102 research outputs found
Scaling-up batch conditions for efficient sucrose hydrolysis catalyzed by an immobilized recombinant Pichia pastoris cells in a stirrer tank reactor
Background: Invert sugar is used greatly in food and pharmaceutical
industries. This paper describes scaling-up batch conditions for
sucrose inversion catalyzed by the recombinant Pichia pastoris BfrA4X
whole cells expressing Thermotoga maritima invertase entrapped in
calcium alginate beads. For the first time, we describe the application
of a kinetic model to predict the fractional conversion expected during
sucrose hydrolysis reaction in both, a model and a prototype bioreactor
with 0.5- and 5-L working volume, respectively. Results: Different
scaled-up criteria used to operate the 0.5-L bioreactor were analyzed
to explore the invert sugar large scale production. After model
inversion studies, a 5-L scaled-up reaction system was performed in a
7-L stirred reactor. Both scaled-up criteria, immobilized biocatalyst
dosage and stirring speed, were analyzed in each type of bioreactors
and the collected data were used to ensure an efficient scale-up of
this biocatalyst. Conclusions: To date, there is not enough information
to describe the large-scale production of invert sugar using different
scaled-up criteria such as dose of immobilized biocatalyst and stirring
speed effect on mass transfer. The present study results constitute a
valuable tool to successfully carry out this type of high-scale
operation for industrial purposes
Schwartz - Zippelov teorem i neke njegove primjene
U ovom radu izložen je rezultat poznat pod nazivom Schwartz - Zippelova lema ili Schwartz - Zippelov teorem. Tema rada pripada pretežno algebri, ali ima značajne primjene u drugim matematičkim područjima kao što je na primjer teorija algoritama, te kombinatorika. Rad se sastoji od tri poglavlja. U uvodu je ukratko opisana tema i cilj rada. Prvo poglavlje sadrži kratku povijest nastanka teorema, različite oblike rezultata pojedinih autora, te kratki opis pojmova korištenih u samom radu. Drugo poglavlje sastoji se od iskaza i dokaza Schwartz - Zippelovog teorema, a u trećem poglavlju izložene su neke primjene tog teorema na probleme koji se mogu svesti na testiranje jednakosti polinoma. Takvi su, primjerice, problem postojanja savršenog sparivanja u grafu i ispitivanje svojstva asocijativnosti u grupoidu. Uz svaku primjenu navedeni su i prikladni primjeri.In this diploma thesis we present the result usually called the Schwartz-Zippel lemma or the Schwartz-Zippel theorem. The nature of this theorem is basically algebraic, but it has significant applications in other areas of mathematics, such as the theory of algorithms and combinatorial theory. The thesis consists of three chapters. The main theme and objective are briefly described in the introduction. The first chapter contains a short history of the theorem’s origins, various forms of the main results by different authors and some comments of basic concepts related to this topic. The statement and a proof of the Schwartz-Zippel theorem are given in the second chapter, together with the general outline of its applications. The third and final chapter consists of some applications to problems which can be reduced to polynomial identity testing, including the existence of a perfect matching in a graph and testing of the associativity property in a groupoi
Cytotoxic Acetogenins from the Roots of Annona purpurea
Annona purpurea, known in Mexico as "cabeza de negro" or "ilama", belongs to the Annonaceae family. Its roots are employed in folk medicine in several regions of Mexico. Taking that information into account, a chemical and biological analysis of the components present in the roots of this species was proposed. Our results demonstrated that the dichloromethane (DCM) extract was exclusively constituted by a mixture of five new acetogenins named annopurpuricins A-E (1-5). These compounds have an aliphatic chain of 37 carbons with a terminal \u3b1,\u3b2 unsaturated \u3b3-lactone. Compounds 1 and 2 belong to the adjacent bis-THF (tetrahydrofuran) \u3b1-monohydroxylated type, while compounds 3 and 4 belong to the adjacent bis-THF \u3b1,\u3b1'-dihydroxylated type; only compound 5 possesses a bis-epoxide system. Complete structure analysis was carried out by spectroscopy and chemical methods. All compounds were evaluated for their antiproliferative activity on three human tumor cell lines (MSTO-211H, HeLa and HepG2). Compounds 1-4 inhibited significantly the growth of HeLa and HepG2 cells, showing GI50 values in the low/subnanomolar range, while 5 was completely ineffective under the tested conditions. The investigation of the mechanism of action responsible for cytotoxicity revealed for the most interesting compound 1 the ability to block the complex I activity on isolated rat liver mitochondria (RLM)
Total RNA quality of lyophilized and cryopreserved dormant grapevine buds
Background: Plant tissues must be preserved in their collection state,
especially for genome-wide expression profile studies. Lyophilization
is a feasible, affordable tool when fresh tissues cannot be shipped at
ultralow temperatures from their origin to the place of analysis. In
this study, the total RNA quality of dormant grapevine buds ( Vitis
vinifera L. cv. \u2018Flame Seedless\u2019) of freeze-dried
samples stored at room temperature conditions was evaluated and
compared to that of cryopreserved (-80\ub0C) grapevine buds. Results:
Good yield and quality of RNA were obtained from freeze-dried dormant
buds stored at room temperature for 0, 3 and 6 weeks after they were
lyophilized. Further experiments confirmed that the extracted total RNA
could be used for actin and \u3b2-tubulin PCR gene amplification.
