Induction Factor Research Articles

A Computational Fluid Dynamics Investigation on the Axial Induction Factor of a Small Horizontal Axis Wind Turbine

Abstract The evolution of wind and hydrokinetic turbines stimulated the development of several tools to evaluate and to predict horizontal axis rotor behavior. From this perspective, the blade element momentum methods stand out as one of the most common approaches due to its reliability and computing speed. In the classical blade element momentum, the axial induction factor is a crucial variable to compute correctly the turbine parameters. Usually, the axial induction is determined by an interactive process that balances the forces at blade sections with momentum equations. The forces are computed based on the airfoil polars evaluated at each blade section with local inlet velocity. This procedure assumes that the swirl terms are linearized, where the lateral pressure forces is neglected. In order to evaluate these tri-dimensional effects on the blade element momentum method, the present work introduces a different methodology to determine the axial induction factor employing computational fluid dynamics simulations. The method was applied for a full-scale horizontal axis rotor with three blades and 1 m of diameter, with wind tunnel experiments for validation. The axial induction factor obtained with the new technique was compared to the classical blade element momentum method. The results show axial induction factor variations along the radial and axial coordinates. An analogy with Glauert power coefficient limit was made, finding a specific limit curve for the tested turbine, and, moreover, a correlation between turbine firing speed and induction factor.

Aerodynamic Rotor Performance of a 3300-kW Modern Commercial Large-Scale Wind Turbine Installed in a Wind Farm

Abstract Wind turbine technology in the world has been developed by continuously improving turbine performance, design, and efficiency. Over the last 40 years, the rated capacity and dimension of the commercial wind turbines have increased dramatically, so the energy cost has declined significantly, and the industry has moved from an idealistic position to an acknowledged component of the power generation industry. For this reason, a thorough examination of the aerodynamic rotor performance of a modern large-scale wind turbine working on existing onshore wind farms is critically important to monitor and control the turbine performance and also for forecasting turbine power. This study focuses on the aerodynamic rotor performance of a 3300-kW modern commercial large-scale wind turbine operating on an existing onshore wind farm based on the measurement data. First, frequency distributions of wind speeds and directions were obtained using measurements over one year. Then, wind turbine parameters such as free-stream wind speed (U∞), far wake wind speed (UW), axial flow induction factor (a), wind turbine power coefficient (CP), tangential flow induction factor (a′), thrust force coefficient (CT), thrust force (T), tip-speed ratio (λ), and flow angle (ϕ) were calculated using the measured rotor disc wind speed (UD), atmospheric air temperature (Tatm), turbine rotational speed (Ω), and turbine power output (P) parameters. According to the results obtained, the maximum P, CP, CT, T, and Ω were calculated as approximately 3.3 MW, 0.45, 0.6, 330 kN, and 12.9 rpm, respectively, while the optimum λ, ϕ, U∞, and Ω for the maximum CP were determined as 7.5–8.5, 6–6.3°, 5–10 m/s, and 6–10 rpm, respectively. These calculated results can contribute to assessing the economic and technical feasibility of modern commercial large-scale wind turbines and supporting future developments in wind energy and turbine technology.

