Heat shock response in photosynthetic organisms: membrane and lipid connections.

The ability of photosynthetic organisms to adapt to increases in environmental temperatures is becoming more important with climate change. Heat stress is known to induce heat-shock proteins (HSPs) many of which act as chaperones. Traditionally, it has been thought that protein denaturation acts as a trigger for HSP induction. However, increasing evidence has shown that many stress events cause HSP induction without commensurate protein denaturation. This has led to the membrane sensor hypothesis where the membrane's physical and structural properties play an initiating role in the heat shock response. In this review, we discuss heat-induced modulation of the membrane's physical state and changes to these properties which can be brought about by interaction with HSPs. Heat stress also leads to changes in lipid-based signaling cascades and alterations in calcium transport and availability. Such observations emphasize the importance of membranes and their lipids in the heat shock response and provide a new perspective for guiding further studies into the mechanisms that mediate cellular and organismal responses to heat stress.

Transfer entropy reconstruction and labeling of neuronal connections from simulated calcium imaging

Neuronal dynamics are fundamentally constrained by the underlying structural network architecture, yet much of the details of this synaptic connectivity are still unknown even in neuronal cultures in vitro. Here we extend a previous approach based on information theory, the Generalized Transfer Entropy, to the reconstruction of connectivity of simulated neuronal networks of both excitatory and inhibitory neurons. We show that, due to the model-free nature of the developed measure, both kinds of connections can be reliably inferred if the average firing rate between synchronous burst events exceeds a small minimum frequency. Furthermore, we suggest, based on systematic simulations, that even lower spontaneous inter-burst rates could be raised to meet the requirements of our reconstruction algorithm by applying a weak spatially homogeneous stimulation to the entire network. By combining multiple recordings of the same in silico network before and after pharmacologically blocking inhibitory synaptic transmission, we show then how it becomes possible to infer with high confidence the excitatory or inhibitory nature of each individual neuron.

Handling of TDM Connections with Cello Media Gateway

UMTS is a 3rd generation telecommunication system, which introduces new network architecture. The change in the network architecture introduces new logical network nodes and changes the role of existing nodes in the network. This architecture changes the current vertically specialized network into a horizontally layered structure. In practice, the layering means that different levels in network hierarchy are separated, and they communicate over well-specified interfaces. The Connectivity Layer, at the bottom of the UMTS network architecture, contains Media Gateways (MGW). The GSM radio access network and UMTS access network are connected to the connectivity network via a MGW. External networks, e.g. ISDN networks, are accessed via other MGWs. The user plane is transported across the connectivity network between/via MGWs. ATM network is used as the backbone in Ericsson’s UMTS core network release 2.0. The main goal of this thesis is to study how the MGW is used to bridge ATM and TDM networks. The Circuit Emulation Service (CES) for ATM is studied, as the conversion from TDM to ATM is made according it. The transportation is made using AAL2 and the issues that it has with voice traffic are studied. The implementation and usage of TDM switching service in MGW are described in detail.

Intrahemispheric cortico-cortical connections of the human auditory cortex.

The human auditory cortex comprises the supratemporal plane and large parts of the temporal and parietal convexities. We have investigated the relevant intrahemispheric cortico-cortical connections using in vivo DSI tractography combined with landmark-based registration, automatic cortical parcellation and whole-brain structural connection matrices in 20 right-handed male subjects. On the supratemporal plane, the pattern of connectivity was related to the architectonically defined early-stage auditory areas. It revealed a three-tier architecture characterized by a cascade of connections from the primary auditory cortex to six adjacent non-primary areas and from there to the superior temporal gyrus. Graph theory-driven analysis confirmed the cascade-like connectivity pattern and demonstrated a strong degree of segregation and hierarchy within early-stage auditory areas. Putative higher-order areas on the temporal and parietal convexities had more widely spread local connectivity and long-range connections with the prefrontal cortex; analysis of optimal community structure revealed five distinct modules in each hemisphere. The pattern of temporo-parieto-frontal connectivity was partially asymmetrical. In conclusion, the human early-stage auditory cortical connectivity, as revealed by in vivo DSI tractography, has strong similarities with that of non-human primates. The modular architecture and hemispheric asymmetry in higher-order regions is compatible with segregated processing streams and lateralization of cognitive functions.

