26,926 research outputs found

    A key to the New World species of holostipous Lejeuneaceae

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    A synopsis and key emphasizing vegetative characters are provided for the 967species (in 36 genera) of Lejeuneaceae with undivided underleaves recorded from the New World

    A re-evaluation of Cheilolejeunea subgenus Xenolejeunea

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    Cheilolejeunea subgenus Xenolejeunea Kachroo & Schust. is emended to account for variability observed in stem anatomy and lobule structure. Cheilolejeunea subgenus Tegulilejeunea Schust. is reduced to synonymy with subgenus Xenolejeunea. A new sectional classification of subgenus Xenolejeunea is proposed (sections Gigantae, Meyenianae, and Xenolejeunea). A key distinguishes among the sections and the 10 species accepted in the subgenus, which is known from Australasia, Oceania and tropical Asia. A nomenclator and discussion is provided for each species. Comments on excluded species conclude the treatment

    New or little known epiphyllous liverworts : 6., Papillolejeunea gen. nov. from Papua New Guinea

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    A new epiphyllous Lejeuneaceae genus, Papillolejeunea is described. It is a segregate of Lejeunea, characterized by a large, 2-4 celled, stout, papilla like first (distal) tooth on a well developed, inflated lobule, while the second (proximal) tooth is reduced, blunt, hidden with the usually involuted free lobule margin. Four new species are described within the genus. One, Papillolejeunea balazsii, forms the Section nov. Papillolejeunea and the type of the genus, characterized by large number of serially arranged mucilage cells on the dorsal surface and margin of the lobe, at the margin of amphigastria and on the perianth keels. Three further species, Papillolejeunea candida, Papillolejeunea papuana and Papillolejeunea touwii constitute the Section nov. Candidae, where no such dorsal and marginal glands occur. The distribution of the genus seems to be restricted to the mountainous area of New Guinea

    Neuroimaging evidence implicating cerebellum in support of sensory/cognitive processes associated with thirst.

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    Recent studies implicate the cerebellum, long considered strictly a motor control structure, in cognitive, sensory, and affective phenomenon. The cerebellum, a phylogenetically ancient structure, has reciprocal ancient connections to the hypothalamus, a structure important in vegetative functions. The present study investigated whether the cerebellum was involved in vegetative functions and the primal emotions engendered by them. Using positron emission tomography, we examined the effects on the cerebellum of the rise of plasma sodium concentration and the emergence of thirst in 10 healthy adults. The correlation of regional cerebral blood flow with subjects' ratings of thirst showed major activation in the vermal central lobule. During the development of thirst, the anterior and posterior quadrangular lobule, lingula, and the vermis were activated. At maximum thirst and then during irrigation of the mouth with water to alleviate dryness, the cerebellum was less activated. However, 3 min after drinking to satiation, the anterior quadrangular lobule and posterior cerebellum were highly activated. The increased cerebellar activity was not related to motor behavior as this did not occur. Instead, responses in ancient cerebellar regions (vermis, fastigal nucleus, archicerebellum) may be more directly related to vegetative and affective aspects of thirst experiences, whereas activity in neocerebellar (posterior) regions may be related to sensory and cognitive aspects. Moreover, the cerebellum is apparently not involved in the computation of thirst per se but rather is activated during changes in thirst/satiation state when the brain is "vigilant" and is monitoring its sensory systems. Some neocerebellar activity may also reflect an intentionality for gratification by drinking inherent in the consciousness of thirst

    Some new additions to the hepatic flora (Jungermanniophyta) for the State of Bahia, Brazil

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    In this paper are recorded 18 taxa of hepatics (Jungermanniophyta) for the first time for the state of Bahia, Brazil. Of these, Harpalejeunea ovata (Hook.) Schiffn. is new for Brazil. Morphological characters, notes on habitat and substrate are given for each species. Illustrations for Harpalejeunea ovata, Pycnolejeunea callosa (Lindenb.) Steph., Pycnolejeunea macroloba (Nees & Mont.) Schiffn., Rectolejeunea berteroana (Gott. ex Steph.) Evans and Trachylejeunea crenata (Mont. & Nees) Schust. are given

    Disrupted functional brain network organization in patients with obstructive sleep apnea.

