**2.4. Abdominal wall anomalies**

The evaluation is the integrity of the abdominal wall is part of routine midtrimester scan, although it can be performed starting with the first trimester examination. Conditions as: oligoamnios, placenta, or uterine wall proximity, excessive movement of the fetus can obstruct the proper visualization of the abdominal anterior wall. It is very important that the integrity of the abdominal wall is assessed by showing the insertion of the umbilical cord and visualization of the bladder in the pelvis, so that that bladder and cloacal exstrophy can be excluded.

The abdominal wall anomalies will be discussed separately in a subsequent chapter.


**Acknowledgements**

The research is supported by the grant from the Russian Science Foundation (project # 19-12-00323).

*Green's Function Method for Electromagnetic and Acoustic Fields in Arbitrarily… DOI: http://dx.doi.org/10.5772/intechopen.94852*


**Numerical Scrutinization of Darcy-Forchheimer Relation in Convective Magnetohydrodynamic Nanofluid Flow Bounded by Nonlinear Stretching Surface in the Perspective of Heat and**

#### **Ghulam Rasool 1, \* , Anum Shafiq 2 , Marei S. Alqarni 3,4 , Abderrahim Wakif 5 , Ilyas Khan 6 and Muhammad Shoaib Bhutta 1**

#### **1. Introduction**

A simple base fluid, for example, water, ethylene glycol, and oil, etc., when upgraded with the suspension of nanometric metallic strong conductive particles, is termed as nanofluid. Such a formulation sufficiently intensifies the conduction abilities of the base fluid. Numerous applications have been discovered for the so-called nanofluids in the industrial and engineering aspects as well as in bio-medicine. For example, vehicle cooling, heat exchangers, cooling and transformer cooling, electronic cooling, and many others are typical and widely used applications of nanofluids. These are also applicable in the medical treatments, especially cancer and tumor treatments, resonance imaging, and wound treatment, etc., and they are typically dependent on the conductive nature of nanofluids. Choi [1] introduced the definition of nanofluid in his experimental work where he proved that the suspension of nanoparticles in typical fluids drastically changes the thermo-physical properties of the fluid. Later on, Buongiorno [2] modeled the same concept in the perspective of convective transport of nanofluids. Adding details to the concept of nanofluids, Buongiorno emphasized the fact that the Brownian diffusion and Thermophoresis are two major slip factors in the transport of nanofluids. Afterwards, several interesting attempts have been reported by renowned researchers of fluid mechanics. For instance, Khan et al. [3] reported convection phenomena in nanofluid flow passing a linear stretching surface using the Keller–Box numerical method for the final solutions of the modeled governing problems. An interesting study of Mustafa et al. [4] disclosed an analysis on stagnation spot flow of nanofluids involving linear stretched sheet. For more details on this topic, one can see [5–24] and cross references cited therein.

Flow past a linear as well as nonlinear stretching surface relates the fluid mechanics with several important industrial and engineering setups, such as hot rolling, polymeric extrusion, continuously stretching done in plastic thin films, crystal growth, fiber production, and metallic extrusion, etc. Numerous articles are available in the literature that explain the flow caused by stretching surfaces, whether linear or nonlinear rates. The importance of linear stretching cannot be neglected but the flow caused by non-linear stretching rates

**Citation:** Rasool, G.; Shafiq, A.; Alqarni, M.S.; Wakif, A.; Khan, I.; Bhutta, M.S. Numerical Scrutinization of Darcy-Forchheimer Relation in Convective Magnetohydrodynamic Nanofluid Flow Bounded by Nonlinear Stretching Surface in the Perspective of Heat and Mass Transfer. *Micromachines* **2021**, *12*, 374. https://doi.org/10.3390/mi12040374

Academic Editor: Junfeng Zhang and Ruijin Wang

Received: 9 March 2021 Accepted: 24 March 2021 Published: 1 April 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

have always played a significant role in the above mentioned procedures, especially in polymeric extrusion. In all such scenarios, the work of Cortell [25] is considered to be a pioneer. He considered a viscous fluid for studying heat and mass transfer developments driven by a nonlinear or linear stretching in the sheet. The prescribed wall temperature and constant wall temperature were both discussed in this study. Vajravelu [26] reported a study on exploration of heat transfer developments in a viscous fluid flow past a stretching sheet surface using power law velocity distribution with nonlinear stretching rate. Rana and Bhargava [27] reported a study on the fluid flow analysis and heat transfer aspects involving a nonlinear stretching rate in nanofluids flow over a sheet.

The type of nanofluids governed in the categorical classification of non-Newtonian fluids have gained special attention for numerous engineering and industrial applications based on their extended contributions in nuclear, chemical, metallic, polymeric, and plastic industries. Shampoos, paints, apple sauce, katchup, as well as different type of oils are typical genuine examples of non-Newtonian fluids. Having extended viscosity, the non-Newtonian fluids are best treated by involving the viscoelastic terms (second grade model), which is known as sub-categorical classification of differential non-Newtonian liquids related with the normal stress attribute. For a better understanding of this model, one can read [28–34] and the references cited therein.

The studies mentioned above are either concerned with a linear stretching surface with effective convective heating or nonlinear stretching sheets without the involvement of convective conditions together with the Darcy–Forchheimer model. Here, for the first time, we involve convective conditions to consider a visco-elastic and strictly incompressible nanoliquid (nanofluid) flow bounded by a nonlinear flat stretching surface. Firstly, the model shapes in mathematical form using the famous Navier stokes equations for incompressible non-Newtonian nanofluid. The leading problems are then transformed into highly nonlinear ordinary problems via suitable transformations. A numerical scheme is implemented for finding the final solutions. From now onward, fluid means means incompressible viscoelastic nanofluid. The next section will physically justify the existence of the problem and mathematical expressions with properly defined boundary conditions. The rest of the article comprises of the results and discussion, a graphical display, and concluding remarks.

#### **2. Problem Formulation**

In this numerical investigation, we have invoked the convective boundary on the flow of nanofluid passing over a nonlinear flate stretching surface. These conditions are invoked to balance the temperature difference within the system. The system relies on Darcy–Forchheimer medium saturated via nanofluid over the stretching surface. Cartesian coordinates are considered to analyze the fluid flow. The flow direction is assumed along positive *x*−direction, whereas no-movement is allowed towards vertical. An induced magnetic effect is directly invoked to the surface normal direction via MHD; however, a tiny Reynolds number helps to dismiss the magnetic impact. The nonlinear stretching rate is taken into account via *n* as a positive integer, whereas the stretching velocity is assumed as *u* = *Uw* = *mxn* at the bottom line. However, the velocity diminishes away from the surface and attains zero value at free surface (*u* = 0). The coefficient of heat and mass flux (*h*1 and *h*2) are involved in convective boundary conditions. Figure 1 sketches a physical display.

