The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals th...The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals that include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Thermal stability, surface activity, dielectric characteristics, chemical resistance, and inertness are just a few of the technical advantages that this group has over hydrocarbons, and since the 1950s, these chemicals have been largely utilized in a variety of domestic and industrial endeavors. The hydrophilic and lipophilic nature of this class of chemicals accounts for its uniqueness. Up until today, the chemistry and ecotoxicology of these chemicals continue to emerge. Issues concerning the destructive power of ignorance expedited by an ineffective regulatory institution continue to show that manufacturing chemicals are insufficient without giving serious thought to issues of openness and humanity’s awareness of its own safety. When discussing the nature of humanity and how it can be defined or redefined, it is important to allude to the significance of integrating business with ethics in its various forms. This paper highlights the importance of holding polluters accountable for PFAS contamination cleanup costs while emphasizing the need for chemical manufacturers to test and disclose the health and environmental effects of PFAS compounds. In addition, the sources, types, properties, applications, distribution, toxicological implications, regulations, and analytical methods associated with PFAS (per- and polyfluoroalkyl substances) are explored. The effectiveness of the remedial methods described in this paper needs to be progressively tested while exploring other sustainable approaches.展开更多
The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals th...The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals that include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Thermal stability, surface activity, dielectric characteristics, chemical resistance, and inertness are just a few of the technical advantages that this group has over hydrocarbons, and since the 1950s, these chemicals have been largely utilized in a variety of domestic and industrial endeavors. The hydrophilic and lipophilic nature of this class of chemicals accounts for its uniqueness. Up until today, the chemistry and ecotoxicology of these chemicals continue to emerge. Issues concerning the destructive power of ignorance expedited by an ineffective regulatory institution continue to show that manufacturing chemicals are insufficient without giving serious thought to issues of openness and humanity’s awareness of its own safety. When discussing the nature of humanity and how it can be defined or redefined, it is important to allude to the significance of integrating business with ethics in its various forms. This paper highlights the importance of holding polluters accountable for PFAS contamination cleanup costs while emphasizing the need for chemical manufacturers to test and disclose the health and environmental effects of PFAS compounds. In addition, the sources, types, properties, applications, distribution, toxicological implications, regulations, and analytical methods associated with PFAS (per- and polyfluoroalkyl substances) are explored. The effectiveness of the remedial methods described in this paper needs to be progressively tested while exploring other sustainable approaches.展开更多
[Objective] The effects of yttrium nitrate （YNO3） on biomass and antioxi- dant systems of paddy rice （Yttrium （Y）; Oxidative stress; Dismutases （SOD）; Per- oxidases （POD）, Catalases （CAT）, Paddy rice （Trit...[Objective] The effects of yttrium nitrate （YNO3） on biomass and antioxi- dant systems of paddy rice （Yttrium （Y）; Oxidative stress; Dismutases （SOD）; Per- oxidases （POD）, Catalases （CAT）, Paddy rice （Triticum aestivum）） together with the occurrences of Y in soils were investigated to assess its ecotoxicological effects on plant. [Method]Y solutions with various concentrations were sprinkled on soil sam- ples, which were well mixed and then put into culture dishes to culture paddy rice seeds for further evaluation. [Result] The results indicated that 25-100 mg/kg Y treatments significantly increased the biomass （total weight, root weight, shoot weight and leaf weight）, chlorophyll （CHL） content and protein content of paddy rice, whereas 200-800 mg/kg Y treatments had a converse effect. Similarly, biomarker for the antioxidant systems including superoxide dismutases （SOD）, peroxidases （POD） and catalases （CAT） all exhibited similar trends in both shoots and roots of paddy rice. At the same time, the malonaldehyde （MDA） content increased at from 25 to 100 mg/kg and decreased with concentrations of Y from 100 to 800 mg/kg in both shoots and roots of paddy rice. This indicated that Y could stimulate the growth of plant at low concentration, but inhibit the growth at relatively high concen- tration. [Conclusion] The levels of Y were 641＋49, 328_＋16 and 473_＋40 mg/kg in soils collected from mining area, farmland and navel orange orchard respectively. The levels of Y in the investigated area were higher than the benefit level （100 mg/kg）, which could cause low biomass as well as low activity of SOD, POD and CAT in paddy rice. Therefore, a more careful use of Y is necessary in crop management.展开更多
