Spatiotemporal variation analysis of water quality using multivariate statistical methods, Case study: Koohsar Lake, Western Iran

The study of water resources and reviewing periodic and spatial changes in the quality of water in aquatic ecosystems are of important necessity due to the reasons including, climate change, water resource constraints, and increased human water requirements. Given the fact that Koohsar Lake water in Zanjan Province is one of the sources of drinking water in the region, the present study aimed to measure the values ​​of 19 parameters of water quality in two seasons of summer and spring at four stations. The samples were transferred to a laboratory under steady-state and sunlight conditions and analyzed according to the standard methods. Statistical analyses were performed using SPSS software. Moreover, the study applied factor analysis using principle components to analyze the variance of data. In addition, the values ​​of the parameters were compared with the permissible limits of drinking water of national standard. The results indicated a significant difference between the parameters studied at stations and different sampling times by repeated measurements. The results of factor analysis also showed that the total of three main components in the summer and spring were 96.573% and 98.581% of the variance of data respectively. The main parameters in the summer included Chlorophyll-a, Na, DO, pH, BOD, COD, TDS, EC, and nitrate. Also, EC, TDS, alkalinity, pH, COD, BOD, Ca, and ammonia were found as the main parameters in the spring. Also, it was found that except for the pH in the spring and at stations 3 and 4 which were below the standard minimum, the lake water in both seasons and all stations, in terms of parameters, was within the standard range and exhibited a good quality for drinking. Implications are discussed in light of the study findings

Brain correlates of perceptual switch during perception rivalry: an ultra-high field 7T functional magnetic resonance imaging study

Introduction Perceptual rivalry while viewing ambiguous stimulus leads to repetitive switches between two perceptions of the same image1. Switches are considered to recruit bottom-up and top-down attentional processes. We aimed to investigate the neural mechanisms of perceptual switch using high resolution ultra-high-field 7-Tesla MRI. Methods 35 healthy subjects (18-70y; 28 women) were recruited. FMRI (voxel size 1.4 mm³) was recorded for 10 minutes while participants viewed a Necker cube 2 (10s breaks every minute). Subjects were instructed to report switch of their perception by pressing a button. Results Perceptual switches were associated with increased activation in the bilateral intraparietal sulcus (which is involved in attention), the insula (part of the salience network), the occipital cortex (including in an area compatible with V4, involved in shape detection), the left motor cortex, and the right cerebellum (whole-brain FWE corrected p<.05) (Fig1). Conclusions We report neural substrates compatible with the top-down and bottom-up attentional processes involved in resolving perceptual rivalry. Our results further suggest that perceptual changes of ambiguous figures are associated with a widespread set of brain activation. Funding: FNRS, ULiège, FEDER, SAO-FRA, Wallonia-Brussels federation References 1. Blake R, Logothetis NK. Visual competition. Nature Reviews Neuroscience. 2002;3(1):13-21. 2. Einhäuser W, Stout J, Koch C, Carter O. Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry. Proceedings of the National Academy of Sciences. 2008;105(5):1704-1709

Association between locus coeruleus activity during wakefulness and sleep features

