[Water-soluble Inorganic Ion Content of PM2.5 and Its Change Characteristics in Urban Area of Beijing in 2022].

To explore the content and variation characteristics of water-soluble ions of atmospheric fine particles (PM2.5) in a Beijing urban area and put forward the pollution prevention and control scheme, the water-soluble ions, gaseous precursors (SO2, NO2), and meteorological factors (temperature, RH) of PM2.5 in 2022 were analyzed and determined. The results showed that the water-soluble ions with the highest proportion in PM2.5 in the Beijing City urban area were NO3-, NH4+, and SO42-, accounting for 52.7% of PM2.5. The mass concentrations of PM2.5 and SNA were lower than the historical results, whereas the proportion of SNA, SOR, and NOR was higher than the historical results. This showed that the fine particulate matter pollution in Beijing has been significantly improved, but it still has strong secondary pollution characteristics. NO3-/SO42-(2.2) was higher than those of historical and nearby provinces and cities, reflecting the expanding influence of mobile sources. In terms of seasonal variation, PM2.5 showed the characteristic of high in autumn and low in summer. The proportion of NO3- was the highest in autumn, spring, and winter; the proportion of SO42- was the highest in summer; and the proportion of NH4+ changed little in each season. The seasonal variation rules of NOR and SOR were almost opposite, which reflected the difference in transformation factors between NOR and SOR. The main forms of SNA in the Beijing urban area were NH4NO3 and (NH4)2SO4. The neutralization degree of cations and anions was the highest in winter, the cation NH4+ was slightly insufficient in summer, and NH4+ was in excess in spring and autumn. The Beijing urban area was an ammonia-rich environment. In terms of pollution level, RH, particulate matter moisture, and water-soluble ions mass concentration all increased with the increase in pollution level, and SNA increased fastest, with its proportion in PM2.5 increasing first and then stabilizing, whereas the contribution rate of other water-soluble ions decreased gradually. In terms of spatial distribution, the mass concentration relationship of SNA at the central urban area and suburbs was NO3- > SO42- > NH4+, which reflected the pollution characteristics dominated by NO3-. The highest contribution rate of SNA to PM2.5 occurred in the eastern region, the central urban area, and the transmission point, indicating that the secondary reaction was relatively active in the central urban area and the eastern region, and the regional transport was also an important source of secondary ions.

[Characteristics and Source Apportionment of VOCs Initial Mixing Ratio in Beijing During Summer].

To clarify the characteristics and source apportionment of the VOCs initial mixing ratio in Beijing in summer, continuous monitoring of VOCs was conducted in the Beijing urban area from May to August 2022, and the initial mixing ratio was calculated using the photochemical ratio method. The results showed that:① during the study period, initial φ(TVOCs) in the Beijing urban area were (30.0 ±11.5)×10-9, in which the proportion of VOCs and alkanes containing oxygen reached 34.2% and 33.2%, respectively. The species with high volume fractions were low carbon substances such as acetone, ethane, acetaldehyde, and propane. ② The initial TVOCs mixing ratio in Beijing showed a slightly unimodal trend, reaching the peak at 11:00 and slightly decreasing in the afternoon. ③ Isoprene, acetaldehyde, n-butanal, and ethylene were the major contributors to the generation of O3, whereas toluene, isoprene, m-paraxylene, and ethylbenzene were the major contributors to the generation of secondary organic aerosols. ④ Based on the initial mixing ratio of PMF analysis, it was found that aging background and secondary sources (30%) contributed the most to VOCs in Beijing, and motor vehicle sources (25%) were the main primary human sources. In addition, solvent and fuel volatile sources contributed 16%, combustion sources contributed 11%, industrial process sources contributed 9%, and natural sources contributed 9%. ⑤ The anthropogenic sources of Beijing were mainly from the eastern and southern regions, whereas the natural sources were from the western and northwestern regions. This research showed that vehicle emissions should be further reduced, and regional joint prevention and control to reduce VOCs in the whole region is an effective means to control VOCs in Beijing.

[Characteristics and Sources of PM2.5 and Its Light-scattering Properties with Different Chemical Compositions in Urban Area of Beijing].