Conventional optical burst switching(OBS)technique adopts purely statistical multiplex mechanismso that the bursts collide with each other very easily.To address this problem,a novel proactive con-tention avoidance sc...Conventional optical burst switching(OBS)technique adopts purely statistical multiplex mechanismso that the bursts collide with each other very easily.To address this problem,a novel proactive con-tention avoidance scheme is proposed,which assigns dedicated wavelengths to each ingress node,then st-numbering algorithm is used to construct the traffic load balanced spanning trees .In this way,contentioncan be eliminated at ingress nodes,and the amount of bursts that could be accommodated by ingressnodes will be maximized.Further,those unused wavelengths left by traffic load balanced spanning treeare also organized as partial trees to carry bursts,thus the link utilization can be improved effectively.Simulation result shows that our scheme can improve the burst loss performance significantly without thewavelength converters or optical buffers comparing to other popular routing and wavelength assignment(RWA)algorithms.展开更多
Objectives To investigate safety and effectivity of potassium inprevention of restenosis after PTCA. Methods Eighty patients with PTCA were randomized into two groups: Control group ( Group Ⅱ n= 40) with conventional...Objectives To investigate safety and effectivity of potassium inprevention of restenosis after PTCA. Methods Eighty patients with PTCA were randomized into two groups: Control group ( Group Ⅱ n= 40) with conventional therapy; Treatment group (Group Ⅰ n = 40) with conventional therapy plus oral potassium (Slow - K 1.2 g, q8h, given 3 days before PTCA and continued to the end ofsub - study). Observation indeces of two groups were compared in follow - up. Results Seventy - seven patients were followed -up(39 in group Ⅰ, 38 in group Ⅱ) All blood indices (including fat, sugar, uric acid, cretonne, Na+, Cl-, Ca2+, Mg2+ ) except blood potassium in both groups were similar. Oral potassium could increase blood potassium level about 0. 3 mmol/L in group Ⅰ without causing any side effects. Suspicious angina pectoris and evidence of myocardial ischemia by ETT were developed in group Ⅱ had 14 patients (28. 9 % ) and Group I had 7 patients (17. 9 % ); 6 of 17 patients(35. 3 % ) in groupⅠ and 11 of 21 patients in group Ⅱ (52. 3 % ) appeared restenosis confirmed by coronary arteriography. 10. 2 % in group Ⅰ (4/39) and 23.7 % in group Ⅱ (9/38) needed revascular-izations(PTCA or CABG) . Conclusions Therapy with potassium after PTCA showed that recurrence of myocardial ischemia, restenosis rate by follow - up coronary arteriography and revascularization rate tended to be lower in group Ⅰ than in group Ⅱ.展开更多
Objectives To assess the effect of delayed opening the infarct - related artery (IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute ante- rior myocardial infarction...Objectives To assess the effect of delayed opening the infarct - related artery (IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute ante- rior myocardial infarction. Methods 64 patients with initial Q - wave anterior myocardial infarction and the infarct - related arteries were total occluded conformed by angiogram at 2 to 14 days after onset were divided into successful PCI group and control group ( not re- ceiving PCI or the IRA not re - opened). 2 - DE was performed at early phase ( about 3 weeks) , 2 and 6 months after onset of AMI respectively to detect the left ventricular function and left ventricular wall motion ab- normality (VWMA). The total congestive heart failure events were recorded during 6 months follow-up. Re- sults VWMA scores, left ventricular ejection frac- tion (LVEF) , left ventricular end - diastolic and end - systolic volume indices ( LVEDVI and LVDSVI) were similar in 2 groups at early phase and 2 months. There were no differences between early phase and 2 months in each group too. VWMA scores and LVEF did not changed at 6 months in each group compared with the early phase and 2 months ( P > 0. 05 ). But LVEDVI and LVESVI were significantly smaller in the successful PCI group than in the control group (P < 0.01, P < 0. 05). The congestive heart failure events were taken place in 19% of patients in control group com- pared with 2% in successful PCI group ( P > 0. 05 ). Conclusions Although the infarct size does not changed, delayed opening the IRA has beneficial effect to the late phase left ventricular dilatation after acuteanterior myocardial infarction.展开更多
