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Objective@#To understand the prevalence and distribution of learning disabilities among middle school students in Beijing.@*Methods@#By using stratified random cluster sampling, 6 365 students in grade one and grade two of 12 public middle schools in urban and rural in Beijing were selected. Criteria for learning disabilities included the following: on campus healthy students without serious physical and mental diseases and normal IQ assessed by combined Raven intelligence test; positive in the teacher rated Screening Scale for Middle School Students with Learning Disabilities; percentile ranking (below the bottom 10% percentile of grade) of the academic performance in the Chinese, mathematics and English tests.@*Results@#The learning disabilities of the subjects were determined by the teachers and it was found that the score of words reading, reading understanding, words spell, written expression, number calculation, mathematical reasoning and the total score of the scale were respectively (20.78±4.00, 18.16 ±4.35, 21.50±3.89, 20.06±3.92, 21.12±5.23. 18.67±5.35, 120.28±19.99) points. There were differences in the total score of learning ability between urban and rural areas, gender and grade. Urban area was better than rural area, girls were better than boys, and junior two students were better than junior one students( t=12.94, 9.94, 3.07, P <0.05). A total of 445(7%) students with learning disabilities were detected. Reading disabilities accounted for 5.0%, dysgraphia 2.7% and math disabilities 4.6%. Prevalence of learning ability differed by urban rural regions, gender and grade, with girls and students from urban areas and grade two being significantly lower( t =12.94, 9.94, 3.07, P <0.05).@*Conclusion@#The prevalence of learning disabilities in middle school students is high, which needs more attention.
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Objective To explore the effects of prenatal infection on the development of lungs by dynamic observation of morphology and numbers of inflammatory cells in lungs of rat pups exposed to antenatal inflammation.Methods Pregnant Wistar rats were randomly divided into experimental group and control group.Pregnant rats of both groups were intraperitoneal injected with either lipopolysaccharide (LPS) 2.5mg/kg or the same volume of normal saline on embryonic day 19 and 20, respectively, and were allowed to term deliver.Onday1, 3, 7, 14, 21and28 (D1, D3, D7, D14, D21 andD28), eight pups of each group were killed by 10％ chloral hydrate (1ml/kg) and lungs were collected.The numbers of myeloperoxidase (MPO) and CD68 as markers of both neutrophils and macrophages were counted.Morphometric assessments were performed by measuring the mean numbers of alveolar, the mean ratio of alveolar surface area to per tissue and the mean thickness of alveolar septum.Results With the increasing of postnatal days, the mean numbers of alveolar and the mean ratio of alveolar surface area to per tissue in both groups increased.The mean thickness of alveolar septum got thinner and the numbers of inflammatory cells decreased.On D1, D3, D7 and D14, the mean alveolar numbers of the experimental group (88, 89, 102 and 127 /mm2) were significantly less than those of the control group (105, 109, 123, 156/mm2), P =0.024, 0.009, 0.013, 0.004, respectively.On D1, D3 and D7, the mean ratios of alveolar surface area to per tissue were significantly larger (0.552,0.603 and0.533) than those of control group (0.478, 0.485 and 0.404), P=0.003, 0.001, 0.000, respectively.On D1 and D3, the alveolar septum thickness was significantly thinner (12.30 and 10.75 μm) thanthatin control group (17.13 and 16.13 μm), P=0.000, 0.000, respectively.On D1, D3, D7 and D14, the mean numbers of neutrophils of the experimental group (681, 582, 393 and 379/mm2) were significantly more than those of control group (164, 211, 145 and 179 /mm2), P =0.000, 0.000, 0.000,0.003, respectively.On D1, D3 and D7, the mean numbers of macrophages (613, 578 and 337 /mm2)were significantly more than those of control group (170, 182 and 127, /mm2) , P=0.000, 0.000, 0.000,respectively.Conclusion Prenatal infection results in larger and fewer alveolars and more inflammatory cells in lungs of rat pups.With the increasing of postnatal days, the alveolar morphology was similar to the controis.
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Objective To explore the therapeutic value of hemoperfusion combined with daytime high capacity hemofiltration in the treatment of severe acute pancreatitis.Methods The clinical data of 25 patients with severe acute pancreatitis treated by hemoperfusion combined with daytime high capacity hemofiltration(the observation group) were retrospectively analyzed,and compared with 30 severe acute pancreatitis patients without blood purification treatment(the control group).Results After the treatment,the biochemical indicator of the observation group was improved obviously compared with pre-treatment.Of the observation group,the hospital slaying time was shorter [(21.6±12.3) d vs(30.8±15.6) d],and the cure rate was higher(72％ vs 40％),and the death rate was lower (16％ vs 30％),compared with the control group(all P ＜ 0.05),but the treatment costs had no difference between the two groups.Conclusion Patients with severe acute pancreatitis on the basis of conventional treatment should conduct as early as possible hemoperfusion combined with daytime high capacity hemofiltration,and it could improve the success rate of the rescue and shorthen the length of hospital stay,and its curative effect was accurate.
