AIM:To study the effect of breviscapine (Bre) on activity of protein kinase Cα (PKCα) and nuclear factor (NF)-κB in pancreas,and the mechanism of Bre attenuating acute pancreatitis (AP). METHODS:One hundred and eig...AIM:To study the effect of breviscapine (Bre) on activity of protein kinase Cα (PKCα) and nuclear factor (NF)-κB in pancreas,and the mechanism of Bre attenuating acute pancreatitis (AP). METHODS:One hundred and eight rats were randomly divided into acute necrotizing pancreatitis (ANP) group,Bre group (ANP + Bre group) and sham operation (SO) group,36 rats in each group. ANP model was induced by a retrograde injection of 4% sodium deoxycholate into the bilio-pancreatic duct. Fifteen minutes after the ANP model was induced,the rats in Bre group were intraperitoneally injected with Bre (0.4 mg/100 g body weight or 0.1 mL/100 g body weight). Survival time and mortality of rats were calculated. Serum amylase and malondialdehyde levels were measured,volume of ascites was recorded and morphology of pancreas and lung was evaluated at 1,5 and 10 h,after the ANP model was induced,respectively. Expressions of PKCα and subunit p65 of NF-κB in pancreas were detected by immunohistochemistry and Western blotting. RESULTS:The life span of rats was longer and the mortality was lower in Bre group than in ANP group 13.51 ± 5.46 vs 25.36 ± 8.11 (P < 0.05). The amylase and MDA levels as well as the volume of ascites were lower and the pathological changes in pancreas and lung were less in Bre group than ANP group (P < 0.05),indicating that the pancreatitis is less severe in Bre group than ANP group. The activation of PKCα and NF-κB p65 in pancreas was induced rapidly and reached their peak at 1 h or 5 h after ANP,but their activity in Bre group was significantly inhibited. CONCLUSION:Bre exerts its therapeutic effect on AP by inhibiting the activation of PKCα and NF-κB p65 in pancreas.展开更多
Helicobacter pylori (H. pylori) is one of the most common pathogenic bacterial infections and is found in the stomachs of approximately half of the world’s population. It is the primary known cause of gast...Helicobacter pylori (H. pylori) is one of the most common pathogenic bacterial infections and is found in the stomachs of approximately half of the world’s population. It is the primary known cause of gastritis, gastroduodenal ulcer disease and gastric cancer. However, combined drug therapy as the general treatment in the clinic, the rise of antibiotic-resistant bacteria, adverse reactions and poor patient compliance are major obstacles to the eradication of H. pylori. Oral site-specific drug delivery systems that could increase the longevity of the treatment agent at the target site might improve the therapeutic effect and avoid side effects. Gastroretentive drug delivery systems potentially prolong the gastric retention time and controlled/sustained release of a drug, thereby increasing the concentration of the drug at the application site, potentially improving its bioavailability and reducing the necessary dosage. Recommended gastroretentive drug delivery systems for enhancing local drug delivery include floating systems, bioadhesive systems and expandable systems. In this review, we summarize the important physiological parameters of the gastrointestinal tract that affect the gastric residence time. We then focus on various aspects useful in the development of gastroretentive drug delivery systems, including current trends and the progress of novel forms, especially with respect to their application for the treatment of H. pylori infections.展开更多
Because of the complexities of tire-road interaction,the wheels of a multi-wheel distributed electricdrive vehicle can easily slip under certain working conditions.As wheel slip affects the dynamic per-formance and st...Because of the complexities of tire-road interaction,the wheels of a multi-wheel distributed electricdrive vehicle can easily slip under certain working conditions.As wheel slip affects the dynamic per-formance and stability of the vehicle,it is crucial to control it and coordinate the driving force.With this aim,this paper presents a driving force coordination control strategy with road identification for eight-wheeled electric vehicles equipped with an in-wheel motor for each wheel.In the proposed control strategy,the road identification module estimates tire-road forces using an unscented Kalman filter al-gorithm and recognizes the road adhesion coefficient by employing the recursive least-square method According to road identification,the optimal sip ratio under the current driving condition is obtainedand a controller based on sliding mode control with a conditional integrator uses this value for accel-eration slip regulation.The anti-slip controller obtains the adjusting torque,which is integrated with the driver-command-based feedforward control torque to implement driving force coordination control.The results of hardware-in-loop simulation show that this control strategy can accurately estimate tire-roadrces as well as the friction coefficient,and thus,can effectively fulfill the purpose of driving force coordinated control under different driving conditions.展开更多
