Spinning a Liquid Wheel and Driving Surface Thermomagnetic Convection with Light.

A typical Tesla thermomagnetic engine employs a solid magnetic wheel to convert thermal energy into mechanical energy, while thermomagnetic convection in ferrofluid is still challenging to observe because it is a volume convection that occurs in an enclosed space. Using a water-based ferrofluid, a liquid Tesla thermomagnetic engine is demonstrated and reports the observation of thermomagnetic convection on a free surface. Both types of fluid motions are driven by light and observed by simply placing ferrofluid on a cylindrical magnet. The surface thermomagnetic convection on the free surface is made possible by eliminating the Marangoni effect, while the spinning of the liquid wheel is achieved through the solid-like behavior of the ferrofluid under a strong magnetic field. Increasing the magnetic field reveals a transition from simple thermomagnetic convection to a combination of the central spin of the spiky wheel surrounded by thermomagnetic convection in the outer region of the ferrofluid. The coupling between multiple ferrofluid wheels through a fluid bridge is further demonstrated. These demonstrations not only unveil the unique properties of ferrofluid but also provide a new platform for studying complex fluid dynamics and thermomagnetic convection, opening up exciting opportunities for light-controlled fluid actuation and soft robotics.

[Application of 16-slice spiral low-dose CT in the diagnosis of tracheobronchial stenosis and obstruction].

OBJECTIVE: To investigate the clinical values of 16-slice spiral low-dose CT (LDCT) in the diagnosis of the tracheobronchial stenosis and obstruction. METHODS: Both 16-slice spiral LDCT and fiberoptic bronchoscopy (FB) were used to examine the tracheobronchial stenosis and obstruction in 28 patients. With the FB findings as the gold standards, we calculated the sensitivity, specificity, and accuracy of 16-slice spiral LDCT in the diagnosis of the tracheobronchial stenosis and obstruction. RESULTS: The sensitivity, specificity, and accuracy of 16-slice spiral LDCT were 91.3%, 97.6%, and 97.9% in the diagnosis of stenosis and obstruction of central airways, and were 98.1%, 86.7% and 97.6% in the diagnosis of those conditions of segmental bronchi. Difference between 16-slice spiral LDCT and FB was not significant in diagnosing the central air ways (P = 0.257) , but was significant in diagnosing segmental bronchi (P = 0.035). Significant consistency existed between 16-slice spiral LDCT and FB in examining the normal structure, stenosis, and obstruction of tracheo-bronchi (P < 0.001). The consistency was good (Kappa = 0.846) for central airways and was moderate for segmental airways (Kappa = 0.694). CONCLUSION: 16-slice spiral LDCT can accurately detect the tracheobronchial stenosis and obstruction and therefore be a useful tool in clinical practice.

[Bone mineral and body composition analysis of whole body in 292 normal subjects assessed by dual X-ray absorptiometry].

OBJECTIVE: To understand whole body bone mineral and body composition changes in normal subjects, and study the relationship between body composition and bone mineral. METHODS: 292 normal subjects aged 10-79 years old, including 140 males and 152 females, were selected to be measured bone mineral content (BMC), bone mineral density (BMD) lean and fat of whole body by dual X-ray absorptiometry (DXA). Individuals were divided into age-groups by every ten years and were analyzed by statistical methods. RESULTS: In males, peak values of BMC, BMD, lean and fat were in the 30-39, 20-39, 30-39, 70-79 age-groups. In females, they were in the 30-39, 30-39, 30-49, 50-69 age-groups respectively. Peak values of BMC, BMD and lean were higher in males than that in females, but peak value of BMD was not significantly higher in males than that in females. Peak value of fat was higher in females than that in males. Loss of BMC and BMD for females were more pronounced than that for males. Loss of lean for males was more pronounced than that for females. There are significant positive correlation between lean, weight and bone mineral in males and females. Fat has significant effect on BMC in females only. CONCLUSIONS: The normal bone mineral and body composition data of whole body for males and females, and the characteristic of changes with aging are provided for analyzing the relationship between bone mineral and body composition with ease.

[Clinical and pathological features of 5 adult patients with Langerhans cell histiocytosis].

OBJECTIVE: To improve the identification of Langerhans cell histiocytosis (LCH). METHODS: 5 adult cases of LCH treated in our hospital since 1990 were studied, the clinical data and pathological findings were analyzed. RESULTS: The sex ratio of male to female was 3 to 2, the mean age in this series of 5 patients was 36.8 years. All patients presented with multifocal or disseminated form of the disease. The involved organs included lung, skeleton, central nervous system, skin, liver, spleen and lymph node. The radiographic presentation of lung involvement includes diffuse micronodular densities (1 case), interstitial fibrosis with cyst formation (2 cases), limited infiltration in unilateral lung field (1 case) and isolated mass (1 case). Sharply demarcated bony rarefaction in radiogram was found in 3 cases. The presence of specific Langerhans cell in the focal lesion, which was the pathological basis for the definitive diagnosis of LCH, was detected in all patients. Systemic chemotherapy with corticosteroid and anthracycline based regimen was given to 5 patients and it caused retraction of the enlarged liver and spleen in 1 case, amelioration of lymph nodes and skin involvement in 2 cases and diminution of enlarged thyroid gland in 1 case, while it had less benefit in lung and bone involvement or to diabetes insipidus. CONCLUSIONS: LCH can be observed in young adults or middle-aged subjects. It should be suspected in patients who presented with diabetes insipidus, characteristic bony lesion and pulmonary involvement. The definitive diagnosis should be made pathologically in time. The proper treatment with low-dose radiotherapy and/or systemic chemotherapy should be taken based on the number and the function of systems involved.