文摘The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals that include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Thermal stability, surface activity, dielectric characteristics, chemical resistance, and inertness are just a few of the technical advantages that this group has over hydrocarbons, and since the 1950s, these chemicals have been largely utilized in a variety of domestic and industrial endeavors. The hydrophilic and lipophilic nature of this class of chemicals accounts for its uniqueness. Up until today, the chemistry and ecotoxicology of these chemicals continue to emerge. Issues concerning the destructive power of ignorance expedited by an ineffective regulatory institution continue to show that manufacturing chemicals are insufficient without giving serious thought to issues of openness and humanity’s awareness of its own safety. When discussing the nature of humanity and how it can be defined or redefined, it is important to allude to the significance of integrating business with ethics in its various forms. This paper highlights the importance of holding polluters accountable for PFAS contamination cleanup costs while emphasizing the need for chemical manufacturers to test and disclose the health and environmental effects of PFAS compounds. In addition, the sources, types, properties, applications, distribution, toxicological implications, regulations, and analytical methods associated with PFAS (per- and polyfluoroalkyl substances) are explored. The effectiveness of the remedial methods described in this paper needs to be progressively tested while exploring other sustainable approaches.
文摘The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals that include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Thermal stability, surface activity, dielectric characteristics, chemical resistance, and inertness are just a few of the technical advantages that this group has over hydrocarbons, and since the 1950s, these chemicals have been largely utilized in a variety of domestic and industrial endeavors. The hydrophilic and lipophilic nature of this class of chemicals accounts for its uniqueness. Up until today, the chemistry and ecotoxicology of these chemicals continue to emerge. Issues concerning the destructive power of ignorance expedited by an ineffective regulatory institution continue to show that manufacturing chemicals are insufficient without giving serious thought to issues of openness and humanity’s awareness of its own safety. When discussing the nature of humanity and how it can be defined or redefined, it is important to allude to the significance of integrating business with ethics in its various forms. This paper highlights the importance of holding polluters accountable for PFAS contamination cleanup costs while emphasizing the need for chemical manufacturers to test and disclose the health and environmental effects of PFAS compounds. In addition, the sources, types, properties, applications, distribution, toxicological implications, regulations, and analytical methods associated with PFAS (per- and polyfluoroalkyl substances) are explored. The effectiveness of the remedial methods described in this paper needs to be progressively tested while exploring other sustainable approaches.
基金Supported by the National Natural Science Foundation of China(21067003,51364015)the National High-Tech Research and Development Program of China(2012BAC11B07)the Jiangxi Natural Science Foundation(20114BAB203024)~~
文摘[Objective] The effects of yttrium nitrate （YNO3） on biomass and antioxi- dant systems of paddy rice （Yttrium （Y）; Oxidative stress; Dismutases （SOD）; Per- oxidases （POD）, Catalases （CAT）, Paddy rice （Triticum aestivum）） together with the occurrences of Y in soils were investigated to assess its ecotoxicological effects on plant. [Method]Y solutions with various concentrations were sprinkled on soil sam- ples, which were well mixed and then put into culture dishes to culture paddy rice seeds for further evaluation. [Result] The results indicated that 25-100 mg/kg Y treatments significantly increased the biomass （total weight, root weight, shoot weight and leaf weight）, chlorophyll （CHL） content and protein content of paddy rice, whereas 200-800 mg/kg Y treatments had a converse effect. Similarly, biomarker for the antioxidant systems including superoxide dismutases （SOD）, peroxidases （POD） and catalases （CAT） all exhibited similar trends in both shoots and roots of paddy rice. At the same time, the malonaldehyde （MDA） content increased at from 25 to 100 mg/kg and decreased with concentrations of Y from 100 to 800 mg/kg in both shoots and roots of paddy rice. This indicated that Y could stimulate the growth of plant at low concentration, but inhibit the growth at relatively high concen- tration. [Conclusion] The levels of Y were 641＋49, 328_＋16 and 473_＋40 mg/kg in soils collected from mining area, farmland and navel orange orchard respectively. The levels of Y in the investigated area were higher than the benefit level （100 mg/kg）, which could cause low biomass as well as low activity of SOD, POD and CAT in paddy rice. Therefore, a more careful use of Y is necessary in crop management.
