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Of the schwannomas that arise from the parapharyngeal space, those in the high cervical region are particularly invasive, requiring mandibular dissection. Because these tumors are benign, however, excessive surgical invasion and postoperative neurological complications should be avoided. Postoperative dropout symptoms may be avoided by intracapsular extraction, including nerve integrity monitoring (NIM) and narrow-band imaging (NBI). Video laryngoscopy surgery is reported to be useful for transoral resection of pharyngeal and laryngeal tumors. This report describes the transoral removal of a giant schwannoma located in the high cervical region from a 74-years-old man using a surgical support device without mandibular dissection. The tumor was located on the right lateral pharyngeal wall and extended from the upper oropharynx to the hypopharynx while compressing the epiglottis to the skull base. No separation was observed between the internal jugular vein and the internal carotid artery. The tumor was diagnosed as a schwannoma with no malignancy on the basis of the histology of a core needle biopsy (CNB), and was completely and safely removed endoscopically using NIM and NBI, with no need for an external incision or mandibular dissection. This case illustrates that even a huge sympathetic schwannoma located in the parapharyngeal space at a high cervical position can be excised transorally using video-laryngoscopic surgery (TOVS) without mandibular dissection.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by type 2 inflammation with accumulation of activated group 2 innate lymphoid cells (ILC2s) and elevation of thymic stromal lymphopoietin (TSLP). A member of the TNF superfamily (TNFSF), TNFSF15, is known to induce the production of type 2 cytokines in ILC2s. Although ILC2s have been implicated in CRSwNP, the presence and role of TNFSFs in ILC2-mediated type 2 inflammation in CRSwNP has not been elucidated. Here, we investigate the involvement of TNFSFs in ILC2-mediated type 2 inflammation in CRSwNP. We found that receptor activator of NF-κB (RANK) ligand (RANK-L (TNFSF11)) was significantly elevated in nasal polyps (NPs), and that the receptor of RANK-L, RANK, was expressed on ILC2s in human peripheral blood and NPs. An agonistic antibody against RANK induced production of type 2 cytokines in human ILC2s, and TSLP significantly enhanced this reaction. The membrane-bound RANK-L was detected mainly on CD45 + immune cells, including TH2 cells in NPs. The co-culture of NP-derived ILC2s and TH2 cells significantly enhanced production of type 2 cytokines, and anti-RANK-L monoclonal antibody suppressed this enhancement. In conclusion, RANK-L, together with TSLP, may play an inductive role in the ILC2-mediated type 2 inflammation in CRSwNP.

IgG4-related disease (IgG4-RD) is a chronic fibroinflammatory disease characterized by elevation of serum IgG4 level as well as infiltration of IgG4+ plasma cells in various affected organs. The etiology of IgG4-RD is still not fully understood. Since IgG4-RD is more prevalent in the elderly, aging in itself is considered to be an important risk factor of IgG4-RD. However, the relationship between the pathogenesis of IgG4-RD and immunosenescence remains unknown. To clarify age-related features underlying IgG4-RD, we focused on T follicular regulatory (Tfr) cells, which share forkhead box P3 with regulatory T cells, since the percentage of Tfr cells is known to depend on age. Studies of blood specimens from patients with IgG4-RD and from healthy volunteers demonstrated a marked elevation of circulating Tfr (cTfr) cells in patients with IgG4-RD. Moreover, the percentage of cTfr cells was significantly correlated with various clinical parameters including the level of serum IgG4 and the number of involved organs in IgG4-RD patients. The percentages of tonsillar and blood Tfr cells were increased with aging in healthy volunteers, whereas the suppressive effect of cTfr cells on B cell function in elderly subjects was impaired in comparison with that in young subjects due to a defect in the production of a regulatory cytokine, IL-10. Given that the number of IL-10-producing cTfr cells in IgG4-RD patients was markedly increased compared with that in healthy elderly subjects, these findings suggest that an abnormal aging process of Tfr cells may be related to the pathogenesis of IgG4-RD.