Conclusion: High-quality RNA that is useful for downstream applications
was obtained from freeze-dried dormant grapevine bud tissue, similarly
to the RNA obtained from cryopreserved dormant grapevine buds
Novel inhibitors of human glucose-6-phosphate dehydrogenase (HsG6PD) affect the activity and stability of the protein
Background: The pentose phosphate pathway (PPP) has received significant attention because of the role of NADPH and R-5-P in the maintenance of cancer cells, which are necessary for the synthesis of fatty acids and contribute to uncontrollable proliferation. The HsG6PD enzyme is the rate-limiting step in the oxidative branch of the PPP, leading to an increase in the expression levels in tumor cells; therefore, the protein has been proposed as a target for the development of new molecules for use in cancer. Methods: Through in vitro studies, we assayed the effects of 55 chemical compounds against recombinant HsG6PD. Here, we present the kinetic characterization of four new HsG6PD inhibitors as well as their functional and structural effects on the protein. Furthermore, molecular docking was performed to determine the interaction of the best hits with HsG6PD. Results: Four compounds, JMM-2, CCM-4, CNZ-3, and CNZ-7, were capable of reducing HsG6PD activity and showed noncompetitive and uncompetitive inhibition. Moreover, experiments using circular dichroism and fluorescence spectroscopy showed that the molecules affect the structure (secondary and tertiary) of the protein as well as its thermal stability. Computational docking analysis revealed that the interaction of the compounds with the protein does not occur at the active site. Conclusions: We identified two new compounds (CNZ-3 and JMM-2) capable of inhibiting HsG6PD that, compared to other previously known HsG6PD inhibitors, showed different mechanisms of inhibition. General significance: Screening of new inhibitors for HsG6PD with a future pharmacological approach for the study and treatment of cancer
Plasma lipidome and risk of atrial fibrillation: results from the PREDIMED trial
The potential role of the lipidome in atrial fibrillation (AF) development is still widely unknown. We aimed to assess the association between lipidome profiles of the Prevenci\uf3n con Dieta Mediterr\ue1nea (PREDIMED) trial participants and incidence of AF. We conducted a nested case–control study (512 incident centrally adjudicated AF cases and 735 controls matched by age, sex, and center). Baseline plasma lipids were profiled using a Nexera X2 U-HPLC system coupled to an Exactive Plus orbitrap mass spectrometer. We estimated the association between 216 individual lipids and AF using multivariable conditional logistic regression and adjusted the p values for multiple testing. We also examined the joint association of lipid clusters with AF incidence. Hitherto, we estimated the lipidomics network, used machine learning to select important network-clusters and AF-predictive lipid patterns, and summarized the joint association of these lipid patterns weighted scores. Finally, we addressed the possible interaction by the randomized dietary intervention. Forty-one individual lipids were associated with AF at the nominal level (p < 0.05), but no longer after adjustment for multiple-testing. However, the network-based score identified with a robust data-driven lipid network showed a multivariable-adjusted ORper+1SD of 1.32 (95% confidence interval: 1.16–1.51; p < 0.001). The score included PC plasmalogens and PE plasmalogens, palmitoyl-EA, cholesterol, CE 16:0, PC 36:4;O, and TG 53:3. No interaction with the dietary intervention was found. A multilipid score, primarily made up of plasmalogens, was associated with an increased risk of AF. Future studies are needed to get further insights into the lipidome role on AF. Current Controlled Trials number, ISRCTN35739639
Geographical variation in therapy for bloodstream infections due to multidrug-resistant enterobacteriaceae: a post hoc analysis of the INCREMENT study
