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791.
Whales repetitively dive deep to feed and should be susceptible to decompression syndrome, though they are not known to suffer the associated pathologies. Avascular osteonecrosis has been recognized as an indicator of diving habits of extinct marine amniotes. Vertebrae of 331 individual modern and 996 fossil whales were subjected to macroscopic and radiographic examination. Avascular osteonecrosis was found in the Oligocene basal odontocetes (Xenorophoidea) and in geologically younger mysticetes, such as Aglaocetus [a sister taxon to Balaenopteridae + (Balaenidae + Eschrichtiidae) clade]. These are considered as early "experiments" in repetitive deep diving, indicating that they independently converged on their similar specialized diving physiologies. 相似文献
792.
Measurement of flow speed in the channels of novel threadlike structures on the surfaces of mammalian organs 总被引:1,自引:0,他引:1
There have been several reports on novel threadlike structures (NTSs) on the surfaces of the internal organs of rats and rabbits
since their first observation by Bonghan Kim in 1963. To confirm this novel circulatory function, it is necessary to observe
the flow of liquid through the NTS as well as the structurally corroborating channels in the NTS. In this article, we report
on the measurement of the flow speed of Alcian blue solution in the NTSs on the organ surfaces of rabbits, and we present
electron microscopic images depicting the cribrous cross-section with channels. The speed was measured as 0.3 ± 0.1 mm/s,
and the flow distance was up to 12 cm. The flow was unidirectional, and the phase contrast microscopic images showed that
the NTSs were strongly stained with Alcian blue. The ultrastructure of the NTSs revealed by cryo-scanning electron microscopy
and high-voltage electron microscopy showed that (1) there were cell-like bodies and globular clumps of matter inside the
sinus of the channel with thin strands of segregated zones which is a microscopic evidence of the liquid flow, (2) the sinuses
have wall structures surrounded with extracellular matrices of collagenous fibers, and (3) there exists a cribriform structure
of sinuses. To understand the mechanism for the circulation, a quantitative analysis of the flow speed has been undertaken
applying a simplified windkessel model. In this analysis, it was shown that the liquid flow through the NTSs could be due
to peristaltic motion of the NTS itself.
Baeckkyoung Sung and Min Su Kim contributed equally to this work. 相似文献
793.
Application of ferrate(VI) in the treatment of industrial wastes containing metal-complexed cyanides : A green treatment 总被引:2,自引:0,他引:2
Ferrate(VI) was employed for the oxidation of cyanide (CN) and simultaneous removal of copper or nickel in the mixed/complexed
systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN (1.00 mmol/L) and removal of Cu (0.095 mmol/L) were investigated
as a function of Fe(VI) doses from 0.3–2.00 mmol/L at pH 10.0. It was found that Fe(VI) could readily oxidize CN and the reduction
of Fe(VI) into Fe(III) might serve e ciently for the removal of free copper ions. The increase in Fe(VI) dose apparently favoured the
CN oxidation as well as Cu removal. Moreover, the pH dependence study (pH 10.0–13.0) revealed that the oxidation of CN was almost
una ected in the studied pH range (10.0–13.0), however, the maximum removal e ciency of Cu was obtained at pH 13.0. Similarly,
treatment was carried out for CN-Ni system having the initial Ni concentration of 0.170 mmol/L and CN concentration of 1.00 mmol
with Fe(VI) dose 2.00 mmol at various pH values (10.0–12.0). Results showed a partial oxidation of CN and partial removal of Ni. It
can be observed that Fe(VI) can partially degrade the CN-Ni complex in this pH range. Further, Fe(VI) was applied for the treatment
of simulated industrial waste/e uent waters treatment containing CN, Cu, and Ni. 相似文献
794.
795.
MiSeon Lee GeunAe Park MinJi Park JongYoon Park JiWan Lee SeongJoon Kim 《环境科学学报(英文版)》2010,22(6):826-833
This study evaluated the reduction e ect of non-point source pollution by applying best management practices (BMPs) to a 1.21 km2
small agricultural watershed using a SWAT (Soil andWater Assessment Tool) model. Two meter QuickBird land use data were prepared
for the watershed. The SWAT was calibrated and validated using daily streamflow and monthly water quality (total phosphorus (TP),
total nitrogen (TN), and suspended solids (SS)) records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcli e
model e ciency was 0.63 for the streamflow and the coe cients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP,
respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian bu er system, the regulation of Universal
Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed. 相似文献
796.
Ku-Fan Chen Chih-Ming Kao Chiu-Wen Chen Rao Y. Surampalli Mu-Sheng Lee 《环境科学学报(英文版)》2010,22(6):864-871
In the first phase of this study, the e ectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was
evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene,
ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate,
and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased
methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study,
enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface
near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that
enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume
to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced
aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron,
sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage
of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased
from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the
downgradient area (located approximately 300 m from the source area). 相似文献
797.
Natarajan Velmurugan Grim Hwang Muthuswamy Sathishkumar Tae Kie Choi Kui-Jae Lee Byung-Taek Oh Yang-Soo Lee 《环境科学学报(英文版)》2010,22(7):1049-1056
A heavy metal contaminated soil sample collected from a mine in Chonnam Province of South Korea was found to be a source
of heavy metal adsorbing biosorbents. Chemical analyses showed high contents of lead (Pb) at 357 mg/kg and cyanide (CN) at 14.6
mg/kg in the soil. The experimental results showed that Penicillium sp. MRF-1 was the best lead resistant fungus among the four
individual metal tolerant fungal species isolated from the soil. Molecular characterization of Penicillium sp. MRF-1 was determined
using ITS regions sequences. E ects of pH, temperature and contact time on adsorption of Pb(II) by Penicillium sp. MRF-1 were
studied. Favorable conditions for maximum biosportion were found at pH 4 with 3 hr contact time. Biosorption of Pb(II) gradually
increased with increasing temperature. E cient performance of the biosorbent was described using Langmuir and Freundlich isotherms.