**Figure 1.** Physical model and coordinate system.

The modified Navier stokes problems are given below:

$$\frac{\partial v}{\partial y} + \frac{\partial u}{\partial x} = 0,\tag{1}$$

$$\begin{split} v\frac{\partial u}{\partial y} + u\frac{\partial u}{\partial x} &= \nu \frac{\partial^2 u}{\partial y^2} - \left[ \frac{B\_0^2 \sigma}{\rho\_f} + \frac{\nu}{K} \right] u - \frac{\mathsf{C}\_b}{K^{1/2}} u^2 \\ &- k\_1 \left( u \frac{\partial^3 u}{\partial x \partial y^2} + \frac{\partial u}{\partial x} \frac{\partial}{\partial y} \left( \frac{\partial u}{\partial y} \right) + v \frac{\partial}{\partial y} \left( \frac{\partial^2 u}{\partial y^2} \right) - \frac{\partial u}{\partial y} \frac{\partial}{\partial x} \left( \frac{\partial u}{\partial y} \right) \right), \end{split} \tag{2}$$

$$a\frac{\partial T}{\partial y} + u\frac{\partial T}{\partial x} = a\frac{\partial}{\partial y}\left(\frac{\partial T}{\partial y}\right) + \frac{(\rho c)\_p}{(\rho c)\_f} \left[D\_{\text{Br}}\left(\frac{\partial \mathcal{C}}{\partial y}\frac{\partial T}{\partial y}\right) + \frac{D\_{Th}}{T\_{\infty}}\left(\frac{\partial T}{\partial y}\right)^2\right] - \frac{1}{\rho c\_f}\frac{\partial q\_r}{\partial y},\tag{3}$$

where *qr* is known as radiative heat flux. Given by Rosseland's approximation:

$$q\_r = -\frac{\partial (T^4)}{\partial y} \left(\frac{4\sigma^\*}{3k^\*}\right)\_{\prime} \tag{4}$$

where *σ* ∗ =Stefan–Boltzmann constant and *k* ∗ = mean absorption, respectively. Here, in,

4*T* 3 ∞*T* − 3*T* 4 ∞ ∼ = *T* 4 , (5)

confirms,

$$\frac{\partial q\_r}{\partial y} = -\frac{\partial^2 T}{\partial y^2} \left( \frac{16\sigma^\* T\_\infty^3}{3k^\*} \right). \tag{6}$$

Therefore, the energy equation has the following final form:

$$\ln \frac{\partial T}{\partial \mathbf{x}} + \upsilon \frac{\partial T}{\partial y} = \varkappa \frac{\partial}{\partial y} \left( \frac{\partial T}{\partial y} \right) + \frac{(\rho c)\_p}{(\rho c)\_f} \left[ \frac{D\_{Th}}{T\_{\infty}} \left( \frac{\partial T}{\partial y} \right)^2 + D\_{Br} \left( \frac{\partial \mathbb{C}}{\partial y} \frac{\partial T}{\partial y} \right) \right] + \frac{\partial^2 T}{\partial y^2} \left( \frac{16 \sigma^\* T\_{\infty}^3}{3k^\*} \right) \frac{1}{(\rho c)\_f}, \tag{7}$$

$$v\frac{\partial \mathbf{C}}{\partial y} + u\frac{\partial \mathbf{C}}{\partial x} = D\_{Br} \left(\frac{\partial}{\partial y}\frac{\partial \mathbf{C}}{\partial y}\right) + \frac{D\_{Th}}{T\_{\infty}} \left(\frac{\partial}{\partial y}\frac{\partial T}{\partial y}\right) \tag{8}$$

Equations (1),(2),(7), and (8) are known as the governing equations with the following boundary conditions, as per the present model,

$$\text{If } u = \text{U}\_{\overline{w}} = m\mathbf{x}^n \text{, } h\_1(T\_f - T) = -k \frac{\partial T}{\partial y'} \text{, } v = 0, \text{ } h\_2(\mathbb{C}\_f - \mathbb{C}) = -D\_{\text{Br}} \frac{\partial \mathbb{C}}{\partial y} \quad \text{at} \quad y = 0, \tag{9}$$

$$
\Delta u = 0, \,\frac{\partial u}{\partial y} = 0, \,\text{C} = \text{C}\_{\infty}, \,\, T = T\_{\infty} \quad \text{as} \quad y \to \infty. \tag{10}
$$

In the above governing equations, *µ* is taken as dynamic viscosity, *ν* = *µ*/*ρf* is known as kinematic viscosity, *ρf* is taken as density, *σ* is involved for electrical conductivity, *α* = *k*/(*ρc*)*f* is well known thermal diffusive force, *k* is typical thermal conductiveness, *h*1 = *hpx n*−1 2 and *h*2 = *hqx n*−1 2 are known as non-uniform heat and mass (transfer) coefficients, respectively, *τ* is known as the ratio given between the effective nanoparticles heating capacity versus effective fluid heating capacity, *DBr* is known for Brownian diffusion, *DTh* is thermophoretic factor, and *B*0 is magnetic effect. Defining,

$$v = -\frac{1}{2} \mathbf{x}^{\frac{n-1}{2}} \left[ \left( \frac{n-1}{n+1} \right) \frac{\partial f}{\partial \eta} \eta + f(\eta) \right] \sqrt{2m\nu(n+1)}, \quad u = mx^n \frac{\partial f}{\partial \eta},$$

$$\phi(\eta) = \frac{\mathbb{C} - \mathbb{C}\_{\infty}}{\mathbb{C}\_{w} - \mathbb{C}\_{\infty}}, \quad \theta(\eta) = \frac{T - T\_{\infty}}{T\_{w} - T\_{\infty}}, \quad \eta = \frac{1}{2} \sqrt{\frac{2\rho\_{ff}m(n+1)}{\mu}} x^{\frac{n-1}{2}} y. \tag{11}$$

Using (15) in (1), (2), (9) and (10) we have

$$\begin{aligned} &f'''' + ff'' + k\_0 \left[ \left(\frac{n+1}{2n}\right) f' f^{iv} + \left(f''\right)^2 - \left(\frac{n+1}{2n}\right) f'^{iv} f' \right] \\ &- \left(\frac{2n}{1+n}\right) (1+F\_r) \left(f'\right)^2 - \lambda \left(\frac{2}{n+1}\right) f' - M^2 \left(\frac{2}{n+1}\right) f' = 0, \end{aligned} \tag{12}$$

$$(1 + 4/3Rd)\theta'' + Prf\theta' + NbPr\theta'\phi' + NtPr\left(\theta'\right)^2 = 0,\tag{13}$$

$$
\phi'' + LePrf\phi' + \frac{Nt}{Nb}\theta'' = 0,
\tag{14}
$$

$$\begin{aligned} f(0) &= 0, & f' &= 1, & \phi'(0) &= -\gamma\_2(1 - \phi(0)), & \theta'(0) &= -\gamma\_1(1 - \theta(0)), \\ f'(\infty) &= 0, & f''(\infty) &= 0, & \phi(\infty) &= 0, & \theta(\infty) &= 0. \end{aligned} \tag{15}$$

Here, *γi* for *i* = 1, 2 are the convective parameters extracted from *h*1 = *hpx n*−1 2 and *h*2 = *hqx n*−1 2 known as non-uniform heat transfer coefficient and mass transfer coefficient, respectively. *Fr* is used for inertial frame, *M* is involved for magnetic impact, *λ* is treated as porosity, *Pr* is the typical Prandtl, *Le* is the well known Lewis number, *k*0 is taken as viscoelastic parameter, and *Nb* and *Nt* Brownian diffusion and thermophoretic factors, respectively. Mathematically,

$$\gamma\_1 = \frac{h\_p}{k} \sqrt{\frac{2\nu}{m(n+1)}}, \gamma\_2 = \frac{h\_q}{D\_{Br}} \sqrt{\frac{2\nu}{m(n+1)}}, \quad F\_r = \frac{\mathbf{C}\_b \mathbf{x}}{K^{1/2}}, \quad M^2 = \frac{2\sigma B\_0^2}{m\mathbf{x}^{n-1}\rho\_f},$$

$$\lambda = \frac{2\nu}{Km\mathbf{x}^{n-1}}, \quad \text{Pr} = \frac{\nu}{\mathbf{a}'}, \quad L\mathbf{e} = \frac{a}{D\_{Br}}, \quad k\_1 = \frac{k\_0 m \mathbf{x}^{n-1}}{\nu}, \tag{16}$$

$$N\mathbf{b} = \frac{\left(\rho\_f c\right)\_p D\_{Br} (\mathbf{C}\_w - \mathbf{C}\_{\infty})}{\left(\rho\_f c\right)\_f \nu}, \quad N\mathbf{t} = \frac{\left(\rho\_f c\right)\_p D\_{Th} (T\_w - T\_{\infty})}{\left(\rho\_f c\right)\_f \nu T\_{\infty}}.$$

