**3. Composite Materials**

The limited mechanical properties, the lack of bioactive behaviour that allow bone apposition and bonding on the polyester implant, and complications associated with the acidic degradation products are major drawbacks of polyester implants. Ceramic materials are high strength, biocompatible, corrosion resistant, and possess a high level of bioactivity. For this purpose, composite polyester implants with ceramic fillers (hydroxyapatite (HA), tricalcium phosphate (TCP)), silicate, and phosphate glasses have been used to improve the overall mechanical properties and endow bioactivity in bioresorbable osteofixation devices. In addition, alkaline dissolution from bioactive ceramic fillers counteracts the decrease of pH in the ambient implantation site by the acidic degradation products of the polyester matrix.


**7. Conclusion**

adjustments for additional financial risk. When you include the business portfolio approach in the values analysis, the group of companies and the need for group reporting further com-

Fourth, and also connected with the previous, the assets' fair value implicitly includes the risks of keeping the individual forms of assets. In no way does it include business risks that are connected with the way of combining these assets and using them in the company operations. Thus, it is evident that reporting based on a fair value is not intrinsically connected with risks of expected earning power of the company, and thus, it provides insufficient information about the risks for the investors in the company owners' equity. The risks included in the assets' fair value are not essential for equity investors, but for creditors, and especially for commercial banks that modify its internal credit ratings and so reduce the asymmetry of

Risk and yield are key value components. Value is realized by risk-reward trade-off during specific time. In the context of economic value, risks determine risk-adjusted discount rate for discounting expected yields, expressed by cash flows. According to modern portfolio theory, the only relevant is systematic or market risk, meaning the risk that could not be avoided by diversification [46, 47]. These assumptions are built into the CAPM [48] as still the most popu-

The risk of achieving expected cash flows is one of the key value components. It is therefore logical that risk management is one of the areas of value management and a means of achieving greater value. Primarily, this is the management of financial risks, and therefore diversification imposes as a means of reducing risk. Diversification helps avoid a significant part of the total risk, the specific part, based on the principle "don't keep all eggs in the same basket." Diversification is basis for financial investments portfolio management. Although the diversification scope of the real investment is limited, diversification can also reduce the risk of keeping such investments. Thus, regardless of the controversy should the company diversify

The increased importance of risk management outside the diversification area appeared at the beginning of 1970s, when, due to leaving the Breton Woods Agreements and the oil shock, significant currency and interest rate risks have emerged. At the same time financial futures contracts, financial options, and other financial derivatives appeared, as the powerful tools to reduce, and even eliminate these risks [49]. The most intense managing of such specific financial risks was in the banks and financial institutions, partially due to the fact that these companies employed most highly educated and well-trained financial analysts, and partly under the influence of financial supervision [50]. Specific risks managing practice transferred to non-financial companies, so that it has become an integral part of the corporate

In modern conditions, risks management becomes an organized activity. Financial institutions are encouraged by financial supervision. Other public companies also require organized

its activities or not, today, it is difficult to find a mono product company.

plicates the valuation.

134 Firm Value - Theory and Empirical Evidence

**6.2. Risk management**

governance [51].

information in relation to other investors.

lar model for establishing risk-adjusted discount rate.

Although the financial function is one of the fundamental functions of every company, Chief Financial Officer (CFO), as stated in this analysis, is needed only for the public companies. He or she is a member of the company's Board whose key task is permanent communication with the investor's public. In that sense, he is the procurator of the Chief Executive Officer (CEO) in the area of mediation between the needs of the company for the money and capital and investor's public. CFO is also responsible for other financial operations: treasurer and controller of the business. Thus, CFO is the most responsible person for the financial statement presentation, as the CEO Deputy, who bears the ultimate responsibility running the business. An accountant may only be responsible for the preparation and the presentation of accounting statements. Because accounting statements are the basis for the financial statements preparation, the responsibility of the accountant is internal, toward the CFO and the Board, and not external, toward the investor's public. Financial officer is not required in private companies because the integrity of the communication for them is an unnecessary and an expensive activity. These companies report for tax purposes and some wider control requirements of the State.

Based on the analysis of the practices and institutional framework of the company's communication with the investor's public, in the context of the totality of corporate management, a special attention is paid to the communication through financial reporting, as it is today commonly observed in the standard set of financial statements, which are indeed accounting statements presented with the combination of historical and fair market prices. The chapter determinates that this reporting practice is not oriented toward investors in public company equities, because this practice enables sufficient insight in the expected earnings power and the risks to achieve it. In that context, a request is set that the correct financial reporting oriented to existing and prospective investors in the company equity, must contain a sufficient objectivized description of the reached earnings power and financial potential in accounting reports to establish the expected earnings power and risks to achieve it, in order to establish the appropriate discount rate.

