Source analysis and health risk assessment of polycyclic aromatic hydrocarbons in atmospheric PM2.5 in a district of Taizhou City from 2019 to 2021 / 环境与职业医学

Background Polycyclic aromatic hydrocarbons (PAHs), one of the main components of fine particulate matter (PM2.5), have a certain impact on ambient air quality, and long-term exposure to PAHs may pose potential health risks to human beings. Objective To identify the distribution characteristics and sources of PAHs in atmospheric PM2.5 in a district of Taizhou City from 2019 to 2021, and to evaluate the health risks of PAHs to the population in the area through the inhalation pathway. Methods From 2019 to 2021, air PM2.5 sampling was carried out at a state-controlled surveillance point in a district of Taizhou City for 7 consecutive days on the 10th-16th of each month, the sampling time was 24 h·d−1, and the sampling flow rate was 100 L·min−1. PM2.5 mass concentration was calculated by gravimetric method. A total of 16 PAHs were determined by ultrasonic extraction-liquid chromatography. Kruskal-Wallis H test was used to compare the distribution charac teristics of PAHs concentrations by years and seasons, characteristic ratio and principal component analysis (PCA) was used to analyze their sources, and a lifetime carcinogenic risk (ILCR) model was used to assess the health risk of PAHs. Results From 2019 to 2021, the annual average concentrations [M (P25, P75)] of ∑PAHs in atmospheric PM2.5 in the selected district of Taizhou City were 6.52 (2.46, 10.59), 8.52 (4.56, 12.29), and 3.72 (1.51, 7.11) ng·m−3, respectively, and the annual benzo[a]pyrene (BaP) excess rates (national limit: 1 ng·m−3) were 27.38% (23/84), 47.62% (40/84), and 19.04% (16/84), respectively, both presenting 2020> 2019 > 2021 (P<0.001, P<0.05). The ∑PAHs concentration distribution showed a seasonal variation, with the highest value in winter and the lowest value in summer (P<0.05). Among the atmospheric PM2.5 samples, the proportion of 5-ring PAHs was the highest, the proportion of 2-3-ring PAHs was the lowest; the proportion of 2-4-ring PAHs showed a yearly upward trend, and the proportion of 5-6-ring PAHs showed yearly downward trend (P<0.05). The characteristic ratio and PCA results suggested that the sources of sampled PAHs were mainly mixed sources such as dust, fossil fuel (natural gas), coal combustion, industrial emissions, and motor vehicle exhaust emissions. The ILCR (RILCR) of PAHs by inhalation for men, women, and children were 1.83×10−6, 2.35×10−6, and 2.04×10−6, respectively, and the annual average RILCR was 2.07×10−6, all greater than 1×10−6. Conclusion For the sampled time period, the main sources of PAHs pollution in atmospheric PM2.5 in the target district of Taizhou City are dust, fossil fuel (natural gas), coal combustion, industrial emissions, motor vehicle emissions, etc., and PAHs may have a potential carcinogenic risk to local residents.

Analysis on the source of students and the way to understand the policy of public and non-public undergraduates majoring in preventive medicine in Shandong Province / 中华医学教育探索杂志

Objective:To explore the source of students and the way to understand the policy of public and non-public undergraduate students majoring in preventive medicine.Methods:Using cluster random sampling, a total of 205 students from the first batch of public funded undergraduates and the same batch of non-public funded undergraduates of preventive medicine from Batch 2020 of two medical colleges in Shandong Province were selected as research objects. Questionnaires were issued on the platform of Sojump to investigate the source of students and the way to understand the policy. SPSS 22.0 statistical software was used to analyze the data, and the relative number and composition ratio were used to describe the counting data. Chi-square test was used to compare the characteristics of students and the understanding degree of the policy between government-funded undergraduates and non-government-funded undergraduates. Multiple responses were used to analyze students' understanding of the policy.Results:There were significant differences in the gender ( χ2=10.29, P<0.001), place of household registration ( χ2=5.61, P=0.018), father's educational level ( χ2=9.78, P=0.044) and the way to understand the policy ( χ2=17.19, P<0.001) of the public and non-public funded undergraduates majoring in preventive medicine. And 88.4% of the students knew about the policy of public medical students through their teachers, classmates and family members. Conclusion:There are more female government-funded undergraduates in preventive medicine than male students, and more rural students than urban students, with the spreading way of from mouth to mouth as the main approach to know this policy.