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    IntroductionObstructive sleep apnea (OSA) subjects show impaired autonomic, affective, executive, sensorimotor, and cognitive functions. Brain injury in OSA subjects appears in multiple sites regulating these functions, but the integrity of functional networks within the regulatory sites remains unclear. Our aim was to examine the functional interactions and the complex network organization of these interactions across the whole brain in OSA, using regional functional connectivity (FC) and brain network topological properties.MethodsWe collected resting-state functional magnetic resonance imaging (MRI) data, using a 3.0-Tesla MRI scanner, from 69 newly diagnosed, treatment-naïve, moderate-to-severe OSA (age, 48.3 ± 9.2 years; body mass index, 31 ± 6.2 kg/m(2); apnea-hypopnea index (AHI), 35.6 ± 23.3 events/h) and 82 control subjects (47.6 ± 9.1 years; body mass index, 25.1 ± 3.5 kg/m(2)). Data were analyzed to examine FC in OSA over controls as interregional correlations and brain network topological properties.ResultsObstructive sleep apnea subjects showed significantly altered FC in the cerebellar, frontal, parietal, temporal, occipital, limbic, and basal ganglia regions (FDR, P < 0.05). Entire functional brain networks in OSA subjects showed significantly less efficient integration, and their regional topological properties of functional integration and specialization characteristics also showed declined trends in areas showing altered FC, an outcome which would interfere with brain network organization (P < 0.05; 10,000 permutations). Brain sites with abnormal topological properties in OSA showed significant relationships with AHI scores.ConclusionsOur findings suggest that the dysfunction extends to resting conditions, and the altered FC and impaired network organization may underlie the impaired responses in autonomic, cognitive, and sensorimotor functions. The outcomes likely result from the prominent structural changes in both axons and nuclear structures, which occur in the condition

    Association between cognitive performance and cortical glucose metabolism in patients with mild Alzheimer's disease

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    Background: Neuronal and synaptic function in Alzheimer's disease (AD) is measured in vivo by glucose metabolism using positron emission tomography (PET). Objective: We hypothesized that neuronal activation as measured by PET is a more sensitive index of neuronal dysfunction than activity during rest. We investigated if the correlations between dementia severity as measured with the Mini Mental State Examination (MMSE) and glucose metabolism are an artifact of brain atrophy. Method: Glucose metabolism was measured using {[}F-18]fluorodeoxyglucose PET during rest and activation due to audiovisual stimulation in 13 mild to moderate AD patients (MMSE score >= 17). PET data were corrected for brain atrophy. Results: In the rest condition, glucose metabolism was correlated with the MMSE score primarily within the posterior cingulate and parietal lobes. For the activation condition, additional correlations were within the primary and association audiovisual areas. Most local maxima remained significant after correcting for brain atrophy. Conclusion: PET activity measured during audiovisual stimulation was more sensitive to functional alterations in glucose metabolism in AD patients compared to the resting PET. The association between glucose metabolism and MMSE score was not dependent on brain atrophy. Copyright (C) 2005 S. Karger AG, Basel

    Studies on Hong Kong Cheilolejeunea with two species new to China

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    Five species of the genus Cheilolejeunea are reported from Hong Kong. Among them, Cheilolejeunea osumiensis (Hatt.) Mizut. and Cheilolejeunea ryukyuensis Mizut. are new to China. Cheilolejeunea intertexta (Lindenb.) Steph. is newly reported for China except Taiwan, and Cheilolejeunea trifaria (Reinw. et al.) Mizut. is documented for the first time for mainland China except Hainan and Taiwan. The detailed description and illustration of Cheilolejeunea osumiensis as well as the key to the five Cheilolejeunea species of Hong Kong are also presented

    Distinct cerebellar foliation anomalies in a Chd7 haploinsufficient mouse model of CHARGE syndrome

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    Mutations in the gene encoding the ATP dependent chromatin‐remodeling factor, CHD7 are the major cause of CHARGE (Coloboma, Heart defects, Atresia of the choanae, Retarded growth and development, Genital‐urinary anomalies, and Ear defects) syndrome. Neurodevelopmental defects and a range of neurological signs have been identified in individuals with CHARGE syndrome, including developmental delay, lack of coordination, intellectual disability, and autistic traits. We previously identified cerebellar vermis hypoplasia and abnormal cerebellar foliation in individuals with CHARGE syndrome. Here, we report mild cerebellar hypoplasia and distinct cerebellar foliation anomalies in a Chd7 haploinsufficient mouse model. We describe specific alterations in the precise spatio‐temporal sequence of fissure formation during perinatal cerebellar development responsible for these foliation anomalies. The altered cerebellar foliation pattern in Chd7 haploinsufficient mice show some similarities to those reported in mice with altered Engrailed, Fgf8 or Zic1 gene expression and we propose that mutations or polymorphisms in these genes may modify the cerebellar phenotype in CHARGE syndrome. Our findings in a mouse model of CHARGE syndrome indicate that a careful analysis of cerebellar foliation may be warranted in patients with CHARGE syndrome, particularly in patients with cerebellar hypoplasia and developmental delay
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