The Biochemistry of Cytoplasmic Incompatibility Caused by Endosymbiotic Bacteria

Many species of arthropods carry maternally inherited bacterial endosymbionts that can influence host sexual reproduction to benefit the bacterium. The most well-known of such reproductive parasites is Wolbachia pipientis. Wolbachia are obligate intracellular α-proteobacteria found in nearly half of all arthropod species. This success has been attributed in part to their ability to manipulate host reproduction to favor infected females. Cytoplasmic incompatibility (CI), a phenomenon wherein Wolbachia infection renders males sterile when they mate with uninfected females, but not infected females (the rescue mating), appears to be the most common. CI provides a reproductive advantage to infected females in the presence of a threshold level of infected males. The molecular mechanisms of CI and other reproductive manipulations, such as male killing, parthenogenesis, and feminization, have remained mysterious for many decades. It had been proposed by Werren more than two decades ago that CI is caused by a Wolbachia-mediated sperm modification and that rescue is achieved by a Wolbachia-encoded rescue factor in the infected egg. In the past few years, new research has highlighted a set of syntenic Wolbachia gene pairs encoding CI-inducing factors (Cifs) as the key players for the induction of CI and its rescue. Within each Cif pair, the protein encoded by the upstream gene is denoted A and the downstream gene B. To date, two types of Cifs have been characterized based on the enzymatic activity identified in the B protein of each protein pair; one type encodes a deubiquitylase (thus named CI-inducing deubiquitylase or cid), and a second type encodes a nuclease (named CI-inducing nuclease or cin). The CidA and CinA proteins bind tightly and specifically to their respective CidB and CinB partners. In transgenic Drosophila melanogaster, the expression of either the Cid or Cin protein pair in the male germline induces CI and the expression of the cognate A protein in females is sufficient for rescue. With the identity of the Wolbachia CI induction and rescue factors now known, research in the field has turned to directed studies on the molecular mechanisms of CI, which we review here.

Extracting angles of attack from blade‐resolved rotor CFD simulations

AbstractThe distribution of the angles of attack over the span of a rotor blade, together with blade element theory, provides a useful framework to understand forces, performance and other fluid dynamic phenomena of axial‐flow rotors. However, the angle of attack is not straightforward to define for a three‐dimensional rotor, where the flow is perturbed by the blade circulation, shed vorticity and wake development.This paper evaluates six methods to extract the angles of attack from blade‐resolved CFD simulations of axial‐flow turbines. Simulations of two different rotors are presented: a low solidity rotor designed for wind and a higher solidity rotor designed for tidal stream energy conversion. Of the analysed methods, five were obtained from the literature and are tested in terms of their internal parameters. The remaining method is named the streamtube analysis method (SAM) and is presented as an improvement on analysis methods that azimuthally average the flow data on the rotor plane, referred to as azimuthal averaging techniques (AATs). The SAM method accounts for the expansion of the streamtubes in flow‐field velocity sampling and exhibits improved convergence on the internal parameters compared with AAT.The six methods are benchmarked in terms of the angles of attack, axial induction factors and the local lift and drag coefficients, identifying that most perform well and converge with each other despite the different underlying assumptions or modelling approaches. However, given the limitations and inherent dependency on internal parameters, the line averaging and SAM are suggested for general flow analysis application.

Optimization Technique for Hydrokinetic Turbine Blades: Pressure Minimization Approach

Everyday rise in world population push for more energy demand. The dependence and usage of fossil fuel in an uncontrolled manner has triggered environmental imbalance. A need to discourage the use of fossil fuel birth renewable energy is a form of energy which is not just environmentally friend but relatively cheap. Hydrokinetic turbine is a device which extracts kinetic energy from moving water to generate power. Hydrokinetic blade is an integral part of hydrokinetic turbine which is one of the components that determines the output power. There is power loss during the operation of the turbine and there is need to reduce this loss. This gives rise to a need to develop an optimization technique that can optimize turbine blade in addition to the existing models. Parameters concentrated on include pressure coefficient, axial induction factor, tangential induction factor, local tip speed ratio and angle of flow