Pollution characteristics and sources of PM2.5 during heating and non-heating periods in Urumqi City in 2021 / 中国热带医学

@#Abstract: Objective　To understand the pollution characteristics and sources of PM2.5 in the atmosphere during heating and non-heating periods in Urumqi City in 2021, and provide scientific basis for pollution control during different periods. Method A total of 188 air samples were collected from area A and area B of Urumqi City, and 12 metal elements and 5 water-soluble ions were quantitatively analyzed, and the pollution sources were analyzed by enrichment factor method and principal component analysis method. Results In 2021, the mass concentrations of PM2.5 in areas A and B of Urumqi were 45.0 (20.0, 158) µg/m3 and 28.0 (17.5, 66.0) µg/m3, respectively, with statistically significant difference (Z=-2.870, P<0.05). During the heating period, the concentrations were 110 (68.0, 250) µg/m3 and 61.0 (31.0, 88.0) µg/m3, respectively, with no statistically significant difference (Z=-3.822, P<0.01). During the non-heating period, the concentrations were 18.0 (13.0, 22.3) µg/m3 and 18.0 (12.8, 22.0) µg/m3, respectively, with no statistically significant difference (Z=-0.596, P>0.05). The SNA (the sum of SO42-, NO3-and NH4+) accounted for 71.7% and 23.4% of PM2.5 in A area during heating and non-heating periods, respectively, with statistically significant difference (Z=-8.057, P<0.01); the corresponding proportions in B area were 60.7% and 24.9%, with statistically significant difference (Z=-6.672, P<0.01). During the heating and non-heating periods, the ratios of NO3-/SO42-are 0.63 and 0.54 in A area were 0.63 and 0.54, respectively, with statistically significant difference (Z=-2.382, P<0.05); and the corresponding ratios in B area were 0.72 and 0.53, respectively, with statistically significant difference (Z=-3.182, P<0.05). The ratio of NO3- to SO42- was less than 1 in both heating and non-heating periods in the two areas. and the correlation between five water-soluble ions was significant (P<0.05). The correlation coefficient between NH4+ and SO42-, NO3-and Cl- in A and B areas during heating periods were all >0.9, indicating that NH4+and SO42-, NO3- and Cl- bind in (NH4)2SO4, NH4HSO4, NH4NO3, and NH4Cl. During non-heating periods, the correlation between NH4+ and each ion was slightly lower. During heating periods in area A, Sb, As, Cd, Pb, and Tl were severely enriched (EF>100). During non-heating periods in the same area, As, Cd, Pb, Tl, and Hg were severely enriched (EF>100). During heating periods in area B, Sb, As, Cd, Pb, and Hg were severely enriched (EF>100), and during non-heating periods in the same area, Sb, Cd, and Hg were severely enriched (EF>100). Coal emission, photochemical secondary pollution, motor vehicle exhaust, dust and industrial pollution were the main sources of PM2.5 pollution in the two areas, and the contribution rate of fixed sources was higher than that of mobile sources. Conclusion In 2021, the mass concentration of PM2.5, water-soluble ions and metal elements in Urumqi City were higher in area A than area B, the heating period was higher than the non-heating period, the excess rate of area A was higher than that in area B, and the contribution rate of fixed air pollution was greater than that of mobile sources.

Characteristics and source analysis of heavy metal pollution in environment in Guizhou Province / 环境与职业医学

Heavy metal pollution poses a serious threat to the environment and human health. Guizhou is a province with apparent regional features of heavy metal pollution such as lead, zinc, mercury, and arsenic in agriculture and mining soils. The coefficient of variation results showed that heavy metal pollution in the soils of agricultural planting areas and mine caves was closely related to human activities, and arsenic and zinc were greatly affected by human activities. In the water environment, mercury pollution presents in mine cave water samples, and cadmium, mercury, and lead pollution present in scenic park water samples. The results of single-factor pollution index showed that mercury in mine cave water samples and cadmium, mercury, and lead in scenic park water samples were graded as severe pollution. The results of Nemero pollution index showed the highest comprehensive pollution level of heavy metals was in scenic park water samples. In atmospheric dust fall, cadmium, mercury, lead are the most prominent pollution. Potential risks to ecological environment were identified for cadmium and mercury in all study areas and lead in other areas outside Wanshan. The results of integrated potential ecological risk index indicated a high-risk level of heavy metal pollution in atmospheric dust fall in the current study area. At present, the heavy metal pollutants in the environment of Guizhou are mainly originated from natural factors such as geological background content and soil-forming parent material, and human activities such as mining, metal smelting, agricultural activities, and sewage irrigation. The analysis showed serious heavy metal pollution in the environment of Guizhou, which caused harm to the local environment. It is crucial that environmental protection measures be taken during human activities.

