Usable Privacy Preservation in Mobile Electronic Personality

Personalised ubiquitous services have rapidly proliferated due technological advancements in sensing, ubiquitous and mobile computing. Evolving societal trends, business and the economic potential of Personal Information (PI) have overlapped the service niches. At the same time, the societal thirst for more personalised services has increased and are met by soliciting deeper and more privacy invasive PI from customers. Consequentially, reinforcing traditional privacy challenges and unearthed new risks that render classical safeguards ine ective. The absence of solutions to criticise personalised ubiquitous services from privacy perspectives, aggravates the situation. This thesis presents a solution permitting users' PI, stored in their mobile terminals to be disclosed to services in privacy preserving manner for personalisation needs. The approach termed, Mobile Electronic Personality Version 2 (ME2.0), is compared to alternative mechanisms. Within ME2.0, PI handling vulnerabilities of ubiquitous services are identi ed and sensitised on their practices and privacy implications. Vulnerability where PI may leak through covert solicits, excessive acquisitions and legitimate data re-purposing to erode users privacy are also considered. In this thesis, the design, components, internal structures, architectures, scenarios and evaluations of ME2.0 are detailed. The design addresses implications and challenges leveraged by mobile terminals. ME2.0 components and internal structures discusses the functions related to how PI pieces are stored and handled by terminals and services. The architecture focusses on di erent components and their exchanges with services. Scenarios where ME2.0 is used are presented from di erent environment views, before evaluating for performance, privacy and usability.

Public and Private Sector Decision Makers Within the Rail Baltica Growth Corridor

Transport volumes have increased and will continue to increase in European Union. Even though the growth has not been equal between different transport modes. Most of the growth has been faced on road transport. European Union aims to balance the unbalanced market shares between the modes by gaining and supporting the competitiveness of railway and waterway transport. In EU railway transportation is seen as solution to increase safety in traffic and decrease the environmental impacts of transportation. The aim of this research is to figure out how it is possible to decrease the environmental impacts by the technology already in use. Main focus of this research is in intermodality and combining the road and railway transportation. This study aims also to figure out demands and expectations towards new Rail Baltica railway route connecting Tallinn and Berlin. The research is conducted by performing a literature review about decreasing environmental impacts and combining road and rail transport. Another viewpoint is taken from the possible effects of tourism to the passenger transport on rails. Knowledge gained by literature review is deepened by additional internet questionnaire study and expert interview study. In decreasing the environmental impacts of transportation electric trains are definitely the best option providing that the electricity is generated from renewable or carbon dioxide free sources. Decrease of environmental impacts has been reached also with acceptance of larger road transport vehicles. According to interviewed passenger transport experts, the whole route from Tallinn to Berlin may not be convenient to be used in passenger transport, just because the route is too long.. In EU freight is transported mainly with semi-trailer combinations, and that is why it could be logical if huckepack trains would be used on Rail Baltica. Huckepack train allows semi-trailers to be transported on rails with time efficient loading-unloading process. Overall, Rail Baltica project is experienced as a future-oriented one and new railway alignment is seen as great alternative option for transport modes using fossil fuels.