In recent years, the concentration of PM2.5 in the Beijing urban area has decreased with the increase in the proportion of secondary inorganic ions. In order to explore the characteristics and sources of the light scattering of PM2.5 with different chemical compositions, PM2.5 with its chemical components and scattering coefficient were continuously measured at hourly resolution in the Beijing urban area from December 2020 to November 2021. The components, scattering characteristics, and sources of PM2.5 were analyzed. The results showed that NO3- was the major component of PM2.5 in the Beijing urban area, and the ω(NO3-) and ω(SNA) were 24% and 46% in PM2.5, respectively. PM2.5 could be divided into six types according to mass concentration and component proportion. The occurrence frequency of the good-type was the highest during the study with a similar duration in the four seasons, and the ω(SNA), ω(OM), and ω(FS) were 32%, 32%, and 28% in PM2.5, respectively. The dust(D)-type and the OM(O)-type appeared mainly in spring and summer with the lowest frequency during the study. FS and OM were their major components, and the ω(FS) and ω(OM) were 66% and 46% in PM2.5, respectively. The OM+SO42-(OS)-type, OM+NO3-(ON)-type, and NO3-(N)-type appeared mainly in the afternoon in summer, in the early morning and morning in winter, and at approximately 07:00 every day in spring. Under the condition of low humidity[relative humidity (RH)<40%], the MSE of N-type PM2.5 was the highest (4.3 m2·g-1), and that of D-type PM2.5 was the lowest (2.1 m2·g-1), reflecting the high scattering ability of SNA. The MSE increased with relative humidity. Under the condition of high humidity (RH>80%), the MSE of all types of PM2.5 rose to 1.5 to 1.8 times the values under low humidity. The variation trends of SAE showed that particle size increased with the rising of RH level. Under non-high humidity conditions, the scattering coefficients reconstructed by the revised IMPROVE formula fitted well with the measured values at hourly resolution, the correlation coefficients were between 0.81 and 0.97, and the slopes were between 1.00 and 1.21 except for that of D-type. The N-type fitting result was the best. Under high-humidity conditions, the R and the slopes were from 0.82 to 0.84 and from 0.48 to 0.53, respectively. The annual Bsca was 203.8 Mm-1, and N-type PM2.5 contributed the most, accounting for 53%, in which the large particles of NH4NO3 were the major contributor. Bsca of good-type PM2.5 was 67.2 Mm-1, in which small particles of OM were the major contributor. Bsca was 1.5 times the annual Bsca(dry), whereas the Bsca values of SNA were 1.8 to 2.1 times the Bsca(dry). The peak value of NO3- and RH simultaneously appeared around 07:00, resulting in the maximum Bsca of NH4NO3 at this time. The peak value of SO42- and the Bsca of (NH4)2SO4 mainly appeared at 16:00 and at 04:00, respectively. The diurnal variation curves of OM concentration and Bsca were consistent, and the bimodal peaks appeared at 13:00 and 20:00, respectively. In spring and winter, NO3-, SO42- and OM mainly came from the plains east of the Taihang Mountains, and their potential source regions were not in any particular place in summer and autumn; the main potential source regions of FS were the northwest areas of Beijing in spring and autumn. The flow with high RH across the south and southeast of the north China plain and the eastern rim of Bohai Sea was likely to increase the weighted potential source contribution factor values of Bsca of SNA in this region.

[Soil organic carbon density and its influencing factors in croplands with different cultivation years in the Northeastern Ulan Buh Desert, China]. / ä¹Œå °å¸ƒå’Œæ²™æ¼ ä¸œåŒ—éƒ¨ä¸åŒè€•ä½œå¹´é™å†œç”°åœŸå£¤æœ‰æœºç¢³å¯†åº¦åŠå ¶å½±å“å› ç´ .