Quantifying proliferative virus particles is one of the most important experimental procedures in virology. Compared with classical overlay materials, newly developed cellulose derivatives enable a plaque-forming assay to produce countable clear plaques easily. HEp-2 cells are widely used in plaque assays for human respiratory syncytial virus (RSV). It is crucial to use an overlay material to keep HEp-2 cell proliferation and prevent RSV particles from spreading over the fluid. Among four cellulose derivatives, carboxymethyl cellulose sodium salt (CMC), hydroxypropyl methylcellulose (HPMC), microcrystalline cellulose (MCC), and hydroxyethyl cellulose (HEC), we found that HPMC was the optimal overlay material because HPMC maintained HEp-2 cell proliferation and RSV infectivity. Although MCC was unsuitable for RSV, it assisted the plaque-forming by human metapneumovirus in TMPRSS2-expressing cells. Therefore, depending on the cells and viruses, it is necessary to use different overlay materials at varying concentrations.

Guanylate-binding protein-1 (GBP-1) is an interferon-inducible large GTPase involved in the epithelial barrier at tight junctions. To investigate the role of GBP-1 in the epithelial barrier, primary human salivary gland duct epithelial cells were treated with the the proinflammatory cytokines IFNγ, IL-1β, TNFα and the growth factor TGF-β. Treatment with IFNγ, IL-1β, or TNFα markedly enhanced GBP-1 and the epithelial barrier function, and induced not only CLDN-7 but also the tricellular tight junction molecule lipolysis-stimulated lipoprotein receptor (LSR). Knockdown of GBP-1 by its siRNA induced endocytosis of tight junction molecules, and prevented the increases of CLDN-7 and LSR with the upregulation of the epithelial barrier function induced by treatment with IFNγ or TNFα. Treatment with a PKCα inhibitor induced expression of GBP-1, CLDN-7 and LSR and enhanced the epithelial barrier function. In almost intact salivary gland ducts from patients with IgG4-related disease (IgG4-RD) indicated significant infiltration of IgG-positive plasma cells, expression of GBP-1, CLDN-7 and LSR was increased. These findings indicated that GBP-1 might play a crucial role in barrier function of normal human salivary gland duct epithelium and perform a preventive role in the duct epithelium of IgG4-RD disease.

Sarcoma caused by radiation therapy is called radiation-induced sarcoma (RIS). This rare pathology is being encountered with increasing frequency due to the longer survival time of patients after radiation therapy. We report a case of RIS in the anterior neck of an 82-year-old man who had achieved complete response from radiation therapy for subglottic cancer 11 years earlier. He presented to our facility with an enlarged anterior cervical tumor. Contrast-enhanced computed tomography (CT) indicated a massive tumor (27×34 × 45 mm) extending from the thyroid cartilage into the hyoid bone. Additional magnetic resonance imaging (MRI) showed a signal-hyperintense mass on T1-weighted imaging and signal heterogeneity on T2-weighted imaging, and contrast-enhanced MRI showed some enhancing effects in the tumor. Considering his history of radiation therapy and these imaging characteristics, RIS was suspected and complete resection of the tumor was performed. Dedifferentiated liposarcoma was diagnosed on histopathological examination. He has been followed-up for 6 months with no apparent recurrence.

Florid reactive follicular hyperplasia (FRFH), which is characterized by large germinal centers (GCs) within normal lymphoid follicles, is often observed in benign lesions of lymph nodes and other tissues. Because of the histologic similarity of FRFH to tumorous lesions such as follicular lymphoma, careful pathological examination is required to evaluate such lesions; however, little is known about the mechanism underlying the development of FRFH. In this study, we investigated T follicular helper (Tfh) cells in hyperplastic tonsils of patients with obstructive sleep apnea syndrome (OSA), which frequently exhibits typical FRFH. When we analyzed tonsils of OSA and recurrent tonsillitis (RT) as a control, tonsils of OSA were found to harbor Tfh cells with a nearly 3-fold higher ratio in total CD4+ T cells than that in tonsils of RT. Further analysis showed that, in comparison to Tfh cells of RT tonsils, Tfh cells of OSA tonsils were relatively tolerant to CD3-mediated activation-induced cell death (AICD) and also expressed lower levels of a Bob1 transcription coactivator and IL-4, which fosters the development of GC-B cells. Given that Bob1 controls the proliferative activity in response to CD3 stimulation and has been suggested to have a role in the production of IL-4 in Tfh cells, the unique structure of FRFH is possibly associated with the function of Bob1lo Tfh cells.