Furthermore, using *Rex* = *mxn*+1/*ν*, the local tiny Reynolds, the non-dimensional forms of physical quantities, are given below:

$$\begin{aligned} (\text{Re}\_x)^{1/2} \left( \frac{n+1}{2} \right)^{-1/2} \mathbb{C}\_f &= [(1-3\mathbf{k}\_0)f''(0)], \\ (\text{Re}\_x)^{-1/2} \left( \frac{n+1}{2} \right)^{-1/2} \mathrm{Nu} &= -\left(1+\frac{4}{3}\right) \mathrm{Rd} \left[ \theta'(0) \right], \\ (\text{Re}\_x)^{-1/2} \left( \frac{n+1}{2} \right)^{-1/2} \mathrm{Sh} &= -\left[\phi'(0) \right], \end{aligned} \tag{17}$$

#### **3. Methodology**

RK45 is one of the most frequently used numerical methods for solving IVPs for its accuracy and efficiency. The built-in codes involve basic concept of converting Boundary value problems into the initial value problems and subsequent problems are solved using a parallel scheme with RK45, such as shooting technique, secant method, etc., using an appropriate set of initial guesses to approximate the solutions. Herein, the boundary value problems are converted into initial value problems together with the given boundary conditions and thereafter, careful selection of initial guess for repeated iterations of the numerical scheme are chosen to obtain the solutions.

#### **4. Results and Discussion**

In this section, we have described the consequences noticed in flow profiles for all relevant parameters that are involved in leading problems of present nanofluid model. The arguments are comprehended by physical justifications as to why the variation is occurred and what consequence is being witnessed. The results are obtained using the numerical method and the data are graphically plotted in increasing and decreasing curves to witness the difference. The first section of the graphs belongs to the velocity profile, the second to temperature distribution, and third is related with the concentration of nanoparticles. In particular, Figure 2 is plotted to see the variation in velocity profile against augmented trend of visco-elastic parameter *k*0. The physical reasoning of the behavior noted for this parameter is connected with the combination of *k*1 and kinematic viscosity *µ* having an inverse relation with fluid viscosity. For larger values of *k*0, the fluid viscosity shows a decline, and a consequent increasing trend is witnessed in the relative profile. The magnetic parameter *M* that is given in Figure 3 with a relevant variation in fluid motion produces a reduction. Physically, the affect of magnetic field is always in anti-directional with the fluid flow because of the surface normal bumps. The certain effect of magnetic field in the direction normal to the fluid flow is, for sure, the reason behind this trend of decline in fluid velocity. The similar trend in velocity profile can be figured out for the Forchheimer number *Fr* that is given in Figure 4, but this time the decline is related with a higher friction and retardation offered by porous medium. The larger the Forchheimer number, the higher the frictional force that is offered to fluid motion and the consequence is a decline in fluid velocity. The thermal layer receives significant modification in the incremental direction for augmented values of thermal radiation *Rd* given in Figure 5. The influence of thermal radiation eases the way of heat flux with a more convenient convection and the corresponding profile receives significant enhancement. Physically, thermal radiation is responsible for the enhancement of the thermal state of the fluid. Elevation in thermal Biot number *γ*1 apparently results in a significant increase of the thermal layer and associated boundary layer thickness enhances, as shown in Figure 6. The heat flux coefficient that is involved in constitution of the said parameter is a sufficient justification for this behavior of thermal profile. Thermophoresis and Brownian motion are the two important factors of nanofluid flow and boundary layer phenomenon. By definition, Brownian motion is an uncertain movement of some particles (nanoparticles in this case) in the given medium for any time *t* > 0. The parameters are both

closed influential to each other as well as on the flow profiles. Here, the thermophoresis enforces a stronger thermophoretic push to the given nanoparticles and the nanoparticles receive certain inpredictive enhanced motion and, therefore, a disturbance appears and thermal profiles increase for both of the given factors shown in Figures 7 and 8, respectively. Figures 9–12 are related with the third important flow profiles, the concentration profiles, which is solely based on the concentration of nanoparticles. In particular, Figure 9 presents the display of variation that is noticed in concentration profile with respect to the elevation in Schmidt number. Physically, the inverse relationship between Brownian diffusion and kinematic viscosity is sufficient to justify the reducing trend noticed in concentration profile for augmented values of Schmidt number. The solute Biot number is an enhancing factor the concentration profile that is given in Figure 10. The coefficient of mass flux involved in the constitutive expression justifies this variation. An enhancement is noticed for elevated values of thermophoresis given in Figure 11. A decline can be seen in concentration profile for augmented Brownian diffusion parameter given in Figure 12. For sure, the decline is based on the in-predictive and uncertain fluctuation of nanoparticles. Figures 13 and 14 are the contour graphs sketched for both the linear and non-linear case, respectively, while Figures 15 and 16 are the density graphs. A minor but significant difference can be seen in both the linear and non-linear case settled at *n* = 1 & 1.5, respectively. Relevant data for skin-friction, heat, and mass flux numbers are given in Tables 1 and 2, respectively. Skin friction jumps for larger porosity and a larger Forchheimer number, therefore, declines the easy movement of fluid.The heat flux and mass flux both receive a reduction for the augmented values of Forchheimer number. Thermal radiation is an enhancing factor for both of the flux rates. An opposite trend is noticed in both Nusselt and Sherwood numbers for thermal Biot number. Heat flux enhances, while mass flux reduces with the passage of time.

**Figure 2.** Visco-elastic parameter versus velocity field.

**Figure 4.** Forchheimer number versus velocity field.

**Figure 5.** Thermal radiation parameter versus thermal profile.

**Figure 6.** Thermal Biot number versus thermal profile.

**Figure 7.** Thermophoresis versus thermal profile.

**Figure 8.** Brownian diffusion versus thermal profile.

**Figure 9.** Schmidt number versus concentration profile.

**Figure 10.** Solute Biot number versus concentration distribution.

**Figure 11.** Thermophoresis versus concentration distribution.

**Figure 12.** Brownian diffusion versus concentration distribution.

For Linear Case

**Figure 13.** Contour graph for linear case.

For non-Linear Case

**Figure 14.** Contour graph for nonlinear case.

#### Density Plot for Linear Case Density Plot for non-Linear Case

**Author Contributions:** Conceptualization, G.R.; methodology, G.R., A.S.; software, G.R., A.S., A.W.; validation, G.R., A.S., A.W., M.S.B.; formal analysis, G.R., A.S., A.W., I.K., M.S.A., M.S.B.; investigation, G.R., A.S., A.W., I.K., M.S.B.; resources, M.S.A.; data curation, G.R., A.S., A.W., M.S.B.; writing—original draft preparation, G.R., A.S., A.W., I.K., M.S.B., M.S.A.; writing—review and editing, G.R., A.S., A.W., I.K., M.S.B., M.S.A.; visualization, G.R., A.S., A.W.,; supervision, M.S.A., I.K.; project administration, M.S.A.; funding acquisition, M.S.A. All authors have read and agreed to the published version of the manuscript.

