The Activity of Spontaneous Action Potentials in Developing Hair Cells Is Regulated by Ca2+-Dependence of a Transient K+ Current

Spontaneous action potentials have been described in developing sensory systems. These rhythmic activities may have instructional roles for the functional development of synaptic connections. The importance of spontaneous action potentials in the developing auditory system is underpinned by the stark correlation between the time of auditory system functional maturity, and the cessation of spontaneous action potentials. A prominent K+ current that regulates patterning of action potentials is IA. This current undergoes marked changes in expression during chicken hair cell development. Although the properties of IA are not normally classified as Ca2+-dependent, we demonstrate that throughout the development of chicken hair cells, IA is greatly reduced by acute alterations of intracellular Ca2+. As determinants of spike timing and firing frequency, intracellular Ca2+ buffers shift the activation and inactivation properties of the current to more positive potentials. Our findings provide evidence to demonstrate that the kinetics and functional expression of IA are tightly regulated by intracellular Ca2+. Such feedback mechanism between the functional expression of IA and intracellular Ca2+ may shape the activity of spontaneous action potentials, thus potentially sculpting synaptic connections in an activity-dependent manner in the developing cochlea

On the improvement of the Knuth’s redundancy algorithm for balancing codes

Abstract: A simple scheme was proposed by Knuth to generate balanced codewords from a random binary information sequence. However, this method presents a redundancy which is twice as that of the full sets of balanced codewords, that is the minimal achievable redundancy. The gap between the Knuth’s algorithm generated redundancy and the minimal one is significantly considerable and can be reduced. This paper attempts to achieve this goal through a method based on information sequence candidates

Predicting the Growth of e-Commerce using Trendline Analysis: A Case Study of Ogun State, Nigeria

There is a growing interest from e-commerce planners and other planning agencies in the Information Technology world to measure and forecast the growth of e-commerce in developing countries like Nigeria. The difficulties lie in finding the best forecasting model that can incorporate both the internal and external barriers that influence the full adoption and diffusion of e-commerce. This study attempts to identify the relevant e-commerce tools and its spread in Ogun East Senatorial District as well as formulating a mathematical model for e-commerce adoption and diffusion. A well-structured questionnaire was used to collect data from 126 respondents and analyzed using Trendline, a built-in analysis tool in Microsoft® Office Excel version 2013. The study identified PCs/laptops, ATM cards, e-mail services, mobile money transfer, e-commerce Websites, and point-of-sales (POS) terminals as e-commerce tools used by the respondents. The results of the study show that majority of the e-commerce users/adopters were single female students between the ages of 21 and 30 years, with university education owing to a proportion of 63% of the respondents while the earliest adopted e-commerce tools in descending order were tablets/smartphones, PCs/laptops, ATM cards, and email services. The results further show that the most popularly-used tools were e-commerce websites (98% responses), email services (94% responses), mobile money transfer (94% responses), POS terminals (94% responses), tablets/smartphones (93% responses), PCs/laptops (87% responses) and ATM cards (80% responses). Based on the findings of this study, it is therefore recommended that government should promote the use and development of e-commerce, notably by reducing the costs of access to technology, through the liberation of trade in software and hardware.

Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate

Self-referencing H+-selective microelectrodes were used to measure extracellular H+ fluxes from horizontal cells isolated from the skate retina. A standing H+ flux was detected from quiescent cells, indicating a higher concentration of free hydrogen ions near the extracellular surface of the cell as compared to the surrounding solution. The standing H+ flux was reduced by removal of extracellular sodium or application of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), suggesting activity of a Na+–H+ exchanger. Glutamate decreased H+ flux, lowering the concentration of free hydrogen ions around the cell. AMPA/kainate receptor agonists mimicked the response, and the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) eliminated the effects of glutamate and kainate. Metabotropic glutamate agonists were without effect. Glutamate-induced alterations in H+ flux required extracellular calcium, and were abolished when cells were bathed in an alkaline Ringer solution. Increasing intracellular calcium by photolysis of the caged calcium compound NP-EGTA also altered extracellular H+ flux. Immunocytochemical localization of the plasmalemma Ca2+–H+-ATPase (PMCA pump) revealed intense labelling within the outer plexiform layer and on isolated horizontal cells. Our results suggest that glutamate modulation of H+ flux arises from calcium entry into cells with subsequent activation of the plasmalemma Ca2+–H+-ATPase. These neurotransmitter-induced changes in extracellular pH have the potential to play a modulatory role in synaptic processing in the outer retina. However, our findings argue against the hypothesis that hydrogen ions released by horizontal cells normally act as the inhibitory feedback neurotransmitter onto photoreceptor synaptic terminals to create the surround portion of the centre-surround receptive fields of retinal neuron