Understanding the changes and influencing factors of soil organic carbon density (SOCD) during the conversion of uncultivated natural soil to croplands is of great significance for the assessment of carbon sequestration in arid areas. In this study, we compared SOCD in the uncultivated soil and that in croplands with different cultivation years (2-5, 12-15, 25-30, 40-50 years) in the Northeastern Ulan Buh Desert. The change of SOCD and its influencing factors at 0-2 m soil depth during the conversion of uncultivated natural soil to croplands were explored by the method of replacing time with space. The results showed that SOCD at the shallow soil depth (0-0.4 m) in croplands increased continuously with cultivation years, but basically at low levels (0.990-1.983 kg·m-2). The SOCD at deep soil (1.2-2 m) increased in the croplands with longer cultivation years (25-30 and 40-50 years), whereas no obvious change trends in both the croplands with shorter cultivation years (2-5 and 12-15 years) and the uncultivated natural soil. The SOCD at deep soil (1.2-2 m) were relatively large (28.9%-38.6%) of the 0-2 m soil depth of uncultivated natural soil and croplands with different cultivation years. The vertical distribution of SOCD in croplands with different cultivation years were well fitted by quadratic functions (with R2 ranging from 0.757 to 0.972). It was noteworthy that soil clay and silt contents had dominant influences on SOCD at all the soil profile (0-2 m), and that cultivation years mainly contributed to the accumulation of SOC at the shallow soil (0-0.4 m).

[Distribution and sequestration of straw carbon in surface and deep soil aggregates under different fertilization treatments]. / ä¸åŒæ–½è‚¥æ¡ä»¶ä¸‹ç§¸ç§†ç¢³åœ¨è¡¨å±‚å’Œæ·±å±‚åœŸå£¤å›¢èšä½“ä¸­çš„åˆ†é ä¸Žå›ºå­˜.

Long-term fertilization causes the differences in water, heat, nutrients and microbial activities between topsoil and deep soil, with consequences on the decomposition and turnover of straw carbon (C) in soils. At a long-term positioning experimental station in Shenyang Agricultural University, we mixed the topsoil (0-20 cm) and deep soil (40-60 cm) samples from different fertilization treatments with 13C-labeled straw for in-situ incubation. We analyzed the content of organic C and its δ13C value in soil aggregates, compared the difference in the distribution of straw C between topsoil and deep soil aggregates, and explored the effects of fertilization on the sequestration of straw C in soil aggregates. Compared with fertilization treatments (i.e., single chemical nitrogen fertilizer application and combination of organic manure with nitrogen fertilizer application), the treatment without fertilization increased the content of straw C of <0.053 mm aggregate in the topsoil by 106.7% and that of >0.25 mm aggregate in the deep soil by 34.2%. The contribution percentage of straw C to organic C of >0.053 mm aggregate in the deep soil was about two times of that in the topsoil. About 22.6% and 11.4% of straw C was distributed into the >0.25 mm and <0.25 mm aggregates of topsoil, and about 29.4% and 8.8% of straw C was distributed into the >0.25 mm and <0.25 mm aggregates of deep soil, respectively. In conclusion, straw addition promoted the regeneration and sequestration of carbon in deep soil macroaggregates and increased the carbon sequestration potential of deep soil.

[Effect of nitrogen additions on soil pH, phosphorus contents and phosphatase activities in grassland]. / æ°®æ·»åŠ å¯¹è‰åœ°ç”Ÿæ€ç³»ç»ŸåœŸå£¤pHã€ç£·å«é‡å’Œç£·é ¸é ¶æ´»æ€§çš„å½±å“.

Phosphorus is a key nutrient for all plant species and a limiting factor for grassland ecosystem function. In recent years, in response to the rapid increase of global nitrogen deposition, soil phosphorus contents and phosphatase activities changed to varying degrees in grassland ecosystems. We conducted a meta-analysis to examine the responses of soil pH, total phosphorus (TP), available phosphorus (AP), as well as activities of alkaline phosphatase (AlP) and acid phosphatase (AcP) in soils to nitrogen addition amount, nitrogen type, experimental duration, and sampling depth. The correlation between soil pH and phosphatase response ratio was investigated. The results showed that nitrogen addition significantly reduced soil pH, TP and AlP activity, while significantly increased AcP activity, but had no significant effect on AP. Soil pH and AlP activity significantly decreased under nitrogen addition >5 g·m-2·a-1, and AcP activity significantly increased under high nitrogen addition (>10 g·m-2·a-1). The contents of TP and AP significantly decreased when nitrogen addition was 5-10 g·m-2·a-1. NH4NO3 treatment significantly reduced soil TP and increased AcP activity, while urea treatment significantly reduced soil pH and AlP activity. Across all nitrogen addition amounts, when the experiment duration was 3 to 10 years, soil TP content and AlP activity were significantly reduced. Soil pH was significantly reduced after three years nitrogen addition, and AcP activitiy was significantly increased after 10 years nitrogen addition. In the 0-10 cm soil layer, the TP content and AlP activity significantly decreased, while the AP content significantly increased. In >10 cm soil layer, the AP content was significantly decreased. The significant negative correlation between soil pH and AcP activity indicated that change in soil pH caused by nitrogen addition may be an important factor for the variation of soil phosphatase activity.

