233 research outputs found
Correlation between morphology and transport properties of quasi-free-standing monolayer graphene
No full textWe investigate the morphology of quasi-free-standing monolayer graphene (QFMLG) formed at several temperatures by hydrogen intercalation and discuss its relationship with transport properties. Features corresponding to incomplete hydrogen intercalation at the graphene-substrate interface are observed by scanning tunneling microscopy on QFMLG formed at 600 and 800 degrees C. They contribute to carrier scattering as charged impurities. Voids in the SiC substrate and wrinkling of graphene appear at 1000 degrees C, and they decrease the carrier mobility significantly
Stay tuned: Inter-individual neural synchronization during mutual gaze and joint attention
No full textEye contact provides a communicative link between humans, prompting joint attention. As spontaneous brain activity may have an important role in coordination of neuronal processing within the brain, their inter-subject synchronization may occur during eye contact. To test this, we conducted simultaneous functional MRI in pairs of adults. Eye contact was maintained at baseline while the subjects engaged in real-time gaze exchange in a joint attention task. Averted gaze activated the bilateral occipital pole extending to the right posterior superior temporal sulcus, the dorso-medial prefrontal cortex, and bilateral inferior frontal gyrus. Following a partner’s gaze towards an object activated the left intraparietal sulcus. After all task-related effects were modeled out, inter-individual correlation analysis of residual time-courses was performed. Paired subjects showed more prominent correlations than non-paired subjects in the right inferior frontal gyrus, suggesting that this region is involved in sharing intention during eye contact that provides the context for joint attention
Riukiaria mundyi Korsós, Nakamura & Tanabe, 2011, sp. n.
No full textRiukiaria mundyi sp. n. Figs 4 –6, 14– 19. Holotype male (NSMT-My 379)— Japan, Southern Ryukyus, Yaeyama Group, Yonaguni-jima Island, Mt. Dunandake, primary forest, N 24.4577 ° E 122.9711 °, 146 m alt., 31 August 2009, leg. Z. Korsós & Y. Nakamura. Paratypes: 3 males, 5 females, 2 juvs. (RUMF, HNHM)—Same locality and date. 1 male, 1 female (RUMF)— Japan, Southern Ryukyus, Yaeyama Group, Yonaguni-jima Island, Adigara Cave area, near construction place, N 24.4599 ° E 122.9594 °, 44 m alt., 2 September 2009, leg. Z. Korsós & Y. Nakamura 2 females (NSMT-My 380)— Japan, Southern Ryukyus, Yaeyama Group, Yonaguni-jima Island, Arakawabana forest trail, 134 m, primary forest, N 24.4441 ° E 123.0107 °, 1 September 2009, leg. Z. Korsós & Y. Nakamura 4 males, 5 females, 3 juvs. (RUMF, HNHM)— Japan, Southern Ryukyus, Yaeyama Group, Yonaguni-jima Island, Kubura-bari, N 24 ° 27.4 ’ E 122 ° 56.6 ’, 50 m alt., rocky grassland, 14 February 2010, leg. R. & Z. Korsós Diagnosis. A member of the genus Riukiaria as defined by Shinohara (1977) and Tanabe and Shinohara (1996) with the simple, forceps-like male gonopod conformation. It differs from congeners first of all by its coloration in life (almost uniformly pinkish-orange), by its exclusive occurrence on a single island (Yonaguni-jima), and in details of gonopod morphology. FIGURES 14–16. Riukiaria mundyi sp. n. 14 = Anterior body part paratype male, dorsal view; 15 = Epiproct of paratype male, dorsal view; 16 = Sternum, coxa, and prefemur of 2 nd legpair of paratype male, posterior view. Scales 1 mm (14,15) and 0.5 mm (16). Etymology. The specific epithet is a patronym in honor of Mr. Imre Mundy (Budapest), a Hungarian engineer, long time friend and supporter of the first author (genitive, masculine). Description. Measurements: Body size generally smaller than in most other Riukiaria species. Length of males 36–42 mm, midbody paranotal width 7.5–8 mm, metatergal length 1.8–2 mm, collum width 6–6.6 mm, length 2.4–3 mm (n= 4). Female body length 36–41 mm, midbody paranotal width 7.8–8.6 mm, metatergal length 1.8–2 mm, collum width 6.3–7.1 mm, length 2.8–3.3 mm (n= 8). Kubura-bari population (see Remarks): Male body length 25–26 mm, midbody paranotal width 5.1–5.3 mm, metatergal length 1.2–1.3 mm, collum width 4.4– 4.6 mm, length 1.9–2.1 mm (n= 4). Female body length 30–31 mm, midbody paranotal width 6.3–6.8 mm, metatergal length 1.3–1.4 mm, collum width 5.2–5.5 mm, length 2.5–2.6 mm (n= 5). Color in life (Fig. 4): Whole body is almost uniformly light orange, pinkish, occasionally tending toward reddish or dark yellowish. Head, prozona, legs, and underside paler, 6 th segment of antennae, tibiae and tarsi whitish. On collum and each metatergum a slightly darker, almost brownish median patch, pronounced towards paranota as oval spots. On preserved specimens (70 % ethanol) the vivid color quickly disappears, only shadows of the abovementioned pattern remains. Coloration of males and females does not differ. Fluorescence in UV light strong (Figs 5–6), especially on prozona and underside, metazona are