Electronic properties of SnO2-based ceramics with double function of varistor and humidity sensor

This is the post-print version of the article. The official published version can be obtained from the link below - Copyright @ 2010 AD-Tech.Tin dioxide based varistor ceramics SnO2-Co3O4-Nb2O5-Cr2O3-xCuO (x=0; 0.05; 0.1 and 0.5) were made and their electrical properties were studied. The highest nonlinearity coefficient and electric field (at current density 10-3 A cm-2) were obtained for 0.1 mol.% CuO addition. It was observed that low-field electrical conductivity is increased with relative humidity, therefore, materials obtained exhibit double function of varistor and humidity sensor. The highest humidity sensitivity coefficient is found for SnO2-Co3O4-Nb2O5-Cr2O3 ceramics (without CuO). Observed varistor and humidity-sensitive properties are explained in the frames of grain-boundary double Schottky barrier concept as a decrease of the barrier height with electric field or relative humidity. Using suggested simple theory and data obtained on isothermal capacitance relaxation, the energy of the grain-boundary monoenergetic trapping states were estimated. These values are less than found for activation energy of electrical conduction (as a measure of the barrier height). These observations confirm the barrier concept.This work is funded by the Royal Society, United Kingdom (2007R1/R26999)

The role of Nav1.9 channel in the development of neuropathic orofacial pain associated with trigeminal neuralgia

BACKGROUND: Trigeminal neuralgia is accompanied by severe mechanical, thermal and chemical hypersensitivity of the orofacial area innervated by neurons of trigeminal ganglion (TG). We examined the role of the voltage-gated sodium channel subtype Nav1.9 in the development of trigeminal neuralgia. RESULTS: We found that Nav1.9 is required for the development of both thermal and mechanical hypersensitivity induced by constriction of the infraorbital nerve (CION). The CION model does not induce change on Nav1.9 mRNA expression in the ipsilateral TG neurons when evaluated 9 days after surgery. CONCLUSIONS: These results demonstrate that Nav1.9 channels play a critical role in the development of orofacial neuropathic pain. New routes for the treatment of orofacial neuropathic pain focussing on regulation of the voltage-gated Nav1.9 sodium channel activity should be investigated

Trypanosoma cruzi alkaline 2-DE: Optimization and application to comparative proteome analysis of flagellate life stages

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Sensory neuron–derived NaV1.7 contributes to dorsal horn neuron excitability

Expression of the voltage-gated sodium channel NaV1.7 in sensory neurons is required for pain sensation. We examined the role of NaV1.7 in the dorsal horn of the spinal cord using an epitope-tagged NaV1.7 knock-in mouse. Immuno–electron microscopy showed the presence of NaV1.7 in dendrites of superficial dorsal horn neurons, despite the absence of mRNA. Rhizotomy of L5 afferent nerves lowered the levels of NaV1.7 in the dorsal horn. Peripheral nervous system–specific NaV1.7 null mutant mice showed central deficits, with lamina II dorsal horn tonic firing neurons more than halved and single spiking neurons more than doubled. NaV1.7 blocker PF05089771 diminished excitability in dorsal horn neurons but had no effect on NaV1.7 null mutant mice. These data demonstrate an unsuspected functional role of primary afferent neuron-generated NaV1.7 in dorsal horn neurons and an expression pattern that would not be predicted by transcriptomic analysis

High performance maleated lignocellulose epicarp fibers for copper ion removal

Natural lignocellulosic fiber epicarp extracted from the babassu coconut (Orbignya speciosa) was chemically modified through reaction with molten maleic anhydride without solvent, with incorporation of 189.34 mg g-1 of carboxylic acid groups into the biopolymer structure. The success of this reaction was also confirmed by the presence of carboxylic acid bands at 1741 and 1164 cm-1 in the infrared spectrum. Identically, the same group is observed through 13C NMR CP/MAS in the solid state, via high field signals in the 167 pm region. Both the precursor and the immobilized maleated biopolymers presented nearly the same thermal stability and similar crystallinity to cellulose. However, the pendant carboxylic groups have the ability to remove copper with maximum sorption through a batchwise process at pH 6.0, as expected from the point of zero charge, determined to be 6.45. The sorption kinetic data were fitted to pseudo-first order, pseudo-second order, Elovich-chemisorption and intra-particle diffusion models and the equilibrium data were fitted to the Langmuir, the Freundlich and Tenkim isotherm models. Taking into account a statistical error function and determination coefficients, the data were fit to the pseudo-first and pseudo-second order kinetic and Langmuir isotherm models, with a maximum sorption capacity of copper ions of 55.09 mg g-1. This value suggests the application of this biopolymer with incorporated carboxylate groups as a favorable agent for copper removal from appropriate systems31118319