基金supported by the National Natural Science Foundation of China(No.60572050)the National High Technology Research and Development Programme of China(No.2008AA01Z211)
文摘Conventional optical burst switching(OBS)technique adopts purely statistical multiplex mechanismso that the bursts collide with each other very easily.To address this problem,a novel proactive con-tention avoidance scheme is proposed,which assigns dedicated wavelengths to each ingress node,then st-numbering algorithm is used to construct the traffic load balanced spanning trees .In this way,contentioncan be eliminated at ingress nodes,and the amount of bursts that could be accommodated by ingressnodes will be maximized.Further,those unused wavelengths left by traffic load balanced spanning treeare also organized as partial trees to carry bursts,thus the link utilization can be improved effectively.Simulation result shows that our scheme can improve the burst loss performance significantly without thewavelength converters or optical buffers comparing to other popular routing and wavelength assignment(RWA)algorithms.
文摘Objectives To investigate safety and effectivity of potassium inprevention of restenosis after PTCA. Methods Eighty patients with PTCA were randomized into two groups: Control group ( Group Ⅱ n= 40) with conventional therapy; Treatment group (Group Ⅰ n = 40) with conventional therapy plus oral potassium (Slow - K 1.2 g, q8h, given 3 days before PTCA and continued to the end ofsub - study). Observation indeces of two groups were compared in follow - up. Results Seventy - seven patients were followed -up(39 in group Ⅰ, 38 in group Ⅱ) All blood indices (including fat, sugar, uric acid, cretonne, Na+, Cl-, Ca2+, Mg2+ ) except blood potassium in both groups were similar. Oral potassium could increase blood potassium level about 0. 3 mmol/L in group Ⅰ without causing any side effects. Suspicious angina pectoris and evidence of myocardial ischemia by ETT were developed in group Ⅱ had 14 patients (28. 9 % ) and Group I had 7 patients (17. 9 % ); 6 of 17 patients(35. 3 % ) in groupⅠ and 11 of 21 patients in group Ⅱ (52. 3 % ) appeared restenosis confirmed by coronary arteriography. 10. 2 % in group Ⅰ (4/39) and 23.7 % in group Ⅱ (9/38) needed revascular-izations(PTCA or CABG) . Conclusions Therapy with potassium after PTCA showed that recurrence of myocardial ischemia, restenosis rate by follow - up coronary arteriography and revascularization rate tended to be lower in group Ⅰ than in group Ⅱ.
文摘Objectives To assess the effect of delayed opening the infarct - related artery (IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute ante- rior myocardial infarction. Methods 64 patients with initial Q - wave anterior myocardial infarction and the infarct - related arteries were total occluded conformed by angiogram at 2 to 14 days after onset were divided into successful PCI group and control group ( not re- ceiving PCI or the IRA not re - opened). 2 - DE was performed at early phase ( about 3 weeks) , 2 and 6 months after onset of AMI respectively to detect the left ventricular function and left ventricular wall motion ab- normality (VWMA). The total congestive heart failure events were recorded during 6 months follow-up. Re- sults VWMA scores, left ventricular ejection frac- tion (LVEF) , left ventricular end - diastolic and end - systolic volume indices ( LVEDVI and LVDSVI) were similar in 2 groups at early phase and 2 months. There were no differences between early phase and 2 months in each group too. VWMA scores and LVEF did not changed at 6 months in each group compared with the early phase and 2 months ( P > 0. 05 ). But LVEDVI and LVESVI were significantly smaller in the successful PCI group than in the control group (P < 0.01, P < 0. 05). The congestive heart failure events were taken place in 19% of patients in control group com- pared with 2% in successful PCI group ( P > 0. 05 ). Conclusions Although the infarct size does not changed, delayed opening the IRA has beneficial effect to the late phase left ventricular dilatation after acuteanterior myocardial infarction.
