Objective To apply 3C3R model in problem design of PBL for pediatrics teaching.Methods The 3C3R model comprises two classes of components:core components and processing components.Core components of the model are 3C,which are content,context and connection while processing components are 3R,which are researching,reasoning and reflecting.3C3R model was used in the problem design for the PBL case of ‘ Why the mouth of Baobao became purple when he was crying?' Totally 76 eight-year program medical students and 7 tutors were enrolled as teaching object.The anonymous questionnaires from the students were collected for assessment of PBL teaching.Results The percentage of students with scores ≥4 for content in PLB problem design was 90.8％,for context was 80.3％,for connection was 64.5％,for researching was 81.6％,for reasoning was 69.7％ and for reflecting was 40.8％.The percentage of tutors with scores ≥4 for content in PLB problem design was 100％,for context was 71.4％,for connection was 28.6％,for researching was 71.4％,for reasoning was100％,for reflecting was57.1％.Both students and tutors held a positive attitude towards the component of content,context,researching and reasoning in problem design model.But the components of connection and reflection needed to be improved.Conclusion The 3C3R model is helpful for problem design of PBL in pediatric teaching.

Objective To evaluate accuracy of density measurements within coronary plaque by multi-slice spiral CT and factors that influence measurements. Methods Four adult cadaver hearts were used. Thrombus and pericardial fat which acquired from specimen (size 2.0, 1.5, 1.0 and 0.5 mm respectively) were placed into coronary artery to simulate coronary plaques. The contrast medium (three different concentrations 1: 30, 1:40, and 1:50) were injected into coronary artery. The raw date were reconstructed with two slice width ( 1. 00 and 0. 75 mm). Results When contrast medium concentrations was 1: 30, the CT values of thrombus were 109 HU ( slice width 1. 00 mm, size 2. 0 mm) , 115 HU ( slice width 1.00 mm, size 1.5 mm), 101 HU (slice width 0.75 mm, size 2.0 mm), 113 HU ( slice width 0. 75 mm,size 1. 5 mm) ; the CT values of fat were - 23 HU ( slice width 1. 00 mm, size 2. 0 mm) , -17 HU(slice width 1.00 mm, size 1.5 mm) , -9 HU(slice width 1.00 mm, size 1.0 nun), -27 HU ( slice width 0.75 mm, size 2. 0 mm) , - 19 HU (slice width 0.75 mm, size 1. 5 mm) , - 13 HU (slice width 0. 75 mm,size 1. 0 mm). When contrast medium concentrations was 1: 40, the CT values of thrombus were 79 HU( slice width 1.00 mm,size 2.0 mm) , 87 HU( slice width 1.00 mm, size 1. 5 mm) , 115 HU( slice width 1. 00 mm,size 1. 0 mm) , 73 HU(slice width 0. 75 mm,size 2. 0 mm) , 80 HU(slice width 0. 75 mm, size 1. 5 mm) , 110 HU( slice width 0. 75 mm, size 1. 0 mm) ; the CT values of fat were - 31 HU ( slice width 1. 00 mm, size 2. 0 mm) , - 22 HU ( slice width 1. 00 mm, size 1. 5 mm) , - 10 HU ( slice width 1.00 mm,size 1.0 mm) , -35 HU(slice width 0. 75 mm,size 2.0 mm) , -25 HU(slice width 0. 75 mm, size 1. 5 mm) , - 19 HU ( slice width 0. 75 mm, size 1. 0 mm). When contrast medium concentrations was 1:50, the CT values of thrombus were 53 HU ( slice width 1. 00 mm, size 2. 0 mm) , 60 HU ( slice width 1.00 mm,size 1.5 mm) ,63 HU(slice width 1.00 mm,size 1.0 mm) ,51 HU(slice width 0.75 mm,size 2. 0 mm) ,64 HU( slice width 0. 75 mm,size 1. 5 mm) ,67 HU( slice width 0. 75 mm,size 1. 0 mm) ,145 HU (slice width 0. 75 mm, size 0. 5 mm) ; the CT values of fat were - 39 HU ( slice width 1. 00 mm, size 2. 0 mm) , -28 HU( slice width 1. 00 mm,size 1. 5 mm) , - 22 HU( slice width 1. 00 mm,size 1. 0 mm) , 17 HU(slice width 1. 00 mm,size 0. 5 mm) , -41 HU(slice width 0. 75 mm,size 2. 0 mm), -36 HU(slice width 0. 75 mm, size 1. 5 mm ) , - 27 HU ( slice width 0. 75 mm, size 1. 0 mm ) , 3 HU ( slice width 0. 75 mm, size 0. 5 mm ) . The density values of thrombus were correlated with size ( t = - 6. 624, P 0. 05) not found statistically significant may be caused by both too close slice width (1.0 mm and 0. 75 mm) and few samples. The slice width(t= -2. 595,P

