Heat Transfer Performance of a Novel Multi-Baffle-Type Heat Sink.

A new type of multi-baffle-type heat sink is proposed in this paper. The heat-transfer coefficient and pressure drop penalty of the employed six heat sink models are numerically investigated under five different inlet velocities. It is shown that Model 6 (M6) has excellent heat transfer performance as its heat-transfer coefficient reaches a value of 1758.59 W/m2K with a pressure drop of 2.96 × 104 Pa, and the temperature difference between the maximum and the minimum temperature of the heating surface is 51.7 K. The results showed that the coolant for M6 is distributed evenly to each channel at the maximal degree. The phenomena of the maldistribution of temperature is effectively improved. Moreover, the thermal resistance and thermal enhancement factor for the six models is also examined. M6 possesses the lowest total thermal resistance and largest thermal enhancement factor compared to the other five models. Furthermore, an experimental platform is set up to verify the simulation results obtained for M6. The simulated heat-transfer coefficient and pressure drop values agree well with the experimental results.

Prenatal diagnosis of foetuses with congenital abnormalities and duplication of the MECP2 region.

MECP2 duplication results in a well-recognised syndrome in 100% of affected male children; this syndrome is characterised by severe neurodevelopmental disabilities and recurrent infections. However, no sonographic findings have been reported for affected foetuses, and prenatal molecular diagnosis has not been possible for this disease due to lack of prenatal clinical presentation. In this study, we identified a small duplication comprising the MECP2 and L1CAM genes in the Xq28 region in a patient from a family with severe X-linked mental retardation and in a prenatal foetus with brain structural abnormalities. Using high-resolution chromosome microarray analysis (CMA) to screen 108 foetuses with congenital structural abnormalities, we identified additional three foetuses with the MECP2 duplication. Our study indicates that ventriculomegaly, hydrocephalus, agenesis of the corpus callosum, choroid plexus cysts, foetal growth restriction and hydronephrosis might be common ultrasound findings in prenatal foetuses with the MECP2 duplication and provides the first set of prenatal cases with MECP2 duplication, the ultrasonographic phenotype described in these patients will help to recognise the foetuses with possible MECP2 duplication and prompt the appropriate molecular testing.

[Clinical selection of endovascular stenting and carotid endarterectomy in treatment of carotid artery stenosis].

OBJECTIVE: To explore reasonable clinical decision in treating carotid artery stenosis under different conditions. METHODS: The data of 133 carotid artery stenosis patients were retrospectively analyzed. Of the patients, 46 cases were treated with carotid angioplasty and stenting (CAS), 87 patients received carotid endarterectomy (CEA). The length of hospital stay and National Institutes of Health Stroke Scale (NIHSS) grade before and after treatment in both groups were observed; the forward flow were assessed by digital subtraction angiography (DSA) before and after treatment; the degree of carotid artery stenosis were determined by using ultrasound during 3 to 24 months after treatment in both groups; the cumulative incidence of major cardiovascular events was concentrated, including appearance of death, stroke or myocardial infarction during 30 days after CAS and CEA and death or homonymy stroke during 31 days to 2 years. RESULTS: Significant difference was found in hospital stay and when NIHSS exceed 20 after treatment between the two groups (P < 0.05); there was no significant difference in the forward flow before and after treatment in both groups; the carotid artery stenosis had been improved significantly after the operation in both groups; the cumulative incidence of major cardiovascular events in CEA group was significantly higher than in CAS group in 30 days after the operation (P < 0.05), but no statistical difference in 31 days to 2 years after the operation. CONCLUSIONS: CAS and CEA has equivalent effects in treating carotid artery stenosis, and should be selected according to the location of stenosis, etiological factors and the condition of opposite carotid artery.