We present two cases of an HIV-associated parotid gland cyst. One case was a 36-year-old HIV infected woman. She was diagnosed with HIV infection and presented with slowly enlarged parotid gland cysts together with elevation of HIV viral RNA copies/mL in her serum. She was performed parotid gland biopsy under the general anesthesia. The histopathologic analysis revealed negative HIV p24-antigen in her parotid gland tissue. The other case was a 43-year-old man found his parotid gland swelling shortly after highly active antiretroviral therapy (HAART). He was diagnosed with HIV infection 2 years previously. He had started HAART several days before. He showed exceeding elevation of IgE in his serum. We treated him with medication using anti-histamic drugs for his cyst. A computed tomography scan revealed a complete response of his parotid gland cyst 4 weeks after the medication. His serum IgE level was decreased to half of the level before the medication. These findings suggested that the parotid gland swelling associated with HIV was due to various factors including immune reconstitution inflammatory syndrome (IRIS). In case such a parotid gland swelling, we could avoid invasive treatments.

NIP-SNAP-1 and -2 are ubiquitous proteins thought to be associated with maintenance of mitochondrial function, neuronal transmission, and autophagy. However, their physiological functions remain largely unknown. To elucidate their functional importance, we screened for proteins that interact with NIP-SNAP-1 and -2, resulting in identification of HSP60 and P62/SQSTM1 as binding proteins. NIP-SNAP-1 and -2 localized in the mitochondrial inner membrane space, whereas HSP60 localized in the matrix. Native gel electrophoresis and filter trap assays revealed that human HSP60 prevented aggregation of newly synthesized NIP-SNAP-2 in an in vitro translation system. Moreover, expression levels of NIP-SNAP-1 and -2 in cells were decreased by knockdown of HSP60, but not HSP10. These findings indicate that HSP60 promotes folding and maintains the stability of NIP-SNAP-1 and -2.

Lipid mediators such as leukotrienes and lipoxines broadly regulate innate and acquired immunity, and their dysfunction causes various immune-mediated disorders. We previously reported a salient feature of arachidonate 5-lipoxyganase (Alox5), which is responsible for the production of such lipid mediators, in the regulation of high affinity antibodies in vivo. The aim of this study was to determine the functional significance of Alox5-related lipid mediators during the processes of acquired humoral responses. The results of in vitro experiments using lymphocytes in tonsils and blood specimens showed that lipoxin A4 (LXA4) and leukotriene B4 (LTB4) have the capacity to differentiate naive CD4+ T cells into T follicular helper (Tfh) cells, which activate naive B cells to form germinal centers. Such a function of LXA4 was further supported by results of in vitro studies using BML-111 and BOC-2, which are an agonist and an antagonist, respectively, of FPR2 of an LXA4-specific cell-surface receptor. The results suggest that such lipid mediators have a potential role in the development of lymphoid follicles through the regulation of Tfh cell differentiation.

An aberrant internal carotid artery (ICA) is a rare abnormality associated with life-threatening otorrhagia if inadvertently injured during middle-ear surgery including myringotomy. We present a case where a 3-year-old girl experienced massive otorrhagia following myringotomy, and computed tomographic scan showed the aberrant ICA. Bleeding was controlled by ear canal packing, but rebleeding occurred. Investigations by carotid angiography demonstrated a pseudoaneurysm of the aberrant ICA in the middle ear. We attempted surgical repair using a high-flow bypass technique; however, the bypass graft was occluded by embolic complications, and eventually, ligation of the ICA was performed, which led to the paralysis of the patient's left limbs. In this report, management of iatrogenic aberrant ICA injuries and pseudoaneurysms in the middle ear are discussed based on the case that we experienced.