Logistics of North-West Russia and Rail Baltica: Standpoints of Private Sector

The main aims of the present report are to describe the current state of railway transport in Russia, and to gather standpoints of Russian private transportation logistics sector towards the development of new railway connection called Rail Baltica Growth Corridor, connecting North-West Russia with Germany through the Baltic States and Poland. North-West Russia plays important role not only in Russian logistics, but also wider European markets as in container sea ports handling is approx. 2.5 mill. TEU p.a. and handling volume in all terminals is above 190 million tons p.a. The whole transportation logistics sector is shortly described as an operational environment for railways – this is done through technical and economic angles. Transportation development is always going in line with economics of the country, so the analysis on economical development is also presented. Logistics integration of the country is strongly influenced by its engagement in the international trade. Although, raw material handling at sea ports and container transports (imports) are blossoming, domestic transportation market is barely growing (in long-term perspective). Thus, recent entrance of Russia into World Trade Organization (WTO) is analyzed theme in this research, as the WTO is an important regulator of the foreign trade and enabler of volume growth in foreign trade related transportation logistics. However, WTO membership can influence negatively the development of Russia’s own industry and its volumes (these have been uncompetitive in global markets for decades). Data gathering in empirical part was accomplished by semi-structured case study interviews among North-West Russian logistics sector actors (private). These were conducted during years 2012-2013, and research compiles findings out of ten case company interviews. Although, there was no sea port involved in the study, most of the interviewed companies relied in European Logistics within significant parts in short sea shipping and truck combined transportation chains (in Russian part also using railways). As the results of the study, it could be concluded that Rail Baltica is seen as possible transport corridor in most of the interviewed companies, if there is enough cargo available. However, interviewees are a bit sceptical, because major and large-scale infrastructural improvements are needed. Delivery time, frequency and price level are three main factors influencing the attractiveness of Rail Baltica route. Price level is the most important feature, but if RB can offer other advantages such as higher frequency, shorter lead times or more developed set of value-added services, then some flexibility is possible for the price level. Environmental issues are not the main criteria of today, but are recognized and discussed among customers. Great uncertainty exists among respondents e.g. on forthcoming sulphur oxide ban on Baltic Sea shipping (whether or not it is going to be implemented in Russia). Rather surprisingly, transportation routes to Eastern Europe and Mediterranean area are having higher value and price space than those to Germany/Central Europe. Border crossing operations (traction monopoly at rails and customs), gauge widths as well as unclear decision-making processes (in Russia), are named as hindering factors. Performance standards for European connected logistics among Russian logistics sector representatives are less demanding as compared to neighbourhood countries belonging to EU.

Jännitevälipiiritaajuusmuuttajan moottorikaapelin maksimipituuden määrittely

Työssä tutkitaan, kuinka pitkää moottorikaapelia on jännitevälipiiritaajuusmuuttajan kanssa mahdollista käyttää niin, että määritellyt reunaehdot vielä toteutuvat. Tavoitteena on tuottaa tietoa myynnille, markkinoinnille, tuotehallinnalle sekä tuoteylläpidolle siitä, miten taajuus-muuttaja toimii pidemmillä moottorikaapeleilla kuin valmistaja suosittelee. Tutkitut moottori-kaapelipituudet olivat 175…1025 metriä ja tutkitut laitteet nimellislähtövirroiltaan 2,4...25 A. Työssä aihetta käsitellään jänniteheijastusten näkökulmasta. Lisäksi tutkitaan moottorikaapelin pituuden vaikutusta taajuusmuuttajan eri komponenttien lämpenemiseen. Taajuusmuuttajan toiminnallisuutta arvioidaan moottorin suunnanvaihtojen avulla sekä turvallista toimintaa oikosulkutestein. Tutkittujen taajuusmuuttajien kohdalla on mahdollista käyttää taajuusmuuttajavalmistajan suositusta pidempiä moottorikaapeleita. Moottoriliittimien ylijännitteitä aiheuttavat jännite-heijastukset eivät aiheuttaneet raja-arvoja ylittäviä huippujännitteitä tutkituilla laitekokoon-panoilla. Myös lämpötilannousu oli maltillista tai jopa vähäistä taajuusmuuttajasta mitatuilla komponenteilla. Moottorisäätö havaittiin toimintakykyiseksi pidemmilläkin moottorikaape-leilla, tosin moottorin vääntömomentti heikkeni moottorikaapelien pituutta kasvatettaessa. Virranmittaus toimi hyvin myös pitkillä kaapeleilla, tuottaen vikalaukaisun kaikissa tehdyissä oikosulkutilanteissa. Moottorin ja taajuusmuuttajan melutaso nousivat moottorikaapelien pi-tuutta kasvatettaessa, vaikkakin moottorin käynti oli tasaista ja katkotonta Moottorikaapelin pituutta voidaan kasvattaa 325 metriin kaikissa tutkituissa laitteissa ilman, että mikään tutkittu ominaisuus vielä olennaisesti heikkenisi. Vielä 525 metrin moottorikaape-leita on mahdollista käyttää, mutta tällöin vääntömomentin tuotto on jo heikompaa.