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Today's financial reporting is institutionally complex because of mixed evaluation bases, historical and fair market value. Standards constantly change, most commonly by broadening the evaluation toward fair market value. This reporting is oriented toward the evaluation of fair market value of assets that the company owns rather than the evaluation oriented to company earnings power that is in the focus of equity investors. Thus, this reporting is oriented to landers. Assets fair market value orientation is not comprehensive, because it commonly excludes externalities, uniqueness of assets combining and intangibles from evaluation. Therefore, it is oriented to lenders showing tangible assets value as company debts collateral. The fair value of assets lags behind earnings power valuation, at least because the evaluation of earnings retained as investment potential are recognized by the market through the net present value of expected investments. Also, fair value is targeted and burdened with subjectivity and evaluation toward painting a picture that will attract investors as the suppliers of company capital.

The chapter develops literature review around the quality of company communications and its potential impact on firm value and firm valuation. It is also primary oriented on financial reporting as the analytical framework for fundamental analysis of the company and its common stocks. Thus, review is limited on this main form of communication. Therefore, it is interesting to investigate the impact of other form of firm communications with investor's public on equity valuation. Another interesting area of investigation is the possibility of impact of fair market principles on earnings management. According to the goals of the chapter, there are many possibilities for further investigation in secondary and primary data, to determine factors that can improve financial reporting and other form of communication with equity investors, particularly about the risk exposure of the firm.


**Author details**

Raufu Olusola Sanusi1 \*, Deola-Tayo Lordbanjou2 , Azeez Olalekan Ibrahim3 , Mohammad Babakatcha Abubakar4 and Oluwole Olalekan Oke5

1 Federal University of Agriculture Abeokuta, Nigeria

2 Federal Ministry of Agriculture and Rural Development, Abuja, Nigeria

3 Federal College of Wildlife Management New Bussa, Nigeria

4 National Cereals Research Institute Badeggi, Nigeria

5 Federal College of Forestry Ibadan, Nigeria

\*Address all correspondence to<EMAIL_ADDRESS>
© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


4.2.2. Model 2

Model 2 is based on a NNW-SSE striking seismic section across Jæren High and Sørvestlandet High on the Eastern flank of Central Graben (Figure 2). The profile extends SSE-wards from the salt structure near well 7/9-1 in the Southeastern part of Jæren High, and crosses the N-S striking Reke Fault Zone, continues along the Southeastern part of Sørvestlandet High, until it ends after crossing the Oda salt structure (well 8/10-4S) in the Oda Field.

The model was based on interpreted and depth-converted seismic sections and maps shown in Figure 12. The seismic section was interpreted by LOTOS down to Base Cretaceous (BCU) and top and base of the salt. The interpretations of the salt structures are based on clear folding or penetration of Jurassic to Cenozoic sequences at the top, often with associated high amplitude reflection above the top of the salt structures (caused by the presence of anhydrite). Down-flank, the interpretation is much more uncertain as the seismic data are very transparent both in the salt and in the surrounding Triassic units. The base of major salt structures is defined by the width of the velocity pull-ups observed below the salt (Figure 12a).

The lack of regional seismic correlation markers within the continental Triassic units and the low impedance contrast between Zechstein salt and Triassic pod units make interpretation and correlation between pods difficult [17]. For the Triassic sequences, no ages were known. For the modeling, 14 Triassic sequences were interpreted and given ages evenly distributed between 248 Ma and 205 Ma.

The profile has five separate salt structures becoming increasingly more prominent throughout Triassic times, as sedimentation focus on small semi-circular pod-basins pushing the salt into the ridges between them. The distribution of these pods can be seen on the Top Zechstein map (Figure 5) and less pronounced on the Base Cretaceous (BCU) map of Figure 12b, best developed North of the

Ula-Gyda Fault Zone. The Triassic pod basins probably became welded to the pre-salt unit as salt was completely removed below these pod basins during Jurassic to Cretaceous times. The smallest structures seem to cease moving during Late Triassic to Jurassic times, whereas the largest structures (i.e., 7/9-1 structure and Oda structure (8/10-4)) seem to have been actively growing well into Cenozoic time. Note the grabens in the Cretaceous unit above the central salt structures (Figure 12a), also seen as green lens-shaped depressions on the Base Cretaceous map (Figure 12b).

