scholarly journals Development of Microalgae Biosensor Chip by Incorporating Microarray Oxygen Sensor for Pesticides Sensing

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 133
Author(s):  
Md. Abul Kashem ◽  
Kazuki Kimoto ◽  
Yasunori Iribe ◽  
Masayasu Suzuki

A microalgae (Pseudokirchneriella subcapitata) biosensor chip for pesticide sensing has been developed by attaching the immobilized microalgae biofilm pon the microarray dye spots (size 100 μm and pitch 200 μm). The dye spots (ruthenium complex) were printed upon SO3-modified glass slides using a polydimethylsiloxane (PDMS) stamp and a microcontact printer (μCP). Emitted fluorescence intensity (FI) variance due to photosynthetic activity (O2 production) of microalgae was monitored by an inverted fluorescent microscope and inhibition of the oxygen generation rate was calculated based on the FI responses both before and after injection of pesticide sample. The calibration curves, as the inhibition of oxygen generation rate (%) due to photosynthetic activity inhibition by the pesticides, depicted that among the 6 tested pesticides, the biosensor showed good sensitivity for 4 pesticides (diuron, simetryn, simazine, and atrazine) but was insensitive for mefenacet and pendimethalin. The detection limits were 1 ppb for diuron and 10 ppb for simetryn, simazine, and atrazine. The simple and low-cost nature of sensing of the developed biosensor sensor chip has apparently created opportunities for regular water quality monitoring, where pesticides are an important concern.

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 474 ◽  
Author(s):  
Bei Wang ◽  
Manuel Baeuscher ◽  
Xiaodong Hu ◽  
Markus Woehrmann ◽  
Katharina Becker ◽  
...  

A novel capacitive sensor for measuring the water-level and monitoring the water quality has been developed in this work by using an enhanced screen printing technology. A commonly used environment-friendly conductive polymer poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) for conductive sensors has a limited conductivity due to its high sheet resistance. A physical treatment performed during the printing process has reduced the sheet resistance of printed PEDOT:PSS on polyethylenterephthalat (PET) substrate from 264.39 Ω/sq to 23.44 Ω/sq. The adhesion bonding force between printed PEDOT:PSS and the substrate PET is increased by using chemical treatment and tested using a newly designed adhesive peeling force test. Using the economical conductive ink PEDOT:PSS with this new physical treatment, our capacitive sensors are cost-efficient and have a sensitivity of up to 1.25 pF/mm.


2019 ◽  
Author(s):  
Jeba Anandh S ◽  
Anandharaj M ◽  
Aswinrajan J ◽  
Karankumar G ◽  
Karthik P

2021 ◽  
Vol 210 (07) ◽  
pp. 55-65
Author(s):  
Larisa Ikoeva ◽  
Oksana Haeva

Abstract. The purpose of the work is to study the influence of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on the photosynthetic productivity of the potatoes of the Barna variety based on the results of field experiments in the forest-steppe zone Republic of North Ossetia-Alania. Methods. Studies on the tasks were carried out in 2018–2020. at the experimental site of the NCRIMFA branch of the VSC of RAS in the conditions of the forest-steppe zone Republic of North Ossetia-Alania according to generally accepted methods. The soil of the experimental plot is medium-power heavy loamy leached chernozem, lined with pebbles. Results. It is established, that biological products under identical soil and weather conditions assisted different progress of plants and approach of phases of vegetation. For all variants of the experiment, the number of stems increased by 0,3–0,7 pcs., the height of the stems of potato plants – by 3,8–4,9 cm in comparison with the control. An intense increase in the mass of tops occurred when using a tank mixture (growth regulator “Regoplant” (25 ml/ha) + microfertilizer “Ultramag Combi” (0,75 l/ha)) – by 74 g/bush, or 15.5 % compared with the control variant. During the growing season, the sum of the photosynthetic potential (FP) was 1,070 thousand m2 •days/ha in the control, and on average 1198–1406 thousand m2•days/ha in the experimental variants. The greatest accumulation of dry matter was noted when using a tank mixture – 917 g/m2. The maximum pure photosynthetic productivity was observed in experimental variant IV – 6,52 g/m2•day compared to the control option. Scientific novelty. For the first time in the forest-steppe zone Republic of North Ossetia-Alania the effect of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on photosynthetic activity of potatoes was studied. Practical significance. The studies carried out make it possible to recommend in potato production the use of a tank mixture of an effective growth regulator “Regoplant” at a dose of 25 ml/ha and microfertilizer “Ultramag Combi” at a dose of 0,75 l/ha, as an ecologically safe and low-cost agricultural method when processing vegetative plants, providing an increase in yield and quality of tubers.