**Data Availability Statement:** All data are available within this manuscript.

**Acknowledgments:** The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University, Abha, Saudi Arabia for funding this work through research groups program under grant number R.G.P-1/128/42.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Nomenclature:**

#### **References**

*Micromachines* **2021**, *12*, 374

*Micromachines* **2021**, *12*, 374


*2.1. Reagents*

Antibodies recognizing NANOG (D73G4), SOX2 (D6D9), KLF4 (D1F2), HO1 (D60G11), Vimentin (D21H3) and Keap1 (D6B12) were obtained from Cell Signaling Technology (Danvers, MA, USA). E-cadherin (610404) was obtained from BD Biosciences (San Jose, CA, USA). Nrf2 (ab-89443), SLUG (ab-27568), SNAIL (ab-53519) and Bach1 (ab-115210) were purchased from Abcam, (Burlingame, CA, USA) and NQO1 (sc-32793), BAX (sc-7480), BCL2 (sc-7382) were obtained from Santa Cruz Biotechnology (Dallas, TX, USA). Nrf2-targeting shRNA lentiviral particles (sc-37030-v) were obtained from Santa Cruz Biotechnology (CA, USA). Bovine serum albumin (BSA), fibroblast growth factor (FGF) and epidermal growth factor (EGF) were purchased from Sigma-Aldrich (St. Louis, MO, USA). ALDEFLUOR Kit (01700) was obtained from STEM CELL technologies (Vancouver, Canada). Nrf2 Transcription Factor Assay Kit (Colorimetric) (ab207223) was obtained from Abcam. Annexin-V-FITC (556419) was obtained from BD Biosciences (San Jose, CA, USA).

#### *2.2. Cell Culture and Irradiation*

MCF-7 and MDA-MB-231 cells were obtained from the American Type Culture Collection (ATCC) and maintained in DMEM supplemented with 10% FBS (Gibco, MD, USA). Cells were irradiated at room temperature with a 60Co-γ rays laboratory irradiator (Gamma Chamber-5000, BRIT, Mumbai) at a dose rate of 2.163 Gy/min for the time required to obtain the prescribed dose. For fractionated doses of radiation, cells were irradiated with 2Gy for three consecutive days, and for an acute dose of 6Gy, cells were irradiated once on

the last day of fractionated irradiation. Corresponding controls were mock irradiated [13]. Control and irradiated cells were further incubated for 24 h postirradiation.

### *2.3. Mammosphere Formation*

After irradiation, mammospheres were formed using single-cell suspensions in an ultralow attachment 6-well plate at a density of 2 × 104 cells/well in specific media for mammosphere culture containing DMEM and Nutrient Mixture F-12 medium supplemented with 20 ng/mL EGF, B27 (1:50, Life Technologies, MA, USA), 20 ng/mL FGF (Sigma-Aldrich, St. Louis, MO, USA) and penicillin/streptomycin (Invitrogen) for 4–5 days. The floating aggregates with a >50 µm diameter were selected as mammospheres, manually counted and dissociated by incubation with 1:5 of 0.25% trypsin/EDTA. The mammosphere-forming efficiency (MFE) was calculated using the following equation: MFE = No. of spheres formed/No. of cells seeded × platting efficiency.


**4. Conclusions**

In this work, we designed and tested a low-cost, low-latency VLC prototype for I2V communications, using a commercial LED-based traffic light as transmitter and a conventional amplified photodiode with low-cost Fresnel lenses as a receiver. Our VLC-based system is based on an open-source microcontroller platform (Arduino Due) and is capable of Active Decode and Relay (ADR) of received information to a further modulation stage to propagate the information to incoming units through, for example, rear car lamps.

We evaluated the PER performance of the system in various configurations for both the 1 and 2 Fresnel lenses. Two baud rates of 115 and 230 kbaud are used for data transmissions. When embedding a 2 Fresnel lens in Optimal configuration, our system attains an error-free transmission (PER < 10−5) up to 36 m with sub-millisecond (820 μs) latency of the full ADR process at 230 kbaud (50 m for 230 kbaud). For a more realistic Flat system configuration, simulating a car approaching the traffic light without an optical tracking mechanism, the error-free transmission is achieved at 115 kbaud with 2 lens and above 24 m. If only PER = 10−3 is required, instead, the 18–50 m range can be covered. We also tested the VLC Fresnel-based system for both the beaconing of situational information and event-triggered message broadcast, finding it suitable for both modes of transmission. The noticeable low-latency feature of this prototype makes it integrable with current 5G-based C-V2X Intelligent Transportation Systems.

For the future, we are planning outdoor measurement campaigns for both I2V, V2V and Infrastructure-to-Vehicle-to-Vehicle (I2V2V) communications. In addition, our system will be tested for various environmental conditions.

**Author Contributions:** Conceptualization, T.N., M.S., S.C., L.M. and J.C.; methodology, T.N., M.S., S.C., L.M. and J.C.; software, T.N. and S.C.; validation, L.M. and J.C.; formal analysis, L.M. and S.C.; investigation, T.N., M.S. and J.C.; resources, J.C.; data curation, M.S. and S.C.; original draft preparation, T.N. and J.C.; supervision, J.C.; funding acquisition, L.M. and J.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work has been carried out under the financial support of Project PON MIUR 2017 "OK-INSAID", of Progetto Premiale MIUR FOE 2015 "OpenLab", and by Project MISE "5G City"—Prato.

**Acknowledgments:** Authors would like to thank the Company ILES srl in Prato (Italy) for providing the traffic light and for support, and Francesco Cataliotti for precious discussions.

**Conflicts of Interest:** The authors declare no conflict of interest.


**6. The risk factors of PTSD**

Researchers who study risk factors for PTSD have identified aspects of demographic data, psychological factors, psychiatric symptoms, and post-trauma social resource factors as important factors that contribute to the development of the disease.


3.1.3. Antimicrobial Activity

The emergence of antibiotic resistance of human pathogenic microorganisms and the need for new antiviral drugs has been a key driver for searching new antimicrobial compounds [75]. Complex lipids from seaweeds could play an active role in this field. In this section we describe the lipids from seaweeds with reported antibacterial, antiviral, anti-algal, anti-fouling, antifungal and anti-protozoal activities (Table 3). In spite of the range of antimicrobial activities tested, there is still opportunity to gain a more in-depth knowledge on this bioactive property of seaweed lipids, namely by testing against other strains of bacteria and virus that are major drivers of infection diseases

The GLs classes MGDG, DGDG, and SQDG from some species of *Laminaria* genus [76,77]; the brown seaweeds *Fucus evanescens* [78], *Alaria fistulosa* [76], *Saccharina cichorioides* [79]; and the red seaweed *Chondria armata* [80], demonstrated activity against a range of bacteria, yeast, and fungus. Likewise, sulfolipids classes from several seaweed species proved antibacterial activity [56]. In addition to antibacterial and antifungal activity, an isolated mixture of SQDG species from the brown seaweed *Lobophora variegata* showed anti-protozoal activity [81]. Isolated sub-fractions enriched in GL from the green seaweed *Ulva prolifera* [82] and the brown seaweed *Sargassum vulgare* [83] showed anti-algal and anti-fouling activities, respectively.