Managing Customer Issues through a Support Channel Network

The importance of after-sales service or service in general can be seen and experienced by customers every day with industrial as well as other non-industrial services or products. This dissertation, drawing on theory and experience, focuses on practical engineering implications, specifically the management of customer issues in the after-sales phase in the mobile phone arena. The main objective of this doctoral dissertation is to investigate customer after-sales issue management, specifically regarding mobile phones. The case studies focus on issue resolution time and the issue of corrective actions. This dissertation consists of a main body and four peer-reviewed journal articles and one manuscript currently under review by a peer-reviewed journal. The main body of this dissertation examines the elements of customer satisfaction, loyalty, and retention with respect to corrective actions to address customer issues and issue resolution time through literature and empirical studies. The five independent works are case studies supporting the thesis research questions. This study examines four questions: 1) What are the factors affecting corrective actions for customers? 2) How can customer issue resolution time be controlled? 3) What are the factors affecting processes in the service chain? and 4) How can communication be measured in a service chain? In this work, both quantitative and qualitative analysis methods are used. The main body of the thesis reviews the literature regarding the elements that bridge the five case studies. The case studies of the articles and surveys lean more toward the methodology of critical positivism and then apply the interpretive approach in interpreting the results. The case study articles employ various statistical methods to analyze and to interpret the empirical and survey data. The statistical methods were used to create a model that is useful for significantly optimizing issue resolution time. Moreover, it was found that samples for verifying issues provided by the customer neither improve the perceived quality of corrective actions nor the perceived quality of issue resolution time. The term “service” in this work is limited to the technical services that are provided by product manufacturers and after-sales authorized service vendors. On the basis of this research work, it has been observed that corrective actions and issue resolution time are associated with customer satisfaction and hence, according to induction theory, to customer loyalty and retention. This thesis utilizes knowledge of marketing and customer relationships to contribute to the existing body of knowledge concerning information and communication technology for after-sales service recovery of mobile terminals. The established models in the thesis contribute to the existing knowledge of the after-sales process of dealing with customer issues in the field of mobile phones. The findings suggest that process managers could focus more on communication and training provided to the staff as new technology evolves rapidly. The study also suggest the managers formulate strategies for how customers can be kept informed on a regular basis of the status of issues that have been escalated for corrective action. The findings also lay the foundation for the comprehensive objective to control the entire product development process, starting with conceptualization. This implies that robust design should be applied to the new products so that problems affecting customer service quality are not repeated. The objective will be achieved when the entire service chain from product development to the final user can be modeled and this model can be used to support the organization at all levels.