**Figure 12.** Interpretation of present-day structures on Model 2. (**a**) Interpreted depth-converted seismic section. (**b**) Map of Base Cretaceous horizon with the position of the modeled profile. (**c**) Detailed interpretation of Triassic sequences and possible interpretation within the salt structures. Continuous stratification can be interpreted through the second diapir from the right, and one can speculate if this really is a salt structure. Between this structure and the large Oda structure to the South, the lower Triassic units seem to downlap onto a paleo-slope. A stippled "core" of the largest structures indicates areas where no apparent stratification could be interpreted. In the temperature modeling, this "core" was used as a minimum-salt model.

Strongly dipping and onlapping Triassic sequences are not found on this NW-SE profile, but are commonly seen, especially in profile crossing the dip of the major WSW facing faults. These dipping units are related to asymmetric salt withdrawal in pods [17] and initial subsidence is related to underlying faults. It is shown by numerical modeling that subsidence in a pod basin can affect other pod basins close to it, it can also prevent subsidence, induce tilting, and cause asymmetric subsidence and even lateral translation of entire pod basins [25].

As interpretation of salt structures was uncertain, three cases was modelled, as shown in Figure 13, and used in the further geohistory- and temperature modelling.

**Figure 13.** Present day geometry input of Model 2, colored by lithology. From top: (**a**) Maximum-salt model; (**b**) minimum-salt model; and (**c**) no-salt model. The locations of wells 7/9-1 and 7/12-11 are projected onto the profile.

Interpretation and sequence analysis of the Triassic sequences suggest that subsidence and development of Triassic basins (pods) started Northwest of the Oda structure relatively early in Triassic time, probably related to fault movement in the pre-salt units and basement. In Late Triassic, sediment deposition started south of the Oda structure. All the five salt-diapirs on this profile developed in parallel until latest Triassic when the minor diapirs halted, while the Oda and 7/9-1 structure continued to grow. These two structures continued to be actively growing at least into Paleogene

times (Eocene-Oligocene). In the model, the structure at ~33 km (second structure from right) reached a maximum height at Base Cretaceous time and lost volume and height in Cretaceous time as the graben above developed and salt-mass was lost to the sides. Some of the time-steps reconstructed in the geohistory are shown in Figure 14.

**Figure 14.** Geohistory reconstruction of Model 2. The figure shows 10 of the total 24 time-steps in the model, including 14 time steps during Triassic time.

### **5. Modelling of Temperature History and Vitrinite Reflectance**

BMT utilizes finite difference calculations by conduction with a rectangular finite difference grid of varying sizes (cf. [23]). For every reconstructed time step in the geohistory, BMT builds a new high-resolution thermal modeling grid. Around small features, the grid size is especially fine to ensure realistic calculations. The difference grid in this study consists of a minimum of 400 × 400 cells of varying sizes. The spatial variation in rock properties and possible differences from one time

step to the next are adjusted for so that appropriate finite difference calculations are maintained. The finite difference calculation by conduction is controlled by the temperatures from the previous time step, thermal conductivity (vertical and horizontal), and specific heat capacity of the basin's lithology/lithologies.

Salt has much higher thermal conductivity than the neighboring sediments (cf. Table 1). This means that a salt diapir that pierces through units of sedimentary rocks will lead heat up through the surrounding, relatively less conductive, sediments that acts as insulation. This could lead to higher temperatures in the units above salt structures and temperature depletion around the base of the salt structure.


**5. Enzyme-Catalyzed Polyphenol Polymerization**

Similar to the antioxidants for food production and biopharmaceutical applications, enzyme-catalyzed polyphenol polymerization reactions have a broad range of practical applications, including antioxidant, antibacterial, anticancer, cardioprotective, and neuroprotective properties [72]. However, the progression of most reactions is impeded under natural conditions; this justifies the need for enzyme-mediated reactions to attain the desired effects. In a recent study, Oliver et al. [72] noted that the impressive therapeutic activity of polyphenols in therapeutic agents and other clinical applications could not be realized without proper adjustment of the production processes and chemical properties. Under natural conditions, polyphenols exhibit poor membrane permeability, rapid metabolism, and poor bioavailability and UV degradation. The challenges have been partly resolved through amidification, esterification, free-radical grafting [73], step-growth, free radical, and enzyme-catalyzed reactions (direct polymerization of polyphenol monomers), and enzyme grafting-mediated conjugation with macromolecules.

