Finite element modelling of thermal and moisture mapping of layered cricket helmets.

This paper presents the development of numerical modelling to simulate thermal and moisture mapping of layered cricket helmets. The 3D laser scanning methodology was used to obtain geometrical data of a dummy human head with non-ventilated (NVL) and ventilated (VL) helmets to generate the meshes. Here, heat transfer and mass diffusion were applied in the finite element simulations to model the temperature and relative humidity (RH) distributions inside NVL and VL helmets, which were processed as the temperature-time and RH-time charts. The simulated results were validated against the corresponding experimental measurements with reasonably good correlation, in terms of the general trend on reginal temperature and RH against time, although parameters such as helmet movement and local sweating were not considered in the modelling to simplify the simulation. The discrepancies between the FE simulation results and the measurements are generally within 7% for in-helmet temperature and 5% for RH, for both types of helmets in the low ambient conditions (20 °C and 50% RH), although such the discrepancy is about 10% for the VL helmet subjected to the high ambient conditions (35 °C and 30% RH). The models developed are ready to be used for parametric studies on non-ventilated helmet to optimize the ventilation openings for improving the thermal comfort.

[The prediction of disease progression by 18Fluorodeoxyglucose-positron emission computed tomography/CT in patients with dermatomyositis and interstitial lung disease].

To investigate the predictive value of [18F]fluorodeoxyglucose-positron emission computed tomography(PET)/CT for disease progression in patients with dermatomyositis (DM) and interstitial lung diseases (ILD). Sixty-seven DM patients who underwent [18F] FDG-PET/CT imaging were retrospectively analyzed from January 2012 to September 2017 at PLA General Hospital. Their clinical manifestations and imaging characteristics were recorded. Compared with those chronically progressed (C-ILD), patients with rapid progression (RP-ILD) had significantly higher erythrocyte sedimentation rate (ESR) and standardized uptake value (SUV) in lungs (P<0.05). In patients with RP-ILD, SUV in lungs was positively correlated with age, disease course, and ESR. Receiver operating characteristic curve analysis suggested that when lung SUV cut off value was 2.25, the sensitivity and specificity to predict disease progression was 77.8% and 72.8%, respectively. Old age, longer disease course, low creatine kinase level, higher ESR, and high SUV are prognostic factors for DM-associated ILD.

[Analysis of neurobehavioral function of school-aged children with sleep disordered breathing].

Objective: To investigate the neurobehavioral function(attention, executive skills, behavior) of school-aged with varying degrees of SDB and control children with no history of SDB recruited from the community.Method: One hundred and sixty-three children aged from 7 to 12 were enrolled in the study. Children were devided into 4 groups through the data of Routine overnight polysomnography(PSG): PS(n=71) group, mild OSAHS (n=29) group, moderate/severe OSAHS(n=21) group, and controls(n=42) group. The Behavior Rating Inventory of Executive Function(BRIEF) and the Child Behavior Checklist(CBCL) were used to assess attention, executive function and behavioral function. Result: There was significant difference of AHI, OAI, RAI, SAI and SpO 2 nadir between the mild/MS groups and the control/PS groups(F=1174.3, 1178.0, 2348.3, 34.7, 377.7, P<0.05). Total sleep time(TST) of the MS OSAHS group was significantly less than that in the control group(F=178.8, P<0.05). Increased rates of behavioral executive dysfunction were found depending on the SDB spectrum(F=181.2, 274.2, 284.5, P<0.05). Children with all severities of SDB had signicantly higher rates of total, internalizing and externalizing behavioral problems compared to control group(F=361.7, 168.3, 564.0, P<0.05). Conclusion:Our study suggests that behavioral, attention, and executive function difficulties are present in children with PS as well as OSAHS. These results have implications for the treatment of milder forms of SDB, particularly PS, which is commonly viewed as benign.

[The application of (18)F fluorodeoxyglucose-positron emission tomography/computed tomography in the diagnosis and treatment of dermatomyositis].