Selective vulnerability of neurons to acute toxicity after proteasome inhibitor treatment: Implications for oxidative stress and insolubility of newly synthesized proteins

Maintaining protein homeostasis is vital to cell viability, with numerous studies demonstrating a role for proteasome inhibition occurring during the aging of a variety of tissues and, presumably, contributing to the disruption of cellular homeostasis during aging. In this study we sought to elucidate the differences between neurons and astrocytes in regard to basal levels of protein synthesis, proteasome-mediated protein degradation, and sensitivity to cytotoxicity after proteasome inhibitor treatment. In these studies we demonstrate that neurons have an increased vulnerability, compared to astrocyte cultures, to proteasome-inhibitor-induced cytotoxicity. No significant difference was observed between these two cell types in regard to the basal rates of protein synthesis, or basal rates of protein degradation, in the pool of short-lived proteins. After proteasome inhibitor treatment neuronal crude lysates were observed to undergo greater increases in the levels of ubiquitinated and oxidized proteins and selectively exhibited increased levels of newly synthesized proteins accumulating within the insoluble protein pool, compared to astrocytes. Together, these data suggest a role for increased oxidized proteins and sequestration of newly synthesized proteins in the insoluble protein pool, as potential mediators of the selective neurotoxicity after proteasome inhibitor treatment. The implications for neurons exhibiting increased sensitivity to acute proteasome inhibitor exposure, and the corresponding changes in protein homeostasis observed after proteasome inhibition, are discussed in the context of both aging and age-related disorders of the nervous system.Fil: Dasuri, Kalavathi. State University of Louisiana; Estados UnidosFil: Ebenezer, Philip J.. State University of Louisiana; Estados UnidosFil: Zhang, Le. State University of Louisiana; Estados UnidosFil: Fernandez Kim, Sun Ok. State University of Louisiana; Estados UnidosFil: Uranga, Romina Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Gavilán, Elena. State University of Louisiana; Estados UnidosFil: Di Blasio, Alessia. State University of Louisiana; Estados UnidosFil: Keller, Jeffrey N.. State University of Louisiana; Estados Unido

Binary balanced codes approaching capacity

Abstract: In this paper, the construction of binary balanced codes is revisited. Binary balanced codes refer to sets of bipolar codewords where the number of “1”s in each codeword equals that of “0”s. The first algorithm for balancing codes was proposed by Knuth in 1986; however, its redundancy is almost two times larger than that of the full set of balanced codewords. We will present an efficient and simple construction with a redundancy approaching the minimal achievable one

Cash transfers and the social determinants of health : a conceptual framework

Cash transfers (CTs) can play a significant role in tackling the social determinants of health (SDoH), but to date there is a lack of conceptual framework for understanding CTs linkages to the SDoH. This article proposes a framework that identifies the linkages between CTs and SDoH, discusses its implications, and argues for active involvement of health promoters in CT design, implementation and evaluation. The development of the framework followed two stages: evidence review and stakeholder involvement. The evidence review entailed a systematic literature search to identify published and unpublished impact evaluation studies of CTs in sub-Saharan Africa. Critical reflection on the evidence synthesized from the literature formed the basis for the development of the framework. Interviews with CT policy makers, managers and development partners were also carried out to help refine the framework. Interviews were audio-recorded and transcripts were analysed using thematic framework analysis. The study finds that there is limited recognition of SDoH in CT policy making and implementation. The evidence reviewed, however, points to strong impacts of CTs on SDoH. The framework thus conceptualizes how CTs work to influence a broad range of SDoH and health inequities. It also highlights how CT architecture and contexts may influence program impacts. The proposed framework can be used by policy makers to guide CT design, adaptation and operations, and by program managers and researchers to inform CTs’ evaluations, respectively. The framework suggests that to optimize CT impact on SDoH and reduce health inequities, health promoters should be actively engaged in terms of the programs design, implementation and evaluation

The local translation of KNa in dendritic projections of auditory neurons and the roles of KNa in the transition from hidden to overt hearing loss