AIM: To study the induction of T cellular immune responses in BALB/c mice immunized with uric acid and dendritic cells (DCs) pulsed with hepatitis B virus surface antigen (HBsAg). METHODS: DCs were generated fro...AIM: To study the induction of T cellular immune responses in BALB/c mice immunized with uric acid and dendritic cells (DCs) pulsed with hepatitis B virus surface antigen (HBsAg). METHODS: DCs were generated from bone-marrow cells of BABL/c mice, and then pulsed or unpulsed with HBsAg protein (HBsAg-pulsed-DCs or unpulsed-DCs) in vitro. BABL/c mice were immunized with HBsAg-pulsed- DCs (1 × 10^6) and uric acid, injected through the tail vein of each mouse. The mice in control groups were immunized with HBsAg-pulsed-DCs alone, unpulsed- DCs alone or 200 μg uric acid alone or PBS alone. The immunization was repeated 7 d later. Cytotoxic T lymphocytes (CTLs) in vivo were determined by the CFSE labeled spleen lysis assay. Spleen cells or spleen T cells were isolated, and re-stimulated in vitro with HBsAg for 120 h or 72 h. Production of IFN-γ, and IL-4 secreted by spleen cells were determined by ELISA method; proliferation of spleen T cells were detected by flow cytometry. RESULTS: The cytotoxicities of HBsAg-specific-CTLs, generated after immunization of HBsAg-pulsed-DCs and uric acid, were 68.63% ±11.32% and significantly stronger than that in the control groups (P 〈 0.01). Compared with control groups, in mice treated with uric acid and HBsAg-pulsed-DCs, the spleen T cell proliferation to HBsAg re-stimulation was stronger (1.34 ± 0.093 vs 1.081±0.028, P 〈 0.01), the level of IFN-t, secreted by splenocytes was higher (266.575 ± 51.323 vs 135.223 ±32.563, P 〈 0.01) , and IL-4 level wasower (22.385 ± 2.252 vs 40.598 ± 4.218, P 〈 0.01). CONCLUSION: Uric acid can strongly enhance T cell immune responses induced by HBsAg-pulsed-DCs vaccine. Uric acid may serve as an effective adjuvant of DC vaccine against HBV infection.展开更多
BACKGROUND Inflammatory cytokines play a vital role in the occurrence of osteoarticular injury and inflammation. Whether inflammation-associated factors interleukin-1β(IL- 1β), IL-6, tumor necrosis factor-α(TNF-α)...BACKGROUND Inflammatory cytokines play a vital role in the occurrence of osteoarticular injury and inflammation. Whether inflammation-associated factors interleukin-1β(IL- 1β), IL-6, tumor necrosis factor-α(TNF-α) and vascular endothelial growth factor (VEGF) are involved in the pathogenesis of keen articular cartilage injury remains poorly understood. AIM To measure the levels of inflammatory factors [IL-1β, IL-6, TNF-α and VEGF] in patients with knee articular cartilage injury. METHODS Fifty-five patients with knee articular cartilage injury were selected as patient groups, who were divided into three grades [mild (n = 20), moderate (n = 19) and severe (n = 16)] according to disease severity and X-ray examinations. Meanwhile, 30 healthy individuals who underwent physical examination were selected as the control group. The levels of IL-1β, IL-6, TNF-α and VEGF were measured by ELISA and immunohistochemical staining. RESULTS Compared with the control group, patient groups displayed significantly higher levels of IL-1β, IL-6, TNF-α and VEGF, and the extent of increase was directly proportional to the severity of injury (P < 0.05). In addition, the number of cells with positive staining of IL-1β, IL-6, TNF-α and VEGF in the synovial membrane were significantly increased, along with increased disease severity (P < 0.05). After treatment, the scores of visual analogue scale and the Western Ontario and McMaster University of Orthopaedic Index in patient groups were 2.26 ± 1.13 and 15.56 ± 7.12 points, respectively, which were significantly lower than those before treatment (6.98 ± 1.32 and 49.48 ± 8.96). Correlation analysis suggested that IL-1β and TNF-α were positively correlated with VEGF. CONCLUSION IL-1β, IL-6, TNF-α and VEGF levels are increased in patients with knee articular cartilage injury, and are associated with the disease severity, indicating they might play an important role in the occurrence and development of knee articular cartilage injury. Furthermore, therapeutically targeting them might be a novel approach for the treatment of keen articular cartilage injury.展开更多
