Organic ISFET Based on Poly (3-hexylthiophene)

We have fabricated organic field-effect transistors (OFETs) with regioregular poly(3-hexylthiophene) (P3HT) operable at low-voltages in liquid solutions, suitable for in vitro biosensing applications. Measurements in electrolytes have shown that the performance of the transistors did not deteriorate and they can be directly used as ion-sensitive transducers. Furthermore, more complex media have been tested, with the perspective of cell analysis. Degradation effects acting on the device operating in liquid could be partly compensated by adopting an alternate current measuring mode

Sensitive and specific detection of E. coli using biomimetic receptors in combination with a modified heat-transfer method

We report on a novel biomimetic sensor that allows sensitive and specific detection of Escherichia colt (E. coli) bacteria in a broad concentration range from 10(2) up to 10(6) CFU/mL in both buffer fluids and relevant food samples (i.e. apple juice). The receptors are surface-imprinted polyurethane layers deposited on stainless-steel chips. Regarding the transducer principle, the sensor measures the increase in thermal resistance between the chip and the liquid due to the presence of bacteria captured on the receptor surface. The low noise level that enables the low detection limit originates from a planar meander element that serves as both a heater and a temperature sensor. Furthermore, the experiments show that the presence of bacteria in a liquid enhances the thermal conductivity of the liquid itself. Reference tests with a set of other representative species of Enterobacteriaceae, closely related to E. coli, indicate a very low cross-sensitivity with a sensor response at or below the noise level

Phase editing as a signal pre-processing step for automated bearing fault detection

Scheduled maintenance and inspection of bearing elements in industrial machinery contributes significantly to the operating costs. Savings can be made through automatic vibration-based damage detection and prognostics, to permit condition-based maintenance.However automation of the detection process is difficult due to the complexity ofvibration signals in realistic operating environments. The sensitivity of existing methods to the choice of parameters imposes a requirement for oversight from a skilled operator.This paper presents a novel approach to the removal of unwanted vibrational components from the signal: phase editing. The approach uses a computationally efficient full band demodulation and requires very little oversight. Its effectiveness is tested on experimental data sets from three different test-rigs, and comparisons are made with two state of the artprocessing techniques: spectral kurtosis and cepstral pre- whitening. The results from the phase editing technique show a 10% improvement in damage detection rates comparedto the state of the art while simultaneously improving on the degree of automation. This outcome represents a significant contribution in the pursuit of fully automatic fault detection

Dispersion of pollutants in soil

This paper analyzes the dispersion of soil pollutants from the sewage treatment mud from Tomesti, Iasi. The results were obtained by sampling soil samples from different depths (0-20 cm, 20-40 cm and 40-60 cm). The soil material, consisting of urban sludge, at all samples collected on the 0-20 cm depth shows well-developed structural aggregates, having a structure that varies from grain to sub-lime polyhedra with a medium development degree. The material exhibits hydrophysical properties - mechanical and hydric stability, consistency being moderately dry in a dry, moderately glue-like state, with macroporous, medium and large macroporous, resulting in good aeration porosity and optimum aerohydric regime. In the range of 20-40 cm the soil material is relatively well structured, with smaller structural aggregates, the lack of groundwater causing an increase in consistency, plasticity and reduction of interspaces between aggregates. For the depth between 40-60 cm the soil is well structured, with medium-sized aggregates with a grainy structure in the first part, subangular polyhedral in the sub-surface, micro and meso-good activity. The study area is the sludge dumps from Tomeşti from Iaşi. It was built in 1994 by removing the soil layer on an area of 9.1 hectares of land and the construction of surrounding and separating dams. Around the warehouse was made a drainage channel that ensures the drainage of the deposit. The warehouse is located in the major river bed of the Bahlui River, on its right side. The straight line to the Iaşi Wastewater Treatment Plant is about 2000 m. The sludge from the process of the Iasi wastewater treatment plant was transported to the warehouse through a pumping station and a discharge pipeline

Amyloid beta oligomers induce neuronal elasticity changes in age-dependent manner: a force spectroscopy study on living hippocampal neurons

Small soluble species of amyloid-beta (Aβ) formed during early peptide aggregation stages are responsible for several neurotoxic mechanisms relevant to the pathology of Alzheimer's disease (AD), although their interaction with the neuronal membrane is not completely understood. This study quantifies the changes in the neuronal membrane elasticity induced by treatment with the two most common Aβ isoforms found in AD brains: Aβ40 and Aβ42. Using quantitative atomic force microscopy (AFM), we measured for the first time the static elastic modulus of living primary hippocampal neurons treated with pre-aggregated Aβ40 and Aβ42 soluble species. Our AFM results demonstrate changes in the elasticity of young, mature and aged neurons treated for a short time with the two Aβ species pre-aggregated for 2 hours. Neurons aging under stress conditions, showing aging hallmarks, are the most susceptible to amyloid binding and show the largest decrease in membrane stiffness upon Aβ treatment. Membrane stiffness defines the way in which cells respond to mechanical forces in their environment and has been shown to be important for processes such as gene expression, ion-channel gating and neurotransmitter vesicle transport. Thus, one can expect that changes in neuronal membrane elasticity might directly induce functional changes related to neurodegeneration