Macrolide antibiotics exert immunomodulatory activity by reducing pro-inflammatory cytokine production by airway epithelial cells, fibroblasts, vascular endothelial cells, and immune cells. However, the underlying mechanism of action remains unclear. Here, we examined the effect of clarithromycin (CAM) on pro-inflammatory cytokine production, including interferons (IFNs), by primary human nasal epithelial cells and lung epithelial cell lines (A549 and BEAS-2B cells) after stimulation by Toll-like receptor (TLR) and RIG-I-like receptor (RLR) agonists and after infection by human respiratory syncytial virus (RSV). CAM treatment led to a significant reduction in poly I:C- and RSV-mediated IL-8, CCL5, IFN-β and -λ production. Furthermore, IFN-β promoter activity (activated by poly I:C and RSV infection) was significantly reduced after treatment with CAM. CAM also inhibited IRF-3 dimerization and subsequent translocation to the nucleus. We conclude that CAM acts a crucial modulator of the innate immune response, particularly IFN production, by modulating IRF-3 dimerization and subsequent translocation to the nucleus of airway epithelial cells. This newly identified immunomodulatory action of CAM will facilitate the discovery of new macrolides with an anti-inflammatory role.

Allergic rhinitis (AR), the most common allergic disorder of the airway, is often accompanied by bronchial asthma. However, little is known about the mechanism by which AR advances to AR comorbid with bronchial asthma (AR+Asthma). To determine the pathophysiologic features of AR and AR+Asthma, we examined subsets of follicular helper T (Tfh) cells and regulatory B (Breg) cells in peripheral blood from AR and AR+Asthma patients. The results showed polarization of Tfh2 cells within Tfh cell subsets in both AR and AR+Asthma cases. Interestingly, the %Breg cells in total B cells were decreased in AR cases and, more extensively, in AR+Asthma cases. Moreover, we found significant correlations of fractional exhaled nitric oxide and blood eosinophil levels with the index %Tfh2 cells per %Breg cells. Our findings indicate that relative decrease in Breg cells under the condition of Tfh2 cell skewing is a putative exaggerating factor of AR to bronchial asthma.

Objective Tracheo-innominate artery fistula (TIF) is a rare but life-threatening complication following tracheostomy or tracheoesophageal diversion (TED). Although successful surgical intervention for TIF has been reported, few studies have been performed in patients with severe motor and intellectual disability (SMID). Therefore, we aimed to analyze TIF in patients with SMID to clarify the clinical variables predicting the occurrence and adequate management for lifesaving of TIF. Methods We retrospectively reviewed the records of patients with SMID undergoing surgical tracheostomy and TED between 2006 and 2012 and identified those with TIF. When TIF occurred, we obtained the clinical status and emergency management. Results Of 70 patients who underwent tracheostomy or TED during the study period, three patients had TIFs; in one case, TIF was avoided by ligation of the innominate artery before TED. The incidence of TIF in those undergoing tracheostomy and TED was 2.3% and 7.4%, respectively. The interval between tracheostomy and TIF was 14–50 months. Conclusions Patients with SMID may have an increased risk of TIF. Prompt diagnosis and surgical intervention to control the bleeding is the only effective management at present.

Micromagnetic models of side shielded perpendicular magnetic recording heads show detailed magnetization configuration of the trailing and side shield during the dynamic writing process. The calculation result indicates possible origins of three kinds. The leakage field at the side shield edge, the side shield saturation, and trailing and side shield domain switching. The side shield edge and the saturation induced fields are based on the geometric boundary and they are limited to just around the side shield edge. However the shield switching field can spread to far track position from the side shield to the trailing shield, and it originates from magnetic boundary of the domains and wall formed during the dynamic writing process. As a result, it produces bump field at far track positions in some trailing and side shields.

