The role of potassium channels in the effects of resveratrol and naringenin on isolated human and rat venous blood vessels

Polifenoli su sloţena biljna, polusintetska i sintetska organska jedinjenja. Hrana sadrţi smešu različitih polifenola, a posebno voće i povrće, zeleni i crni čaj, crveno vino i dr. Nedavna istraţivanja govore u prilog značajne uloge polifenola u prevenciji kardiovaskularnih oboljenja, karcinoma, osteoporoze, neurodegenerativnih oboljenja i diabetes mellitusa. Najveći broj dokaza za to potiče iz in vitro i studija na ţivotinjama. Rezveratrol, polifenol iz crvenog groţđa i crvenog vina, je najviše proučavan polifenol. Za razliku od njega, naringenin, citrusni polifenol, pripada manje proučavanoj grupi polifenola, flavonoidima. Međutim, mehanizam vazodilatatornog i antivazokonstriktornog dejstva ovih polifenola na venskim krvnim sudovima još uvek nije proučen. Postoje dokazi da polifenoli mogu da aktiviraju kalijumove kanale (K-kanale) u glatkim mišićima arterijskih krvnih sudova i da na taj način dovedu do vazodilatacije. Ciljevi našeg istraţivanja bili su: a) da proučimo moguće antivazokonstriktorno i vazodilatatorno dejstvo rezveratrola i naringenina na izolovanoj portnoj veni pacova i humanoj pupčanoj veni, koje su prethodno kontrahovane na različite načine; b) da identifikujemo različite K-kanale vaskularnog glatkog mišića portne vene pacova i humane pupčane vene; c) da ispitamo da li K-kanali imaju značajnu ulogu u antivazokonstriktornom i vazodilatatornom dejstvu rezveratrola i naringenina; d) da proučimo postojanje dodatnog mehanizma dejstva rezveratrola i naringenina, koji je nezavisan od K-kanala, na izolovanim venskim krvnim sudovima. Kontrakcije portne vene pacova bez endotela izazivali smo pomoću električne stimulacije (ES), noradrenalina (NA), adenozin 5-trifosfata (ATP), rastvorom koji sadrţi visoku koncentraciju jona K+, kao i pomoću CaCl2...Polyphenols are complex plant-derived, semisynthetic or synthetic organic compounds. Foods contain complex mixtures of polyphenols, especially fruit and vegetables, green tea, black tea, red wine, etc. Recent studies strongly supports a role for polyphenols in the prevention of cardiovascular diseases, cancers, osteoporosis, neurodegenerative diseases, diabetes mellitus etc. Much of the evidence on the prevention of diseases by polyphenols is derived from in vitro or animal experiments. Resveratrol, polyphenol from grapes and red wine, is the most studied polyphenol, while naringenin, citrus polyphenol, belongs to the most studied group of polyphenols, flavonoids. However, the mechanisms of vasodilator and antivasoconctrictor effects of these polyphenols on venous blood vessels are not established. There are suggestions that polyphenols could activate potassium channels (K-channels) in the vascular smooth muscle cells and to induce relaxation of blood vessels. The aims of our research were: a) to analyze potential antivasoconstrictor and vasodilator effects of resveratrol and naringenin in the isolated rat portal vein and human umbilical vein, previously contracted in different ways; b) to identify K-channels in the vascular smooth muscle of human umbilical vein and rat portal vein; c) to examine whether K- channels play an important role in the antivasoconstictor and vasodilator effects of resveratrol and naringenin; d) to analyze additional potassium channel-independent effects of resveratrol and naringenin in the isolated venous blood vessels. Contractions of rat portal vein without endothelium were produced by electrical field stimulation of perivascular nerves (EFS), norepinephrine (NE), adenosine 5′-triphosphate (ATP), high K+ solution and by CaCl2 in Ca2+-free and high K+, Ca2+- free solution. In order to test whether resveratrol opens big calcium-sensitive (BKCa) channels, its effects were compared with those of NS 1619, a selective opener of BKCa channels..