Power semiconductor nonlinearities in active du/dt output filtering

This doctoral thesis introduces an improved control principle for active du/dt output filtering in variable-speed AC drives, together with performance comparisons with previous filtering methods. The effects of power semiconductor nonlinearities on the output filtering performance are investigated. The nonlinearities include the timing deviation and the voltage pulse waveform distortion in the variable-speed AC drive output bridge. Active du/dt output filtering (ADUDT) is a method to mitigate motor overvoltages in variable-speed AC drives with long motor cables. It is a quite recent addition to the du/dt reduction methods available. This thesis improves on the existing control method for the filter, and concentrates on the lowvoltage (below 1 kV AC) two-level voltage-source inverter implementation of the method. The ADUDT uses narrow voltage pulses having a duration in the order of a microsecond from an IGBT (insulated gate bipolar transistor) inverter to control the output voltage of a tuned LC filter circuit. The filter output voltage has thus increased slope transition times at the rising and falling edges, with an opportunity of no overshoot. The effect of the longer slope transition times is a reduction in the du/dt of the voltage fed to the motor cable. Lower du/dt values result in a reduction in the overvoltage effects on the motor terminals. Compared with traditional output filtering methods to accomplish this task, the active du/dt filtering provides lower inductance values and a smaller physical size of the filter itself. The filter circuit weight can also be reduced. However, the power semiconductor nonlinearities skew the filter control pulse pattern, resulting in control deviation. This deviation introduces unwanted overshoot and resonance in the filter. The controlmethod proposed in this thesis is able to directly compensate for the dead time-induced zero-current clamping (ZCC) effect in the pulse pattern. It gives more flexibility to the pattern structure, which could help in the timing deviation compensation design. Previous studies have shown that when a motor load current flows in the filter circuit and the inverter, the phase leg blanking times distort the voltage pulse sequence fed to the filter input. These blanking times are caused by excessively large dead time values between the IGBT control pulses. Moreover, the various switching timing distortions, present in realworld electronics when operating with a microsecond timescale, bring additional skew to the control. Left uncompensated, this results in distortion of the filter input voltage and a filter self-induced overvoltage in the form of an overshoot. This overshoot adds to the voltage appearing at the motor terminals, thus increasing the transient voltage amplitude at the motor. This doctoral thesis investigates the magnitude of such timing deviation effects. If the motor load current is left uncompensated in the control, the filter output voltage can overshoot up to double the input voltage amplitude. IGBT nonlinearities were observed to cause a smaller overshoot, in the order of 30%. This thesis introduces an improved ADUDT control method that is able to compensate for phase leg blanking times, giving flexibility to the pulse pattern structure and dead times. The control method is still sensitive to timing deviations, and their effect is investigated. A simple approach of using a fixed delay compensation value was tried in the test setup measurements. The ADUDT method with the new control algorithm was found to work in an actual motor drive application. Judging by the simulation results, with the delay compensation, the method should ultimately enable an output voltage performance and a du/dt reduction that are free from residual overshoot effects. The proposed control algorithm is not strictly required for successful ADUDT operation: It is possible to precalculate the pulse patterns by iteration and then for instance store them into a look-up table inside the control electronics. Rather, the newly developed control method is a mathematical tool for solving the ADUDT control pulses. It does not contain the timing deviation compensation (from the logic-level command to the phase leg output voltage), and as such is not able to remove the timing deviation effects that cause error and overshoot in the filter. When the timing deviation compensation has to be tuned-in in the control pattern, the precalculated iteration method could prove simpler and equally good (or even better) compared with the mathematical solution with a separate timing compensation module. One of the key findings in this thesis is the conclusion that the correctness of the pulse pattern structure, in the sense of ZCC and predicted pulse timings, cannot be separated from the timing deviations. The usefulness of the correctly calculated pattern is reduced by the voltage edge timing errors. The doctoral thesis provides an introductory background chapter on variable-speed AC drives and the problem of motor overvoltages and takes a look at traditional solutions for overvoltage mitigation. Previous results related to the active du/dt filtering are discussed. The basic operation principle and design of the filter have been studied previously. The effect of load current in the filter and the basic idea of compensation have been presented in the past. However, there was no direct way of including the dead time in the control (except for solving the pulse pattern manually by iteration), and the magnitude of nonlinearity effects had not been investigated. The enhanced control principle with the dead time handling capability and a case study of the test setup timing deviations are the main contributions of this doctoral thesis. The simulation and experimental setup results show that the proposed control method can be used in an actual drive. Loss measurements and a comparison of active du/dt output filtering with traditional output filtering methods are also presented in the work. Two different ADUDT filter designs are included, with ferrite core and air core inductors. Other filters included in the tests were a passive du/dtfilter and a passive sine filter. The loss measurements incorporated a silicon carbide diode-equipped IGBT module, and the results show lower losses with these new device technologies. The new control principle was measured in a 43 A load current motor drive system and was able to bring the filter output peak voltage from 980 V (the previous control principle) down to 680 V in a 540 V average DC link voltage variable-speed drive. A 200 m motor cable was used, and the filter losses for the active du/dt methods were 111W–126 W versus 184 W for the passive du/dt. In terms of inverter and filter losses, the active du/dt filtering method had a 1.82-fold increase in losses compared with an all-passive traditional du/dt output filter. The filter mass with the active du/dt method was 17% (2.4 kg, air-core inductors) compared with 14 kg of the passive du/dt method filter. Silicon carbide freewheeling diodes were found to reduce the inverter losses in the active du/dt filtering by 18% compared with the same IGBT module with silicon diodes. For a 200 m cable length, the average peak voltage at the motor terminals was 1050 V with no filter, 960 V for the all-passive du/dt filter, and 700 V for the active du/dt filtering applying the new control principle.