Top-level rotor optimisations based on actuator disc theory

Abstract. Ahead of the elaborate rotor optimisation modelling that would support detailed design, it is shown that significant insight and new design directions can be indicated with simple, high-level analyses based on actuator disc theory. The basic equations derived from actuator disc theory for rotor power, axial thrust and out-of-plane bending moment in any given wind condition involve essentially only the rotor radius, R, and the axial induction factor, a. Radius, bending moment or thrust may be constrained or fixed, with quite different rotor optimisations resulting in each case. The case of fixed radius or rotor diameter leads to conventional rotor design and the long-established result that power is maximised with an axial induction factor, a=1/3. When the out-of-plane bending moment is constrained to a fixed value with axial induction variable in value (but constant radially) and when rotor radius is also variable, an optimum axial induction of 1∕5 is determined. This leads to a rotor that is expanded in diameter 11.6 %, gaining 7.6 % in power and with thrust reduced by 10 %. This is the low-induction rotor which has been investigated by Chaviaropoulos and Voutsinas (2013). However, with an optimum radially varying distribution of axial induction, the same 7.6 % power gain can be obtained with only 6.7 % expansion in rotor diameter. When without constraint on bending moment, the thrust is constrained to a fixed value, and the power is maximised as a→0, which for finite power extraction would require R→∞. This result is relevant when secondary rotors are used for power extraction from a primary rotor. To avoid too much loss of the source power available from the primary rotor, the secondary rotors must operate at very low induction factors whilst avoiding too high a tip speed or an excessive rotor diameter. Some general design issues of secondary rotors are explored. It is suggested that they may have the most practical potential for large vertical axis turbines avoiding the severe penalties on drivetrain cost and weight implicit in the usual method of power extraction from a central shaft.

Hydrodynamic Effects of Tidal-Stream Power Extraction for Varying Turbine Operating Conditions

Realistic evaluation of tidal-stream power extraction effects on local hydrodynamics requires the inclusion of the turbine’s operating conditions (TOC). An alternative approach for simulating the turbine’s array energy capture at a regional scale, momentum sink-TOC, is used to assess the impact of power extraction. The method computes a non-constant thrust force calculated based on the turbine’s operating conditions, and it uses the wake induction factor and blockage ratio to characterise the performance of a turbine. Additionally, the momentum sink-TOC relates the changes produced by power extraction, on the velocity and sea surface within the turbine’s near-field extension, to the turbine’s thrust force. The method was implemented in two hydrodynamic models that solved gradually varying flows (GVF) and rapidly varying flows (RVF). The local hydrodynamic effects produced by tidal-stream power extraction for varying the turbine’s operating conditions was investigated in (i) the thrust and power coefficient calculation, (ii) flow rate reduction, and (iii) tidal currents’ velocity and elevation profiles. Finally, for a turbine array that operates at optimal conditions, the potential energy resource was assessed. The maximisation of power extraction for electrical generation requires the use of an optimum turbine wake induction factor and an adequate blockage ratio, so that the power loss due to turbine wake mixing is reduced. On the other hand, the situations where limiting values of these parameters are used should be avoided as they lead to negligible power available. In terms of hydrodynamical models, an RVF solver provided a more accurate evaluation of the turbine’s operating conditions effect on local hydrodynamics. Particularly satisfactory results were obtained for a partial-fence. In the case of a fence configuration, the GVF solver was found to be a computationally economical tool to pre-assess the resource; however, caution should be taken as the solver did not accurately approximate the velocity decrease produced by energy extraction.

Influence of viscosity on chondrogenic differentiation of mesenchymal stem cells during 3D culture in viscous gelatin solution-embedded hydrogels

Differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) is regulated by a variety of cues of their surrounding microenvironments. In particular, mechanical properties of cell culture matrices have been recently disclosed to play a pivotal role in stem cell differentiation. However, it remains elusive how viscosity affects the chondrogenic differentiation of hMSCs during three-dimensional (3D) culture. In this study, a 3D culture system that was established by embedding viscous gelatin solution in chemically cross-linked gelatin hydrogels was used for 3D culture of hMSCs in gelatin solutions with different viscosities. The influence of solution viscosity on chondrogenic differentiation of hMSCs was investigated. Viscous gelatin solutions promoted cell proliferation in the order of low, middle and high viscosity while elastic hydrogels restricted cell proliferation. High viscosity gelatin solution led to increased production of the cartilaginous matrix. Under the synergistic stimulation of chondrogenic induction factors, high viscosity was beneficial for the chondrogenic differentiation of hMSCs. The results suggested the role of viscosity should be considered as one of the dominant mechanical cues affecting stem cell differentiation.

