67 research outputs found
Adolescent brain maturation and cortical folding: evidence for reductions in gyrification
Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM), increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area. In the current study, we acquired high-resolution (3 Tesla) magnetic resonance imaging (MRI) data from 79 healthy subjects (34 males and 45 females) between the ages of 12 and 23 years and performed whole brain analysis of cortical folding patterns with the gyrification index (GI). In addition to GI-values, we obtained estimates of cortical thickness, surface area, GM and white matter (WM) volume which permitted correlations with changes in gyrification. Our data show pronounced and widespread reductions in GI-values during adolescence in several cortical regions which include precentral, temporal and frontal areas. Decreases in gyrification overlap only partially with changes in the thickness, volume and surface of GM and were characterized overall by a linear developmental trajectory. Our data suggest that the observed reductions in GI-values represent an additional, important modification of the cerebral cortex during late brain maturation which may be related to cognitive development
A complexity approach to defining urban energy systems
Urban energy systems have been commonly considered to be socio-technical systems within the boundaries of an urban area. However, recent literature challenges this notion in that it urges researchers to look at the wider interactions and influences of urban energy systems wherein the socio-technical sphere is expanded to political, environmental and economic realms as well. In addition to the inter-sectoral linkages, the diverse agents and multilevel governance trends of energy sustainability in the dynamic environment of cities make the urban energy landscape a complex one. There is a strong case then for establishing a new conceptualisation of urban energy systems that builds upon these contemporary understandings of such systems. We argue that the complex systems approach can be suitable for this. In this paper, we propose a pilot framework for understanding urban energy systems using complex systems theory as an integrating plane. We review the multiple streams of urban energy literature to identify the contemporary discussions and construct this framework that can serve as a common ontological understanding for the different scholarships studying urban energy systems. We conclude the paper by highlighting the ways in which the framework can serve some of the relevant communities
Development of central nervous system metastases as a first site of metastatic disease in breast cancer patients treated in the neoadjuvant trials GeparQuinto and GeparSixto
Background: The incidence of central nervous system (CNS) metastases in breast cancer patients is rising and has become a major clinical challenge. Only few data are published concerning risk factors for the development of CNS metastases as a first site of metastatic disease in breast cancer patients. Moreover, the incidence of CNS metastases after modern neoadjuvant treatment is not clear.
Methods: We analyzed clinical factors associated with the occurrence of CNS metastases as the first site of metastatic disease in breast cancer patients after neoadjuvant treatment in the trials GeparQuinto and GeparSixto (n = 3160) where patients received targeted treatment in addition to taxane and anthracycline-based chemotherapy.
Results: After a median follow-up of 61 months, 108 (3%) of a total of 3160 patients developed CNS metastases as the first site of recurrence and 411 (13%) patients had metastatic disease outside the CNS. Thirty-six patients (1%) developed both CNS metastases and other distant metastases as the first site of metastatic disease. Regarding subtypes of the primary tumor, 1% of luminal A-like (11/954), 2% of luminal B-like (7/381), 4% of HER2-positive (34/809), and 6% of triple-negative patients (56/1008) developed CNS metastases as the first site of metastatic disease. In multivariate analysis, risk factors for the development of CNS metastases were larger tumor size (cT3–4; HR 1.63, 95% CI 1.08–2.46, p = 0.021), node-positive disease (HR 2.57, 95% CI 1.64–4.04, p < 0.001), no pCR after neoadjuvant chemotherapy (HR 2.29, 95% CI 1.32–3.97, p = 0.003), and HER2-positive (HR 3.80, 95% CI 1.89–7.64, p < 0.001) or triple-negative subtype (HR 6.38, 95% CI 3.28–12.44, p < 0.001).
