Changes In Concentration Of Matter Research Articles

Analysis of Particulate Matter Concentration Changes before, during, and Post COVID-19 Lockdown: A Case Study from Victoria, Mexico

The lockdown measures implemented due to the SARS-CoV-2 pandemic to reduce the epidemic curve, in most cases, have had a positive impact on air quality indices. Our study describes the changes in the concentration levels of PM2.5 and PM10 during the lockdown and post-lockdown in Victoria, Mexico, considering the following periods: before the lockdown (BL) from 16 February to 14 March, during the lockdown (DL) from 15 March to 2 May, and in the partial lockdown (PL) from 3 May to 6 June. When comparing the DL period of 2019 and 2020, we document a reduction in the average concentration of PM2.5 and PM10 of −55.56% and −55.17%, respectively. Moreover, we note a decrease of −53.57% for PM2.5 and −51.61% for PM10 in the PL period. When contrasting the average concentration between the DL periods of 2020 and 2021, an increase of 91.67% for PM2.5 and 100.00% for PM10 was identified. Furthermore, in the PL periods of 2020 and 2021, an increase of 38.46% and 31.33% was observed for PM2.5 and PM10, respectively. On the other hand, when comparing the concentrations of PM2.5 in the three periods of 2020, we found a decrease between BL and DL of −50.00%, between BL and PL a decrease of −45.83%, and an increase of 8.33% between DL and PL. In the case of PM10, a decrease of −48.00% between BL and DL, −40.00% between BL and PL, and an increase of 15.38% between the DL and PL periods were observed. In addition, we performed a non-parametric statistical analysis, where a significant statistical difference was found between the DL-2020 and DL-2019 pairs (x2 = 1.204) and between the DL-2021 and DL-2019 pairs (x2 = 0.372), with a p<0.000 for PM2.5, and the contrast between pairs of PM10 (DL) showed a significant difference between all pairs with p<0.01.

Synaptic density in healthy human aging is not influenced by age or sex: a 11C-UCB-J PET study

Rationale11C-UCB-J binds to synaptic vesicle glycoprotein 2A, a protein ubiquitously expressed in presynaptic nerve terminals, and can therefore serve as in vivo proxy of synaptic density. There are discrepancies in postmortem data on stability of synaptic density with healthy aging. In this study, healthy aging and sex as potential modifiers of 11C-UCB-J binding were investigated in healthy volunteers over 7 adult decades, assuming that the number of SV2A vesicles per synapse is not influenced by age or sex. Methods80 healthy volunteers underwent 11C-UCB-J PET and structural T1 and T2 MR imaging. Grey matter changes with aging were firstly evaluated by voxel-based morphometry (VBM). Parametric 11C-UCB-J standardized uptake value ratio (SUVR) images were calculated using the centrum semiovale as reference tissue. To correct for atrophy-related partial volume effects, a region-based voxel-wise type partial volume correction (PVC) was applied in FreeSurfer. The correlations of 11C-UCB-J binding with age and with sex were investigated by a voxel-based and volume-of-interest (VOI)-based approach, and with and without PVC to assess the contribution of underlying morphology changes upon aging. ResultsFull results were available for 78 participants (19–85y; 33 M/45 F). VBM grey matter concentration changes with aging were most predominant in the perisylvian and frontal regions. After PVC, no significantly decreased 11C-UCB-J SUVR with aging was found in the voxel-based analysis, whereas the VOI-based analysis showed a slight decrease in the caudate nucleus (−1.7% decrease per decade, p= 0.0025) only. There was no association between sex and 11C-UCB-J SUVR, nor an interaction between aging and sex for this parameter. ConclusionIn vivo, PET using 11C-UCB-J does not support a cortical decrease of synaptic density with aging, whereas subcortically a small effect with aging in the caudate nucleus was observed. In addition, no association between synaptic density and sex was detected, which allows pooling of datasets of both sexes.

Temporal-Spatial Variation of Surface Suspended Matter and Controlling Factors in the Inner Shelf of the East China Sea in Winter

Based on the observed surface suspended matter in the East China Sea in February 2007 and June 2015, an empirical model was established using L1b’s band 4 data to retrieve surface suspended matter from the Moderate Resolution Imagine Spectroradiometer Terra imagery. The squared correlation coefficient is 0.8358, and the root mean square error is 0.4285 mg L−1. The model reflects the distribution characteristics of surface suspended matter in the inner shelf of the East China Sea. In this paper, the satellite images of the study area were retrieved in January from 2001 to 2015, and the monthly distribution of surface suspended matter were obtained. The inter-annual distribution of the study area is similar, and the concentration of surface suspended matter is higher near the shore than offshore. A large amount of surface suspended matter is transported southeast under the influence of Zhejiang and Fujian coastal current and Taiwan warm current. Only a small amount of surface suspension can reach the Kuroshio area. The surface suspended matter concentration changes obviously near the estuary because of the effect of differences in the flux of the Yangtze River. Meanwhile, winter monsoon, temperature front, El Nino events, and other factors affect the distribution of surface suspended matter in 100 m isobath to coastal water but minimally influence the distribution in 100 m isobath to deep sea.