[Effects of long-term fertilization on soil ammonia-oxidizing microorganisms]. / 长期施肥对土壤氨氧化微生物的影响.

Long-term fertilization can change the supply of soil carbon and nitrogen (N), with consequences on the abundance and community structure of soil microorganisms. Based on the long-term fertilization positioning experiment station of brown earth, we analyzed the dynamics of soil ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) under different fertilization treatments, including no fertilization (CK), low level of inorganic N fertilizer (N2), high level of inorganic N fertilizer (N4), and organic manure combined with inorganic N fertilizer (M2N2), aiming to provide a basis for microbiological mechanism of soil N transformation and improvement of soil fertility. The results showed that the ratio of AOA to AOB abundance was 2.28-61.95 under different fertilization treatments. Compared with that in CK, the AOA abundance was reduced by 1.6%-13.6% after long-term fertilization. The abundance of AOB in N4 treatment decreased first and then increased with soil depths, but with contrary results in other treatments. The Shannon diversity index (H), evenness index (J), and Simpson index (S) of AOB were higher than those of AOA. The AOB diversity was increased at 0-20 cm soil layer in M2N2 treatment, while that of AOA was decreased. Soil AOB clustered with soil depths, and neither AOA nor AOB community clustered with fertilization treatments. In summary, long-term fertilization altered the composition of AOA and AOB. AOA was sensitive to environment, whereas AOB was more abundant and stable.

Threshold for maximal electroshock seizures (MEST) at three developmental stages in young mice.

Early brain development after birth is extremely dynamic, suggesting that potential functional changes occur during this period. In this study, the maximal electroshock seizure threshold (MEST) was used to explore the electrophysiological variation among three developmental stages in young mice (no more than 5 weeks old). The induced electroshock seizure (ES) behavior of early postnatal mice (1-2-weeks old) differed from that during weaning (3 weeks old) and early puberty (4-5-weeks old). Thus, we further explored their respective characteristic responses to the ES parameters. When the stimulation current (SC) was limited to 4.0 mA, only the 1-2-week-old mice were induced to exhibit ES behavior at voltages of 30 V and 40 V, indicating they were more sensitive to maximal electroshock seizure (MES) (response to lower voltage). Surprisingly, however, they showed substantially lower mortality than the older groups under higher voltage conditions (60, 100, 160, and 200 V), suggesting better tolerance to the SC. We also found that when the current limit decreased to 3.5 mA, the 4-5-week-olds mice exhibited stable ES behavior with low mortality, while for 3-week-olds mice, the SC limit required to be reduced to 1.5 mA. In conclusion, our findings showed that neural sensitivity to MES was significantly different in young mice before puberty. Thus, greater attention should be given to distinguishing the developmental period of mice, especially in electrophysiological examination.

[Water use strategy of Tamarix chinensis during a drought year in the coastal wetlands of the Yellow River Delta, China]. / 黄河三角洲海岸带湿地柽柳在干旱年份的水分利用策略.