Even though multiple techniques have been proposed to improve the industrial application of polyphenols, enzyme grafting and catalyzation of the reaction were given preference given polyphenol polymerization under natural conditions is constrained by the reaction mechanisms and chemical composition of the reactants, which impede synthesis using conventional methods [74,75]. The forward polymerization process is augmented by the inclusion of enzymes. The utility of laccase (an enzyme) in catechol, resorcinol, and

hydroquinone selective polymerization was confirmed by Sun et al. [75] (see Figure 5). The process was phased; the initial phases entailed the formation of quinone intermediates through laccase catalysis, followed by oxidation and formation of covalent bonds. In the subsequent steps, carbon-carbon (C-C) and ether bonds were formed, linking catechol units, resorcinol, and hydroquinone units. the polyphenols and the active sites within the enzyme. Alternatively, the suitability of the enzymes in reaction processes could be impaired by unfavorable redox reactions. Since enzymes in isolation do not address the challenges and limitations associated with the synthesis of new products, alternative processes must be developed to improve the yields in enzyme-catalyzed polyphenol polymerization reactions.

[74]. The merits of the laccase-catalyzed polymerization process are offset by the complexity of the reaction mechanism [76]. Hollman and Arends [76] argue that even though catalysts are critical to the progression of reactions, which are unfeasible using conventional methods, there are practical constraints such as unfavorable steric interactions between

*Polymers* **2021**, *13*, x FOR PEER REVIEW 17 of 33

**Figure 5.** Illustration of laccase and peroxidase mediator systems (PMSs) in polymerization reactions [76]. **Figure 5.** Illustration of laccase and peroxidase mediator systems (PMSs) in polymerization reactions [76].

Other experiments have reported the practical benefits of using alternative enzymes, primarily hydrolases, to catalyze bond cleavage reactions and the reverse action of hydrolysis [74]. Similar to laccase hydrolyses, they catalyze polyphenol polymerization via bond-forming reaction. However, hydrolyses are suitable in oxidative polymerization reactions that are specific to peroxidase and laccase catalysts in the presence of phenol derivatives. Other factors that inform the choice of enzymes for polyphenol polymerization include inhibition of laccase-initiated polymerization and peroxidase-initiated polymerization and the use of molecular oxygen in place of hydrogen peroxide [76]. The focus on molecular oxygen was validated by the following considerations. Even though hydrolyses, laccase, and peroxidase polymers have proven to be useful A key benefit associated with the reaction process is the formation of reaction products under mild conditions and the elimination of toxic byproducts such as formaldehyde [74]. The merits of the laccase-catalyzed polymerization process are offset by the complexity of the reaction mechanism [76]. Hollman and Arends [76] argue that even though catalysts are critical to the progression of reactions, which are unfeasible using conventional methods, there are practical constraints such as unfavorable steric interactions between the polyphenols and the active sites within the enzyme. Alternatively, the suitability of the enzymes in reaction processes could be impaired by unfavorable redox reactions. Since enzymes in isolation do not address the challenges and limitations associated with the synthesis of new products, alternative processes must be developed to improve the yields in enzyme-catalyzed polyphenol polymerization reactions.

in polyphenol polymerization, the concerns associated with polyphenol polymerization should be addressed. Various mechanisms were proposed by Hollman and Arends [76] to address the catalyst-related problems; these include the ingenious use of a mediator as a radical transfer catalyst. However, the radical is not incorporated into the end product. The feasibility of this reaction has been demonstrated in the use of phenothiazines to address constraints associated with the sterically hindered/congested phenols and consequently catalyze the polymerization process. In other cases, the production constraints can be offset by the incorporation of ABTS or transition metal ions, particularly Mn2+/3+, to facilitate the pyrrole polymerization process. If transition metal ion species and ABTS Other experiments have reported the practical benefits of using alternative enzymes, primarily hydrolases, to catalyze bond cleavage reactions and the reverse action of hydrolysis [74]. Similar to laccase hydrolyses, they catalyze polyphenol polymerization via bond-forming reaction. However, hydrolyses are suitable in oxidative polymerization reactions that are specific to peroxidase and laccase catalysts in the presence of phenol derivatives. Other factors that inform the choice of enzymes for polyphenol polymerization include inhibition of laccase-initiated polymerization and peroxidase-initiated polymerization and the use of molecular oxygen in place of hydrogen peroxide [76]. The focus on molecular oxygen was validated by the following considerations.

prove less useful, polyoxometallates can be employed. The complexities of polyphenol Even though hydrolyses, laccase, and peroxidase polymers have proven to be useful in polyphenol polymerization, the concerns associated with polyphenol polymerization should be addressed. Various mechanisms were proposed by Hollman and Arends [76] to address the catalyst-related problems; these include the ingenious use of a mediator as a radical transfer catalyst. However, the radical is not incorporated into the end product. The feasibility of this reaction has been demonstrated in the use of phenothiazines to address

constraints associated with the sterically hindered/congested phenols and consequently catalyze the polymerization process. In other cases, the production constraints can be offset by the incorporation of ABTS or transition metal ions, particularly Mn2+/3+, to facilitate the pyrrole polymerization process. If transition metal ion species and ABTS prove less useful, polyoxometallates can be employed. The complexities of polyphenol catalysis underscore the challenges that impact the synthesis and application of sustainable and natural monomers and antioxidants in food packaging, biopharmaceuticals, and agricultural applications.