The studies surveyed pinpoint the evaluation of the complex lipid antiviral activity on Herpes simplex virus (HSV). The SQDG class from the red seaweed *Osmundaria obtusiloba*, the brown seaweed *Sargassum vulgare* and several species within genus *Laminaria* (brown seaweeds), were highlighted by its antiviral activity against HSV-1 [56,84,85] and HSV-2 [84,85]. The role of palmitic acid and sulfonate group on SQDG molecular structure was considered as relevant on activity against HSV virus and on cellular receptors [85].

Prospecting new antimicrobial compounds should follow a systemic protocol once the goal is to design solutions for human protection. Tested compounds must also show low toxicity against erythrocytes, which was evaluated in parallel in some studies that revealed hemolytic activity [76–78].


**7. MRI's uses in the staging and prognosis of retinoblastoma**

Although MRI can aid in the diagnosis of retinoblastoma by the aforementioned characteristics, it is more widely used for the staging of retinoblastoma. Like all other malignancies, tumor staging in retinoblastoma is essential for the prognosis predictions.

The use of MRI has changed the accuracy of assessing metastatic risk factors as the initial retinoblastoma staging of patients before the use of MRI varied after MR imaging were obtained.

The extension of retinoblastoma is usually by direct extension into adjacent structures. Intraocular extension of the tumor can easily be visualized during examination in patients with good posterior pole visualization. MR imaging has been widely used to evaluate the extra-ocular and intracranial extension and can also aid in the evaluation of intraocular tumor extension [11].

Intraocular extension can be detected by choroidal irregularities. Choroidal invasion identification is important in the prognosis of the disease. It changes the prognosis of retinoblastoma by increasing the mortality rate up to 24–65% depending on the severity of invasion [12].

In the assessment of extra-ocular retinoblastoma extension, the most important structure to evaluate is the optic nerve. Involvement of the optic nerve in retinoblastoma alters the prognosis and the management of the disease. The overall mortality rate of retinoblastoma without optic nerve invasion is 10%. If the invasion of the optic nerve reaches through the lamina cribrosa, the mortality may rise up to 15%. Moreover, if the extension is posterior to the lamina cribrosa the mortality rises up to 44%. This makes the optic nerve assessment by MR imaging crucial in any retinoblastoma case with proper identification of the level of optic nerve invasion. On MRI, the affected optic nerve appears thickened and irregular with high enhancement of the nerve itself and the area surrounding it [11].

A study showed that the specificity of MRI in detecting optic nerve invasion past the lamina cribrosa to reach up to 80% and a sensitivity of 74%. This makes MR imaging the most superior non-invasive method in the detection of retinoblastoma optic nerve invasion [13] (**Figures 13** and **14**).

Ophthalmic surgeons require extra measurements of the invasion to take extra precautions during the enucleation of the affected eye. It is important for the MR image to demonstrate if the retrolaminar optic nerve invasion extends more than 5 mm posteriorly. This is particularly crucial to identify prior to surgical intervention as the tumor may be cut through during the enucleation. If such complication happens, the distal part of the tumor that remains is connected to the brain and may progress to brain metastasis. In such cases, the surgeon might consider doing an orbitotomy to be able to reach further posterior and dissect at least 10 mm from

#### **Figure 13.**

*MRI T2 weighted image of brain and orbit showing right globe retrolental hypo-intense tumor core, retro bulbar extension and extensive long segment right optic nerve invasion resulting in right globe proptosis.*

**51**

of over 90%.

*Uses of Radiological Imaging in Retinoblastoma DOI: http://dx.doi.org/10.5772/intechopen.86828*

optic nerve regardless of MR findings.

**8. Conclusion**

**Figure 14.**

*retinoblastoma.*

alters the management plan.

cistern. It represents 1.5–5% of all RB patients [15].

the suggested tumor margin. Despite the advancement of MRI, it has limitations in detecting microscopic optic nerve invasion. Studies have shown a discrepancy between histological results in optic nerve assessment (gold standard) and MRI results [14]. This dictates the need for thorough histopathological assessment of the

*MRI T1 weighted image with contrast of the same patient delineating the retrobulbar extension, enhanced and enlarged right optic nerve, leptomeningeal enhancement due to direct extension and CSF seeding of*

An important disease entity in retinoblastoma is the trilateral retinoblastoma disease. It refers to rare disease that is characterized by bilateral ocular RB and a primitive midline neuroectodermal tumor in the pineal region or the suprasellar

Retinoblastoma is the most common primary ocular malignancy in children. Diagnostic imaging has changed the accuracy of diagnosing and staging retinoblastoma. There are many imaging modalities that are currently in use for retinoblastoma tumor like ultrasonography, computerized tomography and magnetic resonance imaging. MR images of the brain and spinal cord need to be obtained routinely in retinoblastoma patients in institutes where MRI is accessible. They aid in the diagnosis and prognosis of the disease. As the retinoblastoma tumor seeding may spread via cerebrospinal fluid and reach the intracranial resulting in brain metastasis, MRI can clearly delineate these metastatic lesions, which eventually

MRI can show retrolaminar optic nerve and choroidoscleral infiltration and spread

A purely ocular tumor confined within the globe reaches a survival rate of 90% AT 5-years whereas a tumor that has extended outside the globe has a mortality rate

of tumor into the brain and spine more accurately than other diagnostic imaging.

**50**

*Uses of Radiological Imaging in Retinoblastoma DOI: http://dx.doi.org/10.5772/intechopen.86828*

#### **Figure 14.**

*Retinoblastoma - Past, Present and Future*

ing on the severity of invasion [12].

optic nerve invasion [13] (**Figures 13** and **14**).

been widely used to evaluate the extra-ocular and intracranial extension and can

Intraocular extension can be detected by choroidal irregularities. Choroidal invasion identification is important in the prognosis of the disease. It changes the prognosis of retinoblastoma by increasing the mortality rate up to 24–65% depend-

In the assessment of extra-ocular retinoblastoma extension, the most important

A study showed that the specificity of MRI in detecting optic nerve invasion past

Ophthalmic surgeons require extra measurements of the invasion to take extra precautions during the enucleation of the affected eye. It is important for the MR image to demonstrate if the retrolaminar optic nerve invasion extends more than 5 mm posteriorly. This is particularly crucial to identify prior to surgical intervention as the tumor may be cut through during the enucleation. If such complication happens, the distal part of the tumor that remains is connected to the brain and may progress to brain metastasis. In such cases, the surgeon might consider doing an orbitotomy to be able to reach further posterior and dissect at least 10 mm from

the lamina cribrosa to reach up to 80% and a sensitivity of 74%. This makes MR imaging the most superior non-invasive method in the detection of retinoblastoma

*MRI T2 weighted image of brain and orbit showing right globe retrolental hypo-intense tumor core, retro bulbar extension and extensive long segment right optic nerve invasion resulting in right globe proptosis.*

structure to evaluate is the optic nerve. Involvement of the optic nerve in retinoblastoma alters the prognosis and the management of the disease. The overall mortality rate of retinoblastoma without optic nerve invasion is 10%. If the invasion of the optic nerve reaches through the lamina cribrosa, the mortality may rise up to 15%. Moreover, if the extension is posterior to the lamina cribrosa the mortality rises up to 44%. This makes the optic nerve assessment by MR imaging crucial in any retinoblastoma case with proper identification of the level of optic nerve invasion. On MRI, the affected optic nerve appears thickened and irregular with

high enhancement of the nerve itself and the area surrounding it [11].

also aid in the evaluation of intraocular tumor extension [11].

