were considered for this study. RESULTS: At the end of the research, 12 articles were selected, characterized by sample, anatomical structure evaluation method and main results. The normal anatomical pattern was the most prevalent in most studies (75.0%). CT was absent in 41.7% of the findings. The most prevalent anatomical variation was the presence of CT with bifurcation (66.7%). It was also observed the origin of the common and splenic hepatic arteries from the mesenteric arteries (25.0%). The presence of only one branch (16.7%) and quadrifurcation (8.33%) were other findings. CONCLUSION: CT variations are not uncommon findings, with different anatomic variants being reported. Thus, the importance of knowing the possible variations of this structure is emphasized, which may have implications for surgical interventions and imaging studies related to the abdominal region.

Microphotonic needle for minimally invasive endoscopic imaging with sub-cellular resolution.

Ultra-compact micro-optical elements for endoscopic instruments and miniaturized microscopes allow for non-invasive and non-destructive examination of microstructures and tissues. With sub-cellular level resolution such instruments could provide immediate diagnosis that is virtually consistent with a histologic diagnosis enabling for example to differentiate the boundaries between malignant and benign tissue. Such instruments are now being developed at a rapid rate; however, current manufacturing technologies limit the instruments to very large sizes, well beyond the sub-mm sizes required in order to ensure minimal tissue damage. We show here a platform based on planar microfabrication and soft lithography that overcomes the limitation of current optical elements enabling single cell resolution. We show the ability to resolve lithographic features that are as small as 2 µm using probes with a cross section that is only 100 microns in size. We also show the ability to image individual activated neural cells in brain slices via our fabricated probe.

Anatomical variations of the celiac trunk: a systematic review / Variações anatômicas do tronco celíaco: uma revisão sistemática

ABSTRACT Introduction: The celiac trunk (CT) is one of the abdominal portion branches of the aortic artery and, together with the superior mesenteric and inferior mesenteric arteries, participates in the abdominal viscera vascularization through a series of anastomoses. Absence of CT or variation in the number of terminal branches implies in varied abdominal arteries origins, which may have implication in surgical approaches. Objective: To analyze the anatomical variations of the celiac trunk and possible associated surgical clinical implications. Methods: It is a systematic review of articles indexed in the PubMed, Lilacs, SciELO, Springerlink, Scienc Direct and Latindex databases from August to September 2017. Original articles involving the anatomical variations of the celiac trunk in humans were included. The presence/absence of the celiac trunk, the number of terminal branches and the place of origin of its branches in variant cases of the normal anatomical pattern, were considered for this study. Results: At the end of the research, 12 articles were selected, characterized by sample, anatomical structure evaluation method and main results. The normal anatomical pattern was the most prevalent in most studies (75.0%). CT was absent in 41.7% of the findings. The most prevalent anatomical variation was the presence of CT with bifurcation (66.7%). It was also observed the origin of the common and splenic hepatic arteries from the mesenteric arteries (25.0%). The presence of only one branch (16.7%) and quadrifurcation (8.33%) were other findings. Conclusion: CT variations are not uncommon findings, with different anatomic variants being reported. Thus, the importance of knowing the possible variations of this structure is emphasized, which may have implications for surgical interventions and imaging studies related to the abdominal region.

RESUMO Introdução: O tronco celíaco (TC) surge da aorta abdominal e juntamente com as artérias mesentérica superior e mesentérica inferior participa da vascularização de vísceras abdominais por meio de uma série de anastomoses. Ausência do TC ou variação no número de ramos terminais implica em origens variadas das artérias abdominais, o que pode ter implicação em abordagens cirúrgicas. Objetivo: Analisar as variações anatômicas do TC e as possíveis implicações clínico/cirúrgicas associadas. Métodos: Trata-se de uma revisão sistemática de artigos indexados nas bases de dados PubMed, Lilacs, SciELO, Springerlink, Scienc Direct e Latindex, no período de agosto a setembro de 2017. Foram incluídos artigos originais envolvendo as variações anatômicas do TC em humanos. Considerou-se para este estudo a presença/ausência do TC, o número de ramos terminais e o local de origem de seus ramos em casos variantes do padrão anatômico normal. A coleta foi realizada por dois revisores independentes. Resultados: Ao final da busca foram selecionados 12 artigos, caracterizados quanto à amostra, método para avaliar a estrutura anatômica e principais resultados. O padrão anatômico normal foi o mais prevalente na maioria dos trabalhos (75,0%). O TC foi ausente em 41,7% dos achados. A variação anatômica mais prevalente foi a presença do TC com bifurcação (66,7%). Observou-se, ainda, a origem das artérias hepática comum e esplênica a partir das artérias mesentéricas (25,0%). A presença de apenas um ramo (16,7%) e quadrifurcação (8,33%) foram outros achados presentes. Conclusão: Variações do TC não são achados incomuns, sendo relatados diferentes variantes anatômicas. Desse modo, ressalta-se a importância sobre o conhecimento das possíveis variações dessa estrutura, o que pode ter implicação em intervenções cirúrgicas e exames de imagem relacionados à região abdominal.

On-chip thermo-optic tuning of suspended microresonators.

Suspended optical microresonators are promising devices for on-chip photonic applications such as radio-frequency oscillators, optical frequency combs, and sensors. Scaling up these devices demands the capability to tune the optical resonances in an integrated manner. Here, we design and experimentally demonstrate integrated on-chip thermo-optic tuning of suspended microresonators by utilizing suspended wire bridges and microheaters. We demonstrate the ability to tune the resonance of a suspended microresonator in silicon nitride platform by 9.7 GHz using 5.3 mW of heater power. The loaded optical quality factor (QL ~92,000) stays constant throughout the detuning. We demonstrate the efficacy of our approach by completely turning on and off the optical coupling between two evanescently coupled suspended microresonators.

Photonic Needles for Light Delivery in Deep Tissue-like Media.

We demonstrate a new platform for minimally invasive, light delivery probes leveraging the maturing field of silicon photonics, enabling massively parallel fabrication of photonic structures. These Photonic Needles probes have sub-10 µm cross-sectional dimensions, lengths greater than 3 mm-surpassing 1000 to 1 aspect ratio, and are released completely into air without a substrate below. We show the Photonic Needles to be mechanically robust when inserted into 2% agarose. The propagation loss of these waveguides is low-on the order of 4 dB/cm.

Quantum state engineering of light with continuous-wave optical parametric oscillators.

Engineering non-classical states of the electromagnetic field is a central quest for quantum optics(1,2). Beyond their fundamental significance, such states are indeed the resources for implementing various protocols, ranging from enhanced metrology to quantum communication and computing. A variety of devices can be used to generate non-classical states, such as single emitters, light-matter interfaces or non-linear systems(3). We focus here on the use of a continuous-wave optical parametric oscillator(3,4). This system is based on a non-linear χ(2) crystal inserted inside an optical cavity and it is now well-known as a very efficient source of non-classical light, such as single-mode or two-mode squeezed vacuum depending on the crystal phase matching. Squeezed vacuum is a Gaussian state as its quadrature distributions follow a Gaussian statistics. However, it has been shown that number of protocols require non-Gaussian states(5). Generating directly such states is a difficult task and would require strong χ(3) non-linearities. Another procedure, probabilistic but heralded, consists in using a measurement-induced non-linearity via a conditional preparation technique operated on Gaussian states. Here, we detail this generation protocol for two non-Gaussian states, the single-photon state and a superposition of coherent states, using two differently phase-matched parametric oscillators as primary resources. This technique enables achievement of a high fidelity with the targeted state and generation of the state in a well-controlled spatiotemporal mode.