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Åshild J Vågene, Alexander Herbig, Michael G Campana, Nelly M Robles García, Christina Warinner, Susanna Sabin, Maria A Spyrou, Aida Andrades Valtueña, Daniel Huson, Noreen Tuross, Kirsten I Bos, Johannes Krause
Indigenous populations of the Americas experienced high mortality rates during the early contact period as a result of infectious diseases, many of which were introduced by Europeans. Most of the pathogenic agents that caused these outbreaks remain unknown. Through the introduction of a new metagenomic analysis tool called MALT, applied here to search for traces of ancient pathogen DNA, we were able to identify Salmonella enterica in individuals buried in an early contact era epidemic cemetery at Teposcolula-Yucundaa, Oaxaca in southern Mexico...
January 15, 2018: Nature Ecology & Evolution
Yejing Dai, Xingfu Wang, Wenbo Peng, Cheng Xu, Changsheng Wu, Kai Dong, Ruiyuan Liu, Zhong Lin Wang
Cadmium sulfide (CdS) has received widespread attention as the building block of optoelectronic devices due to its extraordinary optoelectronic properties, low work function, and excellent thermal and chemical stability. Here, a self-powered flexible photodetector (PD) based on p-Si/n-CdS nanowires heterostructure is fabricated. By introducing the pyro-phototronic effect derived from wurtzite structured CdS, the self-powered PD shows a broadband response range, even beyond the bandgap limitation, from UV (325 nm) to near infrared (1550 nm) under zero bias with fast response speed...
January 15, 2018: Advanced Materials
Paolo Pazzi, Anastasia Kavkovsky, Anna Shipov, Gilad Segev, Eran Dvir
Canine spirocercosis is caused by the nematode Spirocerca lupi. Migration results in oesophageal fibro-inflammatory nodules that may undergo neoplastic transformation. No studies have assessed pre- or post-surgical prognostic indicators in dogs that undergo intervention for S. lupi induced oesophageal neoplasia. This observational, multi-center study aimed to assess the outcome of dogs with Spirocerca induced sarcoma undergoing endoscopic-guided ablation (n = 12) or surgery (n = 18), and identify prognostic indicators...
January 30, 2018: Veterinary Parasitology
Viphretuo Mere, Rakshitha Kallega, Shankar Kumar Selvaraja
We present a novel photonic wire-to-slot waveguide coupler in SOI. The phase matching between a wire and slot mode is achieved using a mode transformer. The architecture consists of a balanced 50/50 power splitter and a tunable phase matched taper combiner forming a slot waveguide. We show a theoretical wire-to-slot coupling efficiency of 99 % is achievable and experimentally, we demonstrate a coupling efficiency of 99 % in the 1550 nm band. Based on the coupling scheme, we also show excitation of a slot mode in a slotted ring resonator and verified the excitation through the thermo-optic response of the rings...
January 8, 2018: Optics Express
Jiří Čtyroký, Juan Gonzalo Wangüemert-Pérez, Pavel Kwiecien, Ivan Richter, Ján Litvik, Jens H Schmid, Íñigo Molina-Fernández, Alejandro Ortega-Moñux, Milan Dado, Pavel Cheben
Properties of reflection and transmission spectral filters based on Bragg gratings in subwavelength grating (SWG) metamaterial waveguides on silicon-on-insulator platform have been analyzed using proprietary 2D and 3D simulation tools based on Fourier modal method and the coupled-mode theory. We also demonstrate that the coupled Bloch mode theory can be advantageously applied to design of Bragg gratings in SWG waveguides. By combining different techniques, including judiciously positioning silicon loading segments within the evanescent field of the SWG waveguide and making use of its dispersion properties, it is possible to attain sub-nanometer spectral bandwidths for both reflection and transmission filters in the wavelength range of 1550 nm while keeping minimum structural features of the filters as large as 100 nm...
January 8, 2018: Optics Express
Ramon A Martinez, Genevieve Plant, Kaiwen Guo, Brian Janiszewski, Michael J Freeman, Robert L Maynard, Mohammed N Islam, Fred L Terry, Oseas Alvarez, Francois Chenard, Robert Bedford, Ricky Gibson, Agustin I Ifarraguerri
We demonstrate an all-fiber supercontinuum source that generates a continuous spectrum from 1.6 μm to >11  μm with 417 mW on-time average power at 33% duty cycle. By utilizing a master oscillator power amplifier pump with three amplification stages and concatenating solid core ZBLAN, arsenic sulfide, and arsenic selenide fibers, we shift 1550 nm light to ∼4.5  μm, ∼6.5  μm, and >11  μm, respectively. With 69 mW past 7.5 μm, this source provides both high power and broad spectral expansion, while outputting a single fundamental mode...
