1,045 research outputs found
A SiON Microring Resonator-Based Platform for Biosensing at 850 nm
No full textn this paper, we report on the design, fabrication, and characterization of a photonic circuit for biosensing applications. Silicon oxynitride with a bulk refractive index of 1.66 is the core-layer material. The photonic circuit is optimized for a wavelength of ~850 nm, which allows on-chip integration of the light source via cost effective vertical-cavity surface-emitting lasers and of the detector by using standard silicon photodetectors. Design as well as fabrication processes are explained in details. The best characteristics for the single optical components in the photonic circuit are: for single-mode channel waveguides with dimensions of 350 nm × 950 nm; propagation losses of 0.8 dB/cm; bending losses of 0.1 dB/90°-bend (radius of curvature 100 μm); 49/51 splitting ratio for 3-dB power splitters (directional couplers); quality factors up to 1.3 × 105 for microring resonators. Volumetric sensing yields a bulk sensitivity of 80 nm/RIU and a limit of detection of 3 × 10-6 RIU. Therefore, SiON-based photonic circuits represent a reliable material platform for biosensing in the short-wave near infrared region
Design and Optimization of SiON Ring Resonator-Based Biosensors for Aflatoxin M1 Detection
No full textIn this article, we designed and studied silicon oxynitride (SiON) microring-based photonic structures for biosensing applications. We designed waveguides, directional couplers, and racetrack resonators in order to measure refractive index changes smaller than 10−6 refractive index units (RIU). We tested various samples with different SiON refractive indexes as well as the waveguide dimensions for selecting the sensor with the best performance. Propagation losses and bending losses have been measured on test structures, along with a complete characterization of the resonator’s performances. Sensitivities and limit of detection (LOD) were also measured using glucose-water solutions and compared with expected results from simulations. Finally, we functionalized the resonator and performed sensing experiments with Aflatoxin M1 (AFM1). We were able to detect the binding of aflatoxin for concentrations as low as 12.5 nm. The results open up the path for designing cost-effective biosensors for a fast and reliable sensitive analysis of AFM1 in milk
Macroeconomic determinants of agricultural preferential investment credit in Poland
No full textIn the paper the impact of macroeconomic determinants on the number and value of agricultural investment preferential credits in Poland is examined. This kinds of determinants are of an exogenous character and they cannot be controlled by individual farm. They are related to economic growth, price level changes, monetary policy, inflation, changes in foreign trade conditions. The econometric analysis showed that macroeconomic environment influenced farmers’ credit decisions at number and value of taken credits. The statistically significant variables in the case of these measures were the index of price relations of sold agricultural products to goods and services purchased by private farms (“price gap”), interest rate of central bank and real interest rate paid by farmers. Somewhat surprisingly, neither rate of GDP growth nor real effective exchange rate affected the scope of credits. In the case of GDP rate, the result can suggest that farmers expectations does not depend on current phase of business cycle. The reason of luck the influence of terms of foreign exchange can be explained partly by relatively low share of agricultural products in foreign trade turnover.preferential credit, farmers, macroeconomic determinants, Agricultural Finance,
Sensitivity and Limit of Detection of biosensors based on ring resonators
No full textIn this work, we present a study of the Sensitivity (S) and Limit of Detection (LOD) of microring based photonic biosensors as a function of the waveguide composition and dimensions. The target is Aflatoxin, which is a toxin of major concern for south Europe dairy industry. The sensing device is based on an array of multiple SiON microring resonators, fiber-coupled to both an 850 nm VCSEL and a silicon photodetectors, packaged with a microfluidic circuit. Volumetric sensing with glucose–water solutions of various concentrations yields a best sensitivity of 112 nm/RIU. To link these results to the Limit of Detection of the sensors, we also measured the noise of our experimental readout system and then calculated the LOD of our sensors. We found a best value of LOD of 1.6 × 10−6 RIU (referred to volumetric sensing). Finally, we detected Aflatoxin in solutions of various concentrations (down to 1.58 nM) by functionalized sensors. The functionalization is based on a wet silanization and specific DNA-aptamer binding on the chip. Reproducibility and re-usability of the sensor are investigated by several chemical treatments. Optimum procedure allows multiple sequential measurements with a good endurance. This work was supported by the FP7 EU project “Symphony” (Grant agreement no.: 610580). Keywords: Biosensor, Whispering Gallery Mode, Ring resonator, Aflatoxin, Limit of Detection, Sensitivit
Alina Ashbrook letter to the Franklin County Woman Suffrage Association, October 19, 1914
No full textAlina Ashbrook, a resident of Mingo Junction, Ohio, sent this letter to the Franklin County Woman Suffrage Association on October 19, 1914, to request campaigning materials for her town. She had visited Columbus and had heard about advertising balloons which would be used to endorse women's suffrage, and wanted to display them in Mingo Junction as well.
