Background The incidence of postural tachycardia syndrome （POTS） has been increasing in children and adolescents,while clinical characteristics of POTS in the pediatric population are not fully understood.Methods An...Background The incidence of postural tachycardia syndrome （POTS） has been increasing in children and adolescents,while clinical characteristics of POTS in the pediatric population are not fully understood.Methods An observational study was performed in 150 pediatric patients aged between 5 and 18 years who underwent head-up tilt test （HUTT） with the diagnosis of POTS at Peking University First Hospital from March 2008 to August 2013.Demographic data,clinical presentation,autonomic parameters,laboratory findings,and treatments were recorded.Results POTS in children commonly occurred in the age of 7-14 years.Dizziness （84.00％） was the most common symptom,followed by weakness （72.00％） and orthostatic syncope （62.67％）.Positive family history of orthostatic intolerance （Ol） was found in 24.64％ of children with POTS.And 33.09％ of them had preceding infection history as precipitating events.Ten percent of them suffered from orthostatic hypertension.Hyperadrenergic status was documented in 51.28％ of 39 patients who were tested for the standing norepinephrine levels.More than half of POTS patients,with 24-hour urinary sodium level ＜124 mmol/24 hours,were suitable for treatment of salt supplementation.At least 25.74％ of POTS patients were of positive acetylcholine receptor （AChR） antibody.Low iron storage in children with POTS was relatively rare.Most patients responded well to treatments,43.51％ of patients recovered,while 7.63％ of them had relapse after symptoms disappeared.Conclusions POTS is a relatively common condition with complex pathophysiology and heterogeneous clinical manifestation.A comprehensive therapeutic regimen is recommended for the treatment.展开更多
The enthalpies of formation of solid organic compounds containing carbon,nitrogen,oxygen,and hydrogen were estimated using two suggested descriptor sets,separately,by machine learning methods.The two descriptor sets a...The enthalpies of formation of solid organic compounds containing carbon,nitrogen,oxygen,and hydrogen were estimated using two suggested descriptor sets,separately,by machine learning methods.The two descriptor sets are both composed of descriptors of Benson’s groups and corrected groups.The main differences between them are that one is generated based on atoms and the other is based on bonds.An in-house program was specially written in Java to extract all the descriptors with a function to ensure that each atom(or bond)of a molecule is represented by Benson’s groups once for an atom-based(or bond-based)descriptor set.Multiple linear regression and partial least squares were used,separately,to build models to predict the enthalpy of formation for two descriptor sets.The combination of the models constructed by two descriptor sets based on the atoms and the bonds achieved the best-predicted results in this paper,and the corresponding results of the test set are better than that in the literature,from which the original data were retrieved.Further,a small data set of fluorinated molecules was collected,and satisfactory results were also obtained for these molecules containing fluorine with the assistance of the former data set.展开更多
文摘Background The incidence of postural tachycardia syndrome （POTS） has been increasing in children and adolescents,while clinical characteristics of POTS in the pediatric population are not fully understood.Methods An observational study was performed in 150 pediatric patients aged between 5 and 18 years who underwent head-up tilt test （HUTT） with the diagnosis of POTS at Peking University First Hospital from March 2008 to August 2013.Demographic data,clinical presentation,autonomic parameters,laboratory findings,and treatments were recorded.Results POTS in children commonly occurred in the age of 7-14 years.Dizziness （84.00％） was the most common symptom,followed by weakness （72.00％） and orthostatic syncope （62.67％）.Positive family history of orthostatic intolerance （Ol） was found in 24.64％ of children with POTS.And 33.09％ of them had preceding infection history as precipitating events.Ten percent of them suffered from orthostatic hypertension.Hyperadrenergic status was documented in 51.28％ of 39 patients who were tested for the standing norepinephrine levels.More than half of POTS patients,with 24-hour urinary sodium level ＜124 mmol/24 hours,were suitable for treatment of salt supplementation.At least 25.74％ of POTS patients were of positive acetylcholine receptor （AChR） antibody.Low iron storage in children with POTS was relatively rare.Most patients responded well to treatments,43.51％ of patients recovered,while 7.63％ of them had relapse after symptoms disappeared.Conclusions POTS is a relatively common condition with complex pathophysiology and heterogeneous clinical manifestation.A comprehensive therapeutic regimen is recommended for the treatment.
基金Open Research Fund Program of Science and Technology on Aerospace Chemical Power Laboratory,China(No.120201B01)National Natural Science Foundation of China(Nos.21875061,21975066).
文摘The enthalpies of formation of solid organic compounds containing carbon,nitrogen,oxygen,and hydrogen were estimated using two suggested descriptor sets,separately,by machine learning methods.The two descriptor sets are both composed of descriptors of Benson’s groups and corrected groups.The main differences between them are that one is generated based on atoms and the other is based on bonds.An in-house program was specially written in Java to extract all the descriptors with a function to ensure that each atom(or bond)of a molecule is represented by Benson’s groups once for an atom-based(or bond-based)descriptor set.Multiple linear regression and partial least squares were used,separately,to build models to predict the enthalpy of formation for two descriptor sets.The combination of the models constructed by two descriptor sets based on the atoms and the bonds achieved the best-predicted results in this paper,and the corresponding results of the test set are better than that in the literature,from which the original data were retrieved.Further,a small data set of fluorinated molecules was collected,and satisfactory results were also obtained for these molecules containing fluorine with the assistance of the former data set.