Organizational theorists have recently begun to pay research attention to the workforces of emerging countries in Asia, especially the greater China regions. However, little research has focused on the influence of organizational factors on safety in these countries. This study hypothesized that organizational factors, characterized as safety leadership perspective (management commitment, blame culture) and safety climate perspective (harmonious relationships), would influence group-level safety management, which would in turn influence individual level safety awareness and practices. To test this hypothesis, a safety climate questionnaire was distributed to ten Taiwanese plants in high-risk industries. Structural equation modeling (SEM) was used to analyze the linkages among organizational level factors, work-group-level factors, and workers’ safety awareness and practices. We found that safety leadership style and organizational harmony in Taiwanese high-risk industries can exert significant influences on work-group processes, which in turn have greater effects on individual safety awareness and practices. These findings and implications can serve as a basis for safety improvement in areas of the greater China region.

As the magnetic moment of soft under layer (SUL) decreases, the magnetic saturation during the write process becomes severe. It induces some partial erasures in the media write pattern and results in poor write performance such as an output roll-off and signal-to-noise ratio degradation. This erasure is due to the head field longitudinal component at the write gap after the transition writing in the trailing shielded pole perpendicular recording head. In case the SUL has low magnetic moment and high write current is inputted, erasure bubble appears next to the write bubble because the head field perpendicular component switches from positive to negative in the polarity. But the erasure appears even without the negative perpendicular field, and the longitudinal head field of the write gap is dominant for the erasure.

We herein report on a Japanese boy with infantile neuronal ceroid lipofuscinosis (INCL). He was born of incest to a girl and her maternal uncle. His development was normal at 12 months, and began to display regression at 14 months. He lost his social smile and tracking eye movement at 16 months, and could not stand and developed severe hypotonic tetraplegia at 19 months. Myoclonic movement was observed in his trunk, eye and extremities. His height, body weight and head circumstance had been normal. Both MRI and CT scans of his head showed severe cerebral, cerebellar and brainstem atrophy. The electroretinogram showed a decrease in amplitude. Enzyme studies revealed a deficiency of palmitoyl-protein thioesterase activity in his lymphocytes at 0.98 nmol/h/mg protein (control: 90.99+/-34.23). This is the first case of INCL in Japan diagnosed by enzyme activity deficiency.

Gap junctions are considered to play a crucial role in differentiation of epithelial cells and to be associated with tight junction proteins. In this study, to investigate the role of gap junctions in regulation of the barrier function and fence function on the tight junctions, we introduced the Cx26 gene into human airway epithelial cell line Clau-3 and used a disruption model of tight junctions employing the Na(+)/K(+)-ATPase inhibitor ouabain. In parental Calu-3 cells, gap junction proteins Cx32 and Cx43, but not Cx26, and tight junction proteins occludin, JAM-1, ZO-1, claudin-1, -2, -3, -4, -5, -6, -7, -8, -9, and -14 were detected by RT-PCR. The barrier function and fence function of tight junctions were well maintained, whereas the GJIC was low level. Treatment with ouabain caused disruption of the barrier function and fence function of tight junctions together with down-regulation of occludin, JAM-1, claudin-2, and -4 and up-regulation of ZO-1 and claudin-14. In Cx26 transfectants, Cx26 protein was detected by Western blotting and immunocytochemistry, and many gap junction plaques were observed with well-developed tight junction strands. Expression of claudin-14 was significantly increased in Cx26 transfectants compared to parental cells, and in some cells, Cx26 was co-localized with claudin-14. Interestingly, transfection with Cx26 prevented disruption of both functions of tight junctions by treatment with ouabain without changes in the tight junction proteins. Pretreatment with the GJIC blockers 18beta-glycyrrhetinic acid and oleamide did not affect the changes induced by Cx26 transfection. These results suggest that Cx26 expression, but not the mediated intercellular communication, may regulate tight junction barrier and fence functions in human airway epithelial cell line Calu-3.