Container logistic innovations in forest-energy sector: Markets, future service concepts and technical improvements

The report presents the results of the commercialization project called the Container logistic services for forest bioenergy. The project promotes new business that is emerging around overall container logistic services in the bioenergy sector. The results assess the European markets of the container logistics for biomass, enablers for new business creation and required service bundles for the concept. We also demonstrate the customer value of the container logistic services for different market segments. The concept analysis is based on concept mapping, quality function deployment process (QFD) and business network analysis. The business network analysis assesses key shareholders and their mutual connections. The performance of the roadside chipping chain is analysed by the logistic cost simulation, RFID system demonstration and freezing tests. The EU has set the renewable energy target to 20 % in 2020 of which Biomass could account for two-thirds. In the Europe, the production of wood fuels was 132.9 million solid-m3 in 2012 and production of wood chips and particles was 69.0 million solidm3. The wood-based chips and particle flows are suitable for container transportation providing market of 180.6 million loose- m3 which mean 4.5 million container loads per year. The intermodal logistics of trucks and trains are promising for the composite containers because the biomass does not freeze onto the inner surfaces in the unloading situations. The overall service concept includes several packages: container rental, container maintenance, terminal services, RFID-tracking service, and simulation and ERP-integration service. The container rental and maintenance would provide transportation entrepreneurs a way to increase the capacity without high investment costs. The RFID-concept would lead to better work planning improving profitability throughout the logistic chain and simulation supports fuel supply optimization.

Glutamatergic transmission in the nucleus tractus solitarii: from server to peripherals in the cardiovascular information superhighway

Afferent nerves carrying signals from mechanoreceptors in the aortic arch and carotid sinus terminate predominantly in the nucleus tractus solitarii (NTS). Signal transduction and neurotransmission in the NTS are critical for central cardiovascular reflex control, but little was known about either until the late 1970's. None of the numerous neuroactive chemicals found in the NTS had met strict criteria as a neurotransmitter in the baroreflex arc until data suggested that the excitatory amino acid L-glutamate (GLU) might be released from baroreceptor afferent terminals in the NTS. In anesthetized animals microinjection into the NTS of GLU, which can be demonstrated in terminals in the NTS, produces cardiovascular responses like those seen with activation of the baroreceptor reflex. Similar responses occur in awake animals if the chemoreceptor reflex is eliminated; otherwise, in conscious animals responses mimic those of chemoreceptor reflex activation. GLU is released in the NTS upon selective activation of the baroreceptor, and possibly the chemoreceptor, reflex. Responses to selective agonists as well as baroreflex responses are eliminated by GLU antagonists microinjected into the NTS. Non-NMDA (N-methyl-D-aspartic acid) receptors seem to predominate at primary baroreceptor synapses in the NTS while NMDA receptors may be involved at later synapses. Although inhibition of soluble guanylate cyclase attenuates responses to ionotropic glutamate agonists in the NTS, nitric oxide does not seem to play a role in glutamate transmission in the NTS. GLU may also participate in transmission at cardiovascular neurons beyond the NTS. For example, a role has been suggested for GLU in the ventrolateral medulla and spinal cord. Work continues concerning GLU signal transduction and mechanisms that modulate that transduction both at the NTS and at other cardiovascular nuclei

Interaction between NO and oxytocin: Influence on LHRH release

Nitric oxide synthase (NOS)-containing neurons have been localized in various parts of the CNS. These neurons occur in the hypothalamus, mostly in the paraventricular and supraoptic nuclei and their axons project to the neural lobe of the pituitary gland. We have found that nitric oxide (NO) controls luteinizing hormone-releasing hormone (LHRH) release from the hypothalamus acting as a signal transducer in norepinephrine (NE)-induced LHRH release. LHRH not only releases LH from the pituitary but also induces sexual behavior. On the other hand, it is known that oxytocin also stimulates mating behavior and there is some evidence that oxytocin can increase NE release. Therefore, it occurred to us that oxytocin may also stimulate LHRH release via NE and NO. To test this hypothesis, we incubated medial basal hypothalamic (MBH) explants from adult male rats in vitro. Following a preincubation period of 30 min, MBH fragments were incubated in Krebs-Ringer bicarbonate buffer in the presence of various concentrations of oxytocin. Oxytocin released LHRH at concentrations ranging from 0.1 nM to 1 µM with a maximal stimulatory effect (P<0.001) at 0.1 µM, but with no stimulatory effect at 10 µM. That these effects were mediated by NO was shown by the fact that incubation of the tissues with NG-monomethyl-L-arginine (NMMA), a competitive inhibitor of NOS, blocked the stimulatory effects. Furthermore, the release of LHRH by oxytocin was also blocked by prazocin, an a1-adrenergic receptor antagonist, indicating that NE mediated this effect. Oxytocin at the same concentrations also increased the activity of NOS (P<0.01) as measured by the conversion of [14C]arginine to citrulline, which is produced in equimolar amounts with NO by the action of NOS. The release of LHRH induced by oxytocin was also accompanied by a significant (P<0.02) increase in the release of prostaglandin E2 (PGE2), a mediator of LHRH release that is released by NO. On the other hand, incubation of neural lobes with various concentrations of sodium nitroprusside (NP) (300 or 600 µM), a releaser of NO, revealed that NO acts to suppress (P<0.01) the release of oxytocin. Therefore, our results indicate that oxytocin releases LHRH by stimulating NOS via NE, resulting in an increased release of NO, which increases PGE2 release that in turn induces LHRH release. Furthermore, the released NO can act back on oxytocinergic terminals to suppress the release of oxytocin in an ultrashort-loop negative feedback