Tamarix chinensis, the dominant species of plant communities in the coastal wetlands of the Yellow River Delta, was selected to study the water use strategy of coastal plants at different habitats during a drought year. The Δ18O values for xylem water of T. chinensis were analyzed. Potential contributions by different water sources to T. chinensis were estimated using the IsoSource model. The contributions were analyzed to reveal the adaptation mechanism of T. chinensis to water stress at different habitats. The results showed that the main water sources for T. chinensis during a drought year were soil water and groundwater rather than precipitation. However, the water use strategies of T. chinensis changed significantly with different micro-topographies. For dune crests, 72.6%-95.4% water of T. chinensis came from deeper soil water (40-100 cm) and groundwater. However, near the high tide line, T. chinensis absorbed 40.7%-97.3% of the water from the upper soil (0-40 cm) to avoid the salt stress caused by sea water and shallow groundwater. This provided T. chinensis with a competitive advantage related to water consumption and improved its water use efficiency in the coastal ecosystem, which led to mono-dominant shrub community of T. chinensis in this area.

Neurons Differentiated from Transplanted Stem Cells Respond Functionally to Acoustic Stimuli in the Awake Monkey Brain.

Here, we examine whether neurons differentiated from transplanted stem cells can integrate into the host neural network and function in awake animals, a goal of transplanted stem cell therapy in the brain. We have developed a technique in which a small "hole" is created in the inferior colliculus (IC) of rhesus monkeys, then stem cells are transplanted in situ to allow for investigation of their integration into the auditory neural network. We found that some transplanted cells differentiated into mature neurons and formed synaptic input/output connections with the host neurons. In addition, c-Fos expression increased significantly in the cells after acoustic stimulation, and multichannel recordings indicated IC specific tuning activities in response to auditory stimulation. These results suggest that the transplanted cells have the potential to functionally integrate into the host neural network.

[Comparison Test Between On-line Monitoring of Water-soluble Ions and Filter-based Manual Methods for PM2.5].

Concentrations of water-soluble ions were measured in Beijing during 2014 for comparison of URG online monitoring systems and filter-based manual methods. The differences of four main ions components in spring, summer, autumn and winter were compared. The total concentrations of eight ions measured by URG online were higher than those of filter-based manual method. There was no significant differences among the annual concentrations of Cl-,NO3-,Mg2+ and Ca2+ obtained by the two methods, while the concentrations of SO42-,NH4+,Na+,K+ from online were higher than those from filter. NO3-,SO42-,Cl- had good correlations in autumn and winter, and NH4+ only had better fitting performance in winter.

[Distribution and enrichment characteristics of organic carbon and total nitrogen in mollisols under long-term fertilization].

The characteristics and changes of soil organic carbon (SOC) and total nitrogen (TN) in different size particles of soil under different agricultural practices are the basis for better understanding soil carbon sequestration of mollisols. Based on a 31-year long-term field experiment located at the Heilongjiang Academy of Agricultural Sciences (Harbin) , soil samples under six treatments were separated by size-fractionation method to explore changes and distribution of SOC and TN in coarse sand, fine sand, silt and clay from the top layer (0-20 cm) and subsurface layer (20-40 cm). Results showed that long-term application of manure (M) increased the percentages of SOC and TN in coarse sand and clay size fractions. In the top layer, application of nitrogen, phosphorus and potassium fertilizers combined with manure (NPKM) increased the percentages of SOC and TN in coarse sand by 191.3% and 179.3% compared with the control (CK), whereas M application increased the percentages of SOC and TN in clay by 45% and 47% respectively. For subsurface layers, the increase rates of SOC and TN in corresponding parts were lower than that in top layer. In the surface and subsurface layers, the percentages of SOC storage in silt size fraction accounted for 42%-63% and 48%-54%, TN storage accounted for 34%-59% and 41%-47%, respectively. The enrichment factors of SOC and TN in coarse sand and clay fractions of surface layers increased significantly under the treatments with manure. The SOC and TN enrichment factors were highest in the NPKM, being 2.30 and 1.88, respectively, while that in the clay fraction changed little in the subsurface layer.

Divergence of dim-light vision among bats (order: Chiroptera) as estimated by molecular and electrophysiological methods.

