Microinstabilities at perpendicular collisionless shocks: A comparison of full particle simulations with different ion to electron mass ratio

A full particle simulation study is carried out for studying microinstabilities generated at the shock front of perpendicular collisionless shocks. The structure and dynamics of shock waves are determined by Alfven Mach number and plasma beta, while microinstabilities are controlled by the ratio of the upstream bulk velocity to the electron thermal velocity and the plasma-to-cyclotron frequency. Thus, growth rates of microinstabilities are changed by the ion-to-electron mass ratio, even with the same Mach number and plasma beta. The present two-dimensional simulations show that the electron cyclotron drift instability is dominant for a lower mass ratio, and electrostatic electron cyclotron harmonic waves are excited. For a higher mass ratio, the modified two-stream instability is dominant and oblique electromagnetic whistler waves are excited, which can affect the structure and dynamics of collisionless shocks by modifying shock magnetic fields.Comment: 13 pages, 7 figures, Physics of Plasmas, in press; the paper with full resolution images is http://www.phys.aoyama.ac.jp/~ryo/papers/microinsta_PoP.pd

Exploring How Learning Style Relates to General and Career Management Self-Efficacy Beliefs in a Managerial Context

This study examined how learning style relates to self-efficacy beliefs in a managerial context. To make a theoretical frame, the study relied on Kolb’s experiential learning theory and a model of self-efficacy–performance relationship proposed by Gist and Mitchell. The study analyzed not only general efficacy but also specific efficacy focused on career management. Participants of this study consisted of 235 managers who worked for the Ministry of Finance in Indonesia. Results showed that managers’ learning orientation towards abstract conceptualization over concrete experience was associated with increased self-efficacy beliefs, whereas an orientation towards active experimentation over reflective observation was associated with general self-efficacy development but had a marginal influence on career management self-efficacy. This study sheds light on a link between learning style and self-efficacy development in organizations. Based on the findings, the study offers theoretical and practical implications for leveraging learning styles and self-efficacy beliefs in organizations

Secreted Mycobacterium tuberculosis Rv3654c and Rv3655c Proteins Participate in the Suppression of Macrophage Apoptosis

Inhibition of macrophage apoptosis by Mycobacterium tuberculosis has been proposed as one of the virulence mechanisms whereby the pathogen avoids the host defense. The mechanisms by which M. tuberculosis H37Rv strain suppress apoptosis and escapes human macrophage killing was investigated.The screening of a transposon mutant bank identified several mutants, which, in contrast to the wild-type bacterium, had impaired ability to inhibit apoptosis of macrophages. Among the identified genes, Rv3659c (31G12 mutant) belongs to an operon reminiscent of type IV pili. The Rv3654c and Rv3655c putative proteins in a seven-gene operon are secreted into the macrophage cytoplasm and suppress apoptosis by blocking the extrinsic pathway. The operon is highly expressed when the bacterium is within macrophages, compared to the expression level in the extracellular environment. Rv3654c recognizes the polypyrimidine tract binding Protein-associated Splicing Factor (PSF) and cleaves it, diminishing the availability of caspase-8. While M. tuberculosis inhibits apoptosis by the extrinsic pathway, the pathogen does not appear to affect the intrinsic pathway. Inactivation of the intrinsic pathway by pharmacologic agents afftects M. tuberculosis and induces cell necrosis. Likewise, inactivation of PSF by siRNA significantly decreased the level of caspase-8 in macrophages.While M. tuberculosis inhibits the extrinsic pathway of apoptosis, it appears to activate the intrinsic pathway leading to macrophage necrosis as a potential exit strategy

The Mg2+ transporter CNNM4 regulates sperm Ca2+ homeostasis and is essential for reproduction

Ca2+ influx triggers sperm capacitation; however, the underlying regulatory mechanisms remain incompletely understood. Here, we show that CNNM4, a Mg2+ transporter, is required for Ca2+ influx during capacitation. We find that Cnnm4-deficient male mice are almost infertile because of sperm dysfunction. Motion analyses show that hyperactivation, a qualitative change in the mode of sperm motility during capacitation, is abrogated in Cnnm4-deficient sperm. In contrast, tyrosine phosphorylation of flagellar proteins, a hallmark of capacitation, is excessively augmented. These seemingly paradoxical phenotypes of Cnnm4-deficient sperm are very similar to those of sperm lacking a functional cation channel of sperm (CatSper) channel, which plays an essential role in Ca2+ influx during sperm capacitation. Ca2+ imaging analyses demonstrate that Ca2+ influx is perturbed in Cnnm4-deficient sperm, and forced Ca2+ entry into these sperm normalizes the level of tyrosine phosphorylation. Furthermore, we confirm the importance of CNNM4 in sperm by generating germcell- specific Cnnm4-deficient mice. These results suggest a new role of CNNM4 in sperm Ca2+ homeostasis