**50**

**Figure 13.**

*MRI T1 weighted image with contrast of the same patient delineating the retrobulbar extension, enhanced and enlarged right optic nerve, leptomeningeal enhancement due to direct extension and CSF seeding of retinoblastoma.*

the suggested tumor margin. Despite the advancement of MRI, it has limitations in detecting microscopic optic nerve invasion. Studies have shown a discrepancy between histological results in optic nerve assessment (gold standard) and MRI results [14]. This dictates the need for thorough histopathological assessment of the optic nerve regardless of MR findings.

An important disease entity in retinoblastoma is the trilateral retinoblastoma disease. It refers to rare disease that is characterized by bilateral ocular RB and a primitive midline neuroectodermal tumor in the pineal region or the suprasellar cistern. It represents 1.5–5% of all RB patients [15].

### **8. Conclusion**

Retinoblastoma is the most common primary ocular malignancy in children. Diagnostic imaging has changed the accuracy of diagnosing and staging retinoblastoma. There are many imaging modalities that are currently in use for retinoblastoma tumor like ultrasonography, computerized tomography and magnetic resonance imaging. MR images of the brain and spinal cord need to be obtained routinely in retinoblastoma patients in institutes where MRI is accessible. They aid in the diagnosis and prognosis of the disease. As the retinoblastoma tumor seeding may spread via cerebrospinal fluid and reach the intracranial resulting in brain metastasis, MRI can clearly delineate these metastatic lesions, which eventually alters the management plan.

MRI can show retrolaminar optic nerve and choroidoscleral infiltration and spread of tumor into the brain and spine more accurately than other diagnostic imaging.

A purely ocular tumor confined within the globe reaches a survival rate of 90% AT 5-years whereas a tumor that has extended outside the globe has a mortality rate of over 90%.

This drastic difference makes staging and the use of ancillary testing vital for the prognosis and survival rate estimation which further guides the treatment decision.

It is now currently recommended for any newly diagnosed patient with retinoblastoma to undergo an MRI [13].

MRI can also offer hope for future advancement of early diagnosis. It has recently shown to aid in very early fetal diagnosis of retinoblastoma in a fetus with high-risk of RB and may be implemented as a part of future screening protocol in high risk population [16].


Section 4 Wave Propagations

*Progress in Fine Particle Plasmas*

[56] Carpen LG, Acsente T,

Available from: https://www. intechopen.com/online-first/theinteraction-of-tungsten-dust-with-

human-skin-cells

Acasandrei MA, Matei E, Chilom CG, Savu DI, et al. The Interaction of Tungsten Dust with Human Skin Cells [Online First]. Rijeka: IntechOpen; 2019. DOI: 10.5772/intechopen.86632.

**136**

**Chapter 8**

**Abstract**

**1. Introduction**

**139**

Turbulence Generation in

*Ravinder Goyal and R.P. Sharma*

profound under similar plasma conditions.

damping, Landau damping, laboratory plasma, turbulence

Inhomogeneous Magnetized

Plasma Pertaining to Damping

The damping phenomenon is studied due to the collisions of ions and neutral particles and Landau approach on the turbulent spectra of kinetic Alfvén wave (KAW) in magnetized plasma which is inhomogeneous as well. The localization of waves is largely affected by inhomogeneities in plasma which are taken in transverse as well as parallel directions to the ambient magnetic field. There is significant effect of damping on the wave localization and turbulent spectra. Numerical solutions of the equations governing kinetic Alfvén waves in the linear regime give the importance of wave damping phenomena while retaining the effects of Landau (collisionless) damping and ion-neutral collisional damping. A comparative study of the two damping effects reveals that the Landau damping effect is more

**Keywords:** kinetic Alfvén wave, inhomogeneous plasma, ion-neutral collisional

As far as enormous space plasma phenomena like solar wind turbulence, acceleration of solar wind, heating of solar coronal loops, solar flares, etc. are concerned, kinetic Alfvén wave (KAW) has a vital role to play [1]. The dispersion characteristics of KAW make it distinguishable from its parent Alfvén wave [2]. When Alfvén wave propagation develops a large value for wave number perpendicular ð Þ *k*<sup>⊥</sup> to the ambient magnetic field, then it gives rise to kinetic Alfvén wave (KAW). This mode conversion may lead to transportation of large amount of electromagnetic energy across geomagnetic field lines [3]. In Tokamak/ITER plasma where KAW plays an important role, the anomalous diffusion coefficient which depends upon the turbulence level is inversely related to the confinement time. In the scenario where the electric fields are nonstationary, this wave plays a vital role in the phenomenon of particle acceleration [4]. The acceleration and heating [5] of plasma particles are dependent on perpendicular wave number and is attributed to KAW carrying finite perturbations parallel to electric field. Also, the plasma heating is caused by dissipation of turbulence and is essential to interpret the observations of most astronomical [6] and laboratory [7] systems. The turbulent behavior of KAW

Effects on Wave Propagation

## **Chapter 8**


**1. Introduction**

*Rhizoctonia solani* Kühn, the causative agent of damping-off disease in a variety of crop plants such as cucumber, is an economical important soil-borne pathogen [1, 2]. *R. solani* fungus is considered as a difficult pathogen to control due to several characters such as the great variability in the pathogen population, a wide host range, and long-term survival in soil [3]. Further, some cultural practices including the crop rotation, sanitation, and soil solarization with *R. solani* are not sufficiently effective because the pathogen is able to survive for many years in soil. The application of chemical pesticides, mainly methyl bromide, is the most reliable method to

control *R. solani*; however, it causes serious risks including polluting the air, damaging the environment, building fungicides' resistance of pathogen, and harming the human health [4, 5]. Therefore, the biological control method becomes an important component of the disease management to increase crop production and food safety [6].

The biological control becomes an important target of many researchers in the field of biological and agricultural sciences [5]. Biocontrol agents use different mechanisms of action against fungal pathogens, such as antimicrobial compound production activity, mycoparasitism or hyperparasitism, cell wall-lytic enzyme activity, and the application of systemic resistance (ISR) activity [7]. In addition, some biocontrol agents are capable of improving some aspects of plant growth, such as the germination rate, shoot and root weight, nutrients' uptake, and yield [8].

Arbuscular mycorrhizal (AM) fungi have been known to form a symbiotic relationship with around 80% of vascular plants. The symbiotic relationship can provide the plant with many benefits, including enhancement of plant growth and germination rates, increasing supplement of water and nutrients [9, 10]. In return, the AM fungi are completely dependable on the nutrients that are coming from the living root system [9]. In addition, AM fungi have been known to increase the host's resistance to a wide range of fungal and bacteria pathogens, especially rot pathogens [11]. The aim of this study was to examine the influence of different species of arbuscular mycorrhizal (AM) fungi (*Glomus* spp.) to promote systemic resistance against the disease agent of damping-off disease (*R. solani* Kühn) on cucumber (*Cucumis sativus* L.).

#### **2. Materials and methods**

Infected samples were brought from cucumber plants with wilting, yellowing, and dwarfing symptoms from a field related to the College of agriculture, University of Al-Qadisiyah. The plants were washed with sterilized water to remove soil residues and were cut to small pieces. Then, the samples were sterilized with sodium hypochlorite (NaCIO) 1% for 2 min, washed with sterilized water twice, and dried with filter papers. Nine petri dishes of potato dextrose agar (PDA) were inoculated with five pieces of the infected plants and incubated for 3 days at 25°C. Soil samples were diluted for pathogen isolation and the petri dishes were incubated at 27°C. Both plant and soil samples were kept in a refrigerator at 4°C and diagnosed using classification keys [12].

