Biological Role of Dystroglycan in Schwann Cell Function and Its Implications in Peripheral Nervous System Diseases

Dystroglycan is a central component of the dystrophin-glycoprotein complex (DGC) that links extracellular matrix with cytoskeleton, expressed in a variety of fetal and adult tissues. Dystroglycan plays diverse roles in development and homeostasis including basement membrane formation, epithelial morphogenesis, membrane stability, cell polarization, and cell migration. In this paper, we will focus on biological role of dystroglycan in Schwann cell function, especially myelination. First, we review the molecular architecture of DGC in Schwann cell abaxonal membrane. Then, we will review the loss-of-function studies using targeted mutagenesis, which have revealed biological functions of each component of DGC in Schwann cells. Based on these findings, roles of dystroglycan in Schwann cell function, in myelination in particular, and its implications in diseases will be discussed in detail. Finally, in view of the fact that understanding the role of dystroglycan in Schwann cells is just beginning, future perspectives will be discussed

Pulmonary tuberculosis with hypercalcemia

An 80-year-old man was referred to our hospital for further examination of fever, cough and left pleural effusion. The laboratory findings showed acute inflammation, and the elevation of albumin-corrected serum calcium and 1,25-dihydroxyvitamin D3. A chest CT revealed centrilobular particulate opacity in the bilateral lung fields and left pleural effusion, indicating acute hypercalcemia and hypervitaminosis D associated with pulmonary tuberculosis. By the confirmation of Mycobacterium tuberculosis on polymerase chain reaction and cultures of the sputum and pleural effusion, a diagnosis of pulmonary tuberculosis was made. The patient successfully completed a 9-month course of the anti-tuberculosis treatment, and bilateral infiltrative shadows and left pleural effusion in chest X-ray disappeared. Symptoms progressively improved and serum level of albumin-corrected calcium and 1,25-dihydroxyvitamin D3 eventually normalized. While pulmonary tuberculosis is an infrequent cause of hypercalcemia, it should be considered in patients with hypercalcemia and elevated serum level of 1,25-dihydroxyvitamin D3

Additional kernel observer: privilege escalation attack prevention mechanism focusing on system call privilege changes

Cyberattacks, especially attacks that exploit operating system vulnerabilities, have been increasing in recent years. In particular, if administrator privileges are acquired by an attacker through a privilege escalation attack, the attacker can operate the entire system and cause serious damage. In this paper, we propose an additional kernel observer (AKO) that prevents privilege escalation attacks that exploit operating system vulnerabilities. We focus on the fact that a process privilege can be changed only by specific system calls. AKO monitors privilege information changes during system call processing. If AKO detects a privilege change after system call processing, whereby the invoked system call does not originally change the process privilege, AKO regards the change as a privilege escalation attack and applies countermeasures against it. AKO can therefore prevent privilege escalation attacks. Introducing the proposed method in advance can prevent this type of attack by changing any process privilege that was not originally changed in a system call, regardless of the vulnerability type. In this paper, we describe the design and implementation of AKO for Linux x86 64-bit. Moreover, we show that AKO can be expanded to prevent the falsification of various data in the kernel space. Then, we present an expansion example that prevents the invalidation of Security-Enhanced Linux. Finally, our evaluation results show that AKO is effective against privilege escalation attacks, while maintaining low overhead

VLBI Monitoring Observations of Water Masers Around the Semi-Regular Variable Star R Crateris

We monitored water-vapor masers around the semi-regular variable star R Crateris with the Japanese VLBI Network (J-Net) at the 22 GHz band during four epochs with intervals of one month. The relative proper motions and Doppler-velocity drifts of twelve maser features were measured. Most of them existed for longer than 80 days. The 3-D kinematics of the features indicates a bipolar expanding flow. The major axis of the asymmetric flow was estimated to be at P.A. = 136 degrees. The existence of a bipolar outflow suggests that a Mira variable star had already formed a bipolar outflow. The water masers are in a region of apparent minimum radii of 1.3 x 10^12 m and maximum radii of 2.6 x 10^12 m, between which the expansion velocity ranges from 4.3 to 7.4 km/s. These values suggest that the water masers are radially accelerated, but still gravitationally bound, in the water-maser region. The most positive and negative velocity-drifting features were found relatively close to the systemic velocity of the star. We found that the blue-shifted features are apparently accelerated and the red-shifted apparently decelerated. The acceleration of only the blue-shifted features seems to be consistent with that of the expanding flow from the star.Comment: 15 pages, 5 figures, Accepted for publication in PASJ (2001), preprint can be obtained via WWW on http://www.nro.nao.ac.jp/library/report/list.htm

Effect of pH on the performance of an acidic biotrickling filter for simultaneous removal of H₂S and siloxane from biogas

Acidic biotrickling filters (BTF) can be used for simultaneous removal of hydrogen sulfide (H₂S) and siloxane from biogas. In this study, the performance of a BTF under different acidic pH conditions was investigated. The removal profile of H₂S showed that 90% of H₂S removal was achieved during the first 0.4 m of BTF height with down-flow biogas. Decamethylcyclopentasiloxane (D5) removal decreased from 34.5% to 15.6% when the pH increased from 0.88 to 3.98. Furthermore, the high partition coefficient of D5 obtained in under higher pH condition was attributed to the higher total ionic strength resulting from the addition of sodium hydroxide solution and mineral medium. The linear increase in D5 removal with the mass transfer coefficient (kL) indicated that the acidic recycling liquid accelerated the mass transfer of D5 in the BTF. Therefore, the lower partition coefficient and higher kL under acidic pH conditions lead to the efficient removal of D5. However, the highly acidic pH 0.9 blocked mass transfer of H₂S and O2 gases to the recycling liquid. Low sulfur oxidation activity and low Acidithiobacillus sp. content also deteriorated the biodegradation of H₂S. Operating the BTF at pH 1.2 was optimal for simultaneously removing H₂S and siloxane

Kinetics of solid phase interaction between Al and a‐Si:H

金沢大学工学部The kinetics of solid phase interaction between Al and a‐Si:H have been investigated. The experiment led to the observation of low‐temperature crystallization as has been reported. The crystallization temperature was found to be 300–350 °C from diffraction studies. From the x‐ray photoelectron spectroscopy study, electron transfer from Al to Si was observed in the intermixing layer in samples annealed at RT and 200 °C whereas there is no evidence of the electron transfer for 300 and 350 °C annealed samples. To explain these results, a comparison is made with the interaction in the Cr/a‐Si:H system previously reported and the interdiffusion model is proposed