Novel methods for axial fan impeller geometry analysis and experimental investigations of the generated swirl turbulent flow

Geometry analysis of the axial fan impeller, experimentally obtained operating characteristics and experimental investigations of the turbulent swirl flow generated behind the impeller are presented in this paper. Formerly designed and manufactured, axial fan impeller blade geometry (originally designed by Prof Dr-Ing. Z. Protic(dagger)) has been digitized using a three-dimensional scanner. In parallel, the same impeller has been modeled by beta version software for modeling axial turbomachines, based on modified classical calculation. These results were compared. Afterwards, the axial fan operating characteristics were measured on the standardized test rig in the Laboratory for Hydraulic Machinery and Energy Systems, Faculty of Mechanical Engineering, University of Belgrade. Optimum blade impeller position was determined on the basis of these results. Afterwards, impeller with angle 22 without outlet vanes, was positioned in a circular pipe. Rotational speed has been varied in the range from 500 till 2500 rpm. Reynolds numbers generated in this way, calculated for axial velocity component, was in the range from 0.68.10(5) till 2.5.10(5). Laser Doppler anemometry measurements and stereo particle image velocimetry measurements of the three-dimensional velocity field in the swirl turbulent fluid flow behind the axial fan have been performed for each regime. Obtained results point out extraordinary complexity of the structure of generated three-dimensional turbulent velocity fields

Three-dimensional urban solar potential maps: Case study of the i-Scope project

Solar maps as web cartographic products that provide information on solar potential of surfaces on the Earth have been exploited in decision making, awareness raising, and promoting the use of solar energy. Web based solar maps of cities have become popular services as the use of solar energy is especially attractive in urban environments. The article discusses the concept and aspects of urban solar potential maps on the example of the i-Scope project as a case study. The i-Scope roof solar potential service built on 3-D urban information models was piloted in eight European cities. To obtain precise data on solar irradiation, a good quality digital surface model is required. A cost efficient innovative method for generation of digital surface model from stereophotogrammetry for urban areas where no advanced source data (e. g. LiDAR) exist is developed. The method works for flat, shed and gable roofs and provides sufficient accuracy of digital surface model

Bioetička pitanja u vezi sa sigurnošću lijekova kod vulnerabilnih skupina

U cilju procjene stavova studenata medicine u odnosu na sudjelovanje vulnerabilnih subjekata u kliničkim ispitivanjima, proveli smo studiju presjeka (N = 174, studenti dodiplomskih studija Medicinskog fakulteta, Univerziteta u Beogradu). Studija presjeka provedena je tijekom jednog dana, na slučajno odabranim uzorcima studenata 3. godine (95/493 studenata) i 6. godine (79/510 studenata). Ukupno je odgovoreno na 83 % postavljenih pitanja. Rezultati studije pokazali su da studenti našeg fakulteta uglavnom nisu voljni sudjelovati kao dobrovoljci u kliničkim ispitivanjima, niti raditi u nehigijenskim romskim naseljima. Studenti su naglasili važnost dobivanja pristanka i djeteta i roditelja za sudjelovanje u kliničkom ispitivanju. Kada su u pitanju ispitivanja novih lijekova na populaciji starijih dementnih bolesnika, većina ispitanika smatra da informirani pristanak treba biti sličan pristanku za bilo koju drugu populaciju. U zaključku, tekući medicinski kurikulum treba biti više usmjeren na procjenu sigurnosti lijekova u vulnerabilnim skupinama. Posebno je potrebno unaprijediti rad s pripadnicima marginaliziranih skupina (npr. dodatna edukacija, posjeti nehigijenskim romskim naseljima i zajednički projekti)

3D urban solar potential maps - case study of the i-SCOPE project

Solar maps as web cartographic products that provide information on solar potential of surfaces on the Earth have been exploited in decision making, awareness raising, and promoting the use of solar energy. Web based solar maps of cities have become popular services as the use of solar energy is especially attractive in urban environments. The article discusses the concept and aspects of urban solar potential maps on the example of the i-Scope project as a case study. The i-Scope roof solar potential service built on 3-D urban information models was piloted in eight European cities. To obtain precise data on solar irradiation, a good quality digital surface model is required. A cost efficient innovative method for generation of digital surface model from stereophotogrammetry for urban areas where no advanced source data (e. g. LiDAR) exist is developed. The method works for flat, shed and gable roofs and provides sufficient accuracy of digital surface model