PNEUMOCYSTIS pneumonia (PCP) is among the most common opportunistic infections in patients with acquired immune deficiency syndrome (AIDS).Although trimethoprim-sulfamethoxazole (TMP-SMX) is the first line therapy for...PNEUMOCYSTIS pneumonia (PCP) is among the most common opportunistic infections in patients with acquired immune deficiency syndrome (AIDS).Although trimethoprim-sulfamethoxazole (TMP-SMX) is the first line therapy for that condition given its efficacy,approximately one third of patients experienced dose-limiting toxicity.1 For cases of severe to moderate PCP,if TMP-SMX treatment fails or is contraindicated,primaquine combined with clindamycin or intravenous pentamidine is recommended as second line therapy.2 However,both primaquine and pentamidine are associated with severe adverse reactions and often unavailable at hospitals in China.3 As a result,other treatment options have been explored.展开更多
Gastrointestinal(GI)cancer is one of the leading causes of cancer-related deaths worldwide.According to the Global Cancer Statistics,colorectal cancer is the second leading cause of cancer-related mortality,closely fo...Gastrointestinal(GI)cancer is one of the leading causes of cancer-related deaths worldwide.According to the Global Cancer Statistics,colorectal cancer is the second leading cause of cancer-related mortality,closely followed by gastric cancer(GC).Environmental,dietary,and lifestyle factors including cigarette smoking,alcohol intake,and genetics are the most important risk factors for GI cancer.Furthermore,infections caused by Helicobacter pylori are a major cause of GC initiation.Despite improvements in conventional therapies,including surgery,chemotherapy,and radiotherapy,the length or quality of life of patients with advanced GI cancer is still poor because of delayed diagnosis,recurrence and side effect.Resveratrol(3,4,5-trihydroxy-trans-stilbene;Res),a natural polyphenolic compound,reportedly has various pharmacologic functions including anti-oxidant,anti-inflammatory,anti-cancer,and cardioprotective functions.Many studies have demonstrated that Res also exerts a chemopreventive effect on GI cancer.Research investigating the anti-cancer mechanism of Res for the prevention and treatment of GI cancer has implicated multiple pathways including oxidative stress,cell proliferation,and apoptosis.Therefore,this paper provides a review of the function and molecular mechanisms of Res in the prevention and treatment of GI cancer.展开更多
One of the main challenges for multi-wheel hub motor driven vehicles is the coordination of individual drivetrains to improve mobility and stability in the steering process.This paper proposes a dual-steering mode bas...One of the main challenges for multi-wheel hub motor driven vehicles is the coordination of individual drivetrains to improve mobility and stability in the steering process.This paper proposes a dual-steering mode based on direct yaw moment control for enhancing vehicle steering ability in complex environ ments.The control system is designed as a hierarchical structure,with a yaw moment decision layer and a driving force distribution layer.In the higher-level layer,the objective optimization function is con-structed to obtain the slip steering ratio,which represents the degree of vehicle slip steering in the dual-steering mode.Ayaw moment controller using active disturbance rejection control theory is designed for continuous yaw rate control.When the actual yaw rate of the vehicle deviates from the reference yaw rate obtained by the vehicle reference model and the slip steering ratio,the yaw moment controller isactuated to determine the yaw moment demand for vehicle steering.In the lower-level layer,there is a torque distribution controller based on distribution rules,which meets the requirement of yaw moment demand without affecting the total longitudinal driving force of the vehicle.For verifying the validity and feasibility of the dual-steering mode,simulations were conducted on the hardware-in-loop real-time simulation platfomm.Additionally,corresponding real vehicle tests were carried out on an eight-wheel prototype vehicle.Test results were generally consistent with the simulation results,thereby demon-strating that the proposed dual-steering mode reduces steering radius and enhances the steering per-formance of the vehicle.展开更多