slightly greyish. Head smooth, epicranial suture distinct, 2 + 2 frontal setae, several setae scattered above clypeus, with 2 dense rows at its margin and on labrum. Antennae straight, first article globose, 2 nd slightly clavate, subequal with articles 3 –5, 6th longest, about 1.2 x longer than 5 th, 7 th small, slender, slightly longer than wide. Gnathochilarial stipites and lamellae linguales covered densely with short hairs, large, triangular mentum with smaller, distinct, median hair-field. Collum convex, smooth, shiny, lateral and posterior margin with weak ridge, lateral corners triangular, slightly directed caudad. Pro- and metaterga smooth without any traces of tubercles or punctuation, not even wrinkles. Posteriolateral edge of paranota 2–3 triangular, on 4 th and onwards strongly pointed caudad (Fig. 14). Pore formula normal, pores on paranota 5,7,9,10,12,13,15,16, 17, and 18, in median excavation of paranota (in lateral view). Sides between segments 6–13 perfectly parallel, segments 14–19 gradually tapering, posteriolateral projections become more pointed. Epiproct in dorsal view subtriangular (Fig. 15), in lateral view protruding over paraprocts, parallel-sided, slightly curved ventrad, with 7 + 7 setae, 3 + 3 of them sitting on knobs. Paraprocts strongly marginate with 2 + 2 setae, hypoproct with 1 + 1 setae on knobs. Midbody legs well separated (by 1.8–1.9 mm in males, 2.4–2.8 mm in females), sterna wide and smooth. Postgonopodal legs with moderately developed ventral spine on prefemur, increasingly stronger towards body end, femur about twice as long as prefemur, straight, postfemur crassate, tibia straight, both subequal in length and about 1 / 3 rd of femur, tarsus slender, about twice as long as tibia, claw (ca. 0.5 mm long) curved. Sexual characters: Male 2 nd legpair (Fig. 16) coxa with strong median projections about half as long as length of coxa, apically with membraneous tubules surrounded by strong setae, 1 + 1 macrosetae sitting at joint of prefemur (1 anteriorly, and 1 posteriorly). No other sternal or leg modification could be observed. Male gonopodal aperture on segment 7 wide, elliptical, about twice as wide as long, gonopods in situ usually deeply embedded, with acropodites crossing each other. Coxa (Figs 17–18, c) long, slender, about twice as long as wide, without apophysis but with small apophyseal macroseta (cm). Cannula normal, hidden on mesal side. Telopodite consists of two simple processes (Figs 17–18) forming a simple, forceps-like appearance typical for Riukiaria (Tanabe & Shinohara 1996), the shorter branch being the prefemoral process (pfp), growing proximally from the base of prefemur, the latter being thick and short, and densely covered with long hairs. Prefemoral process about 3 / 4 th of length of acropodite, devoid of any seta, knob, or additional process, flattened, parallel-sided, spatula-shaped, almost transparent. Acropodite (as a continuation of prefemur) long, scythe-shaped, arched proximally towards prefemoral process, with its slightly broadened to triangular, pointed tip (s) almost bending back to that. Distinction between prefemur and acropodite indefinite, hairs becoming scarcier at about 1 / 3 rd of total length, but about half length still a strong macroseta (ms) on lateral side of acropodite. Prostatic groove runs straight medially along mesal side of acropodite, and ends indistinctly on its pointed tip. Female cyphopods (Fig. 19) closely packed behind 2 nd legpair, in large, ∞-shaped aperture, valves (v) are oval, nearly as high as wide, densely setose, operculum (op) on lateral side small, less than half as high as valves, with fewer and shorter but stronger setae, receptacles (r) embracing valves both anteriorly and posteriorly, subrectangular, with several series of short hairs only along ventral margin. Distribution. R. mundyi sp. n. is restricted to Yonaguni-jima Island, the southwesternmost member of the Yaeyama Island Group, southern Ryukyus, Okinawa Prefecture, Japan. Remarks. Yonaguni-jima island, the type locality of R. mundyi sp. n., is situated about 100 km east of Taiwan, and 80 km west of Iriomote-jima, another member of the Yaeyamas. On two of this latter island group, Iriomotejima and Ishigaki-jima islands, another species, R. chelifera, occurs. It is slightly larger (body length 45 mm), and its color pattern is different: head, antennae, proterga, large part of metaterga anteriorly dark brown or grey, posterior margin, paranota, tip of epiproct, and legs yellow. This is in strong contrast with the uniformly orange-yellow color of the new species. Male gonopods also differ, acropodite and prefemoral process being straight, slender, and almost equal in length, as opposed to the longer and curved acropodite with macroseta in R. mundyi sp. n. Comparison to the possible Taiwanese species, R. cohaesiva, R. contigua, and R. uraensis (from the region of Taipei, Wulai), all inadequately described and poorly illustrated by Wang (1956, 1957), is impossible without freshly collected material. Specimens