Distributed spatial mode dispersion measurement along strongly coupled multicore fibers based on the correlation analysis of Rayleigh backscattering amplitudes.

We describe a method for measuring spatial mode dispersion (SMD) distribution along a strongly coupled multicore fiber (SC-MCF). The SMD has been defined for characterizing an SC-MCF, and it changes with respect to local fiber bending and twisting. However, conventional measurement methods characterize only the overall SMD, and cannot identify fiber portions where the environmental conditions affect the SMD. This paper demonstrates distributed SMD measurement along an SC-MCF by auto-correlating Rayleigh backscattering amplitudes obtained with coherent optical reflectometry. We confirm our method experimentally, and distinguish the difference between the SMD growth along twisted and non-twisted fiber sections in concatenated SC-MCFs.

Long-range measurement of Rayleigh scatter signature beyond laser coherence length based on coherent optical frequency domain reflectometry.

Long-range C-OFDR measurement of fiber Rayleigh scatter signature is described. The Rayleigh scatter signature, which is an interference pattern of backscatters from the random refractive indices in fibers, is known to be applicable to fiber identification and temperature or strain sensing by measuring its repeatability and its spectral shift. However, these applications have not been realized at ranges beyond the laser coherence length since laser phase noise degrades its repeatability. This paper proposes and demonstrates a method for analyzing the optical power spectrum of local Rayleigh backscatter to overcome the limitation imposed by laser phase noise. The measurable range and spatial performance are also investigated experimentally with respect to the remaining phase noise and noise reduction by signal averaging with the proposed method. The feasibility of Rayleigh scatter signature measurement for long-range applications is confirmed.

A case of an intraventricular inflammatory pseudotumor presumably caused by Epstein-Barr virus infection.

BACKGROUND: Inflammatory pseudotumor primarily affecting the CNS is an extremely rare lesion with uncertain etiology in most cases. CASE DESCRIPTION: A 67-year-old man developed involuntary movement disorder of the left upper extremity. On MRI, a solid homogeneously-enhanced tumor was noted in the right lateral ventricle adjacent to the thalamus. He had histories of right thalamic hypertensive hemorrhage and recurrent chronic nasal sinusitis associated with an orbital mass lesion, presumably an IP. Partial removal of the tumor yielded a diagnosis of IP associated with EBV infection. CONCLUSION: The simultaneous occurrence of multiple IPs was presumably because of an exaggerated immune process after EBV infection. Inflammatory pseudotumor should be considered in any case of intraventricular mass lesion.

Combined stimulation with interferon alpha and retinoic acid synergistically inhibits proliferation of the glioblastoma cell line GB12.

Since malignant glioma displays moderate resistance to conventional therapy, a new treatment modality is needed to improve the outcome of patients with these tumors. In this study, we examined whether combination stimulation with interferon alpha (IFN-alpha) and retinoic acid (RA) affected proliferation of the glioblastoma cell line GB 12 in vitro. Stimulation with IFN-alpha alone inhibited the GB 12 cell proliferation in a dose/time-dependent fashion, as assessed by WST-1 assay and uptake of 3H-thymidine, while RA limited it only slightly. The anti-proliferative action of IFN-alpha against glioblastoma cells was enhanced by the addition of RA. The IFN-alpha/RA combination also induced apoptosis in a substantial portion of the cells, compared with either reagent alone. Bcl-2 family proteins, regulating apoptosis, were altered by these stimuli: Bcl-2 was down-regulated, while Bax-alpha was up-regulated, especially by the combination. These findings suggest that the IFN-alpha/RA combination would synergistically affect glioblastoma cell growth, probably through apoptosis induction as well as a decreased cellular DNA synthesis.

Unexpected accumulation of thallium-201 in bilateral thalamic venous infarction induced by arteriovenous fistula in the posterior fossa: report of a case.

We encountered unexpected accumulation of thallium-201 in a patient with thalamic dementia resulting from bithalamic venous infarction induced by arteriovenous fistula in the posterior fossa The site and degree of abnormal accumulation varied between early and delayed thallium-201 SPECT images. This unexpected and complicated accumulation of thallium-201 appeared to depend on not only breakdown of the blood-brain barrier but also on the hemodynamics of this type of venous infarction.

[Cerebral aneurysms in identical twins].

The hypothesis that genetic factors play a role in the genesis of cerebral aneurysms may be supported by clinical analysis of cerebral aneurysms in identical twins. In addition to reporting the present case, we review the literature on clinical features and genetical considerations in this matter. A forty-two-year-old male presented with subarachnoid hemorrhage (SAH) due to a left MCA aneurysm. At the age of 39, his identical twin brother also had SAH due to a ruptured left MCA aneurysm. This identical twin brother and his father's sisters died of SAH. Venous blood of the patient and his parents was collected to determine apolipoprotein E, angiotensinogen, angiotensin-converting enzyme, and very low density lipoprotein receptor genes. This analysis suggested a strong genetic association of apolipoprotein E epsilon4 with the pathogenesis. Including our cases, 13 cases of cerebral aneurysms in identical twins have been reported. There was a total of 37 aneurysms. Six twins had the same sites of aneurysm. These aneurysms show a tendency to be small in size, and to cause a high frequency of SAH occurring at a similar age. In young adults, cerebral aneurysms in identical twins tend to rupture. A screening diagnosis should be carried out as early as possible on an asymptomatic twin when the other has been discovered to have a ruptured cerebral aneurysm. Preventive treatment and systemic genome-wide linkage study should be conducted.

[Bilateral chronic subdural hematoma in a young adult mimicking subarachnoid hemorrhage].

A 33-year-old man was admitted to our hospital with a sudden severe headache five days after the onset CT scan showed a slight high-density area in the basal cistern, mimicking subarachnoid hemorrhage (SAH), and diffuse brain swelling. However, conventional cerebral angiography and CT angiography failed to demonstrate aneurysms and vascular malformations. MRI showed bilateral subdural hematoma, but no SAH. Irrigation of liquefied subdural hematoma, causing high intracranial pressure, was carried out. Postoperative course was uneventful and his headache resolved within a day. The author presented a case of bilateral chronic subdural hematoma who presented with a sudden severe headache mimicking a SAH. Hyper attenuation in the basal cistern and subarachnoid space in CT, don't always indicate SAH. MRI, including fluid-attenuated inversion recovery (FLAIR) sequences, is useful in differentiating the "pseudo" SAH from "true" SAH, and lead to the right diagnosis.

Electrospinning processed nanofibrous TiO(2) membranes for photovoltaic applications.

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO(2) membranes as electrode materials. A thin TiO(2) film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF(4) aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)/titania nanofibrous membranes can be deposited on the pre-deposited thin TiO(2) film coated FTO by electrospinning of a mixture of PVac and titanium isopropoxide in N,N-dimethylformamide (DMF). The nanofibrous TiO(2) membranes were obtained by calcining the electrospun composite nanofibres of PVac/titania as the precursor. Spectral sensitization of the nanofibrous TiO(2) membranes was carried out with a ruthenium (II) complex, cis-dithiocyanate-N,N(')-bis(2,2(')-bipyridyl-4,4(')-dicarboxylic acid) ruthenium (II) dihydrate. The results indicated that the photocurrent and conversion efficiency of electrodes can be increased with the addition of the pre-deposited TiO(2) film and the adhesion treatment using DMF. Additionally, the dye loading, photocurrent, and efficiency of the electrodes were gradually increased by increasing the average thickness of the nanofibrous TiO(2) membranes. The efficiency of the fibrous TiO(2) photoelectrode with the average membrane thickness of 3.9 µm has a maximum value of 4.14%.