Security of wireless keyboards: Threats, vulnerabilities and countermeasures

Introduction/purpose: This paper provides an overview of research on computer system vulnerabilities caused by compromised electromagnetic radiation by wireless keyboards. Wireless devices that use event-triggered communication have been shown to have critical privacy issues due to the inherent leakage associated with radio frequency emissions. Wireless connectivity technology is a source of signal emanation that must be protected in terms of performance and security. Methods: Wireless device vulnerabilities and side-channel attacks are observed, along with electromagnetic emission of radio waves. Results: The findings highlight a specific wireless keyboard's security and encryption flaws. The results of penetration testing reveal vulnerabilities of targeted wireless keyboards in terms of outdated firmware, encryption, wireless reliability, and connection strength. Conclusion: Wireless keyboards have security flaws that disrupt radio communication, giving a malicious user complete access to the computer to which the keyboard is connected. An attacker can steal sensitive data by observing how the system works using compromised electromagnetic emissions

Upper limits for a narrow resonance in the reaction p + p -> K^+ + (Lambda p)

The reaction pp -> K^+ + (Lambda p) has been measured at T_p = 1.953 GeV and \Theta = 0 deg with a high missing mass resolution in order to study the Lambda p final state interaction. Narrow S = -1 resonances predicted by bag model calculations are not visible in the missing mass spectrum. Small structures observed in a previous experiment are not confirmed. Upper limits for the production cross section of a narrow resonance are deduced for missing masses between 2058 and 2105 MeV/c^2.Comment: 8 pages, 5 figure

Detailed comparison of the pp -> \pi^+pn and pp -> \pi^+d reactions at 951 MeV

The positively charged pions produced in proton-proton collisions at a beam momentum of 1640 MeV/c were measured in the forward direction with a high resolution magnetic spectrograph. The missing mass distribution shows the bound state (deuteron) clearly separated from the $pn$ continuum. Despite the very good resolution, there is no evidence for any significant production of the $pn$ system in the spin-singlet state. However, the $\sigma(pp\to \pi^+pn)/\sigma(pp\to \pi^+d)$ cross section ratio is about twice as large as that predicted from $S$-wave final-state-interaction theory and it is suggested that this is due to $D$-state effects in the $pn$ system.Comment: 8 pages, 3 figure

Mediators of outcome in adolescent psychotherapy and their implications for theories and mechanisms of change: a systematic review

Psychotherapeutic treatment of adolescents requires age-specific approaches and thus plausibly also involves different change mechanisms than adult psychotherapy. To guide further research and improve therapeutic outcomes for adolescents, we reviewed all RCTs investigating mechanisms of change in the psychological treatment of adolescents to identify the most promising age-, disorder- or treatment-specific mediators. Following the preferred reporting items for systematic reviews (PRISMA), 106 studies were included that reported 252 statistical mediation tests assessed with 181 different measures. Most often studied and significant mediators were cognitive, followed by family-related, and behavioral variables. Several mediators were identified to be promising for future investigations: changes in negative thoughts, dysfunctional beliefs and metacognitive skills; family functioning and parenting skills; as well as successful engagement in therapy activities and increased impulse control. Symptom change during therapy was least often a mediator for other therapeutic changes. Relational and emotional mediators were largely understudied, whereas peer-influence appeared a promising mediator for intervention outcomes. Adolescence-specific mediators were most commonly investigated. Majority of studied mediators were not disorder-specific. There was a tendency to mainly test change mechanisms of specific theoretical models without considering other possible change theories. Further, virtually no studies fulfilled all criteria for rigorously investigating mediation and only nine were classified with an overall good study quality. While bearing in mind the current limitations in study designs, methodological rigor and reporting, there appears to be substantial evidence for transdiagnostic age-specific change models in the psychological treatment of adolescents. For future research, need for consensus on a core set of transdiagnostic and transtheoretical mediators and measures is highlighted. These should address likely core mechanisms of change, as well as take into account age-relevant developmental challenges and biological markers.38 página