Exploring the potential of human adipocytes in periodontal regeneration: A review

Stem cells, initially identified in embryonic tissues and later in numerous adult tissues, tend to possess the potentiality to differentiate into various cell types. Though most flexible of all stem cell lines, ethical issues restrict the use of embryonic cells. Furthermore, induced pluripotent stem cells (iPS) and adult stem cells (e.g: bone marrow stroma) can also be used. However, procurement of autologous bone marrow has its potential limitations. An alternate source of autologous adult stem cells which can be procured in large quantities, under local anesthesia, with minimal discomfort would be of keen interest. In the present context, human adult adipose tissue may be the best appropriate alternative source of mesenchymal stem cells. Studies have shown that adipose stem cells (ASCs) extracted from subcutaneous human adult adipose tissue tend to contain heterogeneous cell population called stromal vascular fraction (SVF). It may be used directly or cultured in for selection and expansion of an adherent population, and hence, they are called ASCs. The adipose tissue, obtained by suction-assisted lipectomy (i.e., liposuction), are processed to obtain a fibroblast-like population of cells, also called processed lipoaspirate (PLA). PLA cells has the potentiality to differentiate in vitro into adipogenic, chondrogenic, myogenic, and osteogenic cells in the presence of lineage-specific induction factors. This attributable feature of ASCs may be of significant importance in future clinical cell-based therapy for periodontal disease as well. This review describes current knowledge & recent advances in ASCs & their application. This review describes current knowledge and recent advances in ASCs and their application in periodontal regeneration.

Alterations in growth, antioxidative defense and medicinally important compounds of Curcuma caesia Roxb. under elevated ultraviolet-B radiation

Ultraviolet-B (UV-B) radiation is a well-known stress factor, as involved in the generation of free radicals, and induction factor which permutates growth, metabolic processes, and secondary metabolites synthesis of plants. However, its impact on medicinal plants is less explored particularly in relation to secondary metabolites associated with the medicinally important rhizomes. An endangered medicinal plant (Curcuma caesia Roxb.) grown under natural field conditions was exposed to elevated UV-B (ambient ± 9.6 kJ m−2 d-1) to assess changes in growth, antioxidant profile, defense strategy and the secondary metabolites of the rhizome. Results showed that eUV-B induced the generation of different reactive oxygen species (·O2- radical and H2O2) which were counteracted by induction of UV absorbing pigments (flavonoids and anthocyanin), non-enzymatic (ascorbic acid) and enzymatic antioxidants (peroxidase, ascorbate peroxidase and catalase) at different growth stages. However, phenol, thiol and superoxide dismutase activity showed reduction at all the growth stages. Protection from UV-B was also manifested by an increase in total free radical scavenging activity, metal chelation and reducing activity. Alterations in biomass allocation might be a possible mechanism of defense which persuaded to higher increment in above ground biomass and tuber biomass with 47 % diminution of rhizome biomass. Among the four classes of compounds identified, sterols were increased whereas reductions were more prominent in fatty acids followed by monoterpenes and sesquiterpenes. Increased production of epicurzereonone, elemene, pinandiol, and 1,8-cineole whereas curcumenol, D-camphor, eucalyptol, curcumenone, isocurcumenol, and zederone were reduced. Elevated UV-B also induced the production of some anti-cancerous compounds such as furanodiene and caryophyllene.

NLRP3 inflammasome and endoplasmic reticulum stress in the epileptogenic zone in temporal lobe epilepsy: molecular insights into their interdependence.