editorial reviewedIntroduction The locus coeruleus (LC) is the main source of norepinephrine (NE) in the brain and sends monosynaptic projections to most of the brain (Szabadi, 2013). It contributes to multiple processes such as cognition and arousal (Mather & Harley, 2016). The LC further contributes heavily to the transition between sleep and wakefulness, and between slow wave sleep (SWS) and rapid eye movement sleep (REMS) (Cirelli, Tononi 2005). Through the local release of NE, it governs the synchrony of brain activity and is tightly linked to the oscillatory modes found during sleep, such as sleep spindles and slow waves in animals (Eschenko et al., 2012). While the LC appears to be an important structure for sleep, only limited imaging studies evaluated whether the LC is related to sleep variability due to the difficulty of imaging such a small size nucleus in vivo (Keren et al., 2009). We aimed to investigate the link between LC activity during wakefulness and electroencephalogram (EEG) features of sleep using ultra-high-field 7-Tesla MRI. To trigger a response of the LC, we used a perceptual rivalry task. Subjects saw an ambiguous stimulus which could trigger spontaneous switches between two perceptions of the same image (Blake & Logothetis, 2002). Switches are considered to recruit bottom-up and top-down attentional processes associated with activity of the LC (Einhauser et al., 2008; Murphy et al., 2014). Methods 50 healthy volunteers, including 33 young (age: 22.27y ± 3.21y; 29 women) and 17 late middle-aged (age: 61.35y ± 5.19y; 12 women) individuals completed the protocol. They first underwent a structural 7T MRI session, which allowed collecting high-resolution whole-brain T1-weighted images as well as a sequence dedicated to acquire 6cm LC slab. The latter was used to create in the brain space of each participant an individual LC-mask. All individual LC-masks were gathered into a probabilistic LC-mask in a standardized group brain space. Following 1 week of regular sleep times, participants completed an fMRI session in the morning, 2h to 3h after wake-up time, during which they were administered the perceptual rivalry task (TR= 2.34s; voxel size 1.4x1.4x1.4 mm³). Participant’s habitual and baseline sleep was recorded in-lab under EEG to extract 4 sleep features of interest depicting some of the most canonical characteristics of sleep (i.e., cumulated power of the theta frequency band during REMS, slow wave energy (SWE), sleep onset latency, and REMS percentage). We first conducted a general linear model with the Statistical Parametric Mapping 12 package (SPM12) over the entire brain. We then extracted the activity estimates over individual LC masks and then conducted generalized linear mixed models (GLMMs) to test for associations between the activity of the LC and EEG features of sleep, including age, sex, BMI, and total sleep time as covariates. Results Perceptual switches were associated with increased activation in the left LC after controlling for age, sex, BMI, and total sleep time (whole brain FDR-corrected p 3.055) (Fig1). This supported the extraction of individual LC activity in the individual space to associate with sleep EEG metrics. GLMMs on the LC activity and sleep EEG metrics revealed a positive association between the bilateral LC activity and SWE (cumulated EEG power over the .5-4Hz frequency band) (p = 0.02, F= 5.1), which reflects SWS intensity. A similar positive association was found between the LC activity and EEG cumulated power of the theta frequency band (4-8Hz) during REMS (p = 0.03, F=4.8), which is the dominant oscillatory mode of REMS. No other significant associations were detected. Conclusions These results show that a greater LC activity during wakefulness is associated with a more intense SWS and REMS. Future analyses will consider the relationship between LC activity and sleep microstructure. Funding: FNRS Belgium, ULiège, FEDER, Alzheimer Foundation (SAO-FRA), Wallonia-Brussels federation   References Blake, R., & Logothetis, N. K. (2002). Visual competition. Nature Reviews Neuroscience, 3(1), 13–21. Einhauser, W., Stout, J., Koch, C., & Carter, O. (2008). Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry. Proceedings of the National Academy of Sciences, 105(5), 1704–1709. https://doi.org/10.1073/pnas.0707727105 Eschenko, O., Magri, C., Panzeri, S., & Sara, S. J. (2012). Noradrenergic neurons of the locus coeruleus are phase locked to cortical up-down states during sleep. Cerebral Cortex, 22(2), 426–435. https://doi.org/10.1093/cercor/bhr121 Keren, N. I., Lozar, C. T., Harris, K. C., Morgan, P. S., & Eckert, M. A. (2009). In vivo mapping of the human locus coeruleus. NeuroImage, 47(4), 1261–1267. https://doi.org/https://doi.org/10.1016/j.neuroimage.2009.06.012 Mather, M., & Harley, C. W. (2016). The Locus Coeruleus: Essential for Maintaining Cognitive Function and the Aging Brain. Trends in Cognitive Sciences, 20(3), 214–226. https://doi.org/10.1016/j.tics.2016.01.001 Murphy, P. R., O’Connell, R. G., O’Sullivan, M., Robertson, I. H., & Balsters, J. H. (2014). Pupil diameter covaries with BOLD activity in human locus coeruleus. Human Brain Mapping, 35(8), 4140–4154. https://doi.org/10.1002/hbm.22466 Scammell, T. E., Arrigoni, E., & Lipton, J. O. (2017). Neural Circuitry of Wakefulness and Sleep. Neuron, 93(4), 747–765. https://doi.org/10.1016/j.neuron.2017.01.014 Szabadi, E. (2013). Functional neuroanatomy of the central noradrenergic system. Journal of Psychopharmacology, 27(8), 659–693. https://doi.org/10.1177/026988111349032

