Tree-Like Features Formed on Photoelectrochemically etched n-GaN surfaces ―Revelation of threading dislocations in GaN―

Electrochemical etching behavior of n-type GaN films grown on sapphire has been studied under UV (λ=325 nm) light illumination. As the cases for photoelectrochemical etching of n-type GaAs and InP, three different features appear on etched n-GaN surfaces depending on current density for etching; a high density (10^10 cm^<-2>) of tree-like protrusions at a lower c-urrent density, a relatively flat surface at an intermediate current density, and peeling of the film from the substrate at a higher current density. From the shape and the density of tree-like protrusions, in addition to the analogy of these results with those for n-type GaAs and InP, it is reasonable to conclude that tree-like protrusions formed at a low current density are due to threading dislocations involved in n-GaN films. Thus, the photoelectrochemical etching is found to become a convenient method to detect dislocations in n-type III nitride materials

Cyclic Undrained Behavior of an Undisturbed Gravel for Aseismic Design of a Bridge Foundation

For the aseismic design of a pier foundation constructed on a lightly cemented dense gravel deposit of a 3,910m-long suspension bridge, cyclic and monotonic undrained triaxial tests were performed on undisturbed specimens with a diameter of 30cm taken from the deposit under a sea depth of about 55m. Using the results of the cyclic undrained triaxial tests together with irregular cyclic stresses evaluated for the design earthquake motion by a dynamic FEM analysis, maximum strains in the gravel deposit were obtained by the cumulative damage concept. The strain values thus estimated indicated a sufficiently high degree of seismic stability of the foundation. Further, for the same initial mean Principal stress, the strength for monotonic undrained triaxial compression of isotropically consolidated specimens was found not greater than the strength against irregular cyclic undrained loading of the specimens anisotropically consolidated as in the field. This means that the former strength can be used as an approximated value of the latter

RGMa inhibition promotes axonal growth and recovery after spinal cord injury

Repulsive guidance molecule (RGM) is a protein implicated in both axonal guidance and neural tube closure. We report RGMa as a potent inhibitor of axon regeneration in the adult central nervous system (CNS). RGMa inhibits mammalian CNS neurite outgrowth by a mechanism dependent on the activation of the RhoA–Rho kinase pathway. RGMa expression is observed in oligodendrocytes, myelinated fibers, and neurons of the adult rat spinal cord and is induced around the injury site after spinal cord injury. We developed an antibody to RGMa that efficiently blocks the effect of RGMa in vitro. Intrathecal administration of the antibody to rats with thoracic spinal cord hemisection results in significant axonal growth of the corticospinal tract and improves functional recovery. Thus, RGMa plays an important role in limiting axonal regeneration after CNS injury and the RGMa antibody offers a possible therapeutic agent in clinical conditions characterized by a failure of CNS regeneration

A SCINTIGRAPHIC STUDY OF MASS PERISTALSIS IN HUMAN COLON

Although many attempts have been made to study human colonic motility, the colonic transit is still poorly understood. Both spontaneous and neostigmine-induced peristalsis of the colon were studied with scintigraphy. A polythene tube was inserted into the cecum through a colonofiberscope. 37 MBq of ⁹⁹ᵐTc-DTPA and 75 ml of saline were instilled and dynamic scan was begun. Eight healthy volunteers were examined by the method above mentioned. The sampling time was set at fifteen seconds in six persons and three seconds in the rest. 0.5 mg of neostigmine was injected intravenously to stimulate the paristalsis when no peristalsis occurred within thirty minutes after the study was begun. Dynamic scanning was performed for sixty to ninety minutes. This scintigraphic study revealed that the spontaneous and induced peristalsis were almost identical on colonogram. ⁹⁹ᵐTc-DTPA solution was propelled from the cecum and ascending colon to the sigmoid colon or the rectum for about fifteen seconds during mass peristalsis. Colonogram (time-activity curve) enables us to analyze mass peristalsis easily and more objectively than colonoscintigram. The spontaneous and neostigmine-induced peristalsis seemed to be almost identical in all but one of eight subjects

A Successfully Treated Case of Intrahepatic Cholangiocarcinoma with Exacerbation of Dermatomyositis

