ABSTRACT
Background Printing and copying equipment is likely to release a large amount of particulate matter, thereby endangering human health. However, there is insufficient research on the level of particulate matter released by printers in offices and its influencing factors. Objective This study is designed to investigate the usage of printing equipment in college teachers' offices and the level of indoor particulate matter during printing, and to explore the influence of printer location and indoor ventilation on the particulate matter pollution level released during printer operation. Methods From 9:00 to 16:00 on January 4 to 6, 2021, 20 faculty offices in a university in Beijing were selected by convenient sampling to measure the indoor particulate matter level during printing, and to investigate the printing equipment usage of 31 users in the offices. Besides, experiments were designed to explore the influence of position and distance from a printer, ventilation, and the distance between a printer and a nearby window during ventilation on the number concentration of particulate matter released by the printers. Results Except one printer being placed on the ground, the other 30 printers were placed on office desks (0.71±0.16) m above the ground. Among them, 65% of the printers (n=20) were less than 1 m away from the users horizontally, and 74% of the users (n=23) accessed the printers 1-5 times a week, printing (7.03±4.07) pages per time. The peak mass concentrations in users' offices during printing of PM10, PM2.5, and PM1 were (21.96±12.96), (7.92±5.54), and (5.77±5.00) μg·m−3, respectively, and the peak number concentration of PM0.25−0.28 was (40941±36926) P·L−1. The experiments showed that when the particle sizer was located in the front, side, and back of the printers, the peak values of PM0.25−0.28 number concentration during printing were (24257±551), (12588±1354), and (11192±249) P·L−1, respectively, and the difference among them was statistically significant (F=214.9, P<0.01); when the particle sizer was placed 0.1, 0.2, and 0.3 m away from the printers, the peak values of PM0.25−0.28 number concentration during printing were (24257±551), (19847±1426), and (16480±878) P·L−1, respectively, and the difference among them was statistically significant (F=44.66, P<0.01); when the experiment room was ventilated or not, the peak values of PM0.25−0.28 number concentration during printing were (18595±488) and (24257±551) P·L−1, respectively, and the difference between them was statistically significant (F=192.6, P<0.01); when the distance between the printer and the window was 1, 2, 3 m, the peak values of PM0.25-0.28 number concentration during printing were (16780±823), (18347±348), and (18595±488) P·L−1, respectively, and the difference among them was statistically significant (F=8.407, P<0.05). Conclusion The overall printer workload is small and the concentration of particulate matter in the faculty offices is low when the printers are working. Printer position, distance, ventilation, and the distance from a nearby window under ventilation conditions are factors affecting the concentration of particulate matter released by the printers.
ABSTRACT
Objective To study the relationship between the changes of ten elemental contents in serum and schizophrenia.Methods Calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe), aluminum (Al), arsenic (As), selenium (Se), copper (Cu), lead (Pb), manganese (Mn) in serum in the of schizophrenic patients and normal subjects are measured by inductively coupled plasma mass spectrometer and inductively coupled plasma emission spectrometer, compared the content of elements between the schizophrenia and normal.Results There were significant differences ( P<0.05) in other elements between two groups except lead.The contents of Ca,Fe,Mg,Zn,As,Se,Cu in the patients with schizophrenia were significantly lower than those in control, while Al, Mn were significantly higher than those in control.Most of elements in serum between case and control groups were correlated (P<0.05).Some of element ratios which have physiological significance were significant statistically (P<0.05), such as: Ca/Mg, Ca/Fe and so on.Conclusion These findings suggest that the patients with schizophrenia might have an abnormal elemental metabolism.Given the relationship among the elements, the element ratios are more valuable in reflecting the relationship between schizophrenia and elements.
ABSTRACT
<p><b>OBJECTIVE</b>This study attempts to test the total amount of 41 inorganic elements in traditional Chinese medicine materials (TCMM), to analyze to surpass the set standard of 5 toxic heavy metal elements and to explore possible method of modification.</p><p><b>METHOD</b>By using microwave as digestion tool, ICP-MS and ICP-AES as detective instrument, 41 elements in 466 samples are tested. While the amount of elements Al, Ca, Fe, K, Mg, Mn, P, S, Sr are determined by ICP-AES, the amount of the rest 32 elements are determined by ICP-MS. SPSS 16.0 is used as the statistical tool for data analysis.</p><p><b>RESULT</b>Testing of reference material Astragalus showed that the measurements of each element are within the reference range, and except for element I, RSD of determination for each element is less than 10%, thus the accuracy and precision of the study method is confirmed. Using above mentioned instruments and methods, general information of elements in 466 TCMM are obtained.</p><p><b>CONCLUSION</b>The concentrations of each elements in TCMM varied a lot and are different among each TCMM. The over standard rate of 5 heavy metal elements are lower than previous results, however, the over standard rate is still descending in the order of Cd > Cu > Pb > As > Hg. The content of heavy metal elements in TCMM varies among different areas, especially, over standard of heavy metals are not detected in locality as Gansu, Qinghai, Shanxi, Xinjiang and Hainan provinces.</p>