Observations of large-amplitude, parallel, electrostatic waves associated with the Kelvin-Helmholtz instability by the magnetospheric multiscale mission

On 8 September 2015, the four Magnetospheric Multiscale spacecraft encountered a Kelvin-Helmholtz unstable magnetopause near the dusk flank. The spacecraft observed periodic compressed current sheets, between which the plasma was turbulent. We present observations of large-amplitude (up to 100 mV/m) oscillations in the electric field. Because these oscillations are purely parallel to the background magnetic field, electrostatic, and below the ion plasma frequency, they are likely to be ion acoustic-like waves. These waves are observed in a turbulent plasma where multiple particle populations are intermittently mixed, including cold electrons with energies less than 10 eV. Stability analysis suggests a cold electron component is necessary for wave growth

Dermatoscopic and mucoscopic features of lesions in patients with Behcet's disease

Objective: Behcet's disease (BD), as a vasculitis, can affect small and large vessels. As dermatoscopy has been shown to improve the accuracy in diagnosis of various skin lesions especially vascular patterns, we set this study to find if there is any characteristic pattern in the dermatoscopy of Behcet's mucocutaneous lesions.Methods: This prospective cross-sectional observational study designed to evaluate dermatoscopic features of Behcet's mucocutaneous lesions. Fifty six consecutive patients presenting at the outpatient clinic of the BD Research Unit were included. If present, for each patient one oral, one skin and one genital lesion were evaluated by dermatoscopy. When indicated, pathergy test was performed according to a standard protocol and the results were evaluated by dermatoscopy.Results: A total of 40 oral, 8 genital, 14 skin lesions and 14 pathergy tests were evaluated by dermatoscopy. While vascular component was the most prominent feature in oral aphthae, this component was less prominent in genital lesions. Dot vessels were the most common form of vessels in both oral and skin lesions. All the oral lesions were characterized by a central white structureless area. Skin lesions were characterized by a red structureless background. In pathergy tests, negative pricks showed absence of specific features while positive pricks were characterized by a structureless background in pink, purple or red. No obvious vascular component was detected in any of the pricks.Conclusion: It seems that these findings have no specific clues for the diagnosis of BD, but our study is the first study in this field and the findings may give way to further investigations

Epidemiology of hepatitis B in pregnant Iranian women: a systematic review and meta-analysis

Perinatal transmission is one of the most common routes of hepatitis B virus (HBV) transmission. This study aims to identify the epidemiological features of HBV among pregnant Iranian women. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Two authors independently searched several online databases without time limit until May 2017. The databases include Magiran, Iranmedex, SID, Medlib, IranDoc, Scopus, PubMed, Science Direct, Cochrane, Web of Science and Google Scholar. The data were analyzed based on a random-effects model using Comprehensive Meta-Analysis software version 2. Thirty-seven studies were included in the meta-analysis. The prevalence of HBV among pregnant Iranian women was 1.18 (95 CI: 0.09-1.53). The prevalence of HBV among pregnant women living in urban and rural areas was 1.60 (95 CI: 0.06-4.30) and 1.70 (95 CI: 0.09-3.2), respectively. The prevalence of HBV among housewives and working pregnant women was 4.3 (95 CI: 1.4-12.5) and 1.2 (95 CI: 0.02-5.8), respectively. The risk of developing an HBV infection was significantly associated with illiteracy (p = 0.013), abortion (p = 0.001), blood transfusion (p < 0.001) and addicted spouse (p = 0.045). However, no significant relationship was observed between HBV infection and urbanization (p = 0.65), occupation (p = 0.37), history of surgery (p = 0.32) or tattooing (p = 0.69). Vaccination coverage (receiving at least a single dose) in pregnant women was 9.8 (95 CI: 5.3-17.5). The prevalence of HBV among pregnant women is lower than in the general population of Iran. HBV vaccination coverage was low among pregnant Iranian women. Therefore, health policy-makers are recommended to enforce immunization programs for HBV vaccination among high-risk pregnant women