Combined analysis of grey matter voxel-based morphometry and white matter tract-based spatial statistics in late-life bipolar disorder

Previous magnetic resonance imaging (MRI) studies in young patients with bipolar disorder indicated the presence of grey matter concentration changes as well as microstructural alterations in white matter in various neocortical areas and the corpus callosum. Whether these structural changes are also present in elderly patients with bipolar disorder with long-lasting clinical evolution remains unclear. We performed a prospective MRI study of consecutive elderly, euthymic patients with bipolar disorder and healthy, elderly controls. We conducted a voxel-based morphometry (VBM) analysis and a tract-based spatial statistics (TBSS) analysis to assess fractional anisotropy and longitudinal, radial and mean diffusivity derived by diffusion tensor imaging (DTI). We included 19 patients with bipolar disorder and 47 controls in our study. Fractional anisotropy was the most sensitive DTI marker and decreased significantly in the ventral part of the corpus callosum in patients with bipolar disorder. Longitudinal, radial and mean diffusivity showed no significant between-group differences. Grey matter concentration was reduced in patients with bipolar disorder in the right anterior insula, head of the caudate nucleus, nucleus accumbens, ventral putamen and frontal orbital cortex. Conversely, there was no grey matter concentration or fractional anisotropy increase in any brain region in patients with bipolar disorder compared with controls. The major limitation of our study is the small number of patients with bipolar disorder. Our data document the concomitant presence of grey matter concentration decreases in the anterior limbic areas and the reduced fibre tract coherence in the corpus callosum of elderly patients with long-lasting bipolar disorder.

Dissolved organic matter concentration changes in river waters of Latvia

Dissolved organic matter concentration changes in river waters of Latvia Amounts of natural organic matter in surface waters reflect the character and intensity of biological processes in water bodies, human impact and depend on the physico-geographical environment and land-use in the catchments. Thus, analysis of the concentrations and loadings of organic substances to adjacent water bodies can be used to indicate environmental change and human impacts. This study revealed significant increasing trends of total organic carbon (TOC) and water colour in most of the studied Latvian rivers during the last decade. However, over longer time periods, there have been pronounced oscillations of TOC concentrations, stressing the importance of long-term changes of river discharge. On a yearly basis, there was a positive correlation between parameters of organic matter concentration and discharge in all selected rivers. The impact of discharge on concentrations of organic matter can be masked by other factors, such as changes in precipitation, biological processes, soil types and land-use.

Gray, White Matter Concentration Changes and Their Correlation with Heterotopic Neurons in Temporal Lobe Epilepsy

ObjectiveTo identify changes in gray and white matter concentrations (GMC, WMC), and their relation to heterotopic neuron numbers in mesial temporal lobe epilepsy (mTLE).Materials and MethodsThe gray matter or white matter concentrations of 16 left and 15 right mTLE patients who achieved an excellent surgical outcome were compared with those of 24 healthy volunteers for the left group and with 23 healthy volunteers for the right group, by optimized voxel-based morphometry using unmodulated and modulated images. A histologic count of heterotopic neurons was obtained in the white matter of the anterior temporal lobe originating from the patients' surgical specimens. In addition, the number of heterotopic neurons were tested to determine if there was a correlation with the GMC or WMC.ResultsThe GMCs of the left and right mTLE groups were reduced in the ipsilateral hippocampi, bilateral thalami, precentral gyri, and in the cerebellum. The WMCs were reduced in the ipsilateral white matter of the anterior temporal lobe, bilateral parahippocampal gyri, and internal capsules, but increased in the pons and bilateral precentral gyri. The heterotopic neuron counts in the left mTLE group showed a positive correlation (r = 0.819, p < 0.0001) with GMCs and a negative correlation (r = -0.839, p < 0.0001) with WMCs in the white matter of the anterior temporal lobe. ConclusionThe present study shows the abnormalities of the cortico-thalamo-hippocampal network including a gray matter volume reduction in the anterior frontal lobes and an abnormality of brain tissue concentration in the pontine area. Furthermore, heterotopic neuron numbers were significantly correlated with GMC or WMC in the left white matter of anterior temporal lobe.

