Study on Zymomonas Mobilis Growth and Its Relationship with Glutaminase Production by Using Statistical Tools

Glutaminase is used industrially to enhance flavor and aroma and to enrich foodstuffs nutritionally. It also has potential for pharmaceutical application as anti-leukemia agent. The bacteria of Zymomonas mobilis has been studied for ethanol production, however, there is no study regarding glutaminase production. The aim of the present study was to establish the influencing factors for the growth of Z mobilis and its relationship with glutaminase production using statistical tools. Analysis of variance in blocks was carried out in a complete block design and the Tukey test demonstrated the importance of the components of the culture medium, absence of agitation and fermentation time. Minimum culture medium was used in the optimization varying the glucose concentrations （10, 30, and 50 g/L）, glutamine （0, 0.5 and 1g/L） and culture time （18, 24 and 30 hours）. Maximum production was obtained at 8.86 U/L glutaminase. Optimized conditions were used in the growth kinetics, where typical exponential growth was observed. Glutaminase production was shown to be related to biomass production.

Determination of the Adhesive Content of Medium Density Particleboards Produced with Bio-based Polymer

This work contributes to the use of alternative adhesives in the wood-based industry,where pine wood is commonly used.The investigation identifies the influence and the optimal content(8,12 and 15wt%)of a bio-based polyurethane adhesive in the production of medium density particleboards(MDP).A compaction pressure of 4 MPa at 100oC for 10 minutes is considered in the manufacture of panels based on pine wood residues and bio-based resin.The bulk density,flexural modulus(MOE)and strength(MOR)properties under static three-point bending are obtained according to the Brazilian standard NBR 14810.The results are compared with NBR 14810 and other standards to verify its performance based on the minimum requirements.Bulk density is not significantly affected by the investigated adhesive levels.MOE and MOR reach average values equivalent to 12wt%and 15wt%of the adhesive,and both meet the minimum requirements established in international normative documents.The adhesive level range responsible for maximizingρ,MOE and MOR is between 12.42wt%and 15.79wt%.

Analysis of State Homicide Rates Using Statistical Ranking and Selection Procedures

Nonparametric and parametric subset selection procedures are used in the analysis of state homicide rates (SHRs), for the year 2005 and years 2014-2020, to identify subsets of states that contain the “best” (lowest SHR) and “worst” (highest SHR) rates with a prescribed probability. A new Bayesian model is developed and applied to the SHR data and the results are contrasted with those obtained with the subset selection procedures. All analyses are applied within the context of a two-way block design.

Testing for additivity with B-splines

Regression splines are often used for fitting nonparametric functions, and they work especially well for additivity models. In this paper, we consider two simple tests of additivity: an adaptation of Tukey’s one degree of freedom test and a nonparametric version of Rao’s score test. While the Tukey-type test can detect most forms of the local non-additivity at the parametric rate of O(n-1/2), the score test is consistent for all alternative at a nonparametric rate. The asymptotic distribution of these test statistics is derived under both the null and local alternative hypotheses. A simulation study is conducted to compare their finite-sample performances with some existing kernel-based tests. The score test is found to have a good overall performance.