Nod-like receptor protein 3 (NLRP3) inflammasome-mediated inflammation has emerged as a contributor to epileptogenesis. Endoplasmic reticulum stress (ERS) plays an important role in epilepsy-induced neurodegeneration. NLRP3 activation and ERS reactions share the same induction factors, suggesting that these processes may be interdependent. However, the correlation between NLRP3 and ERS in TLE has not been confirmed. The expression patterns of NLRP3 inflammasome and ERS-related markers in the temporal neocortices of TLE patients were investigated by western blotting, immunohistochemistry and immunofluorescent labelling. Correlations between the protein levels of NLRP3 and the expression of ERS-related markers were assessed using Spearman's rank correlation test. To observe the relationship between the NLRP3 inflammasome and ERS, inhibitors were used in a status epilepticus (SE) model. Our results show that NLRP3 inflammasome components and ERS-related markers were upregulated in the temporal neocortices of TLE patients, and were mainly localized to neurons, astrocytes and microglia. We found a positive correlation between the protein levels of NLRP3 and the expression of ERS-related markers in the temporal neocortices of 20 TLE patients. Furthermore, after blocking the NLRP3 inflammasome with MCC950, the expression of ERS-related markers was markedly decreased in the hippocampi of SE mice. Moreover, TUDCA, a specific ERS inhibitor, also reduced the expression of NLRP3 components in the hippocampus under SE conditions. Taken together, our data reveal the interdependence of the NLRP3 inflammasome and ERS in the epileptogenic zone of TLE patients and in the hippocampi of mice in the early post-SE phase.

Two-scale momentum theory for time-dependent modelling of large wind farms

This paper presents a theory based on the law of momentum conservation to define and help analyse the problem of large wind farm aerodynamics. The theory splits the problem into two sub-problems; namely an 'external' (or farm-scale) problem, which is a time-dependent problem considering large-scale motions of the atmospheric boundary layer (ABL) to assess the amount of momentum available to the ABL's bottom resistance at a certain time; and an 'internal' (or turbine-scale) problem, which is a quasi-steady (in terms of large-scale motions of the ABL) problem describing the breakdown of the ABL's bottom resistance into wind turbine drag and land/sea surface friction. The two sub-problems are coupled to each other through a non-dimensional parameter called 'farm wind-speed reduction factor' or 'farm induction factor,' for which a simple analytic equation is derived that can be solved iteratively using information obtained from both sub-problems. This general form of coupling allows us to use the present theory with various types of flow models for each scale, such as a numerical weather prediction (NWP) model for the external problem and a computational fluid dynamics (CFD) model for the internal problem. The theory is presented for a simplified wind farm situation first, followed by a discussion on how the theory can be applied (in an approximate manner) to real-world problems; for example, how to estimate the power loss due to the so-called 'wind farm blockage effect' for a given large wind farm under given environmental conditions.

ДОРОЖНЫЙ БИТУМ С ТЕХНОГЕННЫМ МОДИФИКАТОРОМ

In this work, for the development of oil bitumens, the high-tar oil of the Karazhanbas field, which is economically unprofitable for processing, is used as an additive to the tar of a mixture of oils of Martyshi + Mangystau. As a modifying and plasticizing agent, a technogenic modifier – elemental sulfur (waste from the Tengiz oil and gas processing complex) was used, and various induction moments were introduced, which are an additional source of structure formation of the oxidized feedstock. The Karazhanbas oil field, although economically unprofitable for processing, is unique in its component composition. It contains a large number of high-molecular and resinous-asphaltene components (resins 24,18% and asphaltenes 4,85%) prone toassociative interactions and structure formation. Asphaltenes, in turn, are stabilizers of molecular weight growth, and, in general, make a significant contribution to improving the technological parameters of the target product-bitumen. The mechanism of action of elemental sulfur is that when dispersed with a reaction mixture, there is an increase in the release of acid gases, such as: H2S, CO, SO2, which is explained by an increase in the rates of polycondensation and compaction reactions. This increases the rate of reaction of bitumen sulphurization in the reaction system. Over time, the intensity of gas release decreases due to a gradual decrease in the rates and further cessation of compaction and polycondensation reactions. The structure of the bitumen stabilizes. Induction moments were used as an additional object of the structure builder. The creation of the induction factors increased the amount of reactive monocularity and bicyclogermacrene hydrocarbons (as confirmed by the indicators of instrumental analysis) that accelerate the formation of high molecular compounds, which leads to increased molecular weight of oxidizable starting material, thereby improving the technological parameters of the resulting bitumen. Technogenic sulfur and induction moments in tandem have a combined effect on the physical and mechanical characteristics of the developed bitumen. Summarizing the above results of experimental work, it should be noted that by choosing the calculated amount of raw materials, additives and varying various induction moments, you can get bitumen of the BN 80/120 brand, and this makes it possible to dispose of man-made waste, which is economically and environmentally appropriate.

