When a spiral groove is formed using superplastic molding, precision casting, additive manufacturing, or other non?mechanical processing technology, it is diffcult to meet the molding precision required for direct use...When a spiral groove is formed using superplastic molding, precision casting, additive manufacturing, or other non?mechanical processing technology, it is diffcult to meet the molding precision required for direct use, and the surface quality and accuracy of the shape need to be improved through a finishing process. In view of the poor reachability of the current tool?based polishing process, a tool?less polishing method using free?abrasive grains for complex spiral grooves is proposed. With this method, by controlling the movement of the workpiece, the design basis and relative motion of the abrasive particles along a helical path remain consistent, resulting in a better polishing profile. A spiral groove of a revolving body is taken as the research object; the influence of the installation method and the position of the parts, as well as the effect of the rotational speed of the abrasive ball on its relative motion along a helical trajectory, are studied, and the polishing cutting process of an abrasive ball is reasonably simplified. A consistent math?ematical model of the trajectory of an abrasive ball relative to the design helix is constructed. The grooved drum parts are verified through a polishing experiment. The spiral groove of the revolving body is modified and polished. Experiments show that the process not only corrects the shape a spiral groove error, but also reduces the surface roughness of a spiral groove. This study provides a theoretical basis for achieving free?abrasive, tool?free polishing.展开更多
Background:The spleen plays a pivotal role in the rapid clearance of parasitized red blood cells in patients with falciparum malaria after artemisinin treatment.Prolonged parasite clearance can be found in patients wh...Background:The spleen plays a pivotal role in the rapid clearance of parasitized red blood cells in patients with falciparum malaria after artemisinin treatment.Prolonged parasite clearance can be found in patients who have had a splenectomy,or those with hemoglobin abnormalities and/or reduced immunity,which are all distinguishable from artemisinin resistance.This paper reports on a case of prolonged parasite clearance in a Chinese splenectomized patient with falciparum malaria imported from Nigeria.Case presentation:A 35-year-old Chinese male suffered 2 days of febrile illness after returning to Zhumadian city of Henan province from Nigeria on October 1,2014.The main symptoms were febrile,including the highest axillary temperature of 40℃,headache,and chills.A peripheral blood smear showed parasitemia(53913 asexual parasites/μl)of Plasmodium falciparum.The patient had not used any chemoprophylaxis against malaria in Nigeria when he worked there as a construction worker between 2009 and 2014.The patient had three episodes of malaria in Nigeria and had a splenectomy due to a traffic accident 8 years ago from the time he was admitted to hospital.The patient was orally administrated a total of 320 mg/2.56 g dihydroartemisinin-piperaquine for 2 days and intravenously administrated a total of 3000 mg artesunate for 18 days.The axillary temperature of the patient ranged between 37.0 and 37.7℃ from Day 0 to Day 3,and blood microscopy revealed falciparum malaria parasitemia(26674 asexual parasites/μl)on Day 3.The patient was afebrile on Day 4,falciparum malaria parasitemia was continuously present and then gradually decreased on the next days,and was negative on Day 21.The patient was cured and left hospital on Day 24 after no plasmodium falciparum was found in the blood on Day 21 to Day 23.No mutation was found in the K13 propeller gene when compared with the PF3D7_1343700 K13 propeller gene reference sequence.Conclusions:This is the first reported case in China of prolonged parasite clearance in a splenectomized patient with imported falciparum malaria.Artemisinin resistance should be distinguished when prolonged parasite clearance is found in a malaria patient who has had splenectomy.展开更多
基金Supported by Key Scientific&Technological Research Project of Henan Province,China(Grant No.102102210497)
文摘When a spiral groove is formed using superplastic molding, precision casting, additive manufacturing, or other non?mechanical processing technology, it is diffcult to meet the molding precision required for direct use, and the surface quality and accuracy of the shape need to be improved through a finishing process. In view of the poor reachability of the current tool?based polishing process, a tool?less polishing method using free?abrasive grains for complex spiral grooves is proposed. With this method, by controlling the movement of the workpiece, the design basis and relative motion of the abrasive particles along a helical path remain consistent, resulting in a better polishing profile. A spiral groove of a revolving body is taken as the research object; the influence of the installation method and the position of the parts, as well as the effect of the rotational speed of the abrasive ball on its relative motion along a helical trajectory, are studied, and the polishing cutting process of an abrasive ball is reasonably simplified. A consistent math?ematical model of the trajectory of an abrasive ball relative to the design helix is constructed. The grooved drum parts are verified through a polishing experiment. The spiral groove of the revolving body is modified and polished. Experiments show that the process not only corrects the shape a spiral groove error, but also reduces the surface roughness of a spiral groove. This study provides a theoretical basis for achieving free?abrasive, tool?free polishing.
基金This work was supported by Project of Science and Technique of Henan,China(No.092102310007)Project of Medical Science and Technique of Henan,China(No.201304053)+1 种基金the Special Funding of the Henan Health Science and Technology Innovation Talent Project(No.4045)The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the paper.
文摘Background:The spleen plays a pivotal role in the rapid clearance of parasitized red blood cells in patients with falciparum malaria after artemisinin treatment.Prolonged parasite clearance can be found in patients who have had a splenectomy,or those with hemoglobin abnormalities and/or reduced immunity,which are all distinguishable from artemisinin resistance.This paper reports on a case of prolonged parasite clearance in a Chinese splenectomized patient with falciparum malaria imported from Nigeria.Case presentation:A 35-year-old Chinese male suffered 2 days of febrile illness after returning to Zhumadian city of Henan province from Nigeria on October 1,2014.The main symptoms were febrile,including the highest axillary temperature of 40℃,headache,and chills.A peripheral blood smear showed parasitemia(53913 asexual parasites/μl)of Plasmodium falciparum.The patient had not used any chemoprophylaxis against malaria in Nigeria when he worked there as a construction worker between 2009 and 2014.The patient had three episodes of malaria in Nigeria and had a splenectomy due to a traffic accident 8 years ago from the time he was admitted to hospital.The patient was orally administrated a total of 320 mg/2.56 g dihydroartemisinin-piperaquine for 2 days and intravenously administrated a total of 3000 mg artesunate for 18 days.The axillary temperature of the patient ranged between 37.0 and 37.7℃ from Day 0 to Day 3,and blood microscopy revealed falciparum malaria parasitemia(26674 asexual parasites/μl)on Day 3.The patient was afebrile on Day 4,falciparum malaria parasitemia was continuously present and then gradually decreased on the next days,and was negative on Day 21.The patient was cured and left hospital on Day 24 after no plasmodium falciparum was found in the blood on Day 21 to Day 23.No mutation was found in the K13 propeller gene when compared with the PF3D7_1343700 K13 propeller gene reference sequence.Conclusions:This is the first reported case in China of prolonged parasite clearance in a splenectomized patient with imported falciparum malaria.Artemisinin resistance should be distinguished when prolonged parasite clearance is found in a malaria patient who has had splenectomy.