Localization of NMDA receptors in the cerebral cortex: a schematic overview

The fundamental role of N-methyl-D-aspartate (NMDA) receptors in many cortical functions has been firmly defined, as has its involvement in a number of neurological and psychiatric diseases. However, until recently very little was known about the anatomical localization of NMDA receptors in the cerebral cortex of mammals. The recent application of molecular biological techniques to the study of NMDA receptors has provided specific tools which have greatly expanded our understanding of the localization of NMDA receptors in the cerebral cortex. In particular, immunocytochemical studies on the distribution of cortical NMDA receptors have shown that NMDA receptors are preferentially localized on dendritic spines, have disclosed an unknown fraction of presynaptic NMDA receptors on both excitatory and inhibitory axon terminals, and demonstrated that cortical astrocytes do express NMDA receptors. These studies suggest that the effects induced by the activation of NMDA receptors are not due solely to the opening of NMDA channels on neuronal postsynaptic membranes, as previously assumed, but that the activation of presynaptic and glial NMDA receptors may mediate part of these effects

Circadian time-dependent effects of fencamfamine on inhibition of dopamine uptake and release in rat striatal slices

Fencamfamine (FCF) is a central stimulant that facilitates central dopaminergic transmission through inhibition of dopamine uptake and enhanced release of the transmitter. We evaluated the changes in the inhibition of uptake and the release of striatal [3H]-dopamine at 9:00 and 21:00 h, times corresponding to maximal and minimal behavioral responses to FCF, respectively. Adult male Wistar rats (200-250 g) maintained on a 12-h light/12-h dark cycle (lights on at 7:00 h) were used. In the behavioral experiments the rats (N = 8 for each group) received FCF (3.5 mg/kg, ip) or saline at 9:00 or 21:00 h. Fifteen minutes after treatment the duration of activity (sniffing, rearing and locomotion) was recorded for 120 min. The basal motor activity was higher (28.6 ± 4.2 vs 8.4 ± 3.5 s) after saline administration at 21:00 h than at 9:00 h. FCF at a single dose significantly enhanced the basal motor activity (38.3 ± 4.5 vs 8.4 ± 3.5 s) and increased the duration of exploratory activity (38.3 ± 4.5 vs 32.1 ± 4.6 s) during the light, but not the dark phase. Two other groups of rats (N = 6 for each group) were decapitated at 9:00 and 21:00 h and striata were dissected for dopamine uptake and release assays. The inhibition of uptake and release of [3H]-dopamine were higher at 9:00 than at 21:00 h, suggesting that uptake inhibition and the release properties of FCF undergo daily variation. These data suggest that the circadian time-dependent effects of FCF might be related to a higher susceptibility of dopamine presynaptic terminals to the action of FCF during the light phase which corresponds to the rats' resting period

Horizontal projections of area 17 in Cebus monkeys: metric features, and modular and laminar distribution

