The Optimal Wavelength of Spectrophotometric Broth Microdilution Antifungal Susceptibility Test for Flucytosine and Three Azoles

이자영,오승환,김혜란,이정녀,장철훈,고원규,신정환,이은정,김시현,정행순 대한진단검사의학회 2009 Annals of Laboratory Medicine Vol.29 No.4

Background : There is no guideline for the appropriate wavelength at which to measure the optical density (OD) value in broth microdilution antifungal susceptibility testing, although a spectrophotometric reading method is commonly used. The present study aimed to analyze the difference in the OD values over the range of visible light and to ascertain the optimal wavelength for the spectrophotometric method of microdilution testing. Methods : We measured the OD of background blank controls of broth medium, antifungal agents, and inocula of five type strains using a Synergy HT multi-detection microplate reader at 5-nm intervals from 380 nm to 760 nm. We also estimated the OD differences between the 50% of growth control and blank control. Results : The OD of the blank control showed a parabola shape with two peaks and steadily decreased at longer wavelengths. The curves of the antifungal agent were similar to those of blank controls, and the influence of each antifungal agent on the OD was minimal. For the difference in OD between 50% of growth control and the blank control, the curve was the opposite of the blank control, and the OD increased steadily at the wavelengths above 600 nm. Conclusions : The range between 600 nm and 700 nm was the optimal wavelength for broth microdilution antifungal susceptibility testing, although any wavelength within the visible light spectrum can be used. Background : There is no guideline for the appropriate wavelength at which to measure the optical density (OD) value in broth microdilution antifungal susceptibility testing, although a spectrophotometric reading method is commonly used. The present study aimed to analyze the difference in the OD values over the range of visible light and to ascertain the optimal wavelength for the spectrophotometric method of microdilution testing. Methods : We measured the OD of background blank controls of broth medium, antifungal agents, and inocula of five type strains using a Synergy HT multi-detection microplate reader at 5-nm intervals from 380 nm to 760 nm. We also estimated the OD differences between the 50% of growth control and blank control. Results : The OD of the blank control showed a parabola shape with two peaks and steadily decreased at longer wavelengths. The curves of the antifungal agent were similar to those of blank controls, and the influence of each antifungal agent on the OD was minimal. For the difference in OD between 50% of growth control and the blank control, the curve was the opposite of the blank control, and the OD increased steadily at the wavelengths above 600 nm. Conclusions : The range between 600 nm and 700 nm was the optimal wavelength for broth microdilution antifungal susceptibility testing, although any wavelength within the visible light spectrum can be used.

PREDICTING EYE HEALTH BASED ON INDIVIDUAL’S AGE-FOCUSING ON THE ABSORBANCE OF LIGHT AS FUNCTION OF WAVELENGTH AND AGE

Seo U CHOI 국제과학영재학회 2015 APEC Youth Scientist Journal Vol.7 No.2

One of the most common phenomenon elder people suffer is the hardness to see the color near blue or violet. This is because absorbance of the lens increase when one becomes older. Since the absorbance of light in the matter depends on the wavelength, absorbance can be simplified as a function of wavelength and the individual's age. So, in order to know the relationship among absorbance, wavelength and age, we should know the relationship between wavelength of the light. Since wavelength can be easily known if RGB value of light is given, Changing HSV value to RGB value is necessary as most of the electronic devices prefer to use HSV. In this research, Artificial Neural Network(ANN) is used to predict eye health of the individual, setting input value as age of person and HSV value of color and output as an absorbance of the lens. Artificial Neural Networks were made using NeurophStudio 2.9(Java Neural Network Framework, SourceForge). More specifically, 3 types of ANN were made, 'HSV to RGB' converter, 'RGB to Wavelength' converter and 'Age+Wavelength to Absorption(of the lens)' converter. Each of the converter performed well. Especially, all of the outputs of 'RGB to wavelength converter' had error rate less than 0.2. The output of the total ANN showed similar tendency with the actual output.

Wavelength-stepped, actively mode-locked fiber laser based on wavelength-division-multiplexed optical delay lines

Lee, Eunjoo,Kim, Byoung Yoon Elsevier 2017 OPTICS COMMUNICATIONS - Vol.405 No.-

<P><B>Abstract</B></P> <P>We propose a new scheme for an actively mode-locked wavelength-swept fiber laser that produces a train of discretely wavelength-stepped pulses from a short fiber cavity. Pulses with different wavelengths are split and combined by standard wavelength division multiplexers with fiber delay lines. As a proof of concept, we demonstrate a laser using an erbium doped fiber amplifier and commercially available wavelength-division multiplexers with wavelength spacing of 0.8 nm. The results show simultaneous mode-locking at three different wavelengths. Laser output parameters in time domain, optical and radio frequency spectral domain, and the noise characteristics are presented. Suggestions for the improved design are discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Wavelength stepped mode-locked fiber laser is proposed and demonstrated. </LI> <LI> Standard telecom components are used for the short fiber cavity. </LI> <LI> Gain competition is reduced by temporal–spectral multiplexing. </LI> <LI> Individual control of physical parameters of each pulse is possible. </LI> <LI> Noise characteristics of each wavelength is presented. </LI> </UL> </P>