Dim-light vision is present in all bats, but is divergent among species. Old-World fruit bats (Pteropodidae) have fully developed eyes; the eyes of insectivorous bats are generally degraded, and these bats rely on well-developed echolocation. An exception is the Emballonuridae, which are capable of laryngeal echolocation but prefer to use vision for navigation and have normal eyes. In this study, integrated methods, comprising manganese-enhanced magnetic resonance imaging (MEMRI), f-VEP and RNA-seq, were utilized to verify the divergence. The results of MEMRI showed that Pteropodidae bats have a much larger superior colliculus (SC)/ inferior colliculus (IC) volume ratio (3:1) than insectivorous bats (1:7). Furthermore, the absolute visual thresholds (log cd/m(2)•s) of Pteropodidae (-6.30 and -6.37) and Emballonuridae (-3.71) bats were lower than those of other insectivorous bats (-1.90). Finally, genes related to the visual pathway showed signs of positive selection, convergent evolution, upregulation and similar gene expression patterns in Pteropodidae and Emballonuridae bats. Different results imply that Pteropodidae and Emballonuridae bats have more developed vision than the insectivorous bats and suggest that further research on bat behavior is warranted.

[Characterization of Water-soluble Ions in PM2.5 of Beijing During 2014 APEC].

The mass concentration of PM2.5 associated with its online and off-line water-soluble ions were obtained during 2014- 10- 2014-11. Secondary inorganic species NO3⁻, SO4²â» and NH4⁺ were the major components of PM2.5 during different observation periods. The total concentration of NO3⁻, SO4²â» and NH4⁺ was (26.8 ± 22.5) µg · m⁻³, which contributed (41.7 ± 8.5)% to PM2.5. The concentration of NO3⁻ was higher than those of others and contributed most to PM2.5. The ions of NO3⁻, SO4²â» NH4⁺ and Cl⁻ all showed three different periods during 2014 Beijing APEC, besides the different meteorological condition, the cumulative effect caused by local emissions and regional pollution could also not be ignored. Although the characteristics of water-soluble ions was different during different observation periods, there was no obvious acidification of PM2.5 in Beijing at the end of autumn and beginning of winter.

Clinical and radiographic predictors in diagnosing sputum smear-negative pulmonary tuberculosis in HIV-negative patients: a cross-sectional study in China.

BACKGROUND: In county-level tuberculosis (TB) dispensaries in China, the accurate diagnosis of sputum smear-negative pulmonary tuberculosis (SNPT) needs to be improved by developing and validating clinical and radiographic predictors. METHODS: The study was conducted simultaneously in three counties per province in Chongqing Municipality and Liaoning Province in China between May 2005 and May 2006. A total of 432 new SNPT patients who are HIV-negative and more than 15 years old diagnosed by expert panels in county-level TB dispensaries were recruited. Their sputum samples were collected for culture before anti-TB treatment, and the treatment outcomes (changes of X-rays) were followed up at the end of the 6th month. RESULTS: Of the 432 SNPT patients, sputum culture positive (9.7%) or culture negative with good changes of X-rays at the end of the 6th month (73.6%) was validated as SNPT. Four predictive variables were associated with validated SNPT in the multivariate logistic regression model: age ≤55 years old (odds ratio (OR) 5.66; 95% CI 2.69-11.91), >60 days of cough (OR 3.73; 95% CI 1.10-12.65), ≥10% of pulmonary consolidation in the lungs (OR 5.40; 95% CI 2.90-10.06), and pulmonary consolidation in the upper lobe anterior segment (OR 3.00; 95% CI 1.57-5.72). The area under the receiver operating characteristic curve of the model was 0.77 (95% CI 0.71-0.83). CONCLUSION: Four predictors of clinical and radiological characteristics that had a good diagnostic performance of SNPT deserve to be recommended as index indicators of SNPT diagnosis in county-level TB dispensaries in China.

[Spatial distribution characteristics of Fe and Mn contents in the new-born coastal marshes in the Yellow River estuary].