OBJECTIVE: To investigate the value of (18)F fluorodeoxyglucose-positron emission tomography/computed tomography ((18)F FDG-PET-CT) in the diagnosis and the evaluation of disease activity and remission of dermatomyositis(DM). METHODS: DM patients who were admitted to the Department of Rheumatology, the People's Liberation Army General Hospital (PLAGH) and underwent (18)F FDG-PET-CT examination were retrospectively reviewed from January 2012 to May 2015.Gender and age matched healthy controls (HC) were also enrolled.The standardized uptake value (SUV) of proximal limb girdle muscles in both groups were recorded and compared, so as between patients with DM or subclinical DM.The correlation between myodynamia of proximal limb girdle muscle, creatine kinase(CK), CK-MB, serum ferritin and SUV of each muscle group were analyzed. RESULTS: There were 58 patients with DM and 29 controls consecutively recruited in the study.The SUV of upper arms (1.814±0.830) g/ml, shoulders (2.134±0.797) g/ml and hips (1.883±0.683) g/ml in patients with classic DM were significantly higher than those with subclinical DM [(0.938±0.218) g/ml, (1.152±0.315) g/ml, (0.945±0.249) g/ml; P<0.05]. SUV of muscles in newly diagnosed patients was (1.051±0.031) g/ml, which was higher than that in subclinical patients.But the difference was not statistically significant (P>0.05). The average SUV of evaluated muscles in DM group (2.033±0.858) g/ml was significantly higher than that in controls (1.076±0.167) g/ml (P<0.001). Receiver operating characteristic(ROC) analysis revealed the area under the curve(AUC) of abnormal SUV detected by (18)F FDG-PET-CT for diagnosing DM was 0.953.The myodynamia of upper arms and SUV was negatively correlated (rs=-0.440, P=0.031). However, the level of serum creatine kinase and SUV was positively correlated (rs=0.500, P=0.013). The average SUV of patients whose time to remission was less than 3 months (1.746±0.466) g/ml was obviously less than that of patients with 3 to 6 months to obtain remission (2.815±0.848) g/ml (P=0.015). CONCLUSIONS: The SUV of proximal limb girdle muscles detected by (18)F FDG-PET-CT has a positive diagnostic value for DM.Moreover, the SUV in upper arms is correlated with the muscle strength and the level of creatine kinase, which reflect disease activity. (18)F FDG-PET-CT might be an alternative method to evaluate the response of treatment.

Development of thermal models of footwear using finite element analysis.

Thermal comfort is increasingly becoming a crucial factor to be considered in footwear design. The climate inside a shoe is controlled by thermal and moisture conditions and is crucial to attain comfort. Research undertaken has shown that thermal conditions play a dominant role in shoe climate. Development of thermal models that are capable of predicting in-shoe temperature distributions is an effective way forward to undertake extensive parametric studies to assist optimized design. In this paper, two-dimensional and three-dimensional thermal models of in-shoe climate were developed using finite element analysis through commercial code Abaqus. The thermal material properties of the upper shoe, sole, and air were considered. Dry heat flux from the foot was calculated on the basis of typical blood flow in the arteries on the foot. Using the thermal models developed, in-shoe temperatures were predicted to cover various locations for controlled ambient temperatures of 15, 25, and 35 degrees C respectively. The predicted temperatures were compared with multipoint measured temperatures through microsensor technology. Reasonably good correlation was obtained, with averaged errors of 6, 2, and 1.5 per cent, based on the averaged in-shoe temperature for the above three ambient temperatures. The models can be further used to help design shoes with optimized thermal comfort.

Recognition mechanisms of the minus-strand origin of phage f1 by Escherichia coli RNA polymerase.

BACKGROUND: The primer RNA for the synthesis of the minus strand of filamentous coliphages is produced by host RNA polymerase at a specific site on the plus strand template. The mechanism used by the enzyme in recognizing the origin is unknown, but minus strand replication requires the holoenzyme form of RNA polymerase. The origin contains two inverted repeats which can form hairpins. RESULTS: When the origin sequence is drawn arranging the two hairpins horizontally, it resembles a stretch of a mostly double-stranded molecule. The nucleotides protected from nucleases by the holoenzyme were found to be located in two regions on this drawing: one around the 35th nucleotide upstream of the RNA start site, and the other ranging from the 10th nucleotide upstream to the 10th downstream, of the start site. The core enzyme did not show any protection. Mutational analyses of the origin indicated that the base-paired structure in the former region was important for origin activity. In the region around the 10th nucleotide upstream of the start site, specific base(s) in the non-template strand were required for origin activity, while the base sequence of the template strand was irrelevant. CONCLUSIONS: It is likely that the recognition mechanism of the origin by RNA polymerase shares common features with that of transcriptional promoters.