The myocardial Na+/H+ exchange (NHE) represents a major mechanism for pH regulation during normal physiological processes but especially during ischaemia and early reperfusion. However, there is now ...very compelling evidence that its activation contributes to paradoxical induction of cell injury. The mechanism for this most probably reflects the fact that activation of the exchanger is closely coupled to Na+ influx and therefore to elevation in intracellular Ca2+ concentrations through the Na+/Ca2+ exchange. The NHE is exquisitely sensitive to intracellular acidosis; however, other factors can also exhibit stimulatory effects via phosphorylation-dependent processes. These generally represent various autocrine and paracrine as well as hormonal factors such as endothelin-1, angiotensin II and alpha1-adrenoceptor agonists, which probably act through receptor-signal transduction processes. Thus far, 6 NHE isoforms have been identified and designated as NHE1 through NHE6. All except NHE6, which is located intracellularly, are restricted to the sarcolemmal membrane. In the mammalian myocardium the NHE1 subtype is the predominant isoform, although NHE6 has also been identified in the heart. The predominance of NHE1 in the myocardium is of some importance since, as discussed in this review, pharmacological development of NHE inhibitors for cardiac therapeutics has concentrated specifically on those agents which are selective for NHE1. These agents, as well as the earlier nonspecific amiloride derivatives have now been extensively demonstrated to possess excellent cardioprotective properties, which appear to be superior to other strategies, including the extensively studied phenomenon of ischaemic preconditioning. Moreover, the salutary effects of NHE inhibitors have been demonstrated using a variety of experimental models as well as animal species suggesting that the role of the NHE in mediating injury is not species specific. The success of NHE inhibitors in experimental studies has led to clinical trials for the evaluation of these agents in high risk patients with coronary artery disease as well as in patients with acute myocardial infarction (MI). Recent evidence also suggests that NHE inhibition may be conducive to attenuating the remodelling process after MI, independently of infarct size reduction, and attenuation of subsequent postinfarction heart failure. As such, inhibitors of NHE offer substantial promise for clinical development for attenuation of both acute responses to myocardial as well as chronic postinfarction responses resulting in the evolution to heart failure.
In order to determine genetic differences between 50 examinees with ischemic cerebrovascular accident (iCVA) and those of comparative group, we have chosen 1883 persons from phenotypic healthy ...population divided into 5 different subgroups. The purpose of our investigation was exploring hereditary characteristics of antigenes linked to erythrocyte membrane. The highest discriminating value in genetic distance had MN and ABO genetic loci. The frequency of M antigen in stroke patients was 70% (in the comparative group 55%), N antigen had frequency 30% in patients with iCVA and 45% in the comparative group. The frequency of the blood group A in the patients with iCV was 32.68% and 27.16% in the comparative group. Blood group B had frequency in the patients 10.69% and in the comparative group 6.72%. O blood group had frequency in the patients 56.73% and in the comparative group 66.12%. Genetic distance between patients with iCVA and the comparative group were determined with gene frequencies, that was shown on the dendrogram. The dendrogram clearly shows that patients with iCVA are separated from all other comparative subgroups. The results of our investigation presented the highest discriminating value of MN and ABO genetic loci. The possibility of linkage between genetic loci for these erithrocyte antigenes (on the 4th and 9th chromosome) and genetic loci which determine iCVA cannot be excluded. Finally we consider that this method can support earlier identification of persons who belong to "high risk group for cerebrovascular disease".
Locally available apricot (Prunus armeniaca L.) shells classified as a waste product from fruit processing, were alkali activated in order to develop an efficient heavy metal ions sorbent for water ...purification. To examine the changes occurred after alkali treatment, raw (SH) and modified apricot shells (SHM) were thoroughly characterized in terms of their chemical composition and surface properties. Chemical analysis revealed that alkaline treatment causes the disintegration of hemicellulose (its content decreased from 19.2 to 3.5%), which was in accordance with FTIR results. SEM micrographs and the mercury intrusion porosimetry revealed a larger surface area and porosity of SHM. Bohem's acid-base titration method indicated that the most of the SHM surface carboxylic groups were in sodium salt form and together with the pH of points of zero charge showed increase of surface alkalinity after modification. Treatment with NaOH enhanced the adsorption capacity by 154, 61 and 90% for Cu2+, Zn2+ and Pb2+, respectively. The amount of cations released from SHM was almost equal to the amount of adsorbed metal ions, suggesting ion exchange mechanism. The pseudo-second order kinetic indicated that the heavy metals cations were bound predominantly by complexation.
In order to establish the effectiveness of the biosorbent in real wastewater sample, SHM was employed for cleaning-up of drain water emanating from atomic adsorption spectrophotometer. The SHM showed high removal efficiency towards multiple metal ions. The amounts of Fe, Pb, Cu and Cr ions were reduced by 97, 87, 81 and 80%, respectively, while Ni and Zn amounts were reduced for 33 and 14%.
Used biosorbent SHM can be successfully regenerated with HCl (desorption>95%) and after regeneration biosorbent can be reused or it can be safely disposed.