Identification of drought extent using NVSWI and VHI in Iaşi county area, Romania

Drought is a stochastic natural phenomenon that appears from considerable lacking in precipitation. Among natural hazards, drought is known to provoke extensive damage and affects a important number of people. Techniques for observing agricultural drought from R.S. are indirect. These depend on using images based parameters to exemplifed soil moisture condition when the soil is often obscured by a vegetation cover. The procedure are mainly based on determing vegetation health or greenness using VI , often in combination with canopy temperature anomalies using thermal infrared wavebands. In this study were used remote sensing images from the Landsat 8 OLI, taken in may and june 2017. The study area was the county of Iasi. To evaluate drought in this study, for Iasi county, Normalized Vegetation Supply Water Index (NVSWI) and Vegetation Health Index (VHI), were used. VSWI is derived from The Vegetation Supply Water Index (VSWI). This index was developed to combine the NDVI and the land surface temperature (LST) to detect the moisture condition. VHI was developed through a combination of Vegetation Condition Index (VCI), one of the important vegetation indicators when monitoring weather-related variations, such as droughts, and Temperature Condition Index (TCI), which reflects the stress of temperature, that both indicies can be successfully used to determine the spatiotemporal extent of agricultural drought. After applying NVSWI to determine the degree of drought we noticed that for the satellite image of May prevailed “slight drought” and for june “normal”. Second index, VHI indicate that in both months, may and june, is “no drought”. It can be concluded that VHI is a very good indicator for studing extreme drought and NVSWI offer information about areas “normal” and “wet”

Analyzing dem characteristics for area affected by drought identified using vhi: A case study of Iaşi county

In this paper was studied areas affected by drought using TCI, VCI and VHI. These indices are based on LST and NDVI. Drought is one of the most widespread and least understood natural phenomena. The droughts are the phenomena which affect large areas and remote sensing data covering large territory can be used to assess the droughts impact and their extent. In this study was used remote sensing images from the Landsat 8 Operational Land Imager (OLI), taken in April and May 2018. Study area, for this paper, geographically, is situated on latitude 47°32'N to 46°49'N and longitude 26°36'E to 28°05'E. This administrative unit is hit by heavy rains, floods, droughts and at larger periods of time by landslide events and earthquakes. NDVI values indicates that vegetation has been developed between 21st April and 7th May. LST values was about the same for images analyzed for study area. VHI is usually used to detect areas affected by severe drought. For these Landsat images analyzed was noticed that large areas were not affected by drought. Some zones were affected by moderate and mid drought – about the same for April and May. For these areas were made analysis to determine any connections between drought and altitude, gradient of slopes and exposure of slopes. Areas affected by moderate and mid drought have slope between 00 and 7.50 , mostly between 50 and 7.50 . Zones with slopes over 7.50 affected by drought is insignificant. Exposure of slopes for areas affected by drought is preponderant east and north-east

Cell detection by surface imprinted polymers SIPs:A study to unravel the recognition mechanisms

Previous studies have shown that selective synthetic cell receptors can be produced by cell imprinting on polymer layers. However, knowledge on the fundamental detection mechanisms remains limited. In this article, while using yeast cells (Saccharomyces cerevisiae) as model cells, the factors influencing cellular recognition by surface-imprinted polymers (SIPs) are studied by means of spectroscopic and microscopy techniques and a transducer platform based on interfacial thermal transport, the so-called heat-transfer method (HTM). These analyses indicate that cell imprinting creates selective binding sites on the surface of the SIP layer in the form of binding cavities that match the cells in shape and size. Also, we show that phospholipid moieties are incorporated into the SIP cavities during imprinting, while membrane proteins do not seem to be transferred. More importantly, we demonstrate that the incorporated phospholipids significantly enhance cell adhesion to the SIP, and thus play a significant role in the cell-SIP binding mechanism. Furthermore, the hydrophobicity of the SIP layer was found to be considerably higher when compared with a non-imprinted polymer layer (NIP), an effect that could not be attributed to the presence of cavities on the surface of the SIP layer. Therefore, we suggest that the role of phospholipids in the SIP recognition mechanism is mediated by long range hydrophobic forces. (C) 2017 Elsevier B.V. All rights reserved.</p

Organic film thickness influence on the bias stress instability in Sexithiophene Field Effect Transistors

In this paper, the dynamics of bias stress phenomenon in Sexithiophene (T6) Field Effect Transistors (FETs) has been investigated. T6 FETs have been fabricated by vacuum depositing films with thickness from 10 nm to 130 nm on Si/SiO2 substrates. After the T6 film structural analysis by X-Ray diffraction and the FET electrical investigation focused on carrier mobility evaluation, bias stress instability parameters have been estimated and discussed in the context of existing models. By increasing the film thickness, a clear correlation between the stress parameters and the structural properties of the organic layer has been highlighted. Conversely, the mobility values result almost thickness independent