A comparative study of the intercellular connections between parasite/host in two Gelidiocolax/Gelidium algal parasitic systems

Comparative ultrastructural study of the intercellular connections between parasite and host cells in two algal parasitic systems, Gelidiocolax christianae Feldmann and Feldmann/Ge/iV/ium spathulatum (Kutz.) Bornet and Gelidiocolax deformans Seoane Camba/Gelidium sesquipedale (Clem.) Thur, shows quantitative and structural differences. The number of free conjunctor cells (before fusión with the adjacent host cells) differs between the two parasitic systems and is inversely related to the number of complex pit connections. The fibrillar cell wall structure of the conjunctor cells and the lamellar structure of the complex pit plugs in the two systems are also different A hypothesis concerning the different activity of the conjuntor cell wall in the two parasitic systems, related with the different structural appearance, is proposed.

Brain Connections Associated With Socio-Cognitive Skills in Preterm and Low Birth Weight School Age Children

Identification of neuroimaging biomarkers following extreme prematurity (EP) and intrauterine growth restriction (IUGR) is crucial for understanding their cognitive and behavioral impairments at school age

Social media marketing strategy: concepts and steps to form connections

The emergence of social media has led many companies to adopt them as marketing channels. Yet these media are novel enough that many marketers are still unsure as to how to plan an effective social media marketing strategy, actually oriented towards engaging prospects. In this article, we discuss how to shape a social media strategy. To do so, we show the key concepts and steps involved in the planning process of this type of digital marketing strategy, and how to measure their impact immediately.

Webometric network analysis : mapping cooperation and geopolitical connections between local government administration on the web

Webben är en enorm källa för information. Innehållet på webbsidorna är en synlig typ av information, men webben innehåller även information av en annan typ, en mera gömd typ i form av sambanden och nätverken som hyperlänkarna skapar mellan webbsajterna och –sidorna som de kopplar ihop. Forskningsområdet webometri ämnar, bland annat, att skapa ny kunskap ur denna gömda information som finns inbyggt i hyperlänkarna samt att skapa förståelse för hurudana fenomen och förhållanden utanför webben kan finnas representerade i hyperlänkarna. Målet med denna forskning var att öka förståelse för användningen av hyperlänkar på webben och speciellt kommunernas användning av hyperlänkar. Denna forskning undersökte hur kommunerna i Egentliga Finland skapade och mottog hyperlänkar samt hurudana nätverk formades av dessa hyperlänkar. Forskningen kartlade nätverk av direkta länkar mellan kommunerna och av samlänkar till och från kommunerna och undersökte ifall dessa nätverk kunde användas för att undersöka geopolitiska förhållanden och samarbete mellan kommunerna i Egentliga Finland. De övergripande forskningsfrågorna som har besvarats i denna forskning är: 1) Från ett webometriskt perspektiv, hur använder kommunerna i Egentliga Finland webben? 2) Kan hyperlänkar (direkta länkar och samlänkar) användas för att kartlägga geopolitiska förhållanden och samarbete mellan kommuner? 3) Vilka är de viktigaste motiveringarna för att skapa länkar mellan, till och från kommunernas webbsajter? Denna forskning kom till ovanligt tydliga resultat för en webometrisk forskning, både när det gäller upptäckta geografiska faktorer som påverkar hyperlänkningarna och de klassificerade motivationerna för att skapa länkarna. Resultaten visade att de direkta hyperlänkarna mellan kommunerna kan användas för att kartlägga geopolitiska förhållanden och samarbete mellan kommunerna för att de direkta länkarna var motiverade av officiella orsaker och de var klart påverkade av distansen mellan kommunerna och av de ekonomiska regionerna. Samlänkningarna in till kommunerna visade sig fungera som ett mått för geografisk likhet mellan kommunerna, medan samlänkningarna ut från kommunerna visade potential för att kunna användas till för att kartlägga kommunernas gemensamma intressen. Forskningen kontribuerade även till utvecklandet av forskningsområdet webometri. En del av de viktigaste kontributionerna av denna forskning var utvecklandet av nya metoder för webometrisk forskning samt att öka kunskap om hur existerande metoder från nätverksanalys kan användas effektivt för webometrisk forskning. Resultaten från denna forskning och de utvecklade metoderna kan användas för snabba kartläggningar av diverse förhållanden mellan olika organisationer och företag genom att använda information gratis tillgängligt på webben.