Impact of repeated short light exposures on sustained pupil responses in an fMRI environment

Light triggers numerous non-image forming (NIF), or non-visual, biological effects. The brain correlates of these NIF effects have been investigated, notably using Magnetic Resonance Imaging (MRI) and short light exposures varying in irradiance and spectral quality. However, it is not clear whether having light in subsequent blocks may induce carry over effects of one light block onto the next, thus biasing the study. We reasoned that pupil light reflex (PLR) was an easy readout of one of the NIF effects of light that could be used to address this issue. We characterized the sustained PLR in 13 to 16 healthy young individuals under short light exposures during three distinct cognitive processes (executive, emotional and attentional). Light conditions pseudo-randomly alternated between monochromatic orange light [0.16 melanopic Equivalent Daylight Illuminance (mel EDI) lux] and polychromatic blue-enriched white light of three different levels [37, 92, 190 mel EDI lux]. As expected, higher melanopic irradiance was associated with larger sustained PLR in each cognitive domain. This result was stable over the light block sequence under higher melanopic irradiance levels as compared to lower ones. Exploratory frequency-domain analyses further revealed that PLR was more variable within a light block under lower melanopic irradiance levels. Importantly, PLR varied across tasks independently of the light condition pointing to a potential impact of the light history and/or cognitive context on PLR. Together, our results emphasize that the distinct contribution and adaptation of the different retinal photoreceptors influence the NIF effects of light and therefore potentially their brain correlates

Predicting trait mindfulness based on childhood maltreatment

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Isolation and identification of cutinase enzyme producing bacteria

Cutinase belongs to the family of serine hydrolases which are capable of hydrolysis of esters and small polyester such as cutin. The cutin of plants is composed of hydroxy and epoxy fatty acids and is substantially imperm-eable to water and only the plant pathogenic bacteria are capable of degrading it. Initially, in order to identify the extent of cutin in cucumber (Cucumis sativus' C. sativus'), golden apples (Golden Delicious apple 'Malus domestica'), red ap-ples (Red Delicious apple 'Malus domestica'') and tomatoes (Solanum lycopersicum Mill. Commun ' S. lycopersicum'), their fruits were obtained. Cutin was extracted from the fruit skin of each studied specimen and compared by chloro-form-methanol method. Then, isolation of enzyme-producing strains was performed by the use of the specific medium containing cutin and enzyme activity assay. DNA of the specimens was extracted, and PCR were performed with univ-ersal primers for 16s DNA. The remainder was devoted to bioinformatic analysis, identification and registration of samples in the gene bank. The results showed that the percentage of extracted cutin in red apple was more than other samples and as a result, red apple are expected to be more resistant against diseases and pests. Also, six cutinase-prod-ucer strains of Klebsiella and Enterobacter were isolated with the help of enzyme activity and special culture medium containing cutin, and their 16s DNA region coding sequences were recorded in the GenBank

Comparing the Activity of Different Regions of the Brain during Overt and Covert Verb Generation, Word Repetition, and Finger, Foot, and Lip Movement

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