Terfezia boudieri: A Desert Truffle With Anticancer and Immunomodulatory Activities.

Desert truffles have high nutritional value and grow wild in the Mediterranean basin and Western Asia. Although, many studies were performed to evaluate truffles nutritious values and phytochemical composition, studies are limited to evaluate their anticancer and/ or immunomodulatory effects. Our study was conducted to evaluate the anticancer and immunomodulatory effects of Terfezia boudieri (desert truffle). Different solvent extracts were prepared from the truffle and MTT assay was used to measure their anticancer activity against cancer cell lines (T47D, MCF-7, MDA-MB231, HCT-116, and Hela). Total phenolic content in each extract was determined by using Folin-Ciocalteu reagent and qualitative phytochemical screening was performed using standard methods. The degree of apoptosis induction (using caspase 3 assay) and vascular endothelial growth factor expression were detected using standard kits. Also, ELISA was used to measure levels of IFN-γ, IL-2, IL-4, and IL-10 secreted by splenocytes after treatment with the extracts. The effect of the extracts on splenocytes proliferation was measured using MTT assay. Macrophage function was evaluated using nitro blue tetrazolium assay and pinocytosis function was evaluated using neutral red method. Terpenoids, phytosterols, and carbohydrates were present in all the solvent extracts, while tannins, alkaloids and flavonoids were detected only in aqueous/methanol and aqueous extracts. The highest total phenolic content was observed in aqueous and aqueous methanol extracts. The growth of cancer cell lines was inhibited by T. boudieri extracts in a dose dependent manner. N-hexane extract was the most potent against most cell lines. Aqueous/methanol extract showed high apoptosis induction and angiogenesis suppression effects. An increase in TH1 cytokines (IFN-γ, IL-2) level and a decrease in TH2 cytokine (IL-4) level were evident after lymphocytes stimulation by aqueous/methanol, n-hexane and ethyl acetate extracts of T. boudieri. Ethyl acetate extract of T. boudieri were the most potent extracts to stimulate lymphocytes proliferation while all other extracts showed moderate stimulation. Aqueous/methanol extract was the most active extract to stimulate phagocytosis. Ethyl acetate extract was the most active extract to stimulate pinocytosis. The use of T. boudieri provides variable health benefits. N-hexane, ethyl acetate, and aqueous/methanol extracts exhibited anticancer activities and are potent stimulators of innate and acquired immunity. Further testing is needed to identify the biologically active compounds and detect them quantitatively using GC-MS analysis.

Leaf proteome pattern of two bread wheat varieties under water deficit stress conditions