The spatial distribution characteristics of Fe and Mn contents in soils of nine different vegetation communities, located in the new-born marshes of the northern Yellow River estuary, were studied in May 2009. The results showed that the horizontal distributions of Fe and Mn contents showed an increasing tendency from Sparganiaceae-Potentilla supina marsh to bare flat. The vertical distribution characteristics of Fe and Mn contents in different marsh soils fluctuated significantly with the vegetation succession. The soil parent materials determined the Fe, Mn contents in the new-born marshes, and seawater, vegetations and soil fine particle also had important influences on their contents. Further analysis showed that Fe contents had significant positive correlation with Mn contents (P < 0.01). Fe, Mn contents also showed significant correlations with silt, clay, TN, NO3(-) -N and organic matter (P < 0.05), indicating that Fe and Mn had close relationships with nitrogen, and the contents of soil fine particles and organic matter were the dominant factors affecting the distribution of Fe and Mn in soils. In addition, the Fe contents ranged from 16.49 g x kg(-1) to 33.11 g x kg(-1) and the average was 22.54 g x kg(-1), which was close to the Fe contents in the tidal marshes of north Jiangsu, the Loess Plateau and the China soil background value, but slightly lower than those in the marshes of the Yangtse River estuary, the mangrove swamps and inland lake wetland. The Mn contents ranged from 305.87 mg x kg(-1) to 711.39 mg x kg(-1) and the average was 451.09 mg x kg(-1), which was lower than the Mn contents in the Loess Plateau and the China soil background value. Hydrology and Water Resources Survey Bureau of the Yellow River Estuary, Dongying 257091, China)

[Study of arsenic concentration and distribution in shell sand of the shell ridge islands by hydride generation atomic fluorescence spectrometry].

The present paper determined the As concentration in shell sand of the shell ridge islands by hydride generation atomic fluorescence spectrometry, studied the distribution of As in shell sand of the shell ridge islands, analysed the correlations of As with other nutrient elements, and discussed the probably influencing factors affecting the As concentration and distribution in shell sand. The results showed that the range of the arsenic concentration in shell sand is between 0.78 and 8.76 mg x kg(-1), the average concentration is 3.11 mg x kg(-1), and this indicated that the As contamination of the shell ridge island is in clean level. The As concentration of the shell sand has a increasing trend followed by the increase with profile depth or the decrease with the particle size, and the difference in As concentrations in shell sand of different particle sizes reached the significant level (p < or = 0.05). The As concentration in shell sand has a very significant positive correlation with the concentrations of Cu, Zn and Mn as well as the TP and TK, whereas the correlations between As and TN or Fe are not significant. The pollutant of As in the shell sand mainly comes from the absorption and fixation by shell sand from the environment but not the accumulation of the shell organism during their growing up.

[Glaucoma model for stem cell transplantation research in New Zealand white rabbits].

Glaucoma is a typical irreversible blind neurodegenerative disease for which there is no effective treatment for halting visual deterioration. The recent development of neural stem cells studies sheds light on a potential resolution for this disease. As a result, an appropriate glaucoma modeling method for stem cell transplantation study is needed. In the present study, Dexamethasone was injected unilaterally into the conjunctiva of New Zealand rabbit at the dose of 2.5 mg (5 mg/mL), three times a week. After eight weeks, the eye ground photography showed that the optic nerve head of the treated eye was expanded, and the blood vessel was geniculate compared to the control eye, while the ocular media remained transparent. The hematoxylin-eosin (HE) stain of the retinal nerve fiber layer (RNFL) sections showed optic neuron death in the treated eye. The Heidelberg Retina Tomography (HRT) results showed optic disk morphological changes consistent with the pathophysiology of glaucoma in the treated eye, including a decrease in the rim area (1.10±0.88) mm(2) and mean RNFL thickness (0.44±0.31) mm, and an increase in the cup/disk ratio 0.17±0.13. Then neural stem cells were injected into the vitreous body of the treated eye. After five months, surviving transplanted cells were observed. These results suggest a simple and reproducible chronic glaucoma model, which is appropriate for neural stem cell transplant research, has been successfully developed.

[Overview of acupuncture and moxibustion application in Kuwait].

To introduce the overview of acupuncture and moxibustion application in Kuwait. All kinds of pain diseases were mainly treated by acupuncture and moxibustion; lumbar disc herniation, cervical spondylosis and knee arthritis were frequently occurred, which were related to the local life styles. Acupuncture and moxibustion therapy was effective for these diseases above and accepted by the locals. The author suggests that it should further spread advantages of acupuncture and moxibustion, develop acupuncture and moxibustion methods, import Chinese herb and enhance the quality of dispatched person, in order to extend the therapeutic range of acupuncture and moxibustion.