Isolated pathogens were stored at 4°C prior to analysis and incubated at 25°C for 3 days. From the colony edge, four populated agar disks (7 mm) were cut and mixed in a 250 ml flask containing 100 ml of potato dextrose broth and 25 mg of chloramphenicol [13]. Sterilized soils were separated on each pot (3 kg) and inoculated with 1 ml from pathogen broth culture, and sterilized water was used for the control. Then, all pots were irrigated and covered for 3 days. Cucumber seeds were disinfected with sodium hypochlorite (NaCIO) 1% for 4 min and were planted in each pot. Germinated, not germinated seeds, and collapsed plants were recorded after 7 and 10 days for planting, and disease intensity was calculated as recommended [14]: 0 = no symptoms; 1 = seed rot, not germinated; 2 = brown rot on the stem base, plant is still standing; 3 = plant is wilted, laying on the ground; and 4 = plant is dead. *DS* was calculated from disease grades 0–3 using the following formula [15]:

$$DS = \frac{\sum (f \ast v)}{N \ast X} \times \mathbf{root} \tag{1}$$

**71**

(**Table 1**).

*Assessment of Biocontrol Potential of Arbuscular Mycorrhizal (*Glomus *spp.)…*

treatment was monitored and estimated as mentioned above [16].

where *DS* = disease severity, *f* = infection class frequencies, *v* = number of plants

unit L−1 concentration). *Glomus*

of each class, *N* = total of observed plants, and *X* = highest value of the evalua-

Cucumber seeds were surface-sterilized using 0.2% NaCIO for 2 min and rinsed several times with distilled water. Arbuscular mycorrhizal (AM) fungi were obtained from the Iraqi Ministry of Sciences and Technology's laboratory. This mixture consists of propagated units of *Glomus clarum* (Nicol. Schenck) and *Glomus*

spp. were identified and separated in two tubes by the experts at Iraqi Ministry of Sciences and Technology's laboratory. Six healthy seeds of cucumber were planted in each pot (25 cm in diameter), which contained 3 kg of sterilized soil (clay:sand, 2:1, v/v) into each pot. For mycorrhizal inoculum, each pot was inoculated with dilution of 5 ml of either *Glomus clarum* or *G. mosseae*/L−1 water twice at the beginning of cultivation and after 14 days. As controls, the pots were provided with no AM + no pathogen, AM only, and pathogen only. For the pathogen inoculum, 5 ml of spore suspension (*R. solani*) was added at the beginning of cultivation. Six treatments were conducted as the following: *Glomus clarum*, *G. mosseae*, *G. clarum* + *R. solani*, *G. mosseae* + *R. solani*, control, and control + *R. solani*. Four replicates were made for each treatment. In this study, all plants did not receive any fertilizer and were watered when necessary at outdoor conditions. The disease severity for each

When the plants emerged above the soil surface, five plants were harvested from each treatment after 5, 10, 15, and 20 days. The plants were washed with tap water to clean off soil particles. Fresh and dry weights were evaluated and recorded after drying the samples by a hot air oven at 60°C for 48 h until gaining constant

Five pathogens were isolated form the infected plants and soil. The fungal identification was performed according to the morphological characteristic as previously reported in literatures [18, 19]. Among five isolated pathogens, *R. solani* showed the highest disease severity (*DS*) on cucumber plants, which was about 63%, while *Penicillium* spp. showed the lowest disease severity (*DS*), which was about 8% (**Figure 1**). Therefore, *R. solani* was the most aggressive pathogen due to the suitable environment condition, and the availability of susceptible hosts and

The effect of AM fungi against *R. solani* on cucumber plants was studied by the inoculation of cucumber plants with the AM, *G. mosseae* + *G. clarum*, which showed a significant reduction in the disease severity of damping-off compared with control (**Figure 2**). Disease severity (*DS*) of mycorrhizal plants was reduced by 46% and 41%, respectively. Furthermore, inoculated plants with mycorrhiza showed fewer symptoms compared with non-mycorrhizal plants. Disease severity in AM-inoculated plants with *G. mosseae* was about 20%, which was slightly less

The effect of AM fungi on the growth parameters of cucumber plants was assessed by shoot dry weight and root dry weight. AM fungi-colonized plants had significantly increased shoot and root dry weights when compared with the nonmycorrhizal plants (**Table 1**). Cucumber plants, colonized with AM (*G. mosseae*), showed a slight increase in all growth parameters compared with the plant colonized with AM (*G. clarum*), which matches with our results on the *DS* experiment

*DOI: http://dx.doi.org/10.5772/intechopen.93313*

*mosseae* (Nicol. Gerd) in a suspension form (1 × 106

tion scale.

weight [17].

**3. Results and discussion**

was used for all subsequent studies.

than AM-inoculated plants with *G. clarum* (**Figure 2**).

*Assessment of Biocontrol Potential of Arbuscular Mycorrhizal (*Glomus *spp.)… DOI: http://dx.doi.org/10.5772/intechopen.93313*

where *DS* = disease severity, *f* = infection class frequencies, *v* = number of plants of each class, *N* = total of observed plants, and *X* = highest value of the evaluation scale.

Cucumber seeds were surface-sterilized using 0.2% NaCIO for 2 min and rinsed several times with distilled water. Arbuscular mycorrhizal (AM) fungi were obtained from the Iraqi Ministry of Sciences and Technology's laboratory. This mixture consists of propagated units of *Glomus clarum* (Nicol. Schenck) and *Glomus mosseae* (Nicol. Gerd) in a suspension form (1 × 106 unit L−1 concentration). *Glomus* spp. were identified and separated in two tubes by the experts at Iraqi Ministry of Sciences and Technology's laboratory. Six healthy seeds of cucumber were planted in each pot (25 cm in diameter), which contained 3 kg of sterilized soil (clay:sand, 2:1, v/v) into each pot. For mycorrhizal inoculum, each pot was inoculated with dilution of 5 ml of either *Glomus clarum* or *G. mosseae*/L−1 water twice at the beginning of cultivation and after 14 days. As controls, the pots were provided with no AM + no pathogen, AM only, and pathogen only. For the pathogen inoculum, 5 ml of spore suspension (*R. solani*) was added at the beginning of cultivation. Six treatments were conducted as the following: *Glomus clarum*, *G. mosseae*, *G. clarum* + *R. solani*, *G. mosseae* + *R. solani*, control, and control + *R. solani*. Four replicates were made for each treatment. In this study, all plants did not receive any fertilizer and were watered when necessary at outdoor conditions. The disease severity for each treatment was monitored and estimated as mentioned above [16].

When the plants emerged above the soil surface, five plants were harvested from each treatment after 5, 10, 15, and 20 days. The plants were washed with tap water to clean off soil particles. Fresh and dry weights were evaluated and recorded after drying the samples by a hot air oven at 60°C for 48 h until gaining constant weight [17].

### **3. Results and discussion**

*Mycorrhizal Fungi - Utilization in Agriculture and Forestry*

safety [6].

(*Cucumis sativus* L.).