This investigation was carried out to study the effect of water deficit stress on leaf proteome pattern and agronomic and physiological characteristics of two spring bread wheat varieties (Arg and Moghan3) with contrasting responses to drought stress. For this purpose, an experiment was conducted as a 2 × 2 factorial arranged as the randomized complete block design with five replications in a greenhouse of University of Tabriz, Iran. The factors consisted of two Arg and Moghan3 varieties and irrigation conditions (normal condition and drought stress, where water was withheld at the pollination stage). Based on the analysis of variance, significant differences were observed between two wheat varieties with respect to all studied characters except leaf chlorophyll content. Drought stress increased leaf temperature and reduced other characters. Leaf proteome analysis was performed by two-dimensional electrophoresis for both wheat varieties at two irrigation conditions. After quantification of spots with PDQuest software, 274 and 202 repeatable protein spots were identified in Arg and Moghan3 varieties, respectively. Among them, based on the induction factor and t-test, 73 and 64 protein spots showed significant changes in abundance in Arg and Moghan3 varieties, respectively. Out of 73 spots identified in Arg, 46 showed an increased expression and 27 showed a decreased expression. In Moghan3, out of 64 protein spots, 18 and 46 protein spots were up- and down-regulated, respectively. Moreover, 15 common protein spots in Arg and Moghan3 with significant changes in expression between normal and drought stress conditions were identified by applying MALDI-TOF/TOF mass spectrometry. Identified proteins were assigned to seven functional categories: photosynthesis, stress, defense and detoxification, glycolysis, transport, protein synthesis and transcription regulation. In general, proteins related to photosynthesis, stress, and defense and detoxification showed major changes which may be considered as important proteins contributing to drought tolerance of Arg in this study.

Biochemical, genetic and transcriptional characterization of multibacteriocin production by the anti-pneumococcal dairy strain Streptococcus infantariusLP90.

Streptococcus pneumoniae infections are one of the major causes of morbility and mortality worldwide. Although vaccination and antibiotherapy constitute fundamental and complementary strategies against pneumococcal infections, they present some limitations including the increase in non-vaccine serotypes and the emergence of multidrug-resistances, respectively. Ribosomally-synthesized antimicrobial peptides (i.e. bacteriocins) produced by Lactic Acid Bacteria (LAB) may represent an alternative or complementary strategy to antibiotics for the control of pneumococal infections. We tested the antimicrobial activity of 37 bacteriocinogenic LAB, isolated from food and other sources, against clinical S. pneumoniae strains. Streptococcus infantarius subsp. infantarius LP90, isolated from Venezuelan water-buffalo milk, was selected because of its broad and strong anti-pneumococcal spectrum. The in vitro safety assessment of S. infantarius LP90 revealed that it may be considered avirulent. The analysis of a 19,539-bp cluster showed the presence of 29 putative open reading frames (ORFs), including the genes encoding 8 new class II-bacteriocins, as well as the proteins involved in their secretion, immunity and regulation. Transcriptional analyses evidenced that the induction factor (IF) structural gene, the bacteriocin/IF transporter genes, the bacteriocin structural genes and most of the bacteriocin immunity genes were transcribed. MALDI-TOF analyses of peptides purified using different multichromatographic procedures revealed that the dairy strain S. infantarius LP90 produces at least 6 bacteriocins, including infantaricin A1, a novel anti-pneumococcal two-peptide bacteriocin.

Inverse aerodynamic design for DEP propeller based on desired propeller slipstream

Considering the multi-propeller characteristics of DEP (distributed electric propulsion) configuration, the lift-to-drag ratio of the wing is improved by optimizing the slipstream of the propeller, rather than changing the chord length and twist distribution along the span of the wing. In this paper, a propeller inverse design method based on slipstream characteristics is developed. In the case of propeller design, only a few general parameters and induction factor distribution form have to be prescribed and the design procedure returns the propeller geometry in terms of chord-length and blade-angle distributions along the radius. Propellers with different induced velocity distributions are designed based on this method. It is found that the propellers with larger induced velocity near the hub can improve the lift-to-drag ratio of the wing without changing the parameters of the wing, drag decreases by 12.32% and the lift-to-drag ratio of the wing with single propeller increase by 16.10%, respectively. A 27.12% drag reduction and 43.21% lift-to-drag ratio improvement can be obtained when three propellers are used.