PARTICULATE MATTER CONCENTRATION AND EMISSION FACTOR IN THREE DIFFERENT LAYING HEN HOUSING SYSTEMS

The aim of this study was to evaluate PM10 concentration in three different laying hens houses (traditional battery cages with aerated open manure storage, aviary system and vertical tiered cages with manure belts with forced air drying) and to evaluate particulate matter emission into atmosphere during one year of observation. Internal and external temperature and relative humidity, ventilation rate, PM10 concentration have been continuously monitored in order to evaluate particulate matter concentration changes during the day and the season and to define PM10 emission factors. PM10 concentration was corrected by gravimetric technique to lower measurements error. In the aviary system house, TSP and fine particulate matter (particles smaller than 2.5 micron) concentration was measured. Average yearly PM10 concentration was remarkably higher in the aviary system house with 0.215 mg m-3 vs 108 mg m-3 for the ventilated belt house and vs 0.094 mg m-3 for the traditional battery cages house. In the Aviary system housing, TSP concentration was 0.444 mg m-3 and PM2.5 was 0.032 mg m-3, highlighting the existence of a severe working environment for men and animals. Recorded values for PM10 emission were 0.433 mg h-1 hen-1 for battery cages housing type, 0.081 mg h-1 hen-1 for ventilated belt cages house, values lower than those available in literature, while the aviary system housing type showed the highest PM10 emission (1.230 mg h-1 hen-1) with appreciable peaks during the morning, together with the increased animal activity and daily farmer operations, as feed administration, cleaning and droppings removal.

Size fractionation of organic matter and heavy metals in raw and treated leachate

This study characterized the organic matter and heavy metals in the leachate from two typical municipal solid waste (MSW) sanitary landfills in China, the recently established (3-year-old) Liulitun landfill and the mature (11-year-old) Beishenshu landfill, using a size fractionation procedure. The organic matter of all raw and treated leachate samples primarily existed in a truly-dissolved fraction with an apparent molecular weight (AMW) of <1 kDa, and its percentage decreased with an increase in overall AMW. The leachate from the newer landfill had a higher percentage of truly-dissolved organic matter. After anaerobic treatment, this leachate had a similar size fraction of organic matter to that seen for the raw leachate of the mature landfill. Biochemical processes had different removal efficiencies for various types of AMW organic matter, and the concentration of moderate AMW organic matter appeared to increase throughout these processes. Most of the heavy metals existed in a colloidal fraction (AMW >1 kDa and particle size <0.45 microm). The behaviors of different species of heavy metals had large variations. The size fractions of heavy metal species were significantly affected by treatment processes and landfill age, except for Zn. The concentration ratio of heavy metals to organic matter was maximal in the colloidal fraction and showed an inverse change to that seen for organic matter concentration changes caused by biochemical processes. Consequently, the pollution levels of heavy metals were substantially increased by treatment processes, although their concentrations decreased.

Gray Matter Concentration Abnormality in Brains of Narcolepsy Patients

ObjectiveTo investigate gray matter concentration changes in the brains of narcoleptic patients.Materials and MethodsTwenty-nine narcoleptic patient with cataplexy and 29 age and sex-matched normal subjects (mean age, 31 years old) underwent volumetric MRIs. The MRIs were spatially normalized to a standard T1 template and subdivided into gray matter, white matter, and cerebrospinal fluid (CSF). These segmented images were then smoothed using a 12-mm full width at half maximum (FWHM) isotropic Gaussian kernel. An optimized voxel-based morphometry protocol was used to analyze brain tissue concentrations using SPM2 (statistical parametric mapping). A one-way analysis of variance was applied to the concentration analysis of gray matter images.ResultsNarcoleptics with cataplexy showed reduced gray matter concentration in bilateral thalami, left gyrus rectus, bilateral frontopolar gyri, bilateral short insular gyri, bilateral superior frontal gyri, and right superior temporal and left inferior temporal gyri compared to normal subjects (uncorrected p < 0.001). Furthermore, small volume correction revealed gray matter concentration reduction in bilateral nuclei accumbens, hypothalami, and thalami (false discovery rate corrected p < 0.05).ConclusionGray matter concentration reductions were observed in brain regions related to excessive daytime sleepiness, cognition, attention, and memory in narcoleptics with cataplexy.

Cortical thickness abnormality in juvenile myoclonic epilepsy

Previous studies on gray matter concentration changes in patients with juvenile myoclonic epilepsy (JME) are inconsistent. To investigate cortical abnormality in JME differently, we measured the cortical thickness in 19 JME patients and 18 normal controls. Results showed that the cortical thicknesses of superior/middle/medial frontal gyri, and superior/middle/ inferior temporal gyri were decreased in JME patients. Moreover, cortical thicknesses of precentral gyrus and medial orbital gyrus of right hemispheres were negatively correlated with disease duration. These findings suggest that JME brains have cortical gray matter atrophy in the frontal and temporal lobes.

Hydrologic and sedimentologic aspects of mining aggregate from the shipsk bank (Baltic sea)

Abstract Investigations aimed at obtaining knowledge about the environmental effects of mining aggregate from the sea bottom were carried out on the Stupsk Bank. Special attention was given to the magnitude and reach of changes of hydrologic conditions, in that to changes in concentration of matter suspended in sea water, and to dynamics of the sea bottom—change of bottom relief, resulting from both natural causes and from mining of the aggregate.