We aimed to describe regional differences in therapy for bloodstream infection (BSI) caused by extended-spectrum ?-lactamase-producing Enterobacteriaceae (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE). 1,482 patients in 12 countries were included from an observational study of BSI caused by ESBL-E or CPE. Multivariate logistic regression was used to calculate adjusted odds ratios (aORs) for the influence of country of recruitment on empirical use of ?-lactam/?-lactamase inhibitors (BLBLI) or carbapenems, targeted use of BLBLI for ESBL-E and use of targeted combination therapy for CPE. The use of BLBLI for empirical therapy was least likely in sites from Israel (aOR 0.34, 95% CI 0.14-0.81), Greece (aOR 0.49, 95% CI 0.26-0.94) and Canada (aOR 0.31, 95% CI 0.11-0.88) but more likely in Italy (aOR 1.58, 95% CI 1.11-2.2) and Turkey (aOR 2.09, 95% CI 1.14-3.81), compared to Spain as a reference. Empirical carbapenems were more likely to be used in sites from Taiwan (aOR 1.73, 95% CI 1.03-2.92) and USA (aOR 1.89; 95% CI 1.05-3.39), and less likely in Italy (aOR 0.44, 95% CI 0.28-0.69) and Canada (aOR 0.10, 95% CI 0.01-0.74). Targeted BLBLI for ESBL-E was more likely in sites from Italy. Treatment at sites within Israel, Taiwan, Turkey and Brazil was associated with less combination therapy for CPE. Although this study does not provide precise data on the relative prevalence of ESBL-E or CPE, significant variation in therapy exists across countries even after adjustment for patient factors. A better understanding of what influences therapeutic choices for these infections will aid antimicrobial stewardship efforts.PH is supported by an Australian Postgraduate Award from the University of
Queensland. The study was funded by the Ministerio de Economía y Competitividad,
Instituto de Salud Carlos III - co-financed by European Development Regional Fund "A way to
achieve Europe" ERDF, Spanish Network for the Research in Infectious Diseases (REIPI
RD12/0015). BGG, JRB, APH and YC also received funds from the COMBACTE-CARE
project (grant agreement 115620), Innovative Medicines Initiative (IMI), the European
Union's Seventh Framework Programme (FP7/2007-2013) and in-kind contributions from
EFPIA companies
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at TeV
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb
collisions at = 2.76 TeV have been measured by the ALICE
Collaboration at the LHC. The data are presented for central and peripheral
collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross
section. The measured charged particle spectra in and GeV/ are compared to the expectation in pp collisions at the same
, scaled by the number of underlying nucleon-nucleon
collisions. The comparison is expressed in terms of the nuclear modification
factor . The result indicates only weak medium effects ( 0.7) in peripheral collisions. In central collisions,
reaches a minimum of about 0.14 at -7GeV/ and increases
significantly at larger . The measured suppression of high- particles is stronger than that observed at lower collision energies,
indicating that a very dense medium is formed in central Pb-Pb collisions at
the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
Strange particle production in proton-proton collisions at TeV with ALICE at the LHC
The production of mesons containing strange quarks (K, ) and both
singly and doubly strange baryons (, Anti-, and
+Anti-) are measured at central rapidity in pp collisions at
= 0.9 TeV with the ALICE experiment at the LHC. The results are
obtained from the analysis of about 250 k minimum bias events recorded in 2009.
Measurements of yields (dN/dy) and transverse momentum spectra at central
rapidities for inelastic pp collisions are presented. For mesons, we report
yields () of 0.184 0.002 stat. 0.006 syst. for K and
0.021 0.004 stat. 0.003 syst. for . For baryons, we find
= 0.048 0.001 stat. 0.004 syst. for , 0.047
0.002 stat. 0.005 syst. for Anti- and 0.0101 0.0020 stat.
0.0009 syst. for +Anti-. The results are also compared with
predictions for identified particle spectra from QCD-inspired models and
provide a baseline for comparisons with both future pp measurements at higher
energies and heavy-ion collisions.Comment: 33 pages, 21 captioned figures, 10 tables, authors from page 28,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/387
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