Performance Analysis of Dynamic Wavelength Allocation Algorithm for TWDM PON with Inexpensive ONUs

Man Soo Han 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.11

In this paper, we introduce a new dynamic wavelength allocation algorithm for a TWDM PON (time and wavelength division multiplexed passive optical network) having inexpensive ONUs (optical network units). The inexpensive ONU has a cheap and low-speed wavelength tuner. The cheap tuner takes from few milliseconds to few seconds to change its wavelength. Most dynamic wavelength allocation algorithms assume that an ONU has a perfect tuner whose tuning time is zero. Unlike most existing algorithms, the proposed algorithm does not ignore the tuning time of an ONU tuner. In the proposed algorithm, an OLT (optical line termination) uses an average grant amount to predict the average packet arrival rates of all ONUs. The OLT decreases the number of active upstream wavelengths if the average grant amount is less than the bandwidth amount of the upstream wavelengths. Otherwise, the OLT increases the number of active upstream wavelengths. Using computer simulations, we show performance of the proposed algorithm and the average number of active upstream wavelengths.

변형된 Time Mapped Prime Sequence를 이용한 Wavelength-Time Code for Optical CDMA

지윤규(Yoon Kyoo Jhee) 大韓電子工學會 2010 電子工學會論文誌-SD (Semiconductor and devices) Vol.47 No.10

변형된 time mapped prime sequences를 time spreading pattern에 이용하여 다양한 wavelength-time codeword를 구현하는 방법을 연구하였다. 이 연구 결과 p<SUB>t</SUB>=3일 때는 autocorrelation sidelobe와 crosscorrelation을 1이하로 유지하며 사용하는 파장 수의 제곱에 해당하는 wavelength-time codeword를 생성할 수 있으며 p<SUB>t</SUB>=5와 p<SUB>t</SUB>=7일 때는 crosscorrelation을 1이하로 유지하면서 p<SUB>ω</SUB>의 wavelength-time codeword에 대해서 autocorrelation sidelobe를 2이하로 제한하는 범위에서 역시 사용하는 파장 수의 제곱에 해당하는 wavelength-time codeword를 생성할 수 있다. In this paper, a new family of wavelength-time codewords using modified time mapped prime sequences as a time spreading pattern is constructed. When p<SUB>t</SUB>=3, we can construct p²<SUB>ω</SUB> wavelength-time codewords with low autocorrelation sidelobe and crosscorrelation of less than or equal to 1. When p<SUB>t</SUB>=5 and p<SUB>t</SUB>=7, the number of wavelength-time codewords of p²<SUB>ω</SUB> can be constructed with good crosscorrelation of 1 and autocorrelation of less than or equal to 2.

공유형 광 지연 선로 버퍼를 갖는 광 패킷 스위치에서 튜닝 가능한 파장 변환기와 내부 파장 개수의 최적화에 의한 스위치 비용 감소

황일선 ( Il-sun Hwang ),임헌국 ( Huhn-kuk Lim ),유기성 ( Ki-sung Yu ),정진욱 ( Jin-wook Chung ) 한국인터넷정보학회 2006 인터넷정보학회논문지 Vol.7 No.6

스위치 비용을 감소시킬 연구의 일환으로 공유형 광 지연 선로 버퍼를 갖는 광 패킷 스위치에서 인터넷 트래픽과 같은 비동기 가변길이 패킷들의 경합 해결을 위해 요구 되어지는 최적화된 튜닝 가능한 파장 변환기의 개수와 내부 파장 개수가 도출 되어 진다. 광 패킷 스위치 디자인 비용에 관련된 튜닝 가능한 파장 변환기의 개수와 내부 파장 개수를 도출하기 위해 스위치 내부에 한정된 수의 파장 변환기와 내부 파장을 고려해 주는 새로운 형태의 스케쥴링 알고리즘을 제안하였다. 세 가지 튜닝 가능한 파장 변환기 구조들에 대해서 최소의 패킷 로스를 보장해 주는 최적화된 파장 변환기의 개수와 내부의 파장 개수가 자원 낭비를 예방해 주기 위해 평가 되어졌다. 하나의 주어진 로드 하에서 파장 변환기 개수와 내부의 파장 개수가 의미 신장하게 감소되어 질 수 있었으며 또한 파장 변환기의 수와 내부 파장의 수를 완전히 갖는 광 패킷 스위치의 성능과 같은 패킷 손실 확률을 보장해 주었다. To reduce switch cost, the optimum numbers of tunable wavelength converters (TWCs) and internal wavelengths required for contention resolution of asynchronous and variable length packets like internet traffics, is presented in the optical packet switch (OPS) with the shared fiber delay line (FDL) buffer. To optimize TWCs and internal wavelengths related to an OPS design cost, we proposed a scheduling algorithm for the limited TWCs and internal wavelengths. For three TWC alternatives (not shared, partially shared, and fully shared cases), the optimum numbers of TWCs and internal wavelengths to guarantee minimum packet loss are evaluated to prevent resource waste. Under a given load, TWCs and internal wavelengths could be significantly reduced, guaranteeing the same packet loss probability as the performance of an OPS with full TWCs and internal wavelengths.