The synthesis-related constraints raise fundamental questions about the commercial exploitation of naturally occurring antioxidants such as tocotrienols and tocopherols [1–3], phenolic compounds, carotenoids [4]. Even though polymerization of natural polyphenols is impacted by the generation of formaldehyde byproducts, unfavorable steric interactions between the polyphenols and the active sites within the enzyme, inhibition of laccaseinitiated polymerization, the process offers practical benefits relative to the use of artificial antioxidant molecules such as α-lipoic acid, N-acetyl cysteine, melatonin, gallic acid, captopril, taurine, catechin, and quercetin [5], or the replacement of catalysts with alternative processes such as amidification, esterification, free-radical grafting [73], step-growth, and free radical-catalyzed reactions to improve the percentage yield (see Table 6).

**Table 6.** Yields, MW, and PD from acrylamide and styrene polymerization as initiators [76].

The outcomes documented by Hollman and Arends [76] validate the polymerization of polyphenols, quercetin, and other organic molecules with suitable antioxidant properties. A critical challenge concerns the shortcomings and tradeoffs of existing polymerization processes.


**Alexander J. Michels \* and Balz Frei**

Linus Pauling Institute, 307 Linus Pauling Science Center, Oregon State University, Corvallis, OR 97331, USA; E-Mail<EMAIL_ADDRESS>
**\*** Author to whom correspondence should be addressed; E-Mail<EMAIL_ADDRESS>Tel.: +1-541-737-5085; Fax: +1-541-737-5075.

*Received: 11 October 2013; in revised form: 23 November 2013 / Accepted: 27 November 2013 / Published: 16 December 2013*

**Abstract:** Research progress to understand the role of vitamin C (ascorbic acid) in human health has been slow in coming. This is predominantly the result of several flawed approaches to study design, often lacking a full appreciation of the redox chemistry and biology of ascorbic acid. In this review, we summarize our knowledge surrounding the limitations of common approaches used in vitamin C research. In human cell culture, the primary issues are the high oxygen environment, presence of redox-active transition metal ions in culture media, and the use of immortalized cell lines grown in the absence of supplemental ascorbic acid. Studies in animal models are also limited due to the presence of endogenous ascorbic acid synthesis. Despite the use of genetically altered rodent strains lacking synthesis capacity, there are additional concerns that these models do not adequately recapitulate the effects of vitamin C deprivation and supplementation observed in humans. Lastly, several flaws in study design endemic to randomized controlled trials and other human studies greatly limit their conclusions and impact. There also is anecdotal evidence of positive and negative health effects of vitamin C that are widely accepted but have not been substantiated. Only with careful attention to study design and experimental detail can we further our understanding of the possible roles of vitamin C in promoting human health and preventing or treating disease.

**Keywords:** vitamin C; ascorbic acid; cell culture; animals; human; study design


**1. Introduction**

In the last decade, interest and investment in space exploration has increased dramatically. This has led to greater demand for satellites, and subsequently, more companies are investing significant resources into lowering the cost of space launches. Previously, the manufacture of a Hybrid Rocket Motor (HRM) was costly and labor-intensive, and the traditional 'cast and cure' method limited the geometry of internal combustion ports [1,2]. In an effort to overcome the manufacturing limitations of hybrid rocket fuel grains, researchers have looked to emerging technology and novel techniques to produce innovative solutions that have previously been unattainable. The most notable of these has been the impressive advancement in rapid prototyping, especially fused deposition manufacturing (FDM), commonly known as 3D printing [3]. FDM has enabled designers to incorporate complex combustion ports into HRMs and has opened up an entirely new set of materials for the fabrication thereof.

The process of the 3D printing involves the laying down of successive layers of material on top of each other until a 3D shape has been created [4]. The material is generally supplied in the form a thin strand, or filament, that is wound onto spools to be fed into a heating reservoir and extrusion nozzle assembly. The nozzle assembly is controlled by a computer numerically controlled (CNC) mechanism and has the ability to travel both horizontally and vertically. This means that the only limitations placed on the size of the object being printing is the size of the print area of the particular printer being used. However, some companies have already created printers that can essentially print large parts, such as a house, in a short period of time (less than a day) [3]. This is achieved by printing the part length-ways on a conveyor belt, with each new layer being added on a 45◦ angle, allowing a full-sized hybrid rocket fuel grain to be completed in a single print. Other companies, such as Gilmour Space Technologies, have created both a proprietary printing method and material [5].