Administration of tetrodotoxin protects artificially raised juvenile tiger puffer Takifugu rubripes from predators

We examined the effects of tetrodotoxin (TTX) administration on artificially raised tiger puffer Takifugu rubripes juvenile survival after release into a mesocosm with predators to clarify the ecological significance of TTX. Pellets containing three different concentrations of TTX [0 as the control, 7 and 14 mouse units (MU)/g diet] were fed to non-toxic artificially raised T. rubripes juveniles for 10 days. TTX accumulation in the various tissues of fish was detected except for in the control diet group. TTX administration did not affect survival or growth of the fish. One hundred fish from each diet group were released together after TTX administration into a salt pond mesocosm (2650 m2) with predators (Lateolabrax sp.) for 5 days. Survival after release was significantly higher in both the fish fed with the 7 MU TTX/g diet (62%) and the 14 MU TTX/g diet (74%) than in the control fish (32%)

An Assessment by In Situ Hybridization Method for Pathogens of Severe Respiratory Infection

It has been shown that the in situ hybridization (ISH)method for the detection of phagocyted bacteria in polymorphonuclear neutrophils is more sensitive than conventional blood culture in patients with sepsis.The present study was designed to further evaluate the clinical utility of the ISH method, using a commercially available kit (Hybrizep(R)), for detecting pathogens in patients with severe respiratory infections. Peripheral blood was taken from patients with severe respiratory infections for both routine blood culture and the ISH method,respectively.In addition,focal samples including sputum,bronchoalveolar lavage,central and thoracic catheter, etc. were simultaneously examined for bacterial culture. A total number of 22 specimens was examined.The positive cases by ISH were 50.0% in the respiratory infections,which were significantly higher than those in blood cultures (9.1%).However, identical pathogens in the ISH method were not isolated from blood and/or other sources in respiratory sites. These findings suggest a possibility of high frequency of bacteremia or multifactorious pathogens in severe respiratory infections.The ISH method may provide additional information on serious respiratory infections for the detection of bacteremia. However, the clinical utility by the ISH method for patients with severe respiratory infection remains undetermined. Shinshu Med J 59 : 223―228, 2011Article信州医学雑誌 59(4): 223-228(2011)departmental bulletin pape

The Synergistic Antitumor Effect of Combined Anti-Human Epidermal Growth Factor Receptor 2 Antibody and Gamma Interferon Therapy on Antibody-resistant Breast Cancer Cells

The anti-human epidermal growth factor receptor 2 （HER2） antibody （Ab） is a molecularly targeted Ab for cancer therapy. In the field of breast cancer, approximately 20％ overexpress HER2 protein. However, the recurrence rate is 30％ and the metastasis rate is 18％ one year after treatment of anti-HER2 Ab for HER2 positive breast cancer. The resistance to Ab treatment is a major problem for patients. We previously reported that anti-HER2 Ab and Gamma Interferon （IFN-γ） combined therapy show a higher anti-tumor effect than typical therapy in in vitro and in vivo mouse experiments. In this study, we evaluated whether anti-HER2 Ab and IFN-γ combined therapy shows a good synergistic effect against drug-resistant HER2 positive breast cancer cells and a higher antitumor effect than chemotherapy as a conventional clinical treatment. Further, we evaluated a synergy effect with the PD-L1 as a new check point inhibitor. The resistant cell lines were made under the continuous presence of Ab until cell growth was not affected by the drug. The resistant cells were divided into the appropriate number of groups, and then treated with anti-cancer therapy. We evaluated the antitumor effect for both the in vitro study and in vivo mouse xenograft model prepared with the same immunogenicity. The differences of immunofluorescence staining of CD8, Gr-1 and PDL-1 in tissues were investigated, especially in relation to the immune system. The combined therapy showed a significantly higher anti-tumor effect than other groups in in vitro and in vivo experiments. The combined therapy affected anti-tumor immunity in this immunofluorescence experiment. Taken together, we showed the possibility that combined therapy could be an effective treatment option for anti-HER2 Ab resistant breast cancer, thus helping patients suffering from cancer progression after developing treatment resistance

Endobronchial Argon Plasma Coagulation for the Palliation of Recurrent Tracheobronchial Adenoid Cystic Carcinoma

This is a non-final version of an article published in final form in Journal of Bronchology, 14(4):278-280, October 2007.The standard treatment of adenoid cystic carcinoma (ACC) of the airway is surgery, if possible, because survival rate is better than other treatments including radiotherapy. Although ACC shows frequent recurrence during the long-term follow-up unless there has been a complete resection (negative surgical margin), no further treatments are recommended. This report describes how argon plasma coagulation using flexible bronchoscopy has been successfully employed in the treatment of ACC after conventional therapy in 1 case of recurrence after surgery and 2 cases of inoperable patients. All of the patients are alive and healthy more than 6 years after diagnosis.ArticleJournal of Bronchology. 14(4):278-280 (2007)journal articl