Einstein manifolds and curvature operator of the second kind

We prove that a compact Einstein manifold of dimension $n\geq 4$ with nonnegative curvature operator of the second kind is a constant curvature space by Bochner technique. Moreover, we obtain that compact Einstein manifolds of dimension $n\geq 11$ with $\left [ \frac{n+2}{4} \right ]$-nonnegative curvature operator of the second kind, 4\ (\mbox{resp.},8,9,10)-dimensional compact Einstein manifolds with $2$-nonnegative curvature of the second kind and $5$-dimensional compact Einstein manifolds with $3$-nonnegative curvature of the second kind are constant curvature spaces. Combing with Li's result [10], we have that a compact Einstein manifold of dimension $n\geq 4$ with $\max\{4,\left [ \frac{n+2}{4} \right ]\}$-nonnegative curvature operator of the second kind is a constant curvature space

Comparsion of bioleaching of copper sulphides by Acidithiobacillus ferrooxidans

Bioleaching of copper sulphides were investigated. The results show that the copper extraction from djurleite, bornite, covellite and chalcopyrite under the optimal conditions were 95.12, 84.5, 54.1, and 18.33%, respectively. A ranking for the bioleaching of copper sulfides was obtained: djurleite > bornite > covellite > chalcopyrite. A determination of the extent of adsorption of A. ferrooxidans on the surface of the minerals showed that the cell density of Acidithiobacillus ferrooxidans on djurleite was the highest. The order of adsorption on the copper sulphides was: djurleite > bornite > covellite > chalcopyrite. The results suggest a difference in affinity of bacteria for different copper sulphides. The higher the leaching rate of copper sulphides, the greater the density of bacteria absorbed on the surface of minerals.Keywords: Bioleaching, copper sulphides, Acidithiobacillus ferrooxidans, cell density, copper extractionAfrican Journal of Biotechnology, Vol. 13(5), pp. 664-672, 29 January, 201

Proizvodnja novog probiotičkog sira tipa Cheddar, veće ACE inhibicijske aktivnosti i većeg udjela γ-aminomaslačne kiseline, s pomoću Lactobacillus casei Zhang, izolirane iz fermentiranoga mliječnog napitka

Cheddar cheese has been manufactured with Lactobacillus casei Zhang as the dairy starter adjunct. L. casei Zhang had previously been isolated from koumiss collected from Xilin Guole in Inner Mongolia and characterized in detail with regard to their probiotic potential. The addition of L. casei Zhang to Cheddar cheese had no adverse effects on sensory criteria. The cheese made with 0.1, 1 and 2 % of the probiotic strain L. casei Zhang adjuncts contained high levels of the Lactobacillus after 6 months of ripening with final counts of 9.6·10^7, 7.7·10^7 and 1.02·10^8 CFU/g, respectively. In the ripe control cheese, without the addition of probiotic strain L. casei Zhang, the number of Lactobacillus reached 5.7·107 CFU/g. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) analysis was used to distinguish the added L. casei Zhang from the natural flora of the cheese and to determine whether L. casei Zhang grew in the cheese. ACE-inhibitory activity and γ-aminobutyric acid (GABA) concentrations in the cheese were measured. Compared with control cheese, experimental cheese with 0.1, 1 and 2 % of probiotic strain L. casei Zhang revealed some increase in ACE-inhibitory activity and GABA mass fraction. In the present study, the production of both ACE-inhibitory activity and GABA in the probiotic cheese with the L. casei Zhang adjunct isolated from koumiss has been found for the first time. The results suggest that cheese with the probiotic strain L. casei Zhang showed good potential for application in the management of hypertension.Proizveden je sir tipa Cheddar s pomoću dodane kulture Lactobacillus casei Zhang, prethodno izolirane iz fermentiranoga mliječnog napitka „koumiss“ (Xilin Guole, središnja Mongolija, Kina). Iscrpno su ispitana probiotička svojstva izolirane kulture. Utvrđeno je da dodatak kulture nije bitno promijenio senzorička svojstva sira. Sir pripremljen s 0,1 % probiotičke kulture imao je nakon 6 mjeseci zrenja 9,6·107 CFU/g, sir s 1 % probiotičke kulture 7,7·107 CFU/g, a sir s 2 % probiotičke kulture 1,02·108 CFU/g bakterija roda Lactobacillus. U zrelom je kontrolnom uzorku sira (bez dodatka L. casei Zhang) broj bakterija Lactobacillus bio 5,7·107 CFU/g. Provedbom ERIC-PCR analize razlučena je dodana kultura L. casei Zhang od prirodne mikroflore sira, te utvrđen njezin rast. Također je izmjerena veća ACE inhibicijska aktivnost te veći udio γ-aminomaslačne kiseline u dobivenom siru, u usporedbi s kontrolnim uzorkom. Rezultati pokazuju da se dodatkom probiotičke kulture L. casei Zhang dobiva sir boljih svojstava, čija veća primjena pridonosi liječenju povišenog arterijskog tlaka

Responsiveness of stroke volume variation and central venous pressure during acute normovolemic and hypervolemic hemodilution.

BackgroundStroke volume variation (SVV) is a robust indicator of fluid responsiveness during volume change. We compared the sensibility of SVV by Vigileo/Flotrac to central venous pressure (CVP) when volume changes in patients undergoing intraoperative acute normovolemic hemodilution (ANH) and acute hypervolemic hemodilution (AHH).MethodsForty patients were randomly divided into an ANH group (n = 20) and an AHH group (n = 20). All patients received general anesthesia and were mechanically ventilated. Data were collected from 7 different time-points in the ANH group: baseline, after withdrawal of 5%, 10%, and 15% of the estimated blood volume (EBV) and after replacement with an equal volume of 6% hydroxyethyl starch 130/0.4 (HES) in 5% EBV increments to baseline. There were four time points in the AHH group: baseline, after 5%, 10%, and 15% expansion of the EBV with 6% HES. At each time-point, CVP, SVV and other hemodynamic parameters measurements were obtained.ResultsAfter removal of 10% and 15% EBV, SVV significantly increased from 10.9 ± 3.0 to 14.1 ± 3.4 and 10.9 ± 3.0 to 16.0 ± 3.3 (P < 0.01), and returned to a final value of 10.6 ± 3.4 after volume replacement. The CVP value was unchanged after removal and replacement of 15% of the EBV. There were no significant changes in SVV after 5%, 10% whereas there was a significant reduction after 15% (8.2 ± 1.7) expansion of the EBV compared with baseline (9.9 ± 1.8) (P = 0.033). However, there was a significant increase in CVP after 10% (10.3 ± 2.4), 15% (11.3 ± 2.2) expansion of the EBV compared with baseline (8.2 ± 2.7) (P < 0.01).ConclusionSVV is a more sensitive parameter for volume than CVP during hypovolemia, on the contrary CVP is more sensitive than SVV during hypervolemia