The objective of this study is to investigate the use of pattern classification methods for distinguishing different types of brain tumors, such as primary gliomas from metastases, and also for grading of gliomas. The availability of an automated computer analysis tool that is more objective than human readers can potentially lead to more reliable and reproducible brain tumor diagnostic procedures. A computer-assisted classification method combining conventional MRI and perfusion MRI is developed and used for differential diagnosis. The proposed scheme consists of several steps including region-of-interest definition, feature extraction, feature selection, and classification. The extracted features include tumor shape and intensity characteristics, as well as rotation invariant texture features. Feature subset selection is performed using support vector machines with recursive feature elimination. The method was applied on a population of 102 brain tumors histologically diagnosed as metastasis (24), meningiomas (4), gliomas World Health Organization grade II (22), gliomas World Health Organization grade III (18), and glioblastomas (34). The binary support vector machine classification accuracy, sensitivity, and specificity, assessed by leave-one-out cross-validation, were, respectively, 85%, 87%, and 79% for discrimination of metastases from gliomas and 88%, 85%, and 96% for discrimination of high-grade (grades III and IV) from low-grade (grade II) neoplasms. Multiclass classification was also performed via a onevs-all voting scheme.

Recent studies of the spinal cord and cerebellum have highlighted the importance of atrophy in the development of neurological impairment in multiple sclerosis. We have therefore developed a technique to quantify the volume of another area commonly involved pathologically in multiple sclerosis: the cerebral white matter. The technique we describe extracts the brain from the skull on four contiguous 5 mm periventricular slices using an algorithm integrated in an image analysis package, and quantifies their volume. Intra-observer scan-rescan reproducibility was 0.56%. We have applied this technique serially to 29 patients with multiple sclerosis selected for an 18-month treatment trial with a monoclonal antibody against CD4+ lymphocytes (deemed clinically ineffective). A decrease in volume beyond the 95% confidence limits for measurement variation was seen in 16 patients by the end of the 18-month period. The rate of development of atrophy was significantly higher in those who had a sustained deterioration in their Kurtzke expanded disability status scale (EDSS) score compared with those who did not (respective means: -6.4 ml year-1 and -1.8 ml year-1, P < 0.05) but in both groups these changes differed significantly from baseline (P < 0.05). Baseline T2 lesion load, change in T2 lesion load over 18 months and the volume of new gadolinium enhancing lesions on monthly scans for the first 10 months showed no correlation with the development of atrophy. This study demonstrates that progressive cerebral atrophy can be detected in individual patients with multiple sclerosis, correlates with worsening disability and gives additional information to that obtained with conventional MRI. The effect of putative therapies aimed at preventing disability could be objectively assessed by this measure.

A ruthenium polypyridyl complex has been synthesized and examined as an emitter material in thin film electroluminescent devices. This material exhibits photoluminescent and electroluminescent effects as well as several reversible one-electron oxidation and reduction processes. Electroluminescent devices fabricated from this ruthenium complex either via spin coating methods or self-assembly techniques exhibit relatively high electroluminescent efficiencies and luminance levels in some cases as high as 100 cd/m2.

To verify the usefulness of diffusion tensor imaging (DTI) and fiber tractography (FT) compared with routine magnetic resonance imaging (MRI) in patients with cervical spinal cord injury, and to clarify the relationship between motor and sensory impairments and DTI and FT parameters, we performed routine MRI and DTI on 10 patients with chronic cervical spinal cord injury and on 10 controls. Quantitative parameters of DTI, such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC), were calculated for each cervical cord level. FT parameters of imaginary crossing fiber numbers were also determined at the C3 level, from C3-C6, and from C3-C7, as well as each connection rate. All patients' clinical motor and sensory functions were examined using the International Standards for the Neurological Classification of Spinal Cord Injury (ISCSCI). FA values in the controls and patients were 0.76 ± 0.08 (mean ± standard deviation) and 0.58 ± 0.11, respectively, and ADC values in the controls and patients were 1.29 ± 0.75 × 10(-3) mm(2)/sec and 1.26 ± 0.66 × 10(-3) mm(2)/sec, respectively. In patients with cervical cord injury, abnormal cervical levels detected on routine MRI were not correlated with clinical findings and DTI parameters, but FA of DTI was correlated with motor function, as were imaginary crossing fiber numbers and connection rates of FT. Quantitative DTI and FT analyses were useful in the evaluation of patients with cervical spinal cord injury. The injured cervical spinal cord can be evaluated in more detail and more precisely using DTI and FT, for which findings are correlated with clinical findings such as neurological impairments.

No abstract

The ultimate transparent electronic devices require complementary and symmetrical pairs of n-type and p-type transparent semiconductors. While several n-type transparent oxide semiconductors like InGaZnO and ZnO are available and being used in consumer electronics, there are practically no p-type oxides that are comparable to the n-type counterpart in spite of tremendous efforts to discover them. Recently, high-throughput screening with the density functional theory calculations attempted to identify candidate p-type transparent oxides, but none of suggested materials was verified experimentally, implying need for a better theoretical predictor. Here, we propose a highly reliable and computationally efficient descriptor for p-type dopability—the hydrogen impurity energy. We show that the hydrogen descriptor can distinguish well-known p-type and n-type oxides. Using the hydrogen descriptor, we screen most binary oxides and a selected pool of ternary compounds that covers Sn2+-bearing and Cu1+-bearing oxides as well as oxychalcogenides. As a result, we suggest La2O2Te and CuLiO as promising p-type oxides.

No abstract

J Korean Neurosurg Soc 48 : [288][289][290] 2010 The common etiologies of pneumocephalus, presence of air in the intracranial cavity, are trauma and cranial surgery. Pneumocephalus after spinal surgery is an unusual postoperative complication. We report the case of a male 59-year-old man who developed a pneumacephalus after posterior lumbar surgery for spinal stenosis. Intraoperatively, a cerebrospinal fluid leak following a dural tear was noted and immediately repaired. The next day, the patient complained of headache and dizziness. Head and lumbar computed tomography scans revealed significant air in the frontal region, several cisterns, intraventricle, and extra-dural area in the spine canal. Symptoms were spontaneously resolved within 2 weeks with conservative management.