of the new species in Yonaguni-jima were mostly collected along the edge of natural, deciduous forests, mostly in moist litter under the large leaves of Alocasia odora, but also close to human-disturbed areas like abandoned construction sites, ruined cave entrances etc. Adult specimens were collected at the locality Kuburabari, too, which is actually a pasture for the native, endemic race of horse (the Yonaguni pony), and these specimens were distinctly smaller than members of the other populations. This is perhaps due to that relatively harsh environment, the wind-swept rocky grassland on the western side of the island, generally poor in organic litter. The species was mentioned and illustrated as an undescribed Riukiaria from Yonaguni-jima island by Tanabe (2005). It was included into the Red Data Book of threatened wildlife of Okinawa and, though categorized as ’data deficient’ (DD), its habitat was proposed for preservation. According to our observations, the species is not confined to any characteristic or undisturbed biotope on Yonaguni-jima Island so perhaps habitat conservation is not the best approach, but considering that the total area of the island itself is only 28.8 square kilometers, the populations of the new and unique species are indeed worthy of legal protection.Published as part of Korsós, Zoltán, Nakamura, Yasuyuki & Tanabe, Tsutomu, 2011, Two new millipede species of the genus Riukiaria (Diplopoda, Polydesmida, Xystodesmidae) endemic to the Ryukyu Archipelago, Japan, pp. 55-68 in Zootaxa 2877 on pages 62-66, DOI: 10.5281/zenodo.27756
Denatured human alpha-defensin attenuates the bactericidal activity and the stability against enzymatic digestion
No full textElsevier, Tanabe, Hiroki ; Ayabe, Tokiyoshi ; Maemoto, Atsuo ; Ishikawa, Chisato ; Inaba, Yuhei ; Sato, Ryu ; Moriichi, Kentaro ; Okamoto, Kotaro ; Watari, Jiro ; Kono, Toru ; Ashida, Toshifumi ; Kohgo, Yutaka, Biochemical and Biophysical Research Communications, 358(1), 2007, 349-335.
authorα-Defensin is an antimicrobial peptide which plays an important role in innate immunity. Human defensin (HD)-5 is stored in the Paneth cells of the small intestine as a pro-form and is cleaved by trypsin, which is co-secreted from the Paneth cell granules. The mature HD-5 is protected from further digestion by the proteolysis enzyme. We generated both recombinant HD-5 and proHD-5, and the reduced form of each peptide in order to determine their physiological roles of the disulfide bonds. The reduced proHD-5 attenuated the bactericidal activity and the stability against the trypsin digestion. Human defensin was protected from the enzymatic degradation by disulfide bridges. We further purified the HD-5 with a disulfide variation in the small intestine of Crohn’s disease patients. The HD-5 was sensitive to the trypsin treatment. These observations evidently predict that a defensin deficiency may be caused by a disulfide disorder in the disease
Disposable Botnets: Long-term Analysis of IoT Botnet Infrastructure
No full textLarge botnets made up of Internet-of-Things (IoT) devices have a steady presence in the threat landscape since 2016. However, it has not explained how attackers maintain control over their botnets. In this paper, we present a long-term analysis of the infrastructure of IoT botnets based on 36 months of data gathered via honeypots and the monitoring of botnet infrastructure. We collected 64,260 IoT malware samples, 35,494 download servers, and 4,736 C&C servers during 2016 to 2021. Not only are most binaries distributed for less than three days, but the connection of bots to the rest of the botnet is also short-lived. To reach the C&C server, the binaries typically contain only a single hard-coded IP address or domain. Long-term dynamic analysis finds no mechanism for the attackers to migrate the bots to a new C&C server. Although malware binaries that use domain names to connect to their C&C servers increased in 2020, the C&C servers themselves have a short lifespan and this tendency has not changed. The picture that emerges is that of highly disposable botnets. IoT botnets are reconstituted from scratch all the time rather than maintained.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Organisation & Governanc
Hard to tune in: neural mechanisms of live face-to-face interaction in individuals with high-functioning autistic spectrum disorder