The apical microvilli are closely related with the development and the maintenance of cell polarization, and the length of microvilli varies in a regular way among cell types. Ezrin, a member of the ezrin/radixin/moesin (ERM) family, seems to be involved in the formation and stabilization of the apical microvilli. We found that phosphorylation of ezrin caused elongation of microvilli via a p38 MAP-kinase signaling pathway in an immortalized mouse hepatic cell line. When, in the oncogenic Raf-1-transfected mouse hepatic cell line, epithelial to mesenchymal transition (EMT) indicated as down-regulation of E-cadherin and up-regulation of Snail occurred, loss of microvilli and down-regulation of ezrin but not radixin and moesin were also observed. In the Raf-1 transfectants treated with the MAP-kinase inhibitor PD98059 and the p38 MAP-kinase inhibitor SB203580, the numbers of microvilli and the expression of ezrin, E-cadherin and Snail were recovered. More interestingly, treatment with SB203580 induced elongation of microvilli and increased phosphorylation of ezrin (at Thr-567 and Tyr-353). Phosphorylated ezrin-positive dots were colocalized with actin-positive dots on the surface of some Raf-1 transfectants treated with SB203580. These results suggested that phosphorylation of ezrin via the p38 MAP-kinase signaling pathway might be involved in the formation of microvilli during development of epithelial cell polarization.

Background/Aims Hepatocyte regeneration is considered to be associated with adaptive changes in expression of gap and tight junctions through multiple signal transduction pathways including p38 MAP-kinase. The role of the stress responsitive MAP-kinase, p38 MAP-kinase, signaling pathway in function of gap and tight junctions was examined during regeneration of rat hepatocytes in vivo and in vitro. Methods We examined changes in formation, expression and function of gap and tight junctions in rat livers after 70% partial hepatectomy and in primary cultures of rat hepatocytes, by using a p38 MAP-kinase inhibitor, SB203580. Results When p38 MAP-kinase was activated during partial hepatectomy, down-regulation of Cx32 and up-regulation of claudin-1 were observed. By SB203580 treatment, the down-regulation of Cx32 was inhibited and the up-regulation of claudin-1 was enhanced, well maintaining the structures of gap and tight junctions. SB203580 treatment did not affect the increase of hepatocyte proliferation. In EGF induced proliferative rat hepatocytes treated with SB203580, the expression and function of Cx32 and claudin-1 were increased. Conclusions Dynamic changes of formation of gap and tight junctions during regeneration of rat hepatocytes in vivo and in vitro are in part controlled via a p38 MAP-kinase signaling pathway, and are independent of cell growth.

The magnetization dynamics of perpendicular writers was studied by using micromagnetic finite element models (micromagnetic-FEM). The obtained head response is different from a conventional dynamic-FEM result, and it shows the head field rise time of 0.5–0.6 ns, same as a longitudinal writer's one. During the switching process the head field has distortions under the write shield and an opposite polarity emphasis at the write shield edge in the profile. These phenomena are related to the flux sink region of the soft-magnetic underlayer (SUL), the interaction between SUL and the write shield, and the SUL domains switching; they can cause a wide-range erasure.

To achieve the recording technology over 10 Gb/in 2 , quite short bit cells have to be written and read probably by an MR head. The resolutions of unshielded and shielded MR heads were estimated for perpendicular and longitudinal recording. Moreover, we designed and fabricated some samples of the MR/Inductive heads that have been developed for perpendicular magnetic recording, and evaluated them with a double-layered medium. The shielded MR head offered high D50 of 170 kFRPI and high-density readback signal of 500 kFRPI. However, when the recorded bit length became shorter than the MR-to-shield gap, the shield had little effect and the output of the shielded head was no longer roughly equal to that of the unshielded head. Even unshielded MR head has good high-density recording characteristics in case of the combination with a perpendicular medium.