Author(s):  
Ryan Ganesha Calibra ◽  
Irfan Ardiansah ◽  
Nurpilihan Bafdal

Water quality is very important for plant’s growth and development. Some of the important part of the water qualities are TDS(Total Dissolved Solid), EC(Electrical Conductivity), pH(Acidity). Cultivation inside a greenhouse provides some benefits but also have some deficiency, such as lack of soil nutrition because most plants inside greenhouse uses non soil growing media. To overcome the deficiency, An automated and remote system is needed to ease the controlling of water quality and nutrition feeding to the plant. This study aims to create low-cost greenhouse water quality monitoring that automatically display the real time data on a website. This research is done by using an engineering design methods. This system can be integrated with auto-pot watering system . The result shows that the system can adjust the TDS and pH as programmed, which are TDS= 1000-1200, and pH =5.5-6.5(these are recommended needs for Tomato plant). The TDS sensor in this reseach have the limitation of reading 0~1500ppm.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1984 ◽  
Author(s):  
Thanda Thatoe Nwe Win ◽  
Thom Bogaard ◽  
Nick van de Giesen

Newly developed mobile phone applications in combination with citizen science are used in different fields of research, such as public health monitoring, environmental monitoring, precipitation monitoring, noise pollution measurement and mapping, earth observation. In this paper, we present a low-cost water quality mobile phone measurement technique combined with sensor and test strips, and reported the weekly-collected data of three years of the Ayeyarwady River system by volunteers at seven locations and compared these results with the measurements collected by the lab technicians. We assessed the quality of the collected data and their reliability based on several indicators, such as data accuracy, consistency, and completeness. In this study, six local governmental staffs and one middle school teacher collected baseline water quality data with high temporal and spatial resolution. The quality of the data collected by volunteers was comparable to the data of the experienced lab technicians for sensor-based measurement of electrical conductivity and transparency. However, the lower accuracy (higher uncertainty range) of the indicator strips made them less useful in the Ayeyarwady with its relatively small water quality variations. We showed that participatory water quality monitoring in Myanmar can be a serious alternative for a more classical water sampling and lab analysis-based monitoring network, particularly as it results in much higher spatial and temporal resolution of water quality information against the very modest investment and running costs. This approach can help solving the invisible water crisis of unknown water quality (changes) in river and lake systems all over the world.


2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Buddhika Jayasena ◽  
Shreyes N. Melkote

Molecular dynamics (MD) simulations are used to gain insights into the process conditions that cause separation of graphene layers from a highly ordered pyrolytic graphite (HOPG) source in a polydimethylsiloxane (PDMS) stamp-assisted mechanical exfoliation process. Specifically, the effects of selected exfoliation process parameters and pre-existing defects, such as layer discontinuities in the graphite source, on the exfoliation process are investigated. The results show that exfoliation of individual and few layer graphene requires delicate control of the normal force applied to the HOPG by the PDMS stamp. The study also shows that defects (e.g., discontinuities) in the HOPG have a significant impact on the thickness of separated layers and the layer separation force. The insights derived from this study are expected to be very useful in the development of a low-cost, scalable, large area graphene production process.


2017 ◽  
Vol 28 (5) ◽  
pp. 599-610
Author(s):  
Shu Wang ◽  
Tian Zhang ◽  
Longzhe Jin

Potassium superoxide-based oxygen supply systems demonstrate a tremendous potential for applications associated with mine emergency rescue. In this study, the air revitalization performance of a potassium superoxide plate operating under natural convection conditions was investigated by a series of passive tests in a sealed chamber. Reaction resistance analysis based on experimental data revealed that increasing air temperature and humidity accelerates oxygen generation but reduces the system respiratory quotient as a result of the increased resistance of internal diffusion. Increasing the amount of plates or using them in combination with a carbon dioxide absorption curtain is a practical, effective method for meeting requirements of both oxygen generation rate and system respiratory quotient in underground refuge. Kinetics model that predicted the mean oxygen generation rate, carbon dioxide absorption rate, system respiratory quotient and total thermal output (Q) was also derived from experimental data in this study. Predicted results were found to be in good agreement with experimental data. The proposed model can aid in the design of air revitalization systems used in refuge stations for underground mines.


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