The emission of dioxins from municipal solid waste incinerators(MSWIs) has become a widespread concern.The effect of meteorological parameters(wind speed,atmospheric stability and mixing height) on the hourly ground l...The emission of dioxins from municipal solid waste incinerators(MSWIs) has become a widespread concern.The effect of meteorological parameters(wind speed,atmospheric stability and mixing height) on the hourly ground level concentration(GLC) of dioxins was estimated using air dispersion models.Moreover,the health risks of dioxin exposure were evaluated for children and adults using the Nouwen equation.The total environmental exposure via air inhalation and food ingestion was calculated,based on linear fit equations.The results indicate that potentially severe pollution from dioxins occurs at a wind speed of 1.5 m/s with atmospheric stability class F.In addition,local residents in the study area are exposed to severe weather conditions most of the time,and the risk exposures for children are far higher than those for adults.The total exposure for children far exceeds the tolerable daily intake of dioxin recommended by the World Health Organization(WHO) of 1-4 pg TEQ/(kg·d) under severe weather conditions.Results from modeling calculations of health risk assessment were consistent with dioxin levels obtained during actual monitoring of emissions.展开更多
INTRODUCTIONRotator cuffinjuries are common in all athletic. Of all rotator cuff injuries, the supraspinatus tendon involves mostly. Severe supraspinatus tendon injury may affect the patient's quality of life. Howeve...INTRODUCTIONRotator cuffinjuries are common in all athletic. Of all rotator cuff injuries, the supraspinatus tendon involves mostly. Severe supraspinatus tendon injury may affect the patient's quality of life. However, supraspinatus tendon injury can be relatively asymptomatic in some cases and may require sonographic examination for diagnosis, With continued improvement in shoulder arthroscopy, surgical treatment for supraspinatus tendon injury has become more effective and less invasive.展开更多
Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM t...Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM that effectively dif-ferentiates multicast streams. It re-arranges the virtual bitmap of the traffic indication map (TIM) to carry traffic status for mul-ticast groups and introduces a concept of sequential transmission of multi-addressed data to facilitate differentiation among mul-ticast groups. Our analysis shows that the enhanced PSM can effectively save power in mixed traffic environments.展开更多
基金Supported by Funds of Natural Science of Shaanxi Education, No.05JK176Natural Science of Shaanxi Province, No.2010JM4023Natural Science of Xianyang City, No. 2010K14-02(6)
文摘AIM:To study the effect of breviscapine (Bre) on activity of protein kinase Cα (PKCα) and nuclear factor (NF)-κB in pancreas,and the mechanism of Bre attenuating acute pancreatitis (AP). METHODS:One hundred and eight rats were randomly divided into acute necrotizing pancreatitis (ANP) group,Bre group (ANP + Bre group) and sham operation (SO) group,36 rats in each group. ANP model was induced by a retrograde injection of 4% sodium deoxycholate into the bilio-pancreatic duct. Fifteen minutes after the ANP model was induced,the rats in Bre group were intraperitoneally injected with Bre (0.4 mg/100 g body weight or 0.1 mL/100 g body weight). Survival time and mortality of rats were calculated. Serum amylase and malondialdehyde levels were measured,volume of ascites was recorded and morphology of pancreas and lung was evaluated at 1,5 and 10 h,after the ANP model was induced,respectively. Expressions of PKCα and subunit p65 of NF-κB in pancreas were detected by immunohistochemistry and Western blotting. RESULTS:The life span of rats was longer and the mortality was lower in Bre group than in ANP group 13.51 ± 5.46 vs 25.36 ± 8.11 (P < 0.05). The amylase and MDA levels as well as the volume of ascites were lower and the pathological changes in pancreas and lung were less in Bre group than ANP group (P < 0.05),indicating that the pancreatitis is less severe in Bre group than ANP group. The activation of PKCα and NF-κB p65 in pancreas was induced rapidly and reached their peak at 1 h or 5 h after ANP,but their activity in Bre group was significantly inhibited. CONCLUSION:Bre exerts its therapeutic effect on AP by inhibiting the activation of PKCα and NF-κB p65 in pancreas.