Auditory Cortical Temporal Processing and Hemispheric Asymmetry Revealed by N1 Dipole Source Activity in Adult Cochlear Implant Users / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Cochlear implant (CI) changes the way that sound inputs are processed in the brain, possibly causing brain reorganization. Given that the pattern and degree of reorganization are known to be related to speech perception skill, information regarding hemispheric asymmetry can be used to predict behavioral performances in CI users. The current study investigated the hemispheric asymmetry of N1 dipole cortical activity in response to the temporally varied speech sounds and its relationship to speech perception abilities in adult CI users. SUBJECTS AND METHOD: The cortical activity was recorded from 64 scalp electrodes in 10 CI users and 11 normal-hearing controls. Speech stimuli were synthesized consonant-vowels, the /ba/-/pa/ continuum that ranged from 0 to 50 ms with a 6-step voice onset time (VOT). N1 dipole amplitudes, latencies, and locations were analyzed as a function of VOT and the direction of implantation. Also investigated was the relationship between N1 dipole lateralization and speech perception. RESULTS: For the N1 dipole location, significant location differences between CI and normal hearing groups were seen at 40 ms VOT in the anterior-posterior direction. For hemispheric asymmetry, the N1 dipole activity in good CI performers was higher in the auditory cortex contralateral to the stimulated ear, while poor CI performers showed greater ipsilateral activity. In addition, a lateralization index at 20 ms VOT showed significant correlation with the /ba/-/pa/ consonant perception scores in noise. CONCLUSION: The results suggest that the hemispheric asymmetry of N1 dipole activity in response to stimuli of temporally varied speech has a substantial clinical value, and that this can be used to estimate CI speech perception.

Electroencephalographic Characteristics of Alcohol Dependent Patients: 3-Dimensional Source Localization

OBJECTIVES: The power spectral analysis of electroencephalogram has been widely used to reveal the pathophysiology of the alcoholic brain. However, the results were not consistent and the three dimensional study can be hardly found. The purpose of this study was to investigate characteristics of the three dimensional electroencephalographic (EEG) activity of alcohol dependent patients using standardized low resolution electromagnetic tomography (sLORETA). METHODS: The participants consisted of 30 alcohol dependent patients and 30 normal healthy controls. All the participants were males who had refrained from alcohol at least one month and were not taking any medications. Thirty two channel EEG data was collected in the resting state with eyes-closed condition during 30 seconds. The three dimensional data was compared between two groups using sLORETA for delta, theta, alpha, beta1, beta2, and beta3 frequency bands. RESULTS: sLORETA revealed significantly increased brain cortical activity in alpha, beta1, beta2, and beta3 bands each in alcohol dependent patients compared to normal controls. The voxels showing the maximum significance were in the left transverse temporal gyrus, left superior temporal gyrus, left anterior cingulate, and left fusiform gyrus in alpha, beta1, beta2, and beta3 bands respectively. CONCLUSIONS: These results suggest that chronic alcohol intake may cause neurophysiological changes in cerebral activity. Therefore, the measuring of EEG can be helpful in understanding the pathophysiology of cognitive impairements in alcohol dependence.

Time-varying source analysis of auditory-visual stimuli evoked event-related potentials / 国际生物医学工程杂志

Objective Dipole source analysis was employed to investigate the transient changes in brain mechanisms at earlier latencies.Methods Fourteen healthy volunteers were recruited in this research and evoked event-related potentials (ERPs) of unimodal and bimodal visual auditory stimuli were recorded by 64-electrodes electroencephalograph (EEG) recording system.All these earlier phases of the stimuli were divided into several subphases by specific time window for source analysis.Results The results showed that ERPs sources were mainly generated from visual and audio cortex,and there were changes in the location and strength of the dipole sources in each sub-phase.Conclusions The result of this study implies a serial processing of sensory information in human cortices in early phase of visual and auditory stimuli.

Análisis de fuentes del EEG en pacientes tratados con estimulación magnética transcraneal a 5 Hz como tratamiento antidepresivo / Electroencephalographic source analysis in patients receiving 5-Hz transcranial magnetic stimulation as antidepressant treatment

