Optoelectronic switches based on diffusive conduction

Cataloged from PDF version of article.We study the process of diffusive conduction that we use in our optoelectronic switches to achieve rapid optical switching (on a picosecond time scale). We present the characteristic Green's function of the diffusive conduction derived for arbitrary initial conditions. We also report the series solutions of the diffusive conduction obtained for different boundary conditions (V=0 and del V=0 along the device contact lines) in different device geometries (rectangular and circular mesas). Using these analytical results, we investigate the effect of boundary conditions on the switching operation and the steady state behavior in optical links. We demonstrate the feasibility of using such diffusive conductive optoelectronic switches to establish optical links in return-to-zero and non-return-to-zero coding schemes. For multichannel optical switching, we discuss possible use of a single optoelectronic switch to accommodate multiple channels at once, with > 100 optical channels (with a 2000 mm(-2) channel density and 50 GHz, leading to a 5 Tb/s aggregate transmission in principle. This approach of using multiple parallel channels on a single switch is completely opposite to the traditional idea of arraying many switches. This proposed scheme eliminates the need for on-chip switch integration and the need for the alignment of the optical channels to the integrated individual switches. (c) 2006 American Institute of Physics

Effects of Passive and active Rest on Physiological Responses and Time Motion Characteristics in Different Small Sided Soccer Games

The purpose of this study was to investigate the effects of resting regimes on physiological responses and time motion characteristics between bouts during small sided games (SSGs) in young soccer players. Sixteen players (average age 16.87 ± 0.34 years; body height 176.69 ± 3.21 cm; body mass 62.40 ± 2.59 kg; training experience 3.75 ± 0.44 years) performed four bouts 2-a-side, 3-a-side and 4-a-side games with three minutes active (SSGar: Running at 70% of HRmax) and passive (SSGpr) rest between bouts at two-day intervals. The heart rate (HR) along with total distance covered in different speed zones - walking (W, 0-6.9 km·h-1), low-intensity running (LIR, 7.0-12.9 km·h-1), moderate-intensity running (MIR, 13.0-17.9 km·h-1) and high-intensity running (HIR, >18km·h-1), were monitored during all SSGs, whereas the rating of perceived exertion (RPE, CR-20) and venous blood lactate (La-) were determined at the end of the last bout of each SSG. The results demonstrated that all SSGpr elicited significantly higher physiological responses compared to SSGar in terms of the RPE and La- (p < 0.05). In addition, 2-a-side SSGpr induced significantly lower %HRmax responses and total distance covered than 2-a-side SSGar (p < 0.05). Moreover, the distance covered at HIR was significantly higher in 4-a-side SSGar than 4-side SSGpr. The results of this study indicate that both SSGs with passive and active rest can be used for soccer specific aerobic endurance training. Furthermore, all SSGs with active recovery should be performed in order to increase players and teams' performance capacity for subsequent bouts. © 2017 Editorial Committee of Journal of Human Kinetics 2017

River water quality assessment using environmentric techniques : case study of Jakara River Basin.

akara River Basin has been extensively studied to assess the overall water quality and to identify the major variables responsible for water quality variations in the basin. A total of 27 sampling points were selected in the riverine network of the Upper Jakara River Basin. Water samples were collected in triplicate and analyzed for physicochemical variables. Pearson product-moment correlation analysis was conducted to evaluate the relationship of water quality parameters and revealed a significant relationship between salinity, conductivity with dissolved solids (DS) and 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and nitrogen in form of ammonia (NH4). Partial correlation analysis (r p) results showed that there is a strong relationship between salinity and turbidity (r p = 0.930, p = 0.001) and BOD5 and COD (r p = 0.839, p = 0.001) controlling for the linear effects of conductivity and NH4, respectively. Principal component analysis and or factor analysis was used to investigate the origin of each water quality parameter in the Jakara Basin and identified three major factors explaining 68.11 % of the total variance in water quality. The major variations are related to anthropogenic activities (irrigation agricultural, construction activities, clearing of land, and domestic waste disposal) and natural processes (erosion of river bank and runoff). Discriminant analysis (DA) was applied on the dataset to maximize the similarities between group relative to within-group variance of the parameters. DA provided better results with great discriminatory ability using eight variables (DO, BOD5, COD, SS, NH4, conductivity, salinity, and DS) as the most statistically significantly responsible for surface water quality variation in the area. The present study, however, makes several noteworthy contributions to the existing knowledge on the spatial variations of surface water quality and is believed to serve as a baseline data for further studies. Future research should therefore concentrate on the investigation of temporal variations of water quality in the basin

Surface water quality contamination source apportionment and physicochemical characterization at the upper section of the Jakara Basin, Nigeria.

The present study investigates the surface water quality of three important tributaries of Jakara Basin, northwestern Nigeria to provide an overview of the relationship and sources of physicochemical and biological parameters. A total of 405 water samples were collected from 27 sampling points and analyzed for 13 parameters: dissolved oxygen (DO), 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids (SS), pH, ammonia-nitrogen (NH3NL), dissolved solids (DS), total solids (TS), nitrates (NO3), chloride (Cl), phosphates (PO4), Escherichia coli (E. coli) and fecal coliform bacteria (FCB). Pearson’s product–moment correlation matrix and principal component analysis (PCA) were used to distinguish the main pollution sources in the basin. Four varimax components were extracted from PCA, which explained 84.86, 83.60, and 78.69 % of the variation in the surface water quality for Jakara, Tsakama, and Gama-Kwari Rivers, respectively. Strong positive loading included BOD5, COD, NH3NL, E. coli, and FCB with negative loading on DO attribute to a domestic waste water pollution source. One-way ANOVA revealed that there was no significant difference in the mean of the three water bodies (p > 0.05). It is therefore recommended that the government should be more effective in controlling the point source of pollution in the area