文摘Helicobacter pylori (H. pylori) is one of the most common pathogenic bacterial infections and is found in the stomachs of approximately half of the world’s population. It is the primary known cause of gastritis, gastroduodenal ulcer disease and gastric cancer. However, combined drug therapy as the general treatment in the clinic, the rise of antibiotic-resistant bacteria, adverse reactions and poor patient compliance are major obstacles to the eradication of H. pylori. Oral site-specific drug delivery systems that could increase the longevity of the treatment agent at the target site might improve the therapeutic effect and avoid side effects. Gastroretentive drug delivery systems potentially prolong the gastric retention time and controlled/sustained release of a drug, thereby increasing the concentration of the drug at the application site, potentially improving its bioavailability and reducing the necessary dosage. Recommended gastroretentive drug delivery systems for enhancing local drug delivery include floating systems, bioadhesive systems and expandable systems. In this review, we summarize the important physiological parameters of the gastrointestinal tract that affect the gastric residence time. We then focus on various aspects useful in the development of gastroretentive drug delivery systems, including current trends and the progress of novel forms, especially with respect to their application for the treatment of H. pylori infections.
基金This work was supported by the Weapons and Equipment Pre-Research Project of China(No.301051102).
文摘Because of the complexities of tire-road interaction,the wheels of a multi-wheel distributed electricdrive vehicle can easily slip under certain working conditions.As wheel slip affects the dynamic per-formance and stability of the vehicle,it is crucial to control it and coordinate the driving force.With this aim,this paper presents a driving force coordination control strategy with road identification for eight-wheeled electric vehicles equipped with an in-wheel motor for each wheel.In the proposed control strategy,the road identification module estimates tire-road forces using an unscented Kalman filter al-gorithm and recognizes the road adhesion coefficient by employing the recursive least-square method According to road identification,the optimal sip ratio under the current driving condition is obtainedand a controller based on sliding mode control with a conditional integrator uses this value for accel-eration slip regulation.The anti-slip controller obtains the adjusting torque,which is integrated with the driver-command-based feedforward control torque to implement driving force coordination control.The results of hardware-in-loop simulation show that this control strategy can accurately estimate tire-roadrces as well as the friction coefficient,and thus,can effectively fulfill the purpose of driving force coordinated control under different driving conditions.
基金Supported by the National Natural Science Foundation of China, No. 30471533
文摘AIM: To study the induction of T cellular immune responses in BALB/c mice immunized with uric acid and dendritic cells (DCs) pulsed with hepatitis B virus surface antigen (HBsAg). METHODS: DCs were generated from bone-marrow cells of BABL/c mice, and then pulsed or unpulsed with HBsAg protein (HBsAg-pulsed-DCs or unpulsed-DCs) in vitro. BABL/c mice were immunized with HBsAg-pulsed- DCs (1 × 10^6) and uric acid, injected through the tail vein of each mouse. The mice in control groups were immunized with HBsAg-pulsed-DCs alone, unpulsed- DCs alone or 200 μg uric acid alone or PBS alone. The immunization was repeated 7 d later. Cytotoxic T lymphocytes (CTLs) in vivo were determined by the CFSE labeled spleen lysis assay. Spleen cells or spleen T cells were isolated, and re-stimulated in vitro with HBsAg for 120 h or 72 h. Production of IFN-γ, and IL-4 secreted by spleen cells were determined by ELISA method; proliferation of spleen T cells were detected by flow cytometry. RESULTS: The cytotoxicities of HBsAg-specific-CTLs, generated after immunization of HBsAg-pulsed-DCs and uric acid, were 68.63% ±11.32% and significantly stronger than that in the control groups (P 〈 0.01). Compared with control groups, in mice treated with uric acid and HBsAg-pulsed-DCs, the spleen T cell proliferation to HBsAg re-stimulation was stronger (1.34 ± 0.093 vs 1.081±0.028, P 〈 0.01), the level of IFN-t, secreted by splenocytes was higher (266.575 ± 51.323 vs 135.223 ±32.563, P 〈 0.01) , and IL-4 level wasower (22.385 ± 2.252 vs 40.598 ± 4.218, P 〈 0.01). CONCLUSION: Uric acid can strongly enhance T cell immune responses induced by HBsAg-pulsed-DCs vaccine. Uric acid may serve as an effective adjuvant of DC vaccine against HBV infection.