Periodic dynamic induction control of wind farms: proving the potential in simulations and wind tunnel experiments

Abstract. As wind turbines in a wind farm interact with each other, a control problem arises that has been extensively studied in the literature: how can we optimize the power production of a wind farm as a whole? A traditional approach to this problem is called induction control, in which the power capture of an upstream turbine is lowered for the benefit of downstream machines. In recent simulation studies, an alternative approach, where the induction factor is varied over time, has shown promising results. In this paper, the potential of this dynamic induction control (DIC) approach is further investigated. Only periodic variations, where the input is a sinusoid, are studied. A proof of concept for this periodic DIC approach will be given by the execution of scaled wind tunnel experiments, showing for the first time that this approach can yield power gains in real-world wind farms. Furthermore, the effects on the damage equivalent loads (DEL) of the turbine are evaluated in a simulation environment. These indicate that the increase in DEL on the excited turbine is limited.

Genomics and Prognosis Analysis of Epithelial-Mesenchymal Transition in Glioma.

Background: Epithelial-mesenchymal transition (EMT) is regulated by induction factors, transcription factor families and an array of signaling pathways genes, and has been implicated in the invasion and progression of gliomas.Methods: We obtained the Clinicopathological data sets from Chinese Glioma Genome Atlas (CGGA). The “limma” package was used to analyze the expression of EMT-related genes in gliomas with different pathological characteristics. We used the “ConsensusClusterPlus” package to divide gliomas into two groups to study their correlation with glioma malignancy. The least absolute shrinkage and selection operator (LASSO) Cox regression was applied to select seven prognosis-associated genes to build the risk signature, and the coefficients obtained from the LASSO algorithm were used to calculate the risk score which we applied to determine the prognostic value of the risk signature. Univariate and multivariate Cox regression analyses were used to determine whether the risk signature is an independent prognostic indicator.Results: We analyzed the differentially expressed 22 common epithelial-mesenchymal transition-associated genes in 508 gliomas graded by different clinicopathological features. Two glioma subgroups (EM1/2) were identified by consistent clustering of the proteins, of which the EM1 subgroup had a better prognosis than the EM2 subgroup, and the EM2 group was associated with cancer migration and proliferation. Significant enrichment analysis revealed that EMT-related transcriptional regulators and signaling pathways genes were highly related to glioma malignancies. Seven EMT-related genes were used to derive risk scores, which served as independent prognostic markers and prediction factors for the clinicopathological features of glioma. And we found the overall survival (OS) was significantly different between the low- and high-risk groups, the ROC curve indicated that the risk score can predict survival rates for glioma patients.Conclusion: EMT-related induction factors, transcriptional regulators and signaling pathways genes are important players in the malignant progression of glioma and may help in decision making regarding the choice of prognosis assessment and provide us clues to understand EMT epigenetic modification in glioma.

Optimization of production conditions of rice α-galactosidase II displayed on yeast cell surface

The yeast surface displayed rice α-galactosidase II (YSD rice α-Gal II) was generated with the pYD1 vector. The expression and cultural conditions for the improvement of production of YSD rice α-Gal II were optimized. The results showed that several induction factors, which were the initial cell density, inoculation ratio, galactose (inducer) concentration, induction time and temperature, determined the activity and expression efficiency of YSD rice α-Gal II. Meanwhile, the medium composition also affected its activity and production. Moreover, the production of YSD rice α-Gal II was further improved by continuous feeding of galactose in the fermenter level. The highest production was obtained at an initial cell density of OD600 = 2.9, 2% inoculation ratio, and 2% galactose, with 0.6 g/L compound nitrogen source ((NH4)2SO4/urea = 2/1, w/w) and 5 g/L sucrose, followed by continuous feeding of galactose (20 g/L with flow rate of 1.5 mL/h). At such conditions, the enzyme activity and productivity reached to 676.2 U/g (DCW) and 1548.5 U/L, respectively, 26.4- and 63.7-fold to that before optimization. The results provided a basic and effective strategy for the industrial production of YSD rice α-Gal II.