Traditionally, the materials used in 3D printing are generally polymers, such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), acrylonitrile styrene acrylate (ASA), or polypropylene (PP), but can include anything from metals, ceramics, food, and concrete to living stem cells [3,6,7]. More recently, the commercial market has seen a rapid increase in the number of filaments with metal particles in its composition, such as brass, copper and aluminum. Although it is possible to 3D print metallic materials [8], the filaments discussed herein have a PLA binding structure, with a fine powder of the desired metal finish added during the manufacturing process.

Favorable comparison of ABS against hydroxyl-terminated polybutadiene (HTPB) as a hybrid rocket fuel suggests that FDM has the potential to revolutionize the fabrication of hybrid rocket fuel grains, and has led a groundbreaking push for the development and enhancement of 3D-printed fuel grains at the Utah State University [9]. This study, carried out at the Utah State University, demonstrated that not only did ABS have an acceptable (although slightly reduced) performance when compared to HTPB, but that it also showed much higher burn-to-burn consistency which was attributed to the FDM process [9]. Similar work has been carried out at Purdue University and at the University of Tennessee [10,11].

The introduction of FDM into the manufacturing process of HRM fuel grains has also allowed for the creation of far more complex combustion port geometries. The traditional method of 'cast and cure,' which is used for materials such as HTPB and para ffin, requires a mold and internal tooling that can be quite complex depending on the desired geometry of the fuel grain [12]. Although recent work has been done on the use of disposable tooling structures, it is generally accepted that once the fuel mixture has cured, the internal tooling must be removed before the motor is ready for use. This has limited the complexity of the design of HRM grain ports, in so far as they must be able to allow for the removal of the tooling after the manufacturing process, generally resulting in straight ports that run the length of the motor. In contrast to this, FDM lays down each successive layer of material on top of the last, which, in components like HRM fuel grains, rarely requires the use of internal support. Even if support structure is required, this is added in the same manner as the fuel and is manufactured from water soluble material that is easily removed after manufacture [13].

Several recent studies have explored the use of rapid prototyping in the design and fabrication of HRM fuel grains. The bulk of research in this field has been carried out at the Utah State University and has centered around the exploration of the e ffects of a helical fuel grain on the performance of the HRM regression rate [12,14–17]. It has been shown that the helical combustion port significantly increased the regression rate when compared to straight cylindrical ports. It has been posited that this is a result of both an increase in the local skin friction, and the suppression of the radial wall blowing effect is due to the centrifugal forces introduced by the helical flow [16]. These centrifugal forces cause compression of the boundary layer, forcing the flame front closer to the fuel port wall and significantly increasing the convective heat transfer. The use of aluminum particles to increase performance of solid and HRMs has long been studied [18–20]. It has been shown that the addition of aluminum particles can increase specific impulse, volumetric heat of oxidation, and radiative heat transfer [21], as well as increase regression rates in HTBP rocket motors by up to 40% [22]. It is generally understood that this increase in regression rate is due to improvement of radiative heat flux from the di ffusion flame zone to the fuel surface area via the radiating metallic particles and higher gas-phase temperature [23,24].

However, it has also been demonstrated that the addition of aluminum particles does not necessarily always result in an increase in regression rates [25]. Regression rate improvement can also be a result of the release of energy during metal oxidation, but the higher temperatures required to melt the aluminum oxide layer often mean that the fuel binder is melted and burnt before the

aluminum [21,24]. The result is that the aluminum particles are ejected from the motor without significantly contributing to the regression rate increase [26], and can form slag build-up on the nozzle wall, as well as drastically increase nozzle throat ablation [20]. A key contributing factor to the performance enhancement abilities of the added aluminum is the size of the particles. It has been shown that nanosized particles perform better than micro-sized particles, resulting in higher combustion efficiencies, better heat transfer, and reduced burn time [23].

This research project conducted a series of small-scale static fire tests of FDM HRMs that were designed and 3D-printed to explore the performance of a variety of commonly available FDM materials. These materials included ABS, ASA, PLA, PP, PETG (Polyethylene terephthalate glycol), Nylon, and AL (PLA with aluminum particles). The main objective of this research study was to analyze and compare the performance of these materials in terms of the mass flux and regression rate.