Metric features and modular and laminar distributions of intrinsic projections of area 17 were studied in Cebus apella. Anterogradely and retrogradely labeled cell appendages were obtained using both saturated pellets and iontophoretic injections of biocytin into the operculum. Laminar and modular distributions of the labeled processes were analyzed using Nissl counterstaining, and/or cytochrome oxidase and/or NADPH-diaphorase histochemistry. We distinguished three labeled cell types: pyramidal, star pyramidal and stellate cells located in supragranular cortical layers (principally in layers IIIa, IIIb a, IIIb ß and IIIc). Three distinct axon terminal morphologies were found, i.e., Ia, Ib and II located in granular and supragranular layers. Both complete and partial segregation of group I axon terminals relative to the limits of the blobs of V1 were found. The results are compatible with recent evidence of incomplete segregation of visual information flow in V1 of Old and New World primates

Catabolism of Ap4A and Ap5A by rat brain synaptosomes

Adenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) and adenosine 5',5'''-P1,P5-pentaphosphate (Ap5A) are stored in and released from rat brain synaptic terminals. In the present study we investigated the hydrolysis of dinucleotides (Ap4A and Ap5A) in synaptosomes from the cerebral cortex of adult rats. Ap4A and Ap5A, but not Ap3A, were hydrolyzed at pH 7.5 in the presence of 20 mM Tris/HCl, 2.0 mM MgCl2, 10 mM glucose and 225 mM sucrose at 37oC. The disappearance of the substrates measured by FPLC on a mono-Q HR column was both time and protein dependent. Since synaptosome integrity was at least 90% at the end of the assay, hydrolysis probably occurred by the action of an ecto-enzyme. Extracellular actions of adenine dinucleotides at central nervous system terminate due to the existence of ecto-nucleotidases which specifically cleave these dinucleotides. These enzymes in association with an ATP diphosphohydrolase and a 5'-nucleotidase are able to promote the complete hydrolysis of dinucleotides to adenosine in the synaptic cleft.

Melatonin modulation of presynaptic nicotinic acetylcholine receptors located on short noradrenergic neurons of the rat vas deferens: a pharmacological characterization

Melatonin, the pineal hormone produced during the dark phase of the light-dark cycle, modulates neuronal acetylcholine receptors located presynaptically on nerve terminals of the rat vas deferens. Recently we showed the presence of high affinity nicotine-binding sites during the light phase, and low and high affinity binding sites during the dark phase. The appearance of the low affinity binding sites was due to the nocturnal melatonin surge and could be mimicked by exposure to melatonin in vitro. The aim of the present research was to identify the receptor subtypes responsible for the functional response during the light and the dark phase. The rank order of potency of agonists was dimethylphenylpiperazinium (DMPP) = cytisine > nicotine > carbachol and DMPP = nicotine = cytisine > carbachol, during the light and dark phase, respectively, due to an increase in apparent affinity for nicotine. Mecamylamine similarly blocked the DMPP response during the light and the dark phase, while the response to nicotine was more efficiently blocked during the light phase. In contrast, methyllycaconitine inhibited the nicotine-induced response only at 21:00 h. Since a7 nicotinic acetylcholine receptors (nAChRs) have low affinity for nicotine in binding assays, we suggest that a mixed population composed of a3ß4 - plus a7-bearing nAChR subtypes is present at night. This plasticity in receptor subtypes is probably driven by melatonin since nicotine-induced contraction in organs from animals sacrificed at 15:00 h and incubated with melatonin (100 pg/ml, 4 h) is not totally blocked by mecamylamine. Thus melatonin, by acting directly on the short adrenergic neurons that innervate the rat vas deferens, induces the appearance of the low affinity binding site, probably an a7 nAChR subtype.

The role of nitric oxide in reproduction

Nitric oxide (NO) plays a crucial role in reproduction at every level in the organism. In the brain, it activates the release of luteinizing hormone-releasing hormone (LHRH). The axons of the LHRH neurons project to the mating centers in the brain stem and by afferent pathways evoke the lordosis reflex in female rats. In males, there is activation of NOergic terminals that release NO in the corpora cavernosa penis to induce erection by generation of cyclic guanosine monophosphate (cGMP). NO also activates the release of LHRH which reaches the pituitary and activates the release of gonadotropins by activating neural NO synthase (nNOS) in the pituitary gland. In the gonad, NO plays an important role in inducing ovulation and in causing luteolysis, whereas in the reproductive tract, it relaxes uterine muscle via cGMP and constricts it via prostaglandins (PG).