49 research outputs found

    Automated office blood pressure measurements in primary care are misleading in more than one third of treated hypertensives: The VALENTINE-Greece Home Blood Pressure Monitoring study

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    Abstract Background This study assessed the diagnostic reliability of automated office blood pressure (OBP) measurements in treated hypertensive patients in primary care by evaluating the prevalence of white coat hypertension (WCH) and masked uncontrolled hypertension (MUCH) phenomena. Methods Primary care physicians, nationwide in Greece, assessed consecutive hypertensive patients on stable treatment using OBP (1 visit, triplicate measurements) and home blood pressure (HBP) measurements (7 days, duplicate morning and evening measurements). All measurements were performed using validated automated devices with bluetooth capacity (Omron M7 Intelli-IT). Uncontrolled OBP was defined as ≥140/90 mmHg, and uncontrolled HBP was defined as ≥135/85 mmHg. Results A total of 790 patients recruited by 135 doctors were analyzed (age: 64.5 ± 14.4 years, diabetics: 21.4%, smokers: 20.6%, and average number of antihypertensive drugs: 1.6 ± 0.8). OBP (137.5 ± 9.4/84.3 ± 7.7 mmHg, systolic/diastolic) was higher than HBP (130.6 ± 11.2/79.9 ± 8 mmHg; difference 6.9 ± 11.6/4.4 ± 7.6 mmHg, p Conclusions In primary care, automated OBP measurements are misleading in approximately 40% of treated hypertensive patients. HBP monitoring is mandatory to avoid overtreatment of subjects with WCH phenomenon and prevent undertreatment and subsequent excess cardiovascular disease in MUCH

    Representing Where along with What Information in a Model of a Cortical Patch

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    Behaving in the real world requires flexibly combining and maintaining information about both continuous and discrete variables. In the visual domain, several lines of evidence show that neurons in some cortical networks can simultaneously represent information about the position and identity of objects, and maintain this combined representation when the object is no longer present. The underlying network mechanism for this combined representation is, however, unknown. In this paper, we approach this issue through a theoretical analysis of recurrent networks. We present a model of a cortical network that can retrieve information about the identity of objects from incomplete transient cues, while simultaneously representing their spatial position. Our results show that two factors are important in making this possible: A) a metric organisation of the recurrent connections, and B) a spatially localised change in the linear gain of neurons. Metric connectivity enables a localised retrieval of information about object identity, while gain modulation ensures localisation in the correct position. Importantly, we find that the amount of information that the network can retrieve and retain about identity is strongly affected by the amount of information it maintains about position. This balance can be controlled by global signals that change the neuronal gain. These results show that anatomical and physiological properties, which have long been known to characterise cortical networks, naturally endow them with the ability to maintain a conjunctive representation of the identity and location of objects

    Brain Responses to Violet, Blue, and Green Monochromatic Light Exposures in Humans: Prominent Role of Blue Light and the Brainstem

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    BACKGROUND: Relatively long duration retinal light exposure elicits nonvisual responses in humans, including modulation of alertness and cognition. These responses are thought to be mediated in part by melanopsin-expressing retinal ganglion cells which are more sensitive to blue light than violet or green light. The contribution of the melanopsin system and the brain mechanisms involved in the establishment of such responses to light remain to be established. METHODOLOGY/PRINCIPAL FINDINGS: We exposed 15 participants to short duration (50 s) monochromatic violet (430 nm), blue (473 nm), and green (527 nm) light exposures of equal photon flux (10(13)ph/cm(2)/s) while they were performing a working memory task in fMRI. At light onset, blue light, as compared to green light, increased activity in the left hippocampus, left thalamus, and right amygdala. During the task, blue light, as compared to violet light, increased activity in the left middle frontal gyrus, left thalamus and a bilateral area of the brainstem consistent with activation of the locus coeruleus. CONCLUSION/SIGNIFICANCE: These results support a prominent contribution of melanopsin-expressing retinal ganglion cells to brain responses to light within the very first seconds of an exposure. The results also demonstrate the implication of the brainstem in mediating these responses in humans and speak for a broad involvement of light in the regulation of brain function