**5. Conclusions**

476 Lactic Acid Bacteria – R & D for Food, Health and Livestock Purposes

lactose by the IL1403 *ccpA* mutant.

strain to grow on lactose.

alternative lactose utilization genes are under the negative control of CcpA, and, therefore, inactivation of the *ccpA* gene could result in their derepression and ability to assimilate

Further studies of Aleksandrzak-Piekarczyk et al. (2005, 2011) and Kowalczyk et al*.* (2008) provided details on interconnected metabolism of *β*-glucosides (cellobiose) and *β*galactosides (lactose) and its variable regulation in *L. lactis* IL1403. Several genes have been implicated in coupled cellobiose and lactose assimilation in *L. lactis* IL1403, such as *bglS* and *celB, ptcA* and *ptcB,* encoding proteins homologous to P-*β*-glucosidase and EII components of cellobiose-specific PTS, respectively (Fig. 1). It has been shown that in *L. lactis* IL1403 the cellobiose-specific PTS system, comprising of *celB, ptcB* and *ptcA*, is also able to transport lactose because cellobiose-specific permease CelB has also an affinity for lactose, and, moreover, is the only permease involved in lactose uptake (Aleksandrzak-Piekarczyk et al., 2011). Furthermore, internalized lactose-P is hydrolyzed exclusively by BglS – an enzyme with dual P-*β*-glucosidase and P-*β*-galactosidase activity, and high affinity for cellobiose (Aleksandrzak-Piekarczyk et al., 2005) (Fig. 1). Thus, BglS activity generates glucose and galactose-P molecules. Glucose enters the Embden-Meyerhof-Parnas glycolytic pathway through phosphorylation by glucokinase, whereas galactose-P requires dephosphorylation performed by an unidentified phosphatase or phosphohexomutase, before entering the Leloir pathway (Neves et al., 2010) (Fig. 1). Moreover, this alternative lactose utilization system has been shown to be tightly controlled by CcpA-directed negative regulation (Fig. 1), since inactivation of the *ccpA* gene led to derepression of *bglS*, *celB, ptcA* and *ptcB* and *L. lactis* IL1403 *ccpA* mutant ability to assimilate lactose (Aleksandrzak-Piekarczyk et al., 2011). In addition to CcpA-mediated repression, the *celB* and *bglS* genes are specifically activated by cellobiose, as its presence leads to an increase in their transcription. This phenomenon has not been observed when other sugars, such as glucose, galactose or salicin, were used as carbon sources (Aleksandrzak-Piekarczyk et al., 2011). Preliminary results suggest that a hypothetical transcriptional regulator, namely YebF, could be engaged in this cellobiosedependent activation of *celB* and *bglS* (Aleksandrzak-Piekarczyk et al., 2011; unpublished personal analysis) (Fig. 1). The YebF protein belongs to the RpiR family of phosphosugar binding proteins (Sorensen & Hove-Jensen, 1996), and, in addition to its sugar binding domain (SIS), it has a putative helix-turn-helix (HTH) DNA-binding domain. In addition to *yebF* mutant ferment lactose inability (Aleksandrzak-Piekarczyk et al., 2005), inactivation of the *yebF* gene in IL1403 resulted in inability to grow on cellobiose (unpublished personal analysis), suggesting the gene's requirement in both cellobiose and lactose assimilation. Further studies on this phenomenon in *L. lactis* are needed to address it in greater detail.

When cellobiose is available, it activates the cellobiose-specific PTS transport system, comprising CelB, PtcB and PtcA proteins, and *L. lactis* IL1403 is able to grow on cellobiose and lactose. This growth is supported by the activity of cellobiose-inducible BglS protein, which splits lactose-P into galactose-P and glucose. Then, after the dephosphorylation step, galactose is further metabolized through the Leloir pathway, while glucose enters glycolysis. Therefore, inactivation of the *ccpA* gene results in derepression of the cellobiosespecific PTS transport system and also of the *bglS* gene, which in turn enable the IL1403

Despite the fact that the metabolism of lactose and *β*-glucosides is very important for the biotechnological processes catalysed by *L. lactis*, thorough studies of the chromosomally encoded features enabling use of these carbon sources were so far rather scarce. The reason for this could be the fact that *L. lactis* demonstrates a very large and complex metabolic capability towards carbohydrates used as carbon and energy sources, and, moreover, that this genetic potential is tightly regulated by various environmental and intracellular factors. It seems that the main obstacle in studies on the complicated

mechanisms involved in assimilation of *β*–glycoside sugars was the lack of complex data specifying the sequences of genes potentially involved in the metabolism of these sugars and its regulation. Indeed, recent access to the genomic sequences of some these bacteria greatly advanced the research on the metabolism of various *β*–glycosides. As expected, the results of sequencing of lactococcal genomes and genes annotations confirmed that there are numerous genes encoding potential *β*-glucosidesspecific transport systems and *β*-glucosidases, sometimes with dual activities. And, to complicate the matter even further, the analysis of the list of genes annotated in *L. lactis* leads to over a hundred transcriptional regulators. A relatively large number of them may be related to carbon metabolism control. These regulators, together with signals modulating their activity, and the controlled genes form a regulatory network that is necessary for sensing the environmental conditions and adjusting the catabolic capacities of the cell.