Conclusions: Especially patients with HER2-positive and triple-negative tumors are at risk of developing CNS metastases despite effective systemic treatment. A better understanding of the underlying mechanisms is required in order to develop potential preventive strategies
Interface between gender myths and history in Margaret Ogola’s The River and the Source (1994) and Marjorie Macgoye’s Coming to Birth (1986)
Culture is central to the understanding of gender relations. Yet, studies have not examined how history (as myth or its product) influences our perception of gender relations. This paper investigates how myth, as a function of language, constructs history. It specifically explains how myth is used to construct and determine gender through a close reading and textual analysis of Margaret Ogola’s The River and the Source and Marjorie Macgoye’s Coming to Birth. The discussion is guided by Roland Barthes’ conceptualization of mythology and Judith Butler’s ideas on definition and cultural construction of gender and power, as well as authority in performance of gender. Findings showed that Ogola and Macgoye situate their fiction within the history and culture of the Luo people, who have traditional myths and legends that explain their existence. They invent characters and events that correspond to history, despite not being historical in themselves. The authors thus portray Africa as a rich combination of myth and history, their major characters embodying the essence of history, or battling it, or somehow relating with it through fantasy. In so doing, the authors engage in gender discourses, challenging patriarchy while highlighting the milestones achieved by women in time
Tung oil-based thermosetting polymers for self-healing applications
Several bio-renewable thermosetting polymers were successfully prepared from tung oil through cationic polymerization for the use as the healing agent in self-healing microencapsulated applications. The tung oil triglyceride was blended with its methyl ester, which was produced by saponification followed by esterification. The changes in storage modulus, loss modulus, and glass transition temperature as functions of the methyl ester content were measured using dynamic mechanical analysis. In addition, the fraction of cross-linked material in the polymer was calculated by Soxhlet extraction, while proton nuclear magnetic resonance, Fourier transform infrared spectroscopy and TEM were used to investigate the structure of the copolymer networks. The thermal stability of the thermosets as a function of their methyl ester blend contents was determined by thermogravimetric analysis. Finally, the adhesive properties of the thermosets were studied using compressive lap shear and the fracture surfaces were analyzed using SEM
Deconstructing gender myths in Margaret Ogola’s I Swear by Apollo and Marjorie Macgoye’s Victoria and Murder in Majengo
This paper explores how Margaret Ogola, in I Swear by Apollo, and Marjorie Oludhe Macgoye, in Victoria and Murder in Majengo, deploy narrative strategies to debunk/(de)construct gender myths as perpetuated by traditional gender roles, marriage and family, and sexuality. It further interrogates how the authors champion religion and education as major factors to catalyse paradigm shift from tradition to modernity, focusing on the significance of location and culture in justifying the paradigm shifts in people’s attitudes and conceptualization of gender and power concerns. Ogola and Macgoye’s attempt to redefine family is examined by illuminating new perspectives that counter traditional concept of family. Within this conceptualization is the changing reality that destabilizes myths on roles and responsibilities of men and women, that is, division of labour by sex within family and society at large, against changing social trends. In so doing, the paper examines modernity, particularly the influence of location and culture, as factors that deconstruct gender myths. The concept of modernity, that is, myths behind modernity, relationship between traditional African and western/modern cultures, are examined in light of how it influences gender and power play. We consider the different approaches Ogola and Macgoye in I Swear by Apollo and Victoria and Murder in Majengo, respectively, give to challenges of life supported by a new culture and modernity in a new cultural space provided by modern contexts
Combining allostratigraphic and lithostratigraphic perspectives to compile subregional records of fluvial responsiveness: The case of the sustainably entrenching Palancia River watershed (Mediterranean coast, NE Spain)
We use a combined allostratigraphic and morpholithostratigraphic approach to establish a relative stratigraphy of macroscale sediment-landform units in the Mediterranean Palancia River watershed (986-km2, NE Spain). Four alloformations signifying important changes in (sub)regional scale geomorphic valley-floor evolution were identified based on data from 1120 field sites and age determinations, and from analyzing high resolution geodata. The formation of the widespread and thick Pleistocene alloformation can be attributed to climatically-induced excessive sediment supply and flood activities during Pleistocene cold intervals — rather than representing time-lagging response to Plio/Pleistocene neotectonic uplift. Triggered by the turn to Holocene climatic conditions, three successively inset alloformations illustrate how stream grading and floodplain narrowing continuously have progressed over the Holocene. The overall degradational valley-floor evolution in the Holocene is interpreted as a response to the antecedent, overly valley-floor aggradation. Allostratigraphic and morphostratigraphic data suggest that the abandonment of the two earlier Holocene alloformations geomorphologically represents a pulsed turn toward intensified entrenchment rather than pulsed sedimentation. The most important benefit of amalgamating allostratigraphic and (morpho)lithostratigraphic concepts is that allostratigraphic ordering provides a formally conclusive approach to scale up (morpho)lithostratigraphic information from the reach scale to much larger scales of geographical extent. Consequently, applying allostratigraphic principles opens a perspective to moving forward toward analyzing the relationships between climate, neotectonics, sea level change, human impact, and fluvial response in coupled hinterland-coastal systems that require to evaluate sedimentary information at larger spatial scales
Endovascular management of complex splenic aneurysm with the "amplatzer" embolic platform : application of cone-beam computed tomography
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