Broadband dispersion compensation using inner cladding modes in photonic crystal fibers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)A photonic crystal fiber is optimized for chromatic dispersion compensation by using inner cladding modes. To this end, a photonic-oriented version of the downhill-simplex algorithm is employed. The numerical results show a dispersion profile that accurately compensates the targeted dispersion curve, as well as its dispersion slope. The presented fiber has a simple structure, while radiation losses can be reduced simply by adding a few more air-hole rings. Fabrication tolerances are also considered showing how fabrication inaccuracies effects can be overridden by just adjusting the compensation length. (C) 2012 Optical Society of America20434673472Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Spanish Ministerio de Educacion y Ciencia (MEC)Generalitat Valenciana [TEC2008-05490, PROMETEO2009-077]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Generalitat Valenciana [TEC2008-05490, PROMETEO2009-077]FAPESP [2011/01524-8

Proliferation Index: A Continuous Model to Predict Prognosis in Patients with Tumours of the Ewing's Sarcoma Family

The prognostic value of proliferation index (PI) and apoptotic index (AI), caspase-8, -9 and -10 expression have been investigated in primary Ewing's sarcoma family of tumours (ESFT). Proliferating cells, detected by immunohistochemistry for Ki-67, were identified in 91% (91/100) of tumours with a median PI of 14 (range 0–87). Apoptotic cells, identified using the TUNEL assay, were detected in 96% (76/79) of ESFT; the median AI was 3 (range 0–33). Caspase-8 protein expression was negative (0) in 14% (11/79), low (1) in 33% (26/79), medium (2) in 38% (30/79) and high (3) in 15% (12/79) of tumours, caspase-9 expression was low (1) in 66% (39/59) and high (3) in 34% (20/59), and caspase-10 protein was low (1) in 37% (23/62) and negative (0) in 63% (39/62) of primary ESFT. There was no apparent relationship between caspase-8, -9 and -10 expression, PI and AI. PI was predictive of relapse-free survival (RFS; p = 0.011) and overall survival (OS; p = <0.001) in a continuous model, whereas AI did not predict outcome. Patients with tumours expressing low levels of caspase-9 protein had a trend towards a worse RFS than patients with tumours expressing higher levels of caspase-9 protein (p = 0.054, log rank test), although expression of caspases-8, -9 and/or -10 did not significantly predict RFS or OS. In a multivariate analysis model that included tumour site, tumour volume, the presence of metastatic disease at diagnosis, PI and AI, PI independently predicts OS (p = 0.003). Consistent with previous publications, patients with pelvic tumours had a significantly worse OS than patients with tumours at other sites (p = 0.028); patients with a pelvic tumour and a PI≥20 had a 6 fold-increased risk of death. These studies advocate the evaluation of PI in a risk model of outcome for patients with ESFT

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p&lt;0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p&lt;0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Writing Resources For Non-native-english-speaking Scientists

[No abstract available]253222

Tapered Graded Index Fibers For Sensing Applications

Optical sensors based on modal interference are improved by tapering a small extension of a graded-index fiber. The tapered section modulates the periodic amplitude of the propagated beam, substantially increasing the sensitivity of these devices. © 2013 Optical Society of America.Liu, Y., Wei, L., Low-cost high-sensitivity strain and temperature sensing using graded-index multimode fibers (2007) Appl. Opt., 46, pp. 2516-2519Biazoli, C.R., Silva, S., Franco, M.A.R., Frazão, O., Cordeiro, C.M.B., Multimode interference tapered fiber refractive index sensors (2012) Appl. Opt., 51, pp. 5941-5945Tripathi, S.M., Kumar, A., Varshney, R.K., Kumar, Y.P., Marin, E., Meunier, J.-P., Strain and temperature sensing characteristics of single-mode-multimode-single-mode structures (2009) J. Lightwave Technol., 27, pp. 2348-2356Tripathi, S.M., Kumar, A., Marin, E., Meunier, J.-P., Single-multi-single mode structure based band pass/stop fiber optic filter with tunable bandwidth (2010) J. Lightwave Technol., 28, pp. 3535-3541Safaai-jazi, A., Propagation properties of tapered graded-index waveguides (1996) J. Mod. Opt., 43, pp. 1921-193