Tools for analysis and conditional deletion of subsets of sensory neurons [version 1; peer review: 4 approved]

Background: Somatosensation depends on primary sensory neurons of the trigeminal and dorsal root ganglia (DRG). Transcriptional profiling of mouse DRG sensory neurons has defined at least 18 distinct neuronal cell types. Using an advillin promoter, we have generated a transgenic mouse line that only expresses diphtheria toxin A (DTA) in sensory neurons in the presence of Cre recombinase. This has allowed us to ablate specific neuronal subsets within the DRG using a range of established and novel Cre lines that encompass all sets of sensory neurons. // Methods: A floxed-tdTomato-stop-DTA bacterial artificial chromosome (BAC) transgenic reporter line (AdvDTA) under the control of the mouse advillin DRG promoter was generated. The line was first validated using a Nav1.8Cre and then crossed to CGRPCreER (Calca), ThCreERT2, Tmem45bCre, Tmem233Cre, Ntng1Cre and TrkBCreER (Ntrk2) lines. Pain behavioural assays included Hargreaves’, hot plate, Randall-Selitto, cold plantar, partial sciatic nerve ligation and formalin tests. // Results: Motor activity, as assessed by the rotarod test, was normal for all lines tested. Noxious mechanosensation was significantly reduced when either Nav1.8 positive neurons or Tmem45b positive neurons were ablated whilst acute heat pain was unaffected. In contrast, noxious mechanosensation was normal following ablation of CGRP-positive neurons but acute heat pain thresholds were significantly elevated and a reduction in nocifensive responses was observed in the second phase of the formalin test. Ablation of TrkB-positive neurons led to significant deficits in mechanical hypersensitivity in the partial sciatic nerve ligation neuropathic pain model. // Conclusions: Ablation of specific DRG neuronal subsets using the AdvDTA line will be a useful resource for further functional characterization of somatosensory processing, neuro-immune interactions and chronic pain disorders

The higher exercise intensity and the presence of allele I of ACE gene elicit a higher post-exercise blood pressure reduction and nitric oxide release in elderly women: an experimental study

<p>Abstract</p> <p>Background</p> <p>The absence of the I allele of the angiotensin converting enzyme (ACE) gene has been associated with higher levels of circulating ACE, lower nitric oxide (NO) release and hypertension. The purposes of this study were to analyze the post-exercise salivary nitrite (NO₂^-) and blood pressure (BP) responses to different exercise intensities in elderly women divided according to their ACE genotype.</p> <p>Methods</p> <p>Participants (n = 30; II/ID = 20 and DD = 10) underwent three experimental sessions: incremental test - IT (15 watts workload increase/3 min) until exhaustion; 20 min exercise 90% anaerobic threshold (90% AT); and 20 min control session without exercise. Volunteers had their BP and NO₂^-measured before and after experimental sessions.</p> <p>Results</p> <p>Despite both intensities showed protective effect on preventing the increase of BP during post-exercise recovery compared to control, post-exercise hypotension and increased NO₂^-release was observed only for carriers of the I allele (p < 0.05).</p> <p>Conclusion</p> <p>Genotypes of the ACE gene may exert a role in post-exercise NO release and BP response.</p

The use of informal care by people with vision impairment

PURPOSE: To estimate and characterize the use of informal care by people with vision impairment in Portugal. METHODS: A total of 546 visually impaired individuals were recruited from Portuguese hospitals. Clinical information was obtained from medical records, socio-demographic details and informal care use were collected during face-to-face interviews. In addition, participants responded to a functional vision questionnaire (activity inventory) to assess their visual ability. Logistic regression was used to determine independent factors associated with informal care use and linear regression was used to determine independent predictors of intensity of informal care use. RESULTS: Informal care was reported by 39.6% of the participants. The probability of reporting informal care was higher in non-married, those with comorbidities, with lower visual ability and worse visual acuity. The median number of caregivers' hours per year was 390 (mean = 470; 95%CI = 488-407), which represent a median opportunity cost of €2,586. Visual ability was the only independent predictor of number of hours of informal care received. CONCLUSIONS: Informal care was frequently used by individuals with impaired vision. Improving visual ability of people with impaired vision when performing valued activities may reduce the burden of visual loss at personal and societal level. This could be achieved with person-centred visual rehabilitation