Influence of maternal nicotine exposure on neonatal rat oxidant-antioxidant system and effect of ascorbic acid supplementation

There have been a few studies that examined the oxidative stress effects of nicotine during pregnancy and lactation. We aimed to determine the adverse effects of maternal nicotine exposure during pregnancy and lactation on oxidant-antioxidant system, and to determine a protective effect of ascorbic acid (Asc). Gravid rats were assigned into four groups. In Group 1, pregnant rats received 6-mg/kg/day nicotine subcutaneously during pregnancy from 1 to 21 days of gestation and lactation (until postnatal day 21). Group 2 received nicotine and Asc for the same period. In Group 3, the rats received nicotine during lactation. Control pregnant rats (Group 4) received only saline subcutaneously. Serum malondialdehyde (MDA), myeloperoxidase (MTO), and superoxide dismutase (SOD) levels were determined at 21 days of age. Nicotine exposure decreased birth weight and pregnancy weight gain. MDA values of the rat pups exposed to nicotine in both Groups 1 and 2 were higher than those of control and Group 3. SOD and MPO values of the groups were similar. Mean birth weight and serum MDA levels of Groups 1 and 2 were similar. Nicotine exposure via placental transfer increases oxidative stress as manifested by an increase in MDA level. Asc supplementation does not prevent the adverse effects of maternal nicotine exposure

Differences in nephrotoxicity risk and renal effects among anti-viral therapies against hepatitis B

Tufan, Zeliha Kocak/0000-0002-3294-014X; Cosar, Arif Mansur/0000-0002-4472-2895; Cosar, Arif Mansur/0000-0002-4472-2895; Gulsen, Murat Taner/0000-0002-8531-9402;WOS: 000347835300007PubMed: 25982037BackgroundResults are conflicting with respect to the renal effects of anti-viral agents used for hepatitis B virus infection. AimTo compare short and long-term renal effects in real-life settings and to determine risk factors for renal impairment during treatment. Methods2221 treatment-naive patients were enrolled. Among these, 895 (302 lamivudine, 27 telbivudine, 282 entecavir, 273 tenofovir and 11 adefovir initiated patients) had repeated measures' of creatinine (baseline, 1st, 6th, 12th and 24th month of treatment). Telbivudine and adefovir groups were excluded from further analysis because of the low number of patients. We calculated the glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) formula at each time point. Hypophosphataemia was also recorded. Risk factors for renal impairment were analysed. ResultsTenofovir caused a decline in GFR at each time point when compared to baseline levels. However, lamivudine and entecavir did not change GFR. GFR-shifting from 90 to 60-89mL/min/1.73m(2) was comparable among groups. The proportion of patients whose baseline creatinine increased more than 25% was comparable among all anti-virals. GFR showed a decline in patients who switched from entecavir to tenofovir. One patient with compensated cirrhosis needed to change from tenofovir because of renal safety. Seven and three patients developed transient hypophosphataemia in the tenofovir and lamivudine groups, respectively. ConclusionsAlthough tenofovir caused a decline in GFR, differences between the anti-viral agents do not appear to be so impressive. In patients with and without renal risk factors at baseline, there is no impact of anti-virals, including tenofovir

Investigation of Magneto-optical Linear Dichroism Property of the TMA Coated Magnetic Fluid

6th International Conference on Nanomaterials - Applications & Properties (NAP) -- SEP 14-19, 2016 -- Minist Educ & Sci Ukraine, Lviv, UKRAINEWOS: 000391877500063In this study magneto-optical linear dichroism (MOLD) effects of the Tetramethylammonium hydroxide (TMA) coated magnetic fluid was investigated. In our study MOLD and optical absorbtion properties of produced magnetic nanoparticles were investigated at the wavelength range of 550-900 nm. For this purpose MOLD measurement system was designed. External magnetic field applied up to 400G during the MOLD measurement. TMA coated magnetic nanoparticles produced by co-precipitation method at room temperature in nitrogen atmosphere. The magnetic, structural and size properties of the particles were measured using X-ray diffractometer (XRD), dynamic light scattering (DLS) and vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of produced Fe3O4 was determined as 62 emu/g and the average particle size was 34 nm. It was observed that with the increase of absorption, the MOLD effect was getting increased

A nanobody-functionalized organic electrochemical transistor for the rapid detection of SARS-CoV-2 and MERS antigens at the physical limit

The COVID-19 pandemic highlights the need for rapid protein detection and quantification at the single-molecule level in a format that is simple and robust enough for widespread point-of-care applications. We here introduce a modular nanobody-organic electrochemical transistor architecture that enables the fast and specific detection and quantification of single-molecule to nanomolar protein antigen concentrations in complex bodily fluids. The sensor combines a new solution-processable organic semiconductor material in the transistor channel with the high-density and orientation-controlled bioconjugation of nanobody fusion proteins on disposable gate electrodes. It provides results after a 10 minutes exposure to 5 µL of unprocessed samples, maintains high specificity and single-molecule sensitivity in human saliva or serum, and is rapidly reprogrammed towards any protein target for which nanobodies exist. We demonstrate the use of this highly modular platform for the detection of green fluorescent protein, SARS-CoV-1/2, and MERS-CoV spike proteins and validate the sensor for COVID-19 screening in unprocessed clinical nasopharyngeal swab and saliva samples