Objective To investigate the relationship between expression of active form of caspase-3 and cell cycle in Fas-mediated apoptosis of B lymphocytoma cell line MML-1. Methods MML-1 cells were incubated with agonistic anti-Fas antibody for different time,and cell apoptosis was induced.Cell apoptotic rates were analysed by flow cytometry,and sensitivity of MML-1 cells to apoptosis was determined.The expression of active form of caspase-3 was analysed by double staining with PI-Triton X and FITC-active caspase-3.Cyclin A,B_1 and E were selected as cell cycle markers for S,G_2/M and G_1 phase of MML-1 cells,and the expression of active form of caspase-3 was detected by flow cytometry. Results The cell apoptotic rate reached 56% after induction by Fas for 6 h.After induction by Fas for 4 h,the active form of caspase-3 was mainly expressed in cells of G_1 phase,while rarely in cells of S and G_2/M phase.Cells with negative cyclin A and B_1 and positive cyclin E expressed active form of caspase-3. Conclusion The expression of active form of caspase-3 in MML-1 cells mediated by Fas might be cell cycle dependent.Cells entering into late G_1 and early S phase first express active form of caspase-3,and their sensitivity to Fas-mediated apoptosis is the highest.

Objective To develop nanometer-scale bubbles with surfaces of N-palmitoyl chitosan(PLCS) as ultrasound contrast agent and evaluate its characteristics and acoustic effects in vivo. Methods The PLCS nanobubbles were prepared using a cutting technique at differential high-frequency of shear speed. Both optical and transmission electron micrography were performed to determine the nanobubble size and morphology. Concentration, size-distribution and zeta potential of the PLCS nanobubbles were measured by cell counting chamber, Malvern lazer particle analyzer and zeta-sizer at 1-day, 45-day and 90-day. The acoustic effects of the PLCS nanobubbles on myocardium and renal tissue in 6 normal rats were observed using bolus infusion of the nanobubbles intravenously. The maximum video intensity(VI) was measured.Results The PLCS nanobubbles with nice round-shape and uniform site-distribution were demonstrated.The mean diameter,concentration and zeta potential of the PLCS nanobubbles were (617 ± 12) nm, (7.2 ±0.6) × 109/ml and (52.9 ± 1.3)mV at the 1-day,and all of parameters did not change significantly in 45-day and 90-day ( P ＞ 0. 05). A significant contrast-enhancement was noted on myocardium and renal tissue during infusion of the nanobubbles. VI on both tissues was (15.6 ± 1.1)GU and (27.3 ± 2.5)GU,respectively. The visual contrast-enhancement last up to (10 ± 2)min. Conclusions The PLCS nanometerscale bubbles have excellent physical-features and contrast-enhanced ultrasound effects in vivo. It may develop as a novel contrast ultrasound agent which could cross endothelial cell membrances.

