A konstitutív hem-oxigenáz enzim (HO-2) ösztrogének által szabályozott expressziójának és a keringési rendszer védelmi mechanizmusában betöltött szerepének vizsgálata patkányban = Regulation of the constitutive heme-oxigenase enzime (HO-2) expression by estrogenes, and its role in cardiovascular defense: in vivo actions of 17beta-estradiol and raloxifene

Szervezetünkben két vazoaktív gáz képződik: a nitrogénmonoxid (NO) és szénmonoxid (CO). Mindkét gázt különböző izoenzimek képzik, az NO szintázok és a CO-t a hem-oxigenáz (HO) izoenzimek. Az NO és CO fontos szerepet tölt be a normál vazodilátor tónus fenntartásában. Az NO enzimregulációval kapcsolatban számos adat található a szakirodalomban. Ezzel szemben a HO enzim szabályozás még kevésbé tanulmányozott terület. Kíséreteinkben in vivo és in vitro rendszereket alkalmaztunk. Kimutattuk, hogy a HO izoenzimek expresszióját az endogén ösztrogének szabályozzák. A HO enzim expresszió a kardiovaszkuláris szövetekben nagyobb nőstényekben, mint hímekben és ovariektomizált nőstényekben. Ugyanakkor a HO enzim expressziója függ a nemi ciklustól is: ösztrusz fázisban kifejezettebb, mint diösztruszban. Csökkent HO enzimexpresszió esetén megnövekszik a hajlam a vazokonstrikcióra, illetve a vaszkuláris endotélium diszfunkcióra. A HO és NO szintáz enzimrendszerek szinergistaként viselkednek a vaszkuláris integritás fenntartásában. Kiegészítő kísérleteinkben rámutattunk, hogy olyan gyulladásos folyamatokban, mint a kísérletes Crohn betegség a HO enzimrendszer aktivációja kulcsfontosságú szerepet tölt be a bél nyálkahártya védelmében. A Crohn betegség gyógyításában használatos 5-amino szalicilsav hatásmechanizmusában a HO rendszer aktivációjának is számottevő jelentősége van. | Two known endogenous vasoactive gases exist in the body: nitric oxide (NO) and carbon monoxide (CO). Both gases are synthesized by specific isoenzyme systems, i.e. by NO synthases and heme-oxygenase (HO) enzymes. Under physiological circumstances, NO and CO play crucial role in the maintenance of the normal vasodilator tone. There are numerous data in the literature in conjunction with the regulation of NO isoenzymes. In contrast less is known on HO enzyme regulatory pathways. We performed in vivo and in vitro studies. It was shown that the expression of HO isoenzymes is up-regulated by endogenous estrogens in cardiovascular tissues. An increased expression of HO isoenzymes was demonstrated in female rats compared to males and ovariectomized females. Moreover, we found an estrus cycle-dependent HO expression: in the estrus phase HO is overexpressed, while in the diestrus phase HO is down-regulated. The decreased expression of HO leads to augmented vasoconstrictive response, and suspectibility of vascular endothelial dysfuction. HO and NO isoenzymes are in synergistic interaction in the maintenance of microvascular integrity. In our additional experiments, we found that the activation of the HO enzyme system has important anti-inflammatory role in the development of colonic mucosal injury in a model of Crohn disease. Such known agent as 5-amino salicylic acid (used in the treatment of inflammatory bowel diseases) acts through the mediation of HO enzyme up-regulation

Customised broadband metamaterial absorbers for arbitrary polarisation

This paper shows that customised broadband absorption of electromagnetic waves having arbitrary polarisation is possible by use of lossy cut-wire (CW) metamaterials. These useful features are confirmed by numerical simulations in which different lengths of CW pairs are combined as one periodic metamaterial unit and placed near to a perfect electric conductor (PEC). So far metamaterial absorbers have exhibited some interesting features, which are not available from conventional absorbers, e.g. straightforward adjustment of electromagnetic properties and size reduction. The paper shows how with proper design a broad range of absorber characteristics may be obtained.Comment: 12 pages, 5 figures, submitted to Optics Expres

Dimethylammonium iodide stabilized bismuth halide perovskite photocatalyst for hydrogen evolution

Metal halide perovskites have emerged as novel and promising photocatalysts for hydrogen generation. Currently, their stability in water is a vital and urgent research question. In this paper a novel approach to stabilize a bismuth halide perovskite [(CH3)(2)NH2](3)[BiI6] (DA(3)BiI(6)) in water using dimethylammonium iodide (DAI) without the assistance of acids or coatings is reported. The DA(3)BiI(6) powder exhibits good stability in DAI solutions for at least two weeks. The concentration of DAI is found as a critical parameter, where the I- ions play the key role in the stabilization. The stability of DA(3)BiI(6) in water is realized via a surface dissolution-recrystallization process. Stabilized DA(3)BiI(6) demonstrates constant photocatalytic properties for visible light-induced photo-oxidation of I- ions and with PtCl4 as a co-catalyst (Pt-DA(3)BiI(6)), photocatalytic H-2 evolution with a rate of 5.7 mu molh(-1) from HI in DAI solution, obtaining an apparent quantum efficiency of 0.83% at 535 nm. This study provides new insights on the stabilization of metal halide perovskites for photocatalysis in aqueous solution

Random networks of core-shell-like Cu-Cu2O/CuO nanowires as surface plasmon resonance-enhanced sensors

The rapid oxide formation on pristine unprotected copper surfaces limits the direct application of Cu nanomaterials in electronics and sensor assemblies with physical contacts. However, it is not clear whether the growing cuprous (Cu2O) and cupric oxides (CuO) and the formation of core-shell-like Cu-Cu2O/CuO nanowires would cause any compromise for non-contact optical measurements, where light absorption and subsequent charge oscillation and separation take place such as those in surface plasmon-assisted and photocatalytic processes, respectively. Therefore, we analyze how the surface potential of hydrothermally synthetized copper nanowires changes as a function of time in ambient conditions using Kelvin probe force microscopy in dark and under light illumination to reveal charge accumulation on the nanowires and on the supporting gold substrate. Further, we perform finite element modeling of the optical absorption to predict plasmonic behavior of the nanostructures. The results suggest that the core-shell-like Cu-Cu2O/CuO nanowires may be useful both in photocatalytic and in surface plasmon-enhanced processes. Here, by exploiting the latter, we show that regardless of the native surface oxide formation, random networks of the nanowires on gold substrates work as excellent amplification media for surface-enhanced Raman spectroscopy as demonstrated in sensing of Rhodamine 6G dye molecules

Near-Bulk Conductivity of Gold Nanowires as Nanoscale Interconnects and the Role of Atomically Smooth Interface

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77445/1/2338_ftp.pd