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•Biosorption of heavy metals on raw and alkali treated apricot shells was studied.•Alkali activation significantly improves adsorption properties of raw sample.•Biosorption mechanism is ion-exchange followed by heavy metals complexation.•Based on desorption study results, biosorbent can be efficiently recovered and reused.•The developed biosorbent was successfully applied on real sample.
This study brings new geochronological and petrochemical data from the metamorphic sole beneath the Rogozna Mts., Western Vardar ophiolite belt. The Rogozna metamorphic sole is located at the base of ...a serpentinite nappe and consists of amphibolites and talc-chlorite schists. The Rogozna amphibolites are medium- to fine-grained rocks with nematoblastic texture and pronounced foliation. They consist of green amphibole (~70vol.%) with variable silica contents (6.4 to 7.8Siapfu), as well as Mg# (molMg/Mg+Fetot; 0.53 to 0.77) and variably albitized plagioclase (~30vol.%; Ab24–Ab98). Amphibolites are overprinted by a retrograde assemblage containing actinolite, epidote, clinoclore, sericite, chlorite, and magnetite. The amphibolites formed due to metamorphism of two basaltic suites: subalkaline/tholeiitic and alkaline. Subalkaline/tholeiitic amphibolites possess low Zr, Nb, Y, Th, Hf, TiO2, and P2O5 values and a LREE-depleted pattern, typical for the N-MORB (normal mid ocean ridge basalt) to BAB (back-arc basalt) origin. Alkaline amphibolites show elevated concentrations of Zr, Nb, Y, Th, Hf, TiO2, and P2O5 with a LREE-enriched pattern typically displayed by OIB (ocean island basalt). Amphibolites were crystallized during intra-oceanic thrusting at temperatures between 685°C and 765°C and at a depth of 12–17km. 40Ar/39Ar cooling ages of amphibole, ranging from 165 to 170Ma, slightly postdate the sole formation. Talc-chlorite schists are related to retrograde greenschist-facies metamorphism. They consist of Fe-rich talc and Cr-rich chlorite (peninite-diabantite) pseudomorphs after amphibole and MORB-type Cr-Al spinel, surrounded by Al- and Mg-poor ferrit chromite. The occurrence of ferrit chromite is related to earlier, amphibolite facies metamorphism. Chlorite pseudomorphs after amphibole were formed at 300–410°C.
This study suggests that there is no essential difference in the emplacement age of the Dinaric and West Vardar ophiolite belts supporting the interpretation involving a single Mesozoic ocean in the Balkan sector.
•Rogozna Mts. metamorphic sole (amphibolites, schists) Western Vardar belt•Amphibolites: subakaline/tholeiitic (N-MORB - BAB), alkaline (E-MORB/OIB)•Amphibolites: 685–765°C, 4–6kbar, 164.9±1.3 to 170.0±1.4Ma•Talc-Chlorite schists: MORB, 300–410°C•Synchronous closure of Dinaric and West Vardar belt — single Ocean
Hydrochar produced via hydrothermal carbonization of grape pomace was considered as novel sorbent of Pb2+ from aqueous solution. In order to enhance the adsorption capacity, hydrochar was chemically ...modified using 2 M KOH solution. Both materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction technique. Batch experiments were performed to examine the effect of sorbent dosage, pH and contact time. Obtained results showed that the KOH treatment increased the sorption capacity of hydrochar from 27.8 mg g−1 up to 137 mg g−1 at pH 5. Adsorption of lead on either of the materials was achieved through ion-exchange mechanism, chemisorption and Pb2+-π interaction. The Sips isotherm model gave the best fit with the experimental data obtained for Pb2+ sorption using activated hydrochar. The adsorption kinetic followed a pseudo second-order model. Thermodynamic parameters implied that the Pb2+ binding for hydrochar surface was spontaneous and exothermic process. Findings from this work suggest that the hydrothermal carbonization is a promising route for production of efficient Pb 2+ sorbents for wastewater treatment.
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•Grape pomace hydrochar and KOH modified hydrochar were tested as Pb2+ sorbents.•Alkali modified hydrochar exhibited a fivefold higher Pb2+ adsorption capacity.•The adsorption kinetic followed a pseudo second-order model.•The Sips isotherm model gave the best fit with the experimental data.•The Pb2+ binding for hydrochar surface was spontaneous and exothermic process.
Hydrochar produced via hydrothermal carbonization of grape pomace was considered as novel sorbent of Pb(2+) from aqueous solution. In order to enhance the adsorption capacity, hydrochar was ...chemically modified using 2 M KOH solution. Both materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction technique. Batch experiments were performed to examine the effect of sorbent dosage, pH and contact time. Obtained results showed that the KOH treatment increased the sorption capacity of hydrochar from 27.8 mg g(-1) up to 137 mg g(-1) at pH 5. Adsorption of lead on either of the materials was achieved through ion-exchange mechanism, chemisorption and Pb(2+)-π interaction. The Sips isotherm model gave the best fit with the experimental data obtained for Pb(2+) sorption using activated hydrochar. The adsorption kinetic followed a pseudo second-order model. Thermodynamic parameters implied that the Pb(2+) binding for hydrochar surface was spontaneous and exothermic process. Findings from this work suggest that the hydrothermal carbonization is a promising route for production of efficient Pb (2+) sorbents for wastewater treatment.
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