Adsorption kinetics was studied using pseudo first-order and pseudo second-order models. Biosorbent Penicillium sp. MRF-1 showed
the maximum desorption in alkali conditions. Consistent adsorption/desorption potential of the biosorbent in repetitive cycles validated
the e cacy of it in large scale. SEM studies given notes on surface modification of fungal biomass under metal stress and FT-IR results
showed the presence of amino groups in the surface structure of the biosorbent. In conclusion, the new biosorbent Penicillium sp.
MRF-1 may potentially be used as an inexpensive, easily cultivatable material for the removal of lead from aqueous solution. 相似文献
798.
Technology and teen drivers 总被引:1,自引:0,他引:1
Lee JD 《Journal of Safety Research》2007,38(2):203-213
The rapid evolution of computing, communication, and sensor technology is likely to affect young drivers more than others. The distraction potential of infotainment technology stresses the same vulnerabilities that already lead young drivers to crash more frequently than other drivers. Cell phones, text messaging, MP3 players, and other nomadic devices all present a threat because young drivers may lack the spare attentional capacity for vehicle control and the ability to anticipate and manage hazards. Moreover, young drivers are likely to be the first and most aggressive users of new technology. Fortunately, emerging technology can also support safe driving. Electronic stability control, collision avoidance systems, intelligent speed adaptation, and vehicle tracking systems can all help mitigate the threats to young drivers. However, technology alone is unlikely to make young drivers safer. One promising approach to tailoring technology to teen drivers is to extend proven methods for enhancing young driver safety. The success of graduated drivers license programs (GDL) and the impressive safety benefit of supervised driving suggest ways of tailoring technology to the needs of young drivers. To anticipate the effects of technology on teen driving it may be useful to draw an analogy between the effects of passengers and the effects of technology. Technology can act as a teen passenger and undermine safety or it can act as an adult passenger and enhance safety. Impact on industry: Rapidly developing technology may have particularly large effects on teen drivers. To maximize the positive effects and minimize the negative effects will require a broad range of industries to work together. Ideally, vehicle manufacturers would work with infotainment providers, insurance companies, and policy makers to craft new technologies so that they accommodate the needs of young drivers. Without such collaboration young drivers will face even greater challenges to their safety as new technologies emerge. 相似文献
799.
PROBLEM: There is a growing concern with the safety of school-aged children. This study identifies the locations of pedestrian/bicyclist crashes involving school-aged children and examines the conditions when these crashes are more likely to occur. METHOD: The 5-year records of crashes in Orange County, Florida where school-aged children were involved were used. The spatial distribution of these crashes was investigated using the Geographic Information Systems (GIS) and the likelihoods of crash occurrence under different conditions were estimated using log-linear models. RESULTS: A majority of school-aged children crashes occurred in the areas near schools. Although elementary school children were generally very involved, middle and high school children were more involved in crashes, particularly on high-speed multi-lane roadways. Driver's age, gender, and alcohol use, pedestrian's/bicyclist's age, number of lanes, median type, speed limits, and speed ratio were also found to be correlated with the frequency of crashes. DISCUSSION: The result confirms that school-aged children are exposed to high crash risk near schools. High crash involvement of middle and high school children reflects that middle and high schools tend to be located near multi-lane high-speed roads. IMPACT ON INDUSTRY: The pedestrian's/bicyclist's demographic factors and geometric characteristics of the roads adjacent to schools associated with school children's crash involvement are of interest to school districts. 相似文献
800.
Choi YH Kang HS Jun I Keum DK Park HK Choi GS Lee H Lee CW 《Journal of environmental radioactivity》2007,93(3):157-169
The transfer of 90Sr to rice plants following its acute ground deposition was examined experimentally in a greenhouse. Lysimeters were flooded after being filled with the soil monoliths from 12 paddy fields. A solution of 90Sr was applied to the standing water in the flooded lysimeters at the pre-transplanting stage or booting stage. Applied 90Sr was mixed with the topsoil only after the pre-transplanting application (PTA). The transfer was quantified with the areal transfer factor (TF(a), m2 kg(-1)-dry) defined as the ratio of the plant concentration to the initial ground deposition. In the PTA, the first-year TF(a) values in the 12 soils were in the range of 8.2 x 10(-3) -2.1 x 10(-2) and 1.7 x 10(-4) -3.6 x 10(-4) for the straws and hulled seeds, respectively. The TF(a) values from the booting-stage application (BSA) were higher than those from the PTA by a factor of up to four. The ratios of the seed TF(a) to the straw TF(a) were, on the whole, higher in the BSA. The 90Sr TF(a) in the PTA was negatively correlated with the soil pH and, to a lesser degree, the exchangeable Ca content. In the second year, the TF(a) in the PTA reduced to 53-90% of that in the first year. A more significant reduction, in general, occurred in a sandier soil. Based on the four consecutive years' transfer data, an overall half-time of the 90Sr TF(a) was estimated to be 2.2 years. 相似文献