Local and privileged expression of dendritic proteins allows segregation of distinct functions in a single neuron but may represent one of the underlying mechanisms for early and insidious presentation of sensory neuropathy. Tangible characteristics of early hearing loss (HL) are defined in correlation with nascent hidden hearing loss (HHL) in humans and animal models. Despite the plethora of causes of HL, only two prevailing mechanisms for HHL have been identified, and in both cases, common structural deficits are implicated in inner hair cell synapses, and demyelination of the auditory nerve (AN). We uncovered that N

Biodegradation of Crude Oil Polluted Soil by Co-Composting with Agricultural Wastes and Inorganic Fertilizer

Pollution of the environment by petroleum products is inevitable due to oil production,   transportation and distribution activities.   The present study is aimed at examining the extent of bioremediation that can be achieved in crude oil polluted soil after supplementing with organic manure (poultry droppings and goat dung); inorganic fertilizer (NPK 15:15:15) and saw dust respectively. A bioremediation study was carried out on soil experimentally polluted with Bonny Light crude oil by supplementation with organic and inorganic nutrients (poultry manure, goat dung, saw dust and NPK fertilizer). The efficacy of the treatments was monitored for 112days by the measurement of total hydrocarbon utilizing bacteria load and some physico-chemical parameters. The polluted soil (Control) sample had mean bacterial counts of 8.8x104, 9.0x104, 9.2´104, 9.9x104 and 7.6x104 cfu/g respectively. Sample treated with NPK fertilizer had mean bacterial counts of 4.4x104, 4.6x104, 4.7x104, 4.9x104 and 5.2x104 cfu/g on days 0,28,56,84 and 112 respectively; sample treated with poultry manure had mean bacterial counts of 1.6x104, 1.8x104, 2.0x104, 2.4x104 and 2.7x104 cfu/g on days 0, 28,56,84 and 112 respectively; the saw dust treated sample had mean bacterial counts of 2.0x104, 2.3x104, 2.7x104, 2.9x104 and 3.0x104 cfu/g on days 0,28,56,84 and 112 respectively while that treated with goat dung had mean bacterial counts of 9.3x104, 9.5x104, 9.6x104, 9.8x104and 9.9x104 cfu/g on days 0,28,56,84 and 112 respectively.  There were differences in the physico-chemical analyses from the diverse samples. After statistical analysis (P£0.05) there was a significant difference between the different treated samples from the control. The results suggest that nutrient supplementation would be effective in the remediation of crude oil polluted soils. The potentials of various treatment options for the bioremediation of crude oil polluted soils seems to hold the most immediate solution especially for use in areas that would be adversely affected by physical or other removal methods. In this study, the reduction of oil in the treated samples is evident, polluted samples supplemented with fertilizer and poultry manure respectively proved to be the best options during the 112 days study period. This study shows that those organic supplements containing nitrogen and phosphorus have great potentials for the remediation of soils contaminated with petroleum hydrocarbon within a reasonable time. Keywords: Bioremediation, Crude Oil Polluted Soil, Organic Manure (poultry droppings and goat dung); Inorganic fertilizer (NPK 15:15:15), Saw dust

Pelvic actinomycosis: unrelated to prior intrauterine device use

Actinomycosis is a chronic, suppurative, granulomatous disease which is typically seen in the cervicofacial and thoracic regions and less commonly abdominopelvic (10-20%). It is caused by an anaerobic, filamentous gram positive bacterium which is a normal commensal of the oropharynx, gastrointestinal tract and genital tract. Pelvic actinomycosis is almost always associated with the current or prior use of an intrauterine contraceptive device. Clinical diagnosis is difficult owing to the close resemblance to an ovarian tumour. Definitive diagnosis is usually made only after histopathological correlation. Reported here is a patient with pelvic actinomycosis unrelated to the use of an intrauterine contraceptive device. This patient presented with clinical features suggestive of chronic pelvic inflammatory disease with a possible benign ovarian tumour. Operative findings were consistent with pelvic inflammatory disease. The typical histopathological features of the Splendor Hoeppli phenomenon with sulphur granules and isolation of the actinomyces organism (which is rare) revealed the diagnosis of actinomycosis of the fallopian tubes. Pelvic actinomycosis is a rare condition and seldom described in the absence of an intrauterine device. High dose, long term antibiotic therapy is the key to successful resolution with surgery reserved for refractory cases. This patient showed good clinical and radiological response