Transcranial Magnetic Stimulation (rTMS) is a technique that allows noninvasive electrical stimulation of the cortex with few side effects. An antidepressant effect has been proposed when rTMS is delivered over prefrontal dorsolateral cortex (DLPFC) ≥5Hz. Quantitative EEG studies have shown increases in alpha and theta power bands as well as frontal interhemispheric asymmetries in most recordings from depressed patients. rTMS over left DLPFC at 5Hz involve a safer and more tolerable procedure, and its neurophysiological correlates has not been explored using EEG source analysis. The aim of this research was to study changes in EEG sources using VARTERA method in a group of patients with major depressive disorder (MDD) treated with 5Hz rTMS over left DLPFC as single or combined treatment with escitalopram. Methods 18 patients with DSM-IV MDD diagnosis without treatment for the current episode were included. Subjects were randomly assigned to one of two groups: A) rTMS+escitalopram 10mg, n=9; B) rTMS+placebo, n=9. Subjects received 15 sessions of rTMS on a daily basis. In order to compare changes in EEG sources two recordings were obtained, prior and after treatment. HDRS, BDI and HARD were used for clinical assessments. Results All patients of group A and eight patients of group B showed response to treatment (considered as a reduction of 50% in HDRS score). An increase in absolute power at 9.37Hz and 10.17Hz in temporal and postcentral gyrus on the left hemisphere was found in group B. Absolute power in those frequencies was decreased in the same regions for group A. In addition, an increased power in beta band frequencies was observed in both hemispheres for group A. Conclusion Increases in alpha band could be the hallmark of the 5Hz rTMS, but it could be reduced by escitalopram. Besides, increases observed in beta band for group A could be related to escitalopram effect.

La estimulación magnética transcraneal repetitiva (EMTr) es una técnica que permite estimular eléctricamente la corteza cerebral de manera no invasiva y con pocos efectos secundarios. Se ha propuesto que la EMTr aplicada sobre la corteza prefrontal dorsolateral (CPFDL) izquierda con frecuencias ≥5Hz tiene efectos antidepresivos. Se ha encontrado que en el electroencefalograma cuantitativo (QEEG por sus siglas en inglés) la mayoría de pacientes deprimidos presentan incrementos en las bandas theta y alfa, así como asimetrías interhemisféricas en la actividad alfa en regiones anteriores. La EMTr sobre la CPFDL izquierda a 5Hz ofrece ventajas considerables en seguridad y tolerabilidad; sin embargo, sus correlatos neurofisiológicos no han sido explorados por el análisis de fuentes del EEG. Objetivo Estudiar los cambios en las fuentes del EEG según el método VARETA en un grupo de pacientes con trastorno depresivo mayor que recibieron EMTr a 5Hz sobre la corteza prefrontal dorsolateral izquierda como tratamiento único o en combinación con escitalopram. Material y métodos Se estudiaron 18 pacientes con diagnóstico de trastorno depresivo mayor de acuerdo con los criterios del DSM-IV sin tratamiento para el episodio en curso. Los sujetos habían sido aleatoriamente asignados a uno de los siguientes grupos de tratamiento: A) EMTr+escitalopram 10mg, n=9; B) EMTr+placebo, n=9. Se aplicó EMTr, a 5Hz en una sesión diaria durante 15 días. Se obtuvieron dos registros electroencefalográficos, uno basal y otro final, con el fin de comparar los cambios en las fuentes de actividad eléctrica cerebral, pretratamiento y post-tratamiento. Se realizaron evaluaciones clinimétricas con las escalas de Hamilton para Depresión y Ansiedad y el Inventario de Depresión de Beck. Resultados Todos los pacientes en el grupo A y ocho pacientes en el grupo B respondieron al tratamiento, con una reducción de 50% o más en la escala HDRS. En el análisis de fuentes se encontró un efecto en el grupo B caracterizado por incremento en la PA de 9.37 a 10.17Hz, en regiones temporales y giro poscentral izquierdos, mismo que se encontró disminuido en el grupo A, Además se encontró un incremento en fracuencias correspondientes a la banda beta en regiones frontales de ambos hemisferios en el grupo A. Conclusiones Podría considerarse que el incremento en la banda alfa es característico de la EMTr a 5Hz, mismo que se ve reducido por efecto del escitalopram. Por otro lado, se observó que el grupo A mostró incrementos en fuentes correspondientes a la banda beta como posible efecto relacionado del fármaco antidepresivo.