Dermatomyositis (DM) is often found in conjunction with malignant tumors such as lung, cervical, and breast cancer. However, the association with intrahepatic cholangiocarcinoma (ICC) is extremely rare. Moreover, to our knowledge, there have been no previous reports of DM discovered because of exacerbation of DM. Our case was a 44-year-old female with dry cough, myalgia, and arthralgia. We performed hepatic resection for intrahepatic ICC. She was diagnosed with DM, and combination treatment with prednisolone and tacrolimus was started. During outpatient visits, her symptoms worsened, and she was hospitalized due to deterioration of her primary disease. On detailed examination, a malignant lesion in the liver was discovered. After operation, the symptoms of DM remain stable by taking prednisolone and tacrolimus. The patient was suspected to have paraneoplastic syndrome, which was discovered due to the exacerbation of the DM that was caused by the intrahepatic ICC

Vaginal Lymphoma with Immune Thrombocytopenic Purpura: An Unusual Case Report

The female genital tract is rarely the initial site of presentation in lymphoma or leukemia. We report a case of non-Hodgkin's lymphoma (NHL) presenting initially in the vagina. The patient, a 75-year-old woman, had a history of immune thrombocytopenic purpura (ITP). She presented with a chief complaint of genital bleeding and introital pain. On transvaginal ultrasonography, a vaginal tumor with an irregular wall was detected, and the internal echo showed a hypoechoic and echogenic pattern. Ultrasonography and magnetic resonance imaging (MRI) suggested that the vaginal tumor was likely to be a hematoma or a hemorrhagic tumor arising from ITP. Incision and resection for a hematoma or a hemorrhagic tumor were carried out in response to genital bleeding, introital pain, and pathological diagnosis. Postoperative microscopic examination confirmed that the tumor was a vaginal NHL. The final diagnosis using the Ann Arbor staging system was high-stage (stage IV) NHL. The patient received chemotherapy, and she remains in remission for 42 months after treatment

Clinical significance of vascular endothelial growth factor and Delta-like ligand 4 in small pulmonary adenocarcinoma

Vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. The notch ligand Delta-like ligand 4 (DLL4) is induced by VEGF and acts as a negative regulator of tumor angiogenesis by reducing the numbers of non-productive sprouting vessels. Several reports have shown the prognostic role of VEGF expression in non-small cell lung cancer. However, the correlation between VEGF and DLL4 expression and their clinical significance in non-small cell lung cancer remains unclear. The aim of this study was to analyze the correlation between the expression of VEGF/DLL4 and the clinicopathological background. Fifty-eight patients with lung adenocarcinomas measuring less than 3 cm in diameter who underwent surgical resection at Kawasaki Medical School Hospital from 2008 to 2010 were enrolled in this study. The expressions of VEGF, DLL4, CD31, and Ki-67 were analyzed using immunohistochemical staining. The tumor cells were VEGF-positive in 44 patients (75.9%) and DLL4-positive in 41 patients (70.7%). No statistically significant association was observed between the patients\u27 characteristics and VEGF/DLL4 expression. A high VEGF expression level tended to be associated with a high DLL4 expression level (P = 0.050, r = 0.258). The mean Ki-67 index was significantly lower in the patients with high VEGF expression (9.5 vs. 18.2, P = 0.011), but no significant difference was observed when patients were compared according to their DLL4 expression levels (11.8 vs. 11.0, P = 0.804). The mean Ki-67 index was higher in the VEGF_ DLL4_ patients than in the VEGFhigh DLL4high patients by a marginally significant difference (20.1 vs. 10.9 P = 0.056). The 3-year recurrence-free survival rates of the VEGF_/DLL4_ and the VEGF_/DLL4_ patients were 83.3% and 35.7%, respectively. The prognosis of the VEGF_/DLL4_ patients was significantly better than that of the VEGF_/DLL4_ patients (P = 0.032). To investigate the significance of the difference in tumor proliferation and prognosis between the VEGF_/DLL4_ and the VEGF_/DLL4_ patients, we evaluated the morphologic effect of VEGF/DLL4 expression on the intratumoral capillaries by counting the number of capillaries and calculating the luminal area (μm^2). No significant differences were seen between either the VEGF or DLL4 expression levels and the mean number of intratumoral capillaries or the luminal area (μm^2). In conclusion, VEGF_/DLL4_ patients with small pulmonary adenocarcinoma had a significantly poorer prognosis, although no significant difference in a morphological evaluation of the capillaries was seen between VEGF_/DLL4_ and VEGF_/DLL4_ patients