The aim of this work was to increase the efficacy of erythromycin ethyl succinate by encapsulation in beeswax lipid matrix using Myrj 52 as emulsifier. Different batches of SLM＇s （solid-lipid microparticles） were f...The aim of this work was to increase the efficacy of erythromycin ethyl succinate by encapsulation in beeswax lipid matrix using Myrj 52 as emulsifier. Different batches of SLM＇s （solid-lipid microparticles） were formulated and stable ones were selected. The encapsulation efficiency and loading capacities were calculated. The batch with the highest loading capacity was used for further assays. The particle size was determined by light microscopy. The sensitivity of different clinical bacterial isolates to erythromycin was tested using in vitro cultures and E. coli was selected for efficacy tests. The activity of the formulated drug was tested in the in vitro culture and compared to that of the unformulated drug. White albino mice were infected with E. coli and left for one day to develop significant bacteremia. They were then divided into 4 groups （n = 4） and treated with the formulation and unformulated drug at a dose of 7.14 mg/kg 8 hourly for 56 hours. A third group was given SLM＇s that do not contain drug, while another group was left untreated. The selected batch has an encapsulation efficiency of 94.83% with a loading capacity of 3.88%. The particle size was 17 ± 4 μm. At the end of the three day period of treatment, the group treated with unformulated erythromycin had much stooling anti weakness in the mice, and some deaths were recorded, while that treated with the formulation had 33.8% bacteremia and the clinical signs had largely subsided. The other two groups recorded deaths the following day after bacteremia induction. The results show marked improvement in efficacy of erythromycin ethyl succinate by formulation in SLMs with beeswax and lecithin as lipid matrix.展开更多
正交时频空间调制(orthogonal time frequency space,OTFS)技术作为一种多载波技术,同样存在峰均功率比较大的问题,高PAPR信号容易进入功率放大器的非线性工作区,导致接收信号的非线性失真,信号经过信道传输后会进一步影响系统的误码率(...正交时频空间调制(orthogonal time frequency space,OTFS)技术作为一种多载波技术,同样存在峰均功率比较大的问题,高PAPR信号容易进入功率放大器的非线性工作区,导致接收信号的非线性失真,信号经过信道传输后会进一步影响系统的误码率(bit error rate,BER)性能.针对该问题,利用chirp信号相位和为1的特点,采用基于chirp信号预编码的PAPR抑制方法,并在此基础上结合选择映射(selective mapping,SLM)法,将多组频域chirp信号与时频域信号点乘,再经过海森堡变换后选取PAPR最小的一组备选信号作为时域信号.仿真结果表明,与原始OTFS信号相比,基于频域chirp信号的OTFS系统的PAPR降低了0.9 dB,与传统SLM方法相比,使用基于频域chirp信号的SLM改进方法的OTFS系统,减少了IFFT次数的同时保证了系统的PAPR抑制性能.展开更多
文摘The aim of this work was to increase the efficacy of erythromycin ethyl succinate by encapsulation in beeswax lipid matrix using Myrj 52 as emulsifier. Different batches of SLM＇s （solid-lipid microparticles） were formulated and stable ones were selected. The encapsulation efficiency and loading capacities were calculated. The batch with the highest loading capacity was used for further assays. The particle size was determined by light microscopy. The sensitivity of different clinical bacterial isolates to erythromycin was tested using in vitro cultures and E. coli was selected for efficacy tests. The activity of the formulated drug was tested in the in vitro culture and compared to that of the unformulated drug. White albino mice were infected with E. coli and left for one day to develop significant bacteremia. They were then divided into 4 groups （n = 4） and treated with the formulation and unformulated drug at a dose of 7.14 mg/kg 8 hourly for 56 hours. A third group was given SLM＇s that do not contain drug, while another group was left untreated. The selected batch has an encapsulation efficiency of 94.83% with a loading capacity of 3.88%. The particle size was 17 ± 4 μm. At the end of the three day period of treatment, the group treated with unformulated erythromycin had much stooling anti weakness in the mice, and some deaths were recorded, while that treated with the formulation had 33.8% bacteremia and the clinical signs had largely subsided. The other two groups recorded deaths the following day after bacteremia induction. The results show marked improvement in efficacy of erythromycin ethyl succinate by formulation in SLMs with beeswax and lecithin as lipid matrix.
文摘正交时频空间调制(orthogonal time frequency space,OTFS)技术作为一种多载波技术,同样存在峰均功率比较大的问题,高PAPR信号容易进入功率放大器的非线性工作区,导致接收信号的非线性失真,信号经过信道传输后会进一步影响系统的误码率(bit error rate,BER)性能.针对该问题,利用chirp信号相位和为1的特点,采用基于chirp信号预编码的PAPR抑制方法,并在此基础上结合选择映射(selective mapping,SLM)法,将多组频域chirp信号与时频域信号点乘,再经过海森堡变换后选取PAPR最小的一组备选信号作为时域信号.仿真结果表明,与原始OTFS信号相比,基于频域chirp信号的OTFS系统的PAPR降低了0.9 dB,与传统SLM方法相比,使用基于频域chirp信号的SLM改进方法的OTFS系统,减少了IFFT次数的同时保证了系统的PAPR抑制性能.