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Objective To investigate the effect of human umbilical cord blood stem cells on flash visual evoked potentials (F-VEP) of the traumatic optic neuropathy rats.Methods Forty-eight Sprague-Dawley rats were randomly divided into an injury group (Group A) and 3 treatment groups (Groups B,C,and D).A traumatic optic neuropathy model was built in Group A,and the rats in Groups B,C,and D were injected with the neurotrophic factor,human umbilical cord blood stem cells,and the mixture of the neurotrophic factor and human umbilical cord blood stem cells,respectively.F-VEP was recorded in both eyes of rats at the 1st h,1st week,2nd week,3rd week,and 4th week after the optic nerve injury.Results At all time points,there were significant difference in the wave latency and amplitude between Group A and normal control eyes (P＜0.01).The differences of the wave latency and amplitude between Group A and Groups B,C,and D were statistically significant at various time points after the injury except for the wave latency at the 1st h post-operation (P＞0.05).The amplitude in Group D was higher while the latency was shorter than those of Group B at all time points since the 1st week (P＜0.05).The comparisons at the same point in the remaining treatment groups were not significantly different (P＞0.05).Conclusion The mixture of human umbilical cord blood stem cells and neurotrophic factor has a promotion effect for the recovery of F-VEP of optic nerve in traumatic optic neuropathy in rats to some degrees.
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Abstract The processs of female Osteoporosis and its prevention by Physical activity were simulated using anisotropic bone remodelling model with mechanostat combining with finite element method. The results show that bone mass declines slowly at the beginning, bone loss accelerates in postmenopause and bone mass declines 25. 84%-28.63% at the age of 60 and 38.50%-40.44% at the age of 80. Bone mass increases 3.05%-10.26% by an increase of 10%-20% in physical activity. The above results are consistent with clinical observations,which proves that declination of mechanical usage is the primary factor leading to osteoporosis, menopause quickens the process of female osteoporosis, physical activity can decelerate it.
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Aged , Female , Humans , Middle Aged , Biomechanical Phenomena , Bone Remodeling , Computer Simulation , Exercise , Physiology , Models, Biological , Osteoporosis, PostmenopausalABSTRACT
We tested the mechanical properties of fiber layers in adult anulus fibrosus of lumbar interverbral disc 4,5. Aulus fibrosus of lumbar interverbral disc was delaminated by using microsurgical technique. 8 testing points were taken in each layer according to the fibers going and 5 testing specimens were taken from each testing point. The length was 15-20mm, the width 1-2mm, and the thickness 0. 1-0. 5mm. By using tension test,the relationship curves of stress and strain were tested, the fitting curves and equations were obtained, and then the elastic modulus, damage strain and damage stress were obtained. Therefore we knew the parameters and equations of mechanical properties of each testing point. We got the result that the elastic modulus of each testing point, along the radius from outside to inside, decreased with the increase of layers. The damage stress decreased linearly from outside to inside. The damage strains of the outside 9 layers increased slightly with the increase of layers, and the others were almost constants, i. e. 0.34 +/- 0.14. We get the conclusion that analus fibrosus of intervertebral disc has special mechanical properties corresponding with its functions, which is in a close relationship with lumbar vertebral diseases.
Subject(s)
Adult , Humans , Male , Biomechanical Phenomena , Elasticity , Intervertebral Disc , Physiology , Lumbar Vertebrae , Physiology , Stress, Mechanical , Tensile Strength , PhysiologyABSTRACT
At present, the numerical model of bone remodeling is inadequate to copy the physiological process of bone remodeling. According to the physiological mechanism of bone remodeling and the anisotropy of bone mechanics properties, an anisotropic bone modeling model with mechanostat was developed, and then was applied to a study on the remodeling evolution of 2D squareplate model. Good results were obtained. The model can be used in the study of implant, osteoporosis and other bone diseases.
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Anisotropy , Biomechanical Phenomena , Bone Remodeling , Physiology , Bone and Bones , Physiology , Models, Biological , OsteoporosisABSTRACT
The structure of cancellous bone is cellular. There are two basic models of cancellous bone structure namely the model of rod-rod structure and the model of framework of perforated plate. This paper presents several models of structure developed from the model of rod-rod structure to the model of framework of perforated plate. We computed the elastic modulus of cancellous bone based on these modes using homogenization. The relationship between the elastic modulus(E) of cancellous bone and the apparent density(p) was determined to be E = 1.78rho1.88.
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Humans , Biomechanical Phenomena , Bone Density , Bone and Bones , Elasticity , Models, Anatomic , Stress, MechanicalABSTRACT
Bone is a load-bearing organ in human body. Fatigue damage occurs readily at the modest loads to which bone is subjected during its habitual physiological usage. Even bone fracture may occur during vigorous activity. The nature of fatigue damage is that in bone there are very fine microcracks which are smaller than typical microcracks, and may occur at the level of hydroxyapatite crystals. But bone can repair microdamage by bone remodeling. Osteocytes play an important role of signaling during bone remodeling. Some researchers attempted to describe the process of bone fatigue damage and repair by mathematic, mechanical models in order to understand it well and to apply it well in clinical practice.