D-microfibers

A simple mechanical setup was used to polish a standard single mode optical fiber in order to make it asymmetric. The polished fiber was tapered down maintaining the D-shape transversal profile. Its broken symmetry along with the extended evanescent field, due to the dimensions of the microfiber, implies a potentially high birefringent waveguide as well as a high-sensitivity external refractive index device. An experimental maximum sensitivity of S≈(3.0±0.2)×104 nm/RIU was achieved, other experimental and numerical results supporting our initial assumptions are also presented. © 1983-2012 IEEE.311630563061Ortigosa-Blanch, A., Knight, J.C., Wadsworth, W.J., Arriaga, J., Mangan, B.J., Birks, T.A., Russell, P.S.J., Highly birefringent photonic crystal fibers (2000) Opt Lett, 25 (18), pp. 1325-1327. , http://ol.osa.org/ab-stract.cfm?URI=ol-25-18-1325, SeptBeltrán-Mejia, F., Chesini, G., Silvestre, E., George, A.K., Knight, J.C., Cordeiro, C.M., Ultrahigh-birefringent squeezed lattice photonic crystal fiber with rotated elliptical air holes (2010) Opt Lett, 35 (4), pp. 544-546. , http://ol.osa.org/abstract.cfm?URI=ol-35-4-544, FebJung, Y., Brambilla, G., Oh, K., Richardson, D.J., Highly birefringent silicamicrofiber (2010) Opt. Lett, 35 (3), pp. 378-380. , http://ol.osa.org/abstract.cfm?URI=ol-35-3-378, FebLi, J., Sun, L.-P., Gao, S., Quan, Z., Chang, Y.-L., Ran, Y., Jin, L., Guan, B.-O., Ultrasensitive refractive-index sensors based on rectangular silica microfibers (2011) Opt Lett, 36 (18), pp. 3593-3595. , http://ol.osa.org/ab-stract.cfm?URI=ol-36-18-3593, SepXuan, H., Ju, J., Jin, W., Highly birefringent optical microfibers (2010) Opt Exp, 18 (4), pp. 3828-3839. , http://www.opticsexpress.org/abstract.cfm?URI=oe-18-4-3828, FebKou, J.-L., Huang, Z.-D., Zhu, G., Xu, F., Lu, Y.-Q., Wave guiding properties and sensitivity of D-shaped optical fiber microwire devices (2011) Appl. Phys. B, 102, pp. 615-619. , http://dx.doi.org/10.1007/s00340-010-4244-yBirks, T., Li, Y., The shape of fiber tapers (1992) J. Lightw. Technol., 10 (4), pp. 432-438Silvestre, E., Pinheiro-Ortega, T., Andrés, P., Miret, J.J., Ortigosa-Blanch, A., Analytical evaluation of chromatic dispersion in photonic crystal fibers (2005) Opt Lett, 30 (5), pp. 453-455. , http://ol.osa.org/abstract.cfm?URI=ol-30-5-453, MarPress, W.H., Teukolsky, S.A., Vetterling, W.T., Flannery, B.P., (1992) Numerical Recipes in C (2nd Ed.): The Art of Scientific Computing, , New York, NY, USA: Cambridge Univ. PressRashleigh, S.C., Measurement of fiber birefringence by wavelength scanning: Effect of dispersion (1983) Opt. Lett., 8 (6), pp. 336-338. , http://ol.osa.org/ab-stract.cfm?URI=ol-8-6-336, JunHeller, W., Remarks on refractive index mixture rules (1965) J. Phys. Chem., 69 (4), pp. 1123-1129. , http://pubs.acs.org/doi/abs/10.1021/j100888a006Astle, M., Weast, R., (1979) CRC Handbook of Chemistry and Physics, , Boca Raton FL USA: CRC Pres

Oam Mode Converter In Twisted Fibers

We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM.Allen, L., Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes (1992) Phys. Rev. A, 45, p. 8185Wang, J., Terabit free-space data transmission employing orbital angular momentum multiplexing (2012) Nat. Photonics, 6, pp. 488-496Nicolet, A., Geometrical transformations and equivalent materials in computational electromagnetism (2008) COMPEL, 27, p. 806Alexeyev, C.N., Generation and conversion of optical vortices in long-period twisted elliptical fibers (2012) Appl. Opt., 51, pp. C193-C197Usuga, M.A., Beltran-Mejia, F., Cordeiro, C., Tafur Monroy, I., OAM generation in circular and elliptical twisted fibers preparatio

D-Microfibers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A simple mechanical setup was used to polish a standard single mode optical fiber in order to make it asymmetric. The polished fiber was tapered down maintaining the D-shape transversal profile. Its broken symmetry along with the extended evanescent field, due to the dimensions of the microfiber, implies a potentially high birefringent waveguide as well as a high-sensitivity external refractive index device. An experimental maximum sensitivity of S approximate to (3.0 +/- 0.2) x 10(4) nm/RIU was achieved, other experimental and numerical results supporting our initial assumptions are also presented.311627562761Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2011/01524-8, 2010/13149-4