No full textIndividuals with autism spectrum disorders (ASD) are known to have difficulty with eye contact. This might make it difficult for partners to communicate with them face-to-face. To elucidate the neural substrates of live inter-subject interactions of ASD patients and typically-developed (normal) subjects, we conducted hyper-scanning functional MRI with 21 subjects with autistic spectrum disorder (ASD) paired with normal subjects, and with 19 pairs of normal subjects as a control. Baseline eye contact was maintained while subjects performed a real-time joint-attention task. The task-related effects were modeled out, and inter-individual correlation analysis was performed on the residual time-course data. ASD–Normal pairs were less accurate at detecting gaze direction than Normal–Normal pairs. Performance was impaired both in ASD subjects and in their normal partners. The left occipital pole activation caused by gaze processing was reduced in ASD subjects, suggesting that deterioration of eye-cue detection in ASD is related to impairment of early visual processing of gaze. By contrast, their normal partners showed greater activity in the bilateral occipital cortex and the right prefrontal area, indicating a compensatory workload. Inter-brain coherence in the right IFG reported previously in Normal–Normal pairs during eye contact was diminished in ASD–Normal pairs. Intra-brain functional connectivity between the right IFG and right superior temporal sulcus (STS) in normal subjects paired with ASD subjects was reduced compared with in Normal–Normal pairs. This functional connectivity was positively correlated with performance of normal partners in eye-cue detection. Considering the integrative role of the right STS in gaze processing, inter-subject synchronization during eye contact might be a prerequisite for eye-cue detection by the normal partner
Neural substrates and inter-individual functional connectivity during mutual gaze and joint attention using dual functional MRI
No full textIncreased circulating levels and salivary gland expression of interleukin-18 in patients with Sjögren's syndrome: relationship with autoantibody production and lymphoid organization of the periductal inflammatory infiltrate
No full textIL-18, an immunoregulatory and proinflammatory cytokine, has been shown to play an important pathogenic role in Th1-driven autoimmune disorders. In this study, we evaluated the circulating levels and salivary-gland expression of IL-18 in patients with Sjögren's syndrome (SS), a mainly Th1-mediated disease. IL-18 serum levels were measured by ELISA in 37 patients with primary SS, 42 with rheumatoid arthritis, and 21 normal controls. We demonstrated high IL-18 serum levels in SS, similar to those in rheumatoid arthritis patients and significantly higher than in controls (P < 0.01). In addition, IL-18 serum concentrations were significantly higher in anti-SSA/Ro+ and anti-SSB/La+ than in anti-SSA/Ro- and anti-SSB/La- SS patients (respectively, P = 0.01, P < 0.01). Serum IL-18 correlated strongly with anti-SSA/Ro (P = 0.004) and anti-SSB/La (P = 0.01) titers. Salivary gland IL-18 expression was investigated by single/double immunohistochemistry in 13 patients with primary SS and in 10 with chronic sialoadenitis, used as controls. The expression of IL-18 was also examined in periductal inflammatory foci in relation to the acquisition of features of secondary lymphoid organs such as T–B compartmentalization, formation of follicular dendritic cell networks, and presence of germinal-center-like structures. IL-18 expression in SS salivary glands was detected in 28 of 32 periductal foci of mononuclear cells (87.5%), while no IL-18 production by infiltrating cells was detected in patients with chronic sialoadenitis. Within the inflammatory foci, IL-18 immunoreactivity co-localized almost exclusively with CD68+ macrophages. In addition, IL-18 was found in 15 of 19 foci (78.9%) with no evidence of T–B cell compartmentalization (nonsegregated) but in 100% of the segregated aggregates, both in T- and B-cell-rich areas. Strikingly, IL-18 was strongly expressed by CD68+ tingible body macrophages in germinal-centre-like structures both in SS salivary glands and in normal lymph nodes. IL-18 expression was observed in the ducts of all SS biopsies but in only 4 of 10 patients with nonspecific chronic sialoadenitis (P < 0.01). This study provides the first evidence of increased circulating levels and salivary gland expression of IL-18 in SS, suggesting an important contribution of this cytokine to the modulation of immune inflammatory pathways in this condition
Neural substrates and inter-individual functional connectivity during mutual gaze and joint attention using dual functional MRI
No full textBilayer-induced asymmetric quantum Hall effect in epitaxial graphene
No full textThe transport properties of epitaxial graphene on SiC(0001) at quantizing magnetic fields are investigated. Devices patterned perpendicularly to SiC terraces clearly exhibit bilayer inclusions distributed along the substrate step edges. We show that the transport properties in the quantum Hall regime are heavily affected by the presence of bilayer inclusions, and observe a significant departure from the conventional quantum Hall characteristics. In particular, we observe anomalous values of the quantized resistance and a peculiar asymmetry with magnetic field which was not observed before for graphene on SiC. A quantitative model involving enhanced inter-channel scattering mediated by the presence of bilayer inclusions is presented that successfully explains the observed symmetry properties
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