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Detailed knowledge of sugar metabolism and the regulators controlling gene expression in *Lactococcus lactis* may contribute to the improvement of mechanisms controlling significant cellular processes in these bacteria. In the case of industrial microorganisms, acting on the defined regulatory network may drastically affect the properties of the bacteria and have an impact on bioprocesses.

Lastly, is shown as an example that by the use of a simple microbiological screen, it is possible and worthwhile to modify the metabolic potential of lactococcal strains initially unable to assimilate lactose. By inactivation of the *ccpA* gene or induction of particular genes by supplementation of the medium with cellobiose and thus activation of YebF, it is possible to turn on an alternative lactose assimilation pathway in *L. lactis* IL1403. In contrast to plasmid-located *lac*-operons, the *cel-lac* system is within the chromosome, resulting in a stable, highly adapted strain, potentially valuable for the dairy industry.


*Edited by Mehdi Khodaei and Luca Petaccia*

Nowadays, nanomaterials are attracting huge attentions not only from a basic research point of view but also for their potential applications. Since finding the structure-property-processing relationships can open new windows in the application of materials, the material characterizations play a crucial role in the research and development of materials science. The increasing demand for energy with the necessity to find alternative renewable and sustainable energy sources leads to the rapid growth in attention to energy materials. In this book, the results of some outstanding researches on synchrotron-based characterization of nanostructured materials related to energy applications are presented.

ISBN 978-953-51-3013-0

X-ray Characterization of Nanostructured Energy Materials by Synchrotron Radiation

Photo by fanjianhua / iStock


*Edited by Federico Piscione*

Angina is the most common disorder affecting patients with ischemic heart disease. This book provides a thorough review of fundamental principles of diagnosis, pathophysiology and treatment of angina pectoris, representing an invaluable resource not only for cardiologists, but also for general practitioners and medical students.

ISBN 978-953-307-359-0

Angina Pectoris

Photo by man\_at\_mouse / iStock


Meet the editor

Heimo Mikkola, born in Finland in 1945, has been a bird-watcher since the age of eleven, but has concentrated on owls since 1965. His thesis for his MSc was on the great grey owl, and his Ph.D. thesis was on the ecological relationships of European owls. In 1988, Dr. Mikkola became an adjunct professor at the University of Eastern Finland. His life-long international career with the Food and Agriculture Organization (FAO) of the Unit-

ed Nations started in 1974 in Colombia and ended with him as the resident representative of FAO in Uruguay in 2007. In 2014, he was nominated as "Champion of Owls" in Houston, USA, mainly because of his worldwide distributed and translated owl books. Thus far, he has written some 300 papers and more than 10 books on birds. Since retirement, he has edited eight books with IntechOpen.

Contents

**Section 1**

**Section 2**

and Evolution in Birds *by Michael Wink*

in Marine Ecosystems

*by Roelof D. Coertze and Arie M. Rijke*

*Sood A. Ndimuligo and Pius Y. Kavana*

and Land Birds

and Challenges

**Section 3**

**Preface XI**

Systematics and Taxonomy **1**

**Chapter 1 3**

Bird Colours and Feather Structure **23**

**Chapter 2 25**

**Chapter 3 39**

Abundances and Distribution **49**

**Chapter 4 51**

**Chapter 5 71**

DNA Analyses Have Revolutionized Studies on the Taxonomy

Haloarchaea May Contribute to the Colour of Avian Plumage

*by Rosa María Martínez-Espinosa and Javier Torregrosa-Crespo*

Viscous Drag Reduction and Contour Feather Geometry in Water

Seabirds of the Benguela Ecosystem: Utilisation, Long-Term Changes

Avifauna in Relation to Habitat Disturbance in Wildlife Management

*Alistair M. McInnes, Desmond Tom and Robert J.M. Crawford*

Areas of the Ruvuma Miombo Ecosystem, Southern Tanzania *by Ally K. Nkwabi, John K. Bukombe, Hamza K. Kija, Steven D. Liseki,*

*by Azwianewi B. Makhado, Rodney Braby, Bruce M. Dyer, Jessica Kemper,*