Facile preparation of flexible porous carbon fibers as self-supporting sulfur cathode hosts for high-performance Li-S batteries.

Lithium-sulfur batteries are expected to be prospective candidates of high-energy-storage systems due to their high theoretical specific capacity. However, poor electrical conductivity, severe polysulfide shuttle effect and low sulfur utilization generally cause inferior electrochemical performance, hence hindering the practical development.  In this study, common makeup cotton derived self-supporting porous carbon fibers (SPCFs) are prepared by a facile simultaneous activation/pyrolysis process accompanied by the effectively regulation of a KHCO3 activator. The as-prepared SPCF materials have mutually cross-linked porous skeletons with an ultrahigh specific surface area of 2124.9 m2 g-1 and a large pore volume of 1.01 cm3 g-1, whilst exhibiting robust flexibility. When directly used as a self-supporting carbon current collector for encapsulating sulfur, the interconnected and abundant porous carbon fibers can not only immobilize soluble polysulfides, but also form a highly conductive network for the favorable redox transformation of adsorbed polysulfides. Moreover, the voids between the carbon skeletons can alleviate the volume change of sulfur cathodes during charge/discharge. Owing to these structure merits, the optimized SPCF-based sulfur cathode with a sulfur loading of 3.0 mg cm-2 shows a high coulombic efficiency of approximately 99% and delivers a first discharge capacity of 778 mA h g-1 at 0.2 C. Even at a relatively high current rate of 0.5 C, the reversible capacity of 450 mA h g-1 can be obtained after 300 cycles. The above-mentioned self-supporting porous carbon current collectors provide a guidance for high-performance lithium-sulfur batteries.

Quantitative evaluation in combination with nonquantitative evaluation in early patellar cartilage osteoarthritis at 3.0 T.

PURPOSE: To evaluate quantitative T1 and T2 relaxation times and magnetization transfer ratios (MTRs) in the early diagnosis of patellar cartilage osteoarthritis (OA) and to quantify and possibly refine the current Kellgren-Lawrence score criteria. MATERIALS AND METHODS: A total of 92 cases of knee joints with 40 normal volunteers and 30 patients with OA were prospectively evaluated. The knee joints with OA were divided into mild and moderate groups according to the Kellgren-Lawrence score criteria. The discriminative analysis method was used to analyze the accuracy of the original grouped cases correctly classified by age, sex, T1 relaxation times, T2 relaxation times, and MTR values. Linear regression analysis was used between T1 relaxation time, T2 relaxation time, and MTR values. RESULTS: The mean T1 relaxation times decreased with the severity of OA, and a significant difference was only found between the normal and moderate OA groups (P<0.05). The mean T2 relaxation times increased, and significant differences were found between the normal and mild OA groups and the normal and moderate OA groups (P<0.001). The MTR values were 35.8%±4.2%, 36.1%±3.2%, and 35.4%±3.8%, respectively. There were no significant differences between the normal and OA groups. In addition, T1 relaxation times were positively correlated with MTR values (P<0.01). A discriminative analysis using a synthesis of all the influential factors indicated a high accuracy rate (93.9%) for the correct classification of the original grouped cases. CONCLUSION: Quantitative T1 and T2 relaxation times were useful in the diagnosis of early OA; T2 relaxation times were more relatively sensitive. The functional usefulness of MTR values may be limited. T1 relaxation times positively correlated with MTR values. Multiple quantitative parameters, combined with some relative nonquantitative clinical parameters and Kellgren-Lawrence scores, may be useful in the early stage of OA and provide better information for clinical treatment and follow-up.

[Primary intermediate hemangioendothelioma of bone: a study of 5 cases].