文摘BACKGROUND Inflammatory cytokines play a vital role in the occurrence of osteoarticular injury and inflammation. Whether inflammation-associated factors interleukin-1β(IL- 1β), IL-6, tumor necrosis factor-α(TNF-α) and vascular endothelial growth factor (VEGF) are involved in the pathogenesis of keen articular cartilage injury remains poorly understood. AIM To measure the levels of inflammatory factors [IL-1β, IL-6, TNF-α and VEGF] in patients with knee articular cartilage injury. METHODS Fifty-five patients with knee articular cartilage injury were selected as patient groups, who were divided into three grades [mild (n = 20), moderate (n = 19) and severe (n = 16)] according to disease severity and X-ray examinations. Meanwhile, 30 healthy individuals who underwent physical examination were selected as the control group. The levels of IL-1β, IL-6, TNF-α and VEGF were measured by ELISA and immunohistochemical staining. RESULTS Compared with the control group, patient groups displayed significantly higher levels of IL-1β, IL-6, TNF-α and VEGF, and the extent of increase was directly proportional to the severity of injury (P < 0.05). In addition, the number of cells with positive staining of IL-1β, IL-6, TNF-α and VEGF in the synovial membrane were significantly increased, along with increased disease severity (P < 0.05). After treatment, the scores of visual analogue scale and the Western Ontario and McMaster University of Orthopaedic Index in patient groups were 2.26 ± 1.13 and 15.56 ± 7.12 points, respectively, which were significantly lower than those before treatment (6.98 ± 1.32 and 49.48 ± 8.96). Correlation analysis suggested that IL-1β and TNF-α were positively correlated with VEGF. CONCLUSION IL-1β, IL-6, TNF-α and VEGF levels are increased in patients with knee articular cartilage injury, and are associated with the disease severity, indicating they might play an important role in the occurrence and development of knee articular cartilage injury. Furthermore, therapeutically targeting them might be a novel approach for the treatment of keen articular cartilage injury.
文摘PNEUMOCYSTIS pneumonia (PCP) is among the most common opportunistic infections in patients with acquired immune deficiency syndrome (AIDS).Although trimethoprim-sulfamethoxazole (TMP-SMX) is the first line therapy for that condition given its efficacy,approximately one third of patients experienced dose-limiting toxicity.1 For cases of severe to moderate PCP,if TMP-SMX treatment fails or is contraindicated,primaquine combined with clindamycin or intravenous pentamidine is recommended as second line therapy.2 However,both primaquine and pentamidine are associated with severe adverse reactions and often unavailable at hospitals in China.3 As a result,other treatment options have been explored.
基金Supported by National Natural Science Foundation of China,No.21576254National Natural Science Foundation of China,No.81903560Dalian Young Star of Science and Technology Project,No.2018RQ81.
文摘Gastrointestinal(GI)cancer is one of the leading causes of cancer-related deaths worldwide.According to the Global Cancer Statistics,colorectal cancer is the second leading cause of cancer-related mortality,closely followed by gastric cancer(GC).Environmental,dietary,and lifestyle factors including cigarette smoking,alcohol intake,and genetics are the most important risk factors for GI cancer.Furthermore,infections caused by Helicobacter pylori are a major cause of GC initiation.Despite improvements in conventional therapies,including surgery,chemotherapy,and radiotherapy,the length or quality of life of patients with advanced GI cancer is still poor because of delayed diagnosis,recurrence and side effect.Resveratrol(3,4,5-trihydroxy-trans-stilbene;Res),a natural polyphenolic compound,reportedly has various pharmacologic functions including anti-oxidant,anti-inflammatory,anti-cancer,and cardioprotective functions.Many studies have demonstrated that Res also exerts a chemopreventive effect on GI cancer.Research investigating the anti-cancer mechanism of Res for the prevention and treatment of GI cancer has implicated multiple pathways including oxidative stress,cell proliferation,and apoptosis.Therefore,this paper provides a review of the function and molecular mechanisms of Res in the prevention and treatment of GI cancer.
