4.Pollution characteristics and sources of PM2.5 during heating and non-heating periods in Urumqi City in 2021
LI Ting ; ZHANG Ying ; LI Er-shuai ; MA Yu-xi
China Tropical Medicine 2023;23(6):631-
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.
5.Encephalic lymphomatoid granulomatosis.
Li YU ; Zhen-Xi LIU ; Sha XIAO ; Cheng-Yi LUO
Chinese Journal of Pathology 2005;34(2):121-122
7.Early diagnostic indices for melioidosis:report of 49 cases
Rong LIN ; Xi LI ; Hai CHEN ; Anle YU
Journal of Third Military Medical University 2003;0(23):-
Objective To study the early diagnostic indices of melioidosis by analyzing 49 cases. Methods Unconditional logistic regression analysis was used to analyze the clinical data of 49 cases of melioidosis and 98 cases of bacterial pneumonia who were admitted in our hospital and Peoples' Hospital of Hainan Province from December 1996 to December 2007. Their social characteristic,background diseases,clinical manifestations,laboratory findings,radiologic examination and complications were studied. Results Background disease (such as diabetes),hepatosplenomegaly,septic shock,sepsis et al were the main causes of melioidosis. Conclusion Chills,fever,hepatosplenomegaly,diabetes mellitus,septic shock and sepsis are all factors that should be considered with melioidosis.
8.Mechanism of Antimicrobial Peptide Resistance
Fu CHEN ; Yu-Ping LUO ; Xi GONG ; Si-Guang LI ;
Microbiology 2008;0(11):-
Antimicrobial peptides are a class of small peptides with anti-extrogenous pathogen activities.They are derived from organism and possess antibacterial,antifungus,antiviruses and anticancer cell actions.In recent years,it’s found that some microbial pathogens are able to resist antimicrobial peptides.The constitutive and inducible mechanism of a pathogen resists a given peptide were reviewed in this paper.
9.Changes of Amplitude of Ion Channels Currents in Developing Hippocampal Neurons
zhen-biao, LI ; xi-ru, WU ; yu-wu, JIANG
Journal of Applied Clinical Pediatrics 2004;0(11):-
Objective To study the changes of the amplitude of ion channels currents in developing hippocampal neurons.Methods Using whole-cell patch-clamp techniques in cultured hippocampal neurons whose cultured day were 6 d and 16 d,respectively,changes of the amplitude of ion channels currents in developing hippocampal neurons were explored.Results Compared with the hippocampal neuron whose cultured day was 6 d,there were no statistical differences of the amplitude of voltage dependent sodium currents of hippocampal neuron whose cultured day was 16 d.The amplitude of voltage dependent potassium currents of hippocampal neuron whose cultured day was 16 d were significantly increased(P
10.Changes of N-Methyl-D-Aspartate-Receptor-Channels Current in Developing Hippocampal Neurons after Hypoxia and Effect of Adenosine Intervention
zhen-biao, LI ; xi-ru, WU ; yu-wu, JIANG
Journal of Applied Clinical Pediatrics 2004;0(12):-
Objective To study the changes of N-methyl-D-aspartate(NMDA)-receptor-channels current in developing hippocampal neurones during hypoxia and effect of adenosine intervention.Methods Whole-cell patch-clamp techniques cultured hippocampal neurons whose cultured day were 6 days and 16 days respectively,the amplitude of the NMDA-receptor-channels currents of hippocampal neuron were determined.And the effect of hypoxia on the NMDA-receptor-channels current,and adenosine regulatory mechanisms in cultured hippocampal neurons were explored.Results During hypoxia,compared with control group,the amplitude of the NMDA-receptorchannels currents of hippocampal neuron whose cultured day was 6 days were significantly increased(P