Efeito da disponibilidade de água e de luz na colonização micorrízica e no crescimento de Tabebuia avellanedae Lorentz ex Griseb. (Bignoniaceae)

Em plantas cultivadas em substrato não esterilizado, inoculado ou não com fungos micorrízicos arbusculares, analisou-se, através de dois experimentos em separado, o efeito de quatro intensidades de luz (70%, 50%, 30% e 4% da luz solar incidente) e de dois regimes hídricos (saturado e insaturado) sobre o crescimento e micorrização de plântulas de Tabebuia avellanedae Lorentz ex Griseb. (ipê-roxo; Bignoniaceae). As variáveis analisadas foram área foliar, massa seca à altura do caule, taxas de crescimento, densidade estomática, teor de prolina e intensidade de colonização micorrízica. As plântulas apresentaram diferenças morfológicas, fisiológicas e na intensidade de colonização micorrízica, em função dos tratamentos aplicados. Essas diferenças foram no sentido de minimizar os possíveis estresses causados por intensidade luminosa e disponibilidade hídrica desfavoráveis. Os resultados permitiram o relato de que os ajustamentos morfológicos e fisiológicos apresentados pela espécie podem conferir a ela vantagens no estabelecimento de plântulas em clareiras e ambientes mais secos e, também, na sobrevivência em ambientes mais sombreados.

Influence of stiffness in bolted connections in wooden plane structure of truss type

Trusses are structural systems commonly used in projects, being employed mainly in roof structures, present in most rural buildings. The design of trusses, as well as other structural systems, requires the determination of displacements, strains and stresses. However, the project is developed from an ideal model of calculation, considering free rotation between the elements of a connection. This paper presents a computer program for the analysis of bidimensional wooden trusses with connections formed with two screws per node. The formulation is based on the flexibility method, taking into account the influence of the effect of semi-rigid connections formed by two screws. An example of a structure is presented and analyzed by the program developed here, highlighting the importance of behavior analysis on semi-rigid connections.

Connections that work – Linked Open Data demystified

Esitys Kirjastoverkkopäivillä 22.10.2014 Helsingissä – Presentation of Jakob Voß at the Library Network Days, October 22, 2014 in Helsinki.

P-selectin, carcinoma metastasis and heparin: novel mechanistic connections with therapeutic implications

Metastasis is a multistep cascade initiated when malignant cells penetrate the tissue surrounding the primary tumor and enter the bloodstream. Classic studies indicated that blood platelets form complexes around tumor cells in the circulation and facilitate metastases. In other work, the anticoagulant drug heparin diminished metastasis in murine models, as well is in preliminary human studies. However, attempts to follow up the latter observation using vitamin K antagonists failed, indicating that the primary mechanism of heparin action was unrelated to its anticoagulant properties. Other studies showed that the overexpression of sialylated fucosylated glycans in human carcinomas is associated with a poor prognosis. We have now brought all these observations together into one mechanistic explanation, which has therapeutic implications. Carcinoma cells expressing sialylated fucosylated mucins can interact with platelets, leukocytes and endothelium via the selectin family of cell adhesion molecules. The initial organ colonization of intravenously injected carcinoma cells is attenuated in P-selectin-deficient mice, in mice receiving tumor cells pretreated with O-sialoglycoprotease (to selectively remove mucins from cell surfaces), or in mice receiving a single dose of heparin prior to tumor cell injection. In each case, we found that formation of a platelet coating on cancer cells was impeded, allowing increased access of leukocytes to the tumor cells. Several weeks later, all animals showed a decrease in the extent of established metastasis, indicating a long-lasting effect of the short-term intervention. The absence of obvious synergism amongst the three treatments suggests that they all act via a common pathway. Thus, a major mechanism of heparin action in cancer may be inhibition of P-selectin-mediated platelet coating of tumor cells during the initial phase of the metastatic process. We therefore suggest that heparin use in cancer be re-explored, specifically during the time interval between initial visualization of a primary tumor until just after definitive surgical removal.

Interhemispheric connections between primary visual areas: beyond the midline rule

In the last five years, a number of detailed anatomical, electrophysiological, optical imaging and simulation studies performed in a variety of non-human species have revealed that the functional organization of callosal connections between primary visual areas is more elaborate than previously thought. Callosal cell bodies and terminals are clustered in columns whose correspondence to features mapped in the visual cortex, such as orientation and ocularity, are starting to be understood. Callosal connections are not restricted to the vertical midline representation nor do they establish merely point-to-point retinotopic correspondences across the hemispheres, as traditionally believed. In addition, anatomical studies have revealed the existence of an ipsilateral component of callosal axons. The aim of this short review is to propose how these new data can be integrated into an updated scheme of the circuits responsible for assembling the primary visual field map.