January 15, 2018: Optics Letters
Axel Schönbeck, Fabian Thies, Roman Schnabel
Strongly squeezed light at telecommunication wavelengths is a necessary resource for one-sided device-independent quantum key distribution via fiber networks. Reducing the optical pump power that is required for its generation will advance this quantum technology towards efficient out-of-laboratory operation. Here, we investigate the second-harmonic pump power requirement for parametric generation of continuous-wave squeezed vacuum states at 1550 nm in a state-of-the-art doubly resonant standing-wave periodically poled potassium titanyl phosphate cavity setup...
January 1, 2018: Optics Letters
Naifu Jin, Kirk T Semple, Longfei Jiang, Chunling Luo, Dayi Zhang, Francis L Martin
Exposure to environmental insults generally occurs at low levels, making it challenging to measure bacterial responses to such interactions. Additionally, microbial behaviour and phenotype varies in differing bacterial types or growth phases, likely giving rise to growth- or species-specific responses to environmental stimuli. The present study applied a spectrochemical tool, infrared (IR) spectral interrogation coupled with multivariate analysis, to investigate the growth- and species-specific responses of two bacterial strains, Gram-negative Pseudomonas fluorescens and Gram-positive Mycobacterium vanbaalenii, to low concentrations of tetracycline, nanoparticulate silver (AgNP) or mixtures thereof...
January 12, 2018: Analyst
Vic A Narurkar, Tina S Alster, Eric F Bernstein, Tina J Lin, Anya Loncaric
<p>BACKGROUND: Fractional photothermolysis (FP) is a popular treatment option for photodamaged skin and addresses shortcomings of ablative skin resurfacing and nonablative dermal remodeling. Previous studies have demonstrated that FP using the 1550nm wavelength has led to improvement of ultrastructural changes and clinical effects associated with photodamaged skin in the deeper dermal structures, while treatment with the 1927nm wavelength has shown clinical effects in the superficial dermis. Both wavelengths produce precise microscopic treatment zones (MTZs) in the skin...
January 1, 2018: Journal of Drugs in Dermatology: JDD
Ulf Dammer, Roswitha Bogner, Christel Weiss, Florian Faschingbauer, Jutta Pretscher, Matthias W Beckmann, Marc Sütterlin, Sven Kehl
AIM: We aimed to determine the influence of body mass index (BMI) on induction of labor. METHODS: In this historical multicenter cohort study, 2122 labor inductions were analyzed. Women were divided into four groups according to their body mass index (BMI): BMI < 30 (normal group [NG]), 30 ≤ BMI < 35 (group 1 [G1]), 35 ≤ BMI < 40 (group 2 [G2]), and BMI ≥ 40 (group 3 [G3]). The primary outcome measure was the induction-to-delivery interval...
January 8, 2018: Journal of Obstetrics and Gynaecology Research
Jing-Yuan Wu, Young Tea Chun, Shunpu Li, Tong Zhang, Junzhan Wang, Pawan Kumar Shrestha, Daping Chu
Inverse photoresponse is discovered from phototransistors based on molybdenum disulfide (MoS2 ). The devices are capable of detecting photons with energy below the bandgap of MoS2 . Under the illumination of near-infrared (NIR) light at 980 and 1550 nm, negative photoresponses with short response time (50 ms) are observed for the first time. Upon visible-light illumination, the phototransistors exhibit positive photoresponse with ultrahigh responsivity on the order of 104 -105 A W-1 owing to the photogating effect and charge trapping mechanism...
January 8, 2018: Advanced Materials
Zhengyong Liu, Lin Htein, Kang-Kuen Lee, Kin-Tak Lau, Hwa-Yaw Tam
This paper presents a sensitive and large dynamic range pressure sensor based on a novel birefringence microstructured optical fiber (MOF) deployed in a Sagnac interferometer configuration. The MOF has two large semicircle holes in the cladding and a rectangular strut with germanium-doped core in the center. The fiber structure permits surrounding pressure to induce large effective index difference between the two polarized modes. The calculated and measured group birefringence of the fiber are 1.49 × 10-4, 1...
January 8, 2018: Scientific Reports
Muhammad Imran Shahzad, Mohsin Meraj, Majid Nazeer, Ibrahim Zia, Asif Inam, Khalid Mehmood, Hina Zafar
Suspended Solids Concentration (SSC) in water is related to its quality and transparency. Satellite remote sensing has proven to be an efficient means of monitoring water quality in large deltas because in situ sampling methods are costly, laborious, time consuming, and spatially constrained. In this study, the potential of Landsat's Enhanced Thematic Mapper Plus (ETM+) sensor was explored to develop a model for remote sensing-based quantification of SSC within the large, turbid Indus Delta Region (IDR, south of Pakistan)...