Objective To explore the indications for percutaneous renal biopsy of asymptomatic hematuria in children. Methods The renal pathological types of 485 children with asymptomatic hematuria were analyzed retrospectively. According to the degree of hematuria and whether or not combined with proteinuria, the children were divided into microscopic hematuria group, gross hematuria group and hematuria with proteinuria group. The microscopic hematuria group was further divided into urine red blood cell<15/HPF group, (15～30)/HPF group, and >30/HPF group according to hematuria degree. Results In 227 males and 258 females with the average age of 7.23±2.93 years, there were 318 cases in microscopic hematuria group, in which the most common pathological types were minor lesions (64.8%), followed by focal glomerular lesions (16.7%) and focal segmental glomerulosclerosis (8.2%). There were 119 cases in gross hematuria group, in which the most common pathological types were also minor lesions (26.1%), followed by IgA nephropathy (24.4%) and mesangial proliferative glomerulopathy (20.2%). There were 48 cases in hematuria with proteinuria group, in which the most common pathological types were IgA nephropathy (29.2%) and minor lesions (29.2%). The distribution of the pathological types among microscopic hematuria group, gross hematuria group and hematuria with proteinuria group were statistically different (χ2=152.03, P<0.001). In three groups, microscopic hematuria group had the highest proportion of minor lesions, while gross hematuria group and hematuria with proteinuria group had higher proportion of IgA nephropathy and mesangial proliferative glomerulonephritis . In microscopic hematuria group, there were 149 children with urine red blood cell<15/HPF, 96 with urine red blood cell (15～30)/HPF, and 73 with urine red blood cell >30/HPF. There was no difference in pathological types among three sub-groups (χ2=15.18, P=0.51), and mild lesions were the most common pathological types in each group. Conclusion Renal biopsy should be performed at earliest possible time to make pathological diagnosis in asymptomatic hematuria children with gross hematuria or proteinuria.

Objective:To study the physical activity level and its influence factors among residents in one suburb of Beijing,so as to provide specific interventions for different people in different circum-stances and to provide reference for health relevant policy-making in the future.Methods:In the study, 7 31 9 subjects aged 1 8 years or above were involved.The self-designed questionnaires based on Health Belief Model (HBM)had acceptable validity and reliability.The physical activity levels were calculated to classify sufficient or insufficient amount by a thousand-step equivalent greater than or equal to 6 or 1 0. Multiple variable Logistic regression was used to explore the influence factors of the physical activity among the residents.Results:The residents’median amount of physical activity in the suburb district of Beijing were 9.1 thousand-step equivalent with quartile of (3.8,20.4).The percentages of the thou-sand-step equivalent greater than or equal to 6 or 1 0 were 63.7% and 47.7%,respectively.The median amounts of physical activity from work or household chores,transportation and recreation physical activi-ties were 4.0,1 .0,0.0 and the components of the total amount of physical activity from those were 61 .7%,1 8.3% and 20.1 %,respectively.There were 8.6% residents whose life did notinvolve moder-ate or vigorous intensity activities.By using factor analysis,five factors were extracted from the scale based on the HBM;These factors together contributed to 63.7% of the sum of the squared loadings.The differences of physical activity levels on education level,age,gender,self-efficacy,cues,subjective and objective barriers were statistically significant (P <0.05).Those who were female,with older age,lower education level,higher self-efficacy,fewer cues,fewer subjective and objective barriers preferred to do more physical activities.Conclusion:The physical activity levels among the residents in the suburb dis-trict of Beijing are moderate and high,and most amount of physical activities from work or household chores.Those who are male and whose ages are from 1 8 to 29 years and whose education levels are of university or above should be focused on intervention.Specific interventions should be developed for dif-ferent people in different situations;More attention should be paid to improve the residents’self-efficacy and reduce the subjective and objective barriers of physical activity,and we also should actively advocate people to have more leisure exercise so as to improve the physical activity level among all residents.

Objective To identify the risk factors for postoperative cognitive dysfunction (POCD) in elderly patients undergoing total knee arthroplasty (TKA).Methods Ninety-six American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients,aged 65-80 yr,with body mass index of 18-25 kg/m2,undergoing elective TKA under total Ⅳ anesthesia,were divided into POCD group and non-POCD group according to whether POCD occurred on 7th day after surgery.The patient baseline characteristics in the perioperative period,plasma concentrations of interleukin-1beta (IL-1β),tumor necrosis factor-alpha (TNFα),neuron-specific enolase (NSE) and S-100β protein,and visual analogue scale (VAS) scores at 1 and 2 days after operation were recorded.Logistic regression analysis was used to identify the risk factors for POCD.Results Thirty-eight patients developed POCD at 7 days after operation,and the incidence was 39％.The results of logistic regression analysis showed that the number of operations,VAS score during activity at 1 day after operation,and concentrations of TNF-α,IL-1β,NSE and S-100β protein in plasma were risk factors for POCD (P＜0.05).Conclusion The number of operations,VAS score during activity at 1 day after operation,and concentrations of TNF-α,IL-1β,NSE and S-100β protein in plasma are risk factors for POCD in elderly patients undergoing TKA.