    Grounding Word Learning in Space

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    Humans and objects, and thus social interactions about objects, exist within space. Words direct listeners' attention to specific regions of space. Thus, a strong correspondence exists between where one looks, one's bodily orientation, and what one sees. This leads to further correspondence with what one remembers. Here, we present data suggesting that children use associations between space and objects and space and words to link words and objects—space binds labels to their referents. We tested this claim in four experiments, showing that the spatial consistency of where objects are presented affects children's word learning. Next, we demonstrate that a process model that grounds word learning in the known neural dynamics of spatial attention, spatial memory, and associative learning can capture the suite of results reported here. This model also predicts that space is special, a prediction supported in a fifth experiment that shows children do not use color as a cue to bind words and objects. In a final experiment, we ask whether spatial consistency affects word learning in naturalistic word learning contexts. Children of parents who spontaneously keep objects in a consistent spatial location during naming interactions learn words more effectively. Together, the model and data show that space is a powerful tool that can effectively ground word learning in social contexts

    Exploration of cephalexin adsorption mechanisms onto bauxite and palygorskite and regeneration of spent adsorbents with cold plasma bubbling

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    Abstract The aim of the present study was the direct comparison of two popular minerals, bauxite and palygorskite, as adsorbents for the removal of cephalexin (CPX) from aqueous solutions and the regeneration of the spent adsorbents through cold atmospheric plasma. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, initial CPX concentration, adsorbent dosage, pH and temperature. The adsorbents were characterized by ATR-FTIR, N2 sorption, SEM and XRD, while several isotherm, kinetic and thermodynamic models were evaluated attempting to shed light on the adsorption mechanisms. CPX adsorption on both adsorbents was better described by Langmuir model, with an adsorption capacity of 112.36 mg/g for palygorskite and 11.79 mg/g for bauxite. Thermodynamics revealed the endothermic and the spontaneous character of the process, indicating chemisorption as the main adsorption mechanism for both adsorbents. The pseudo-second-order and the Elovich models fitted satisfactorily the adsorption onto bauxite, while adsorption onto palygorskite was well presented by Weber–Morris model, indicating that pore diffusion is also involved in the process. The adsorption capacity of both minerals decreased significantly after being used for several adsorption cycles and then almost completely recovered (regeneration efficiency was 99.6% and 98% for palygorskite and bauxite, respectively) inside a novel cold plasma microbubble reactor energized by high-voltage nanopulses, revealing the potential of these adsorbents to be reused. In addition to the regeneration of the adsorbents, the cold plasma completely eliminated the CPX transferred from the solid to the aqueous phase during the regeneration process

    Activation of midlumbar neurones by afferents from anterior hindlimb muscles in the cat.

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    1. It has been suggested that a group of interneurones located in the midlumbar segments of the spinal cord might play a role in switching from the stance to swing phases of the step cycle during locomotion. We have further examined the input to these neurones from proprioceptive afferents to test whether the connections to these cells are consistent with this role. 2. Electrical stimulation of group I and group II afferents in branches of the femoral nerve which supply iliopsoas, the major hip flexor muscle, excited a large majority of intermediate zone midlumbar interneurones which receive input from quadriceps group II afferents. The central latencies and properties of the EPSPs indicate that both group I and group II afferents from iliopsoas make monosynaptic connections with many midlumbar interneurones. 3. Group II afferents from both the ankle flexor tibialis anterior and the digit dorsiflexor extensor digitorum longus excited midlumbar interneurones. Similarly, they were also excited by group II afferents from both of the two main anatomical divisions of the sartorius muscle. 4. The frequent and potent excitation of midlumbar neurones from group I and II afferents in iliopsoas suggests that they may be excited at the end of the stance phase of the step when these muscles are stretched. This possibility is discussed in relation to recent work on the functional control of the step cycle

    Information encoding in the inferior temporal visual cortex: contributions of the firing rates and the correlations between the firing of neurons

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    The encoding of information by populations of neurons in the macaque inferior temporal cortex was analyzed using quantitative information-theoretic approaches. It was shown that almost all the information about which of 20 stimuli had been shown in a visual fixation task was present in the number of spikes emitted by each neuron, with stimulus-dependent cross-correlation effects adding for most sets of simultaneously recorded neurons almost no additional information. It was also found that the redundancy between the simultaneously recorded neurons was low, approximately 4% to 10%. Consistent with this, a decoding procedure applied to a population of neurons showed that the information increases approximately linearly with the number of cells in the population
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