Current Source Distribution of Periodic Lateralized Epileptiform Discharge: Comparison With Diffusion-Wighted MR Imaging in Viral Encephalitis

BACKGROUND: Periodic lateralized epileptiform discharges (PLEDs) are the main electroencephalograph (EEG) findings that imply the existence of acute or subacute structural lesions. The purpose of this study was to investigate the electrophysiologic characteristics of PLEDs by identifying the relationship between the current-source distribution (CSD) of PLEDs and the high signal intensity of diffusion-weighted magnetic resonance imaging (MRI; HSI-DWI) in viral encephalitis. METHODS: Six patients were enrolled. Twenty typical EEG, 1-s epochs, including the negative peak of the PLEDs, were averaged into an averaged-PLED (a-PLED). The CSD at the negative peak point of the a-PLED was located on the Talairach human brain map in each patient. The CSDs of the patients were compared with the anatomic locations of encephalitic lesions observed on diffusion-weighted MRI. RESULTS: In all patients, the locations with HSI-DWI were observed in the cortical areas. In two out of the six patients the locations of CSD and those of HSI-DWI were matched. In the other patients, they were partly matched. The matched areas were observed in the frontal, temporal, and parietal areas. The additional areas of CSD were in both insular areas, and those of HSI-DWI were in the frontal, temporal, parietal, and occipital areas. CONCLUSIONS: This study showed that the CSDs of PLEDs in viral encephalitis were mostly matched with the HSI-DWI in the cortical area of the frontal, temporal, and parietal areas. The cortical lesion itself in viral encephalitis may be part of the neural generator of PLEDs.

Distributed Current Source Analysis of Alpha-Frequency Band in Alpha Coma: Drug Intoxication versus Pontine Infarction

Alpha coma is a coma state with predominant alpha activities in electroencephalography. There are two different patterns of alpha coma, depending upon the distribution of alpha activity. The causes may vary with the distribution pattern. To clarify the difference in alpha-activity distribution, we conducted current-source analysis of the alpha-frequency band in two patients with alpha-coma caused by drug intoxication and pontine infarction, respectively. The current-source analysis of alpha-frequency bands may make it easier to distinguish the distribution patterns.

Current-source Analysis of Interictal Spikes in a Patient With Ictal Crying

Ictal crying has been associated with ictal activities in the medial frontal or medial temporal area of the nondominant hemisphere. We applied current-source analysis to the interictal spikes of a patient with episodes of ictal crying without sad feelings, but fear sensation. The current sources were in the medial frontal area of both cerebral hemispheres, the temporal area and the posterior cingulate gyrus of the right hemisphere.

Increased EEG Current-Source Density in the High Beta Frequency Band Induced by Levetiracetam Adjunctive Therapy in Refractory Partial Epilepsy

BACKGROUND AND PURPOSE: Levetiracetam (LEV) is an antiepileptic drug (AED) that has favorable effects on cognition. Although neuropsychological studies have demonstrated these favorable outcomes on cognition, there are few electrophysiologic data describing the functional changes exerted by LEV. The purpose of this study was to determine the effects of LEV adjunctive therapy on the current-source density (CSD) in the high beta frequency band (22-30 Hz) of EEG background activity in refractory partial epilepsy (RPE). METHODS: We conducted a 24-week, open-label, prospective study in 24 patients with RPE. Scalp electroencephalography and neuropsychological tests (NPTs) were conducted twice, once before the LEV trial and then again after 24 weeks of medication. RESULTS: The CSD in the 22-30 Hz band of EEG background activity increased in the bilateral anterior cingulate gyri, left parahippocampal gyrus, and a small area of the right anterior parahippocampal gyrus after the LEV trial. Neither seizure freedom nor the dosage increment of LEV elicited meaningful CSD changes. Verbal memory and executive function were improved after the 24-week LEV trial. CONCLUSIONS: To our knowledge, this is the first study to examine the changes in CSD induced by LEV adjunctive therapy in RPE patients. The CSD changes and NPT results suggest that LEV enhances the activities of the neuronal networks in the prefrontal cortex and left hippocampus.

Current Source Analysis of Interictal Spikes in Two Patients With Gelastic Epilepsy-Hypothalamic Hamartoma Syndrome

BACKGROUND: Interictal spikes in gelastic epilepsy-hypothalamic hamartoma syndrome are mainly in the fronto-temporal area. Current source analysis of the interictal spikes has not been done enough. We tried the current source analysis in 2 patients with gelastic epilepsy-hypothalamic hamartoma syndrome using both of the discrete and distributed models. METHODS: Twenty 1 sec epochs including the negative peak of the spikes, were selected from one or two electroencephalographic recordings respectively in each patient. These 20 epochs were averaged into a single spike. The current dipole sources of the averaged spike were analyzed and located on a spherical head model. The current source density of the negative peak point of the averaged spike was located on the Talairach human brain map. RESULTS: The current dipole sources were in the right subcallosal gyrus, or the right or left anterior cingulate gyri. The current source density was distributed in the bilateral medial frontal area including the anterior cingulate gyri. CONCLUSIONS: The interictal spikes of patients with gelastic epilepsy-hypothalamic hamartoma syndrome may be generated by the current sources located in the bilateral medial frontal area.