Analytical Model for Multi-Fiber WDM Networks with Sparse and Limited Wavelength Conversion

정한유(Han-You Jeong),서승우(Seung-Woo Seo),최윤호(Yoon-Ho Choi) 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.4B

본 논문에서는 다수의 광섬유로 이루어진 광링크와 산재하여 있는 제한 영역 파장변환 능력을 가진 노드들로 구성된 광통신망의 불통확률을 정확하게 계산할 수 있는 새로운 성능분석 모형을 제안한다. 제안하는 성능분석 모형은 다수의 광섬유로 이루어진 광링크 상에서 사용 가능한 파장들의 분포와 제한 영역 파장변환 이후의 사용 가능한 파장들의 분포, 그리고 다수의 광링크가 연결된 광경로에서의 불통 확률을 계산하기 위한 재귀적 공식을 도출함을 특징으로 한다. NSFNET 망에서 수행한 시뮬레이션 결과를 통해 제안하는 성능분석 모형이 광통신망의 불통확률을 정확히 예측함을 보인다. 또한, 파장 연속성 제약이 없는 경우의 이상적인 불통확률에 근접하는 성능을 얻기 위해서 소수의 제한영역 파장변환 노드와 소수의 광섬유만으로 구성된 광링크를 포설하는 것으로 충분함을 보인다. In this paper, we present a new analytical model for estimating the blocking performance of multi-fiber WDM networks with sparse and limited wavelength conversion (SLWC). The proposed model is a reduced-load approximation model that can obtain accurate estimates of blocking probability of such networks. Our model employs three new recurrence formulae to obtain the free wavelength distribution on a multi-fiber link, the free wavelength distribution after limited-range wavelength conversion, and the end-to-end blocking probability of a multi-hop path, respectively. From the numerical results on the NSFNET, we demonstrate that the blocking performance of two-fiber NSFNET with three wavelength-convertible nodes, each of which translates an input wavelength to its adjacent output wavelengths, closely approximates the blocking performance of full wavelength conversion.

Phototactic Responses of Various Wavelengths and Light Conditions toward Spodoptera exigua (Hübner)

Min-Seok Oh,Ju-Hyun Jeon,Hoi-Seon Lee 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05

The aim of this study was to evaluate light emitting diodes (LEDs) as the potential attractants against Spodoptera exigua on various wavelengths, light intensity and light duration, and compared to that of commercial control, flourescent lamp. The phototactic response to S. exigua was tested by single and complex wavelengths. The single wavelengths were composed as follows: blue (470 nm), green (520 nm), yellow (590 nm) and red (625 nm). The complex wavelengths was combined with two single wavelengths, such as blue-green, blue-yellow, blue-red, green-yellow, green-red and yellow-red. When the optimal light condition was investigated, the all light treatments attracted the highest number of S. exigua at 40 lux intensity and 60 min duration. Based on the single wavelengths under optimal light condition, the green LED exhibited the highest attraction rate (88.9%), followed by blue (81.1%), yellow (63.3%) and red (56.7%), respectively. In case of complex wavelengths under same conditions, the bluegreen complex (93.3%) had the significantly highest attractive activity, whereas blue-yellow, blue-red, green-yellow, green-red and yellow-red wavelengths were slightly decreased in comparison with single wavelengths. These data clearly show that blue-green complex had the greatest attraction against S. exigua.

A Cost Analysis of Microalgal Biomass and Biodiesel Production in Open Raceways Treating Municipal Wastewater and under Optimum Light Wavelength

( Zion Kang ),( Byung Hyuk Kim ),( Rishiram Ramanan ),( Jong Eun Choi ),( Ji Won Yang ),( Hee Mock Oh ),( Hee Sik Kim ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.1

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.

Proposal for a Wavelength-Independent Optical Sensor Based on an Asymmetric Mach-Zehnder Interferometer

Yanxia Luo,Rui Yin,Wei Ji,Qingjie Huang,Zisu Gong,Jingyao Li 한국광학회 2020 Current Optics and Photonics Vol.4 No.6

A wavelength-independent optical sensor based on an asymmetric Mach-Zehnder interferometer (AMZI) is proposed. The optical sensor based on an AMZI is very sensitive to wavelength, and wavelength drift will lead to measurement error. The optical sensor is compensated to reduce its dependence on wavelength. The insensitivity of the optical sensor to wavelength mainly depends on the compensation structure, which is composed of an AMZI cascaded with another AMZI and can compensate the wavelength drift. The influence of wavelength drift on the optical sensor can be counteracted by carefully designing the size parameters of the compensation structure. When the wavelength changes from 1549.9 nm to 1550.1 nm, the error after compensation can be lower than 0.066%. Furthermore, the effect of fabrication tolerance on compensation results is analyzed. The proposed compensation method can also be used to compensate the drift of other parameters such as temperature, and can be applied to the compensation of other interference-based optical devices.