January 3, 2018: Journal of Environmental Management
Reshama Navathe, Gabriele Saccone, Michela Villani, Jacquelyn Knapp, Yury Cruz, Rupsa Boelig, Amanda Roman, Vincenzo Berghella
BACKGROUND: It is unknown if universal second-trimester transvaginal ultrasound (TVU) cervical length (CL) screening in asymptomatic women with singleton gestations and no prior spontaneous preterm birth (SPTB) affects the incidence of symptoms of preterm labor (PTL) later in pregnancy. OBJECTIVE: To evaluate the incidence of threatened PTL before and after the implementation of universal second trimester TVU CL screening. STUDY DESIGN: This was a retrospective cohort study of all consecutive singleton gestations without prior SPTB presenting to obstetric triage for threatened PTL between 23 0/7 and 33 6/7 week in 2011 (1 January-31 December), and in 2014 (1 January-31 December) at Thomas Jefferson University Hospital (TJU) (Philadelphia, PA)...
January 5, 2018: Journal of Maternal-fetal & Neonatal Medicine
Si Zhu, Bei Shi, Qiang Li, Yating Wan, Kei May Lau
In this paper, we present a parametric study of high performance microdisk lasers at 1.55 μm telecom wavelength, monolithically grown on on-axis (001) Si substrates incorporating quantum dots (QDs) as gain elements. In the optimized structure, seven layers of QDs were adopted to provide a high gain as well as a suppressed inhomogeneous broadening. The same laser structure employing quantum wells (QWs) on Si was concurrently evaluated, showing a higher threshold and more dispersive quantum efficiency than the QDs...
December 11, 2017: Optics Express
Lixing You, Junjie Wu, Yingxin Xu, Xintong Hou, Wei Fang, Hao Li, Weijun Zhang, Lu Zhang, Xiaoyu Liu, Limin Tong, Zhen Wang, Xiaoming Xie
High-performance superconducting nanowire single-photon detectors (SNSPDs) have facilitated numerous experiments and applications, particularly in the fields of modern quantum optics and quantum communication. Two kinds of optical coupling methods have thus far been developed for SNSPDs: one produces standard fiber-coupled SNSPDs in which the fibers vertically illuminate the meandered nanowires; the other produces waveguide-coupled SNSPDs in which nanowires are fabricated on the surface of a waveguide that guides photons, and the fibers are coupled to the waveguide...
December 11, 2017: Optics Express
Jishi Cui, Zhiping Zhou
We investigated the Ge-on-Si photodetector's performance enhancement by optimizing the detector length, therefore, the location of the distributed Bragg reflector (DBR). Since the unabsorbed signal light in the photodetector oscillates between the germanium and silicon layers, but the DBR is on the silicon layer, the optimized location of the DBR will result in shorter devices, with increased bandwidth, reduced dark current, and consistent responsivity. The 5 μm long photodetector with an optimized DBR location shows responsivity of 0...
December 15, 2017: Optics Letters
Aparupa Kar, Nabamita Goswami, Ardhendu Saha
A proposal on high-resolution electro-optical beam steering is conceptualized analytically using a long-range surface plasmon resonance configuration comprising a liquid crystal layer of E44 for 1550 nm wavelength. With the tuning of the refractive index of E44 through variations of applied voltage from 0 to 10 V, an optical beam steering can be attained considering the composite effect of spatial and angular Goos-Hanchen and Imbert-Fedorov shifts. As compared with the existing beam shift processes in μrad by mechanical means, here, the computed angular resolution is 3...
December 10, 2017: Applied Optics
Jad Jabbour, Thomas Robey
INTRODUCTION: Vocal fold immobility (VFI) is an important sequela of preterm birth due to patent ductus arteriosus (PDA) ligation and invasive ventilation. A minority of these patients experience VFI resolution. The purpose of this study is to determine factors associated with VFI resolution in preterm infants. METHODS: This is a case control study of preterm (<37 weeks gestation) infants admitted to a metropolitan Level IV neonatal intensive care unit from 2006 to 2012...
December 2017: International Journal of Pediatric Otorhinolaryngology
Chunlei Sun, Yu Yu, Xinliang Zhang
We propose and experimentally demonstrate an ultra-compact multimode waveguide crossing that can process two modes simultaneously. The symmetric Y-junction is introduced to split the high-order modes into fundamental ones, easing the subsequent processing. The footprint of the proposed crossing is as compact as 21  μm×21  μm. The measured results show an insertion loss of ∼1.82  dB for the TE0 mode and ∼0.46  dB for the TE1 mode at 1550 nm, as well as a crosstalk of <-18  dB from 1510 to 1600 nm...
December 1, 2017: Optics Letters
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