基金This work was supported by the Weapons and Equipment Pre-Research Project of China(No.301051102).
文摘One of the main challenges for multi-wheel hub motor driven vehicles is the coordination of individual drivetrains to improve mobility and stability in the steering process.This paper proposes a dual-steering mode based on direct yaw moment control for enhancing vehicle steering ability in complex environ ments.The control system is designed as a hierarchical structure,with a yaw moment decision layer and a driving force distribution layer.In the higher-level layer,the objective optimization function is con-structed to obtain the slip steering ratio,which represents the degree of vehicle slip steering in the dual-steering mode.Ayaw moment controller using active disturbance rejection control theory is designed for continuous yaw rate control.When the actual yaw rate of the vehicle deviates from the reference yaw rate obtained by the vehicle reference model and the slip steering ratio,the yaw moment controller isactuated to determine the yaw moment demand for vehicle steering.In the lower-level layer,there is a torque distribution controller based on distribution rules,which meets the requirement of yaw moment demand without affecting the total longitudinal driving force of the vehicle.For verifying the validity and feasibility of the dual-steering mode,simulations were conducted on the hardware-in-loop real-time simulation platfomm.Additionally,corresponding real vehicle tests were carried out on an eight-wheel prototype vehicle.Test results were generally consistent with the simulation results,thereby demon-strating that the proposed dual-steering mode reduces steering radius and enhances the steering per-formance of the vehicle.
基金Project supported by the National Basic Research Program of China (973) (No. 2011CB201500)the National High-Tech R&D Program (863) of China (No. 2009AA064704)the Key Science and Technology Projects of Zhejiang Province,China (No. 2008C13022-3)
文摘The emission of dioxins from municipal solid waste incinerators(MSWIs) has become a widespread concern.The effect of meteorological parameters(wind speed,atmospheric stability and mixing height) on the hourly ground level concentration(GLC) of dioxins was estimated using air dispersion models.Moreover,the health risks of dioxin exposure were evaluated for children and adults using the Nouwen equation.The total environmental exposure via air inhalation and food ingestion was calculated,based on linear fit equations.The results indicate that potentially severe pollution from dioxins occurs at a wind speed of 1.5 m/s with atmospheric stability class F.In addition,local residents in the study area are exposed to severe weather conditions most of the time,and the risk exposures for children are far higher than those for adults.The total exposure for children far exceeds the tolerable daily intake of dioxin recommended by the World Health Organization(WHO) of 1-4 pg TEQ/(kg·d) under severe weather conditions.Results from modeling calculations of health risk assessment were consistent with dioxin levels obtained during actual monitoring of emissions.
文摘INTRODUCTIONRotator cuffinjuries are common in all athletic. Of all rotator cuff injuries, the supraspinatus tendon involves mostly. Severe supraspinatus tendon injury may affect the patient's quality of life. However, supraspinatus tendon injury can be relatively asymptomatic in some cases and may require sonographic examination for diagnosis, With continued improvement in shoulder arthroscopy, surgical treatment for supraspinatus tendon injury has become more effective and less invasive.
基金Project (Nos. 60574087 and 60721003) supported by the National Natural Science Foundation of China
文摘Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM that effectively dif-ferentiates multicast streams. It re-arranges the virtual bitmap of the traffic indication map (TIM) to carry traffic status for mul-ticast groups and introduces a concept of sequential transmission of multi-addressed data to facilitate differentiation among mul-ticast groups. Our analysis shows that the enhanced PSM can effectively save power in mixed traffic environments.