Accidents occurring in nuclear power plants cannot be depended upon to train experts of nuclear operators. Generally, this expertise is developed through the simulator training. In this training course, only limited varieties of malfunctions can be presented. Thus, it would be impossible for operators to cope with any other possible anomalies of diverse varieties. Operators have to reorganize knowledge and experiences obtained in the training. Of course, prescribed procedures are far from covering them. This paper presents the structure and contents of a “operator's mental model” and it can deal with flexible operations under any situation. Based on the record of the simulator experiments, in-depth analyses were conducted by interviewing with experienced operators in order to model operators' thinking patterns and also to arrive at the aims behind their actions and utterances. Summarizing the findings obtained, fundamental functions of the mental model in coping with anomalies resulted in the following: (1) suggesting suitable preventive measures by envisioning the ongoing (future) scenario of plant dynamics; (2) identifying causes by investigating symptoms and implying causal remedies to eliminate them or to avoid influences from them and (3) adopting immediate responses simply formulated by “if alarm A then action B”. These functions, as well as the mental model itself, can be made available by getting information on plant status and operator's structured knowledge together. The substances and structures of the mental models could be proposed, including implications of how to create it for a specific event, and finally they were synthesized into a more generalized format.

This paper is concerned with a model to simulate a team's decision-making process, named the disagreement solution model which composes “SYBORG; Simulation System for the Behavior of an Operating Group”. SYBORG simulates the behavior of an operator team coping with abnormal occurrences or events during power plant operations. The disagreement solution model takes into consideration several factors including: the arousal level, confidence, experience, rank, as well as other human characteristics (ascendancy, credibility, etc.) which seem to influence a team's decision-making process. In comparing simulation results produced with this model with actual experimental results, it was determined that the disagreement solution model successfully simulates the decision-making process of a control team under instances or situations of tension. In addition, this research also proposes that errors made within the team's decision-making process can be generally defined as the inability to find a fault in a wrong decision, to indicate errors, or the inability to select the best from many ideas struck upon by the members. Based on this definition, an operating teams' decision-making process, where errors in decisions can be made, may also be simulated by this model.

A case of melanin pigmented oncocytic metaplasia is reported. A 62-year-old man presented with a history of discomfort of the ear of a 2 weeks' duration. Nasoscopic examination revealed a black nodule of about 5mm at the left Eustachian opening, and several black spots were discovered around the bilateral torus tubarius. The nodule was biopsied to determine the histology. Microscopically, there were oncocytic cells with abundant pigmented granules showing glandular pattern. Such a pigmented variant of benign oncocytic lesion is very rare.

Fe-Si films have been prepared using a rf-sputtering apparatus, and the magnetic properties have been investigated. It is confirmed that Fe-Si/SiO 2 multilayered films improve the domain configurations and the magnetic properties, such as the initial permeability and the coercivity. These improved multilayered films were assembled as thin and narrow width main poles for single-pole type heads. A thinner main pole gave the higher D 50 and the value of 173 kFRPI was obtained at a film thickness of 75 nm. Also, reproduce sensitivity increases with decreasing track width, while the reproduced waveform and recording sensitivity were independent of the track width.

We examined the t  J and the t  t ′ J models in one dimension by numerical diagonalization. We introduced and calculated a quantity Q measuring the mixing of the charge and spin degrees of freedom in a wavefunction. In the case of t '/| t |=0, Q for the ground state vanishes in the limit of J /| t |→0, corresponding to the well-known perfect separation of the wave function. As J /| t | increases, Q increases rapidly for small J /| t | and becomes very close to the value of the Gutzwiller wavefunction for J /| t |=2. In the case of finite t ′/| t |, Q is finite even if J /| t |=0, showing that the hole motion drived by the second neighbor hopping t ′ effectively exchanges electronic spins or mixes the spin and the charge degrees of freedom.