OBJECTIVE: To study the radiologic and pathologic features of primary intermediate hemangioendothelioma of the bone. METHODS: Five cases of primary intermediate hemangioendothelioma of bone encountered in the past three years were enrolled into the study. The clinical, radiologic, pathologic and immunohistochemical features of the tumors were reviewed. RESULTS: The patients included 3 children with Kaposiform hemangioendothelioma and 2 elderly with retiform hemangioendothelioma. Four of the cases affected long bones and the remaining case affected the clavicle. One case showed multifocal involvement of the humerus. Radiologically, the tumors showed borderline to low-grade bony destruction, with various degrees of cortical defect. Intralesional or perilesional bone formation was demonstrated in 4 cases and radial spicules were seen in 1 case. The histopathologic features of primary intermediate hemangioendothelioma of bone were similar to those of soft tissue, except for the presence of reactive bone formation. Immunohistochemically, the tumor cells were positive for CD31 (5/5), CD34 (5/5), vimentin (5/5) and smooth muscle actin (3/5) but negative for cytokeratin and epithelial membrane antigen. CONCLUSIONS: Primary intermediate hemangioendothelioma of bone is a distinct entity and similar histologic classification applies as in its soft tissue counterparts. Comparison of the biologic behavior requires long-term follow-up studies.

The application of T1 and T2 relaxation time and magnetization transfer ratios to the early diagnosis of patellar cartilage osteoarthritis.

OBJECTIVES: We compare the T1 and T2 relaxation times and magnetization transfer ratios (MTRs) of normal subjects and patients with osteoarthritis (OA) to evaluate the ability of these techniques to aid in the early diagnosis and treatment of OA. MATERIALS AND METHODS: The knee joints in 11 normal volunteers and 40 patients with OA were prospectively evaluated using T1 relaxation times as measured using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T2 relaxation times (multiple spin-echo sequence, T2 mapping), and MTRs. The OA patients were further categorized into mild, moderate, and severe OA. RESULTS: The mean T1 relaxation times of the four groups (normal, mild OA, moderate OA, and severe OA) were: 487.3 +/- 27.7, 458.0 +/- 55.9, 405.9 +/- 57.3, and 357.9 +/- 36.7 respectively (p <0.001). The mean T2 relaxation times of the four groups were: 37.8 +/- 3.3, 44.0 +/- 8.5, 50.9 +/- 9.5, and 57.4 +/- 4.8 respectively (p < 0.001). T1 relaxation time decreased and T2 relaxation time increased with worsening degeneration of patellar cartilage. The result of the covariance analysis showed that the covariate age had a significant influence on T2 relaxation time (p < 0.001). No significant differences between the normal and OA groups using MTR were noted. CONCLUSION: T1 and T2 relaxation times are relatively sensitive to early degenerative changes in the patellar cartilage, whereas the MTR may have some limitations with regard to early detection of OA. In addition, The T1 and T2 relaxation times negatively correlate with each other, which is a novel finding.

[Chondroblastoma occurring in atypical sites].

OBJECTIVE: To study the clinical, pathologic and radiologic features of chondroblastoma occurring in sites other than epiphysis and apophysis of long bones, and to investigate possible reasons for misdiagnosis. METHODS: The clinical, pathologic and radiologic data of 18 chondroblastoma cases occurring in atypical sites were collected from 5 major hospitals in Shanghai during the past 12 years. S-100 immunostaining was performed to confirm the cartilaginous differentiation of the tumor cells. RESULTS: Chondroblastoma occurred in small bones of feet in 10 of the 18 cases (55.6%) studied, being commonest in the talus and calcaneus bones. Mean age of the patients was 27.8 years, with 55.6% over 25 years of age. Radiologic examination revealed expansive, multilocular and well-demarcated radiolucent lesions in most cases. There was local cortical destruction in 5 cases (28%) and soft tissue infiltration in 1 case. In 10 cases (55.6%), the tumor was associated with aneurismal bone cyst or simple bone cyst formation. None of the cases studied was accurately diagnosed clinically before the operation. In 2 cases, the pathology was also misdiagnosed, often being diagnosed as aneurismal bone cyst or giant cell tumor. CONCLUSIONS: Chondroblastoma occurring in atypical sites are often associated with atypical age, radiologic features and pathologic findings at presentation. Thorough understanding of the potential pitfalls is essential in order to avoid misdiagnosis.