The Franklin County Woman Suffrage Association was formed in 1912, after the Ohio Constitutional Convention elected to bring to a vote the question of removing the words "white male" from the state constitution with regard to voting rights. Headquartered in the Chamber of Commerce building in Columbus, Ohio, the organization put out regular publications, organized public speeches and meetings, distributed literature and held parades in support of the suffrage movement. Women's suffrage in Ohio was defeated in a special election in 1912 and again in 1914 and 1916 before a resolution narrowly passed in 1917 allowing municipal voting by women in Columbus. In 1920, the 19th Amendment passed, extending the vote to women and prohibiting state and federal government from denying suffrage on the basis of sex
Aptamer- and Fab’- Functionalized Microring Resonators for Aflatoxin M1 Detection
No full textSilicon oxynitride (SiON) microring resonators are used to develop a biosensor device to detect Aflatoxin M1 (AFM1), a carcinogenic mycotoxin present in milk. Two different surface functionalization strategies are tested to realize an affinity biosensing device. Both strategies are based on the formation of a silane surface layer able to bind either specific DNA-aptamers or antigen binding fragments (Fab'). The sensing device consists of an array of four SiON microring resonators, fiber-coupled to a vertical cavity surface emitting laser operating at 850 nm. Detection is realized with off-chip silicon photodetectors. With both functionalizations, we demonstrate a specific detection of AFM1 in buffer, while the nonspecific detection of Ochratoxin is not occurring. Repeatability and reproducibility of both functionalization strategies are discussed
An integrated optical biosensor platform
No full textA tiny, low-cost evanescent-field biosensor chip with a directly integrated optical detector enables carcinogenic contaminant detection and shows promise for point-of-use application
Force of Nature: Alina Scholtz and the Empowerment of Women on Mid-Century Landscape Design
No full textTo answer the question of women’s empowerment in mid-century landscape architecture, this essay will focus on the legacy of the “mother founder”1 of Polish landscape architecture, Alina Scholtz admitted for her immense independence and involvement at work.Scholtz was a designer and educator, serving as a professor of landscape architecture at the Warsaw University of Life Sciences. Her diverse portfolio ranged from palace gardens to housing estates and playgrounds. Her realisations were changeable in time, as a living matter of plants, which are led by the sun and water, create an architectural mass and systems of components in the urban landscape.From the beginning, landscape architecture, similarly to interior design, was treated as a “decorative” addition to “prime” architecture.2 Women dominated the discipline. Over the course of her career, Scholtz has worked with many aspiring women architects, landscape architects and urban planners whose names are unknown. Alina Scholtz was an exception to the rule. She was the leader of the landscape architecture team strongly feminised - in the „Zieleń” („Greenery”) studio at the Biuro Odbudowy Stolicy (BOS)3. She made major contributions to the International Federation of Landscape Architects4 and the SARP5 conferences, promoting the value of greenery designs in reconstructing cities after WWII and advocating Poland’s opinions on the subject on a global scale.The methodology will include an analysis of the documents belonging to archives of the BOS in Warsaw, the Landscape Architecture department, archives of the Museum of Architecture in Wrocław, archives of the Frederyk Chopin Museum in Żelazowa Wola and National Archive in Warsaw, Otwock section, an interview with the Centrala Group, Małgorzata Kuciewicz and Simone De Iacobis, who were responsible for the exhibition on Alina Scholtz in Warsaw, in 2022, and study of photographs, official correspondence as well as letters to the Scholtz family and drawings and publications related to the subject.1 Czerniewska-Andryszczyk, Klara, Ewa Perlińska-Kobierzyńska, Natalia Budnik, Małgorzata Kuciewicz, Simone De Iacobis. Alina Scholtz Projektantka warszawskiejzieleni. Warsaw: Muzeum Warszawy, 2021., P. 82 Czerniewska-Andryszczyk, Klara, Ewa Perlińska-Kobierzyńska, Natalia Budnik, Małgorzata Kuciewicz, Simone De Iacobis. Alina Scholtz Projektantka warszawskiejzieleni. Warsaw: Muzeum Warszawy, 2021., P. 93 Biuro Odbudowy Stolicy (BOS) - an institution established in 1945 by a decree of the National Council to rebuild Warsaw, destroyed during World War II.4 Scholtz was a foundation member of IFLA in 19485 Stowarzyszenie Architektów Polskich (SARP) - founded in 1934, the national professional association for Polish architects.AR2A011Architectural History ThesisArchitecture, Urbanism and Building Science
Authoring Culture Video, Chapter 05: Craft
No full textA student video offering insight and explanation of the material in Authoring Culture, Chapter 5, Craft. The author is Alina Yastrebova, with collaborators Sean Munoz and Anthony Miocic. The piece was produced in the Foundation of Twenty-First Century Writing class during the Spring semester, 2025, taught by Dr. Brendan Riley. Length: 04:17.https://digitalcommons.colum.edu/authoring_culture/1019/thumbnail.jp
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