**2. Materials and methods**

using classification keys [12].

control *R. solani*; however, it causes serious risks including polluting the air, damaging the environment, building fungicides' resistance of pathogen, and harming the human health [4, 5]. Therefore, the biological control method becomes an important component of the disease management to increase crop production and food

The biological control becomes an important target of many researchers in the field of biological and agricultural sciences [5]. Biocontrol agents use different mechanisms of action against fungal pathogens, such as antimicrobial compound production activity, mycoparasitism or hyperparasitism, cell wall-lytic enzyme activity, and the application of systemic resistance (ISR) activity [7]. In addition, some biocontrol agents are capable of improving some aspects of plant growth, such as the germination rate, shoot and root weight, nutrients' uptake, and yield [8]. Arbuscular mycorrhizal (AM) fungi have been known to form a symbiotic relationship with around 80% of vascular plants. The symbiotic relationship can provide the plant with many benefits, including enhancement of plant growth and germination rates, increasing supplement of water and nutrients [9, 10]. In return, the AM fungi are completely dependable on the nutrients that are coming from the living root system [9]. In addition, AM fungi have been known to increase the host's resistance to a wide range of fungal and bacteria pathogens, especially rot pathogens [11]. The aim of this study was to examine the influence of different species of arbuscular mycorrhizal (AM) fungi (*Glomus* spp.) to promote systemic resistance against the disease agent of damping-off disease (*R. solani* Kühn) on cucumber

Infected samples were brought from cucumber plants with wilting, yellowing, and dwarfing symptoms from a field related to the College of agriculture, University of Al-Qadisiyah. The plants were washed with sterilized water to remove soil residues and were cut to small pieces. Then, the samples were sterilized with sodium hypochlorite (NaCIO) 1% for 2 min, washed with sterilized water twice, and dried with filter papers. Nine petri dishes of potato dextrose agar (PDA) were inoculated with five pieces of the infected plants and incubated for 3 days at 25°C. Soil samples were diluted for pathogen isolation and the petri dishes were incubated at 27°C. Both plant and soil samples were kept in a refrigerator at 4°C and diagnosed

Isolated pathogens were stored at 4°C prior to analysis and incubated at 25°C for 3 days. From the colony edge, four populated agar disks (7 mm) were cut and mixed in a 250 ml flask containing 100 ml of potato dextrose broth and 25 mg of chloramphenicol [13]. Sterilized soils were separated on each pot (3 kg) and inoculated with 1 ml from pathogen broth culture, and sterilized water was used for the control. Then, all pots were irrigated and covered for 3 days. Cucumber seeds were disinfected with sodium hypochlorite (NaCIO) 1% for 4 min and were planted in each pot. Germinated, not germinated seeds, and collapsed plants were recorded after 7 and 10 days for planting, and disease intensity was calculated as recommended [14]: 0 = no symptoms; 1 = seed rot, not germinated; 2 = brown rot on the stem base, plant is still standing; 3 = plant is wilted, laying on the ground; and 4 = plant is dead. *DS* was calculated from disease grades 0–3 using the following formula [15]:

∑ ∗ ( ) = × ∗ 100 *f v DS*

*N X* (1)

**70**

Five pathogens were isolated form the infected plants and soil. The fungal identification was performed according to the morphological characteristic as previously reported in literatures [18, 19]. Among five isolated pathogens, *R. solani* showed the highest disease severity (*DS*) on cucumber plants, which was about 63%, while *Penicillium* spp. showed the lowest disease severity (*DS*), which was about 8% (**Figure 1**). Therefore, *R. solani* was the most aggressive pathogen due to the suitable environment condition, and the availability of susceptible hosts and was used for all subsequent studies.

The effect of AM fungi against *R. solani* on cucumber plants was studied by the inoculation of cucumber plants with the AM, *G. mosseae* + *G. clarum*, which showed a significant reduction in the disease severity of damping-off compared with control (**Figure 2**). Disease severity (*DS*) of mycorrhizal plants was reduced by 46% and 41%, respectively. Furthermore, inoculated plants with mycorrhiza showed fewer symptoms compared with non-mycorrhizal plants. Disease severity in AM-inoculated plants with *G. mosseae* was about 20%, which was slightly less than AM-inoculated plants with *G. clarum* (**Figure 2**).

The effect of AM fungi on the growth parameters of cucumber plants was assessed by shoot dry weight and root dry weight. AM fungi-colonized plants had significantly increased shoot and root dry weights when compared with the nonmycorrhizal plants (**Table 1**). Cucumber plants, colonized with AM (*G. mosseae*), showed a slight increase in all growth parameters compared with the plant colonized with AM (*G. clarum*), which matches with our results on the *DS* experiment (**Table 1**).

#### **Figure 1.**

*Pathogenicity test for isolated pathogens against damping-off diseases on cucumber. Each column represents the mean of five replicates. Bars on the pillars represent standard error and LSD = 5.73 (P = 0.01).*

#### **Figure 2.**

*Evaluation of arbuscular mycorrhizal (AM) fungi on the disease severity of damping-off diseases on cucumber. Each column represents the mean of four replicates. Bars on the pillars represent standard error and LSD (P = 0.01).*

Mycorrhizal fungi are considered as ideal biocontrol agents due to some characteristics such as the ability to form a mutualistic symbiosis relationship with the roots of most vascular plant species [20]. Moreover, the plant-mycorrhiza relationship benefits the plant not only to control soil-borne pathogens but also to enhance the plant's resistance to various abiotic stresses and increases the nutrients' absorption [21].

In the present study, inoculated plant with mycorrhizal fungi reduces significantly the disease severity of *R. solani* pathogen, which may be attributed to increase the nutrients' status, reduce the direct competition for root space and resources with the pathogen, induce the plant's immunity to involve certain systemic mechanisms such as the systemic acquired resistance (SAR) and cell wall defenses, and enhance the production of defense compounds such as phenolics, -1,3-glucanase, and chitinolytic enzymes [9]. Additionally, inoculated plants with mycorrhizal fungi (*G. mosseae*) showed a lower disease severity than *G. clarum*, which may lead to a potential active control tool. Furthermore, the inoculation with mycorrhizal fungi increases both the root dry weight and shoot dry weight, which supports our hypothesis.

Mycorrhizal fungi play a main part in plant defense against pathogens and form a mutual relationship with plants. In summary, both mycorrhiza species could be

**73**

Iraq

**Author details**

**Acknowledgements**

**Table 1.**

Al-Qadisiyah, Iraq

Baker Diwan Getheeth Aljawasim1

provided the original work is properly cited.

and Mustafa A. Manshood1

\*, Hussein M. Khaeim2

1 Department of Plant Protection, College of Agriculture, Al-Muthanna University,

© 2020 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,

an important tool to control soil-borne pathogens, increase plant nutrient absorption, and increase resistance to abiotic stresses. In future research, specific systemic mechanisms of mycorrhiza fungi against pathogens should be investigated more.

**Treatment Shoot dry weight (g/plant) Root dry weight (g/plant)**

**15 days**

Control 0.5 0.8 0.9 1.1 0.2 0.4 0.7 0.9 Control **+** *R. solani* 0.1 0.3 0.4 0.5 0.08 0.1 0.2 0.3 *Glomus clarum* 0.4 0.6 0.7 1.2 0.15 0.3 0.6 0.8 *G. mosseae* 0.6 0.7 0.8 1.1 0.2 0.4 0.7 0.9 *G. clarum + R. solani* 0.3 0.5 0.6 0.9 0.15 0.2 0.5 0.6 *G. mosseae + R. solani* 0.4 0.6 0.8 1 0.2 0.3 0.6 0.7

**20 days**

**5 days**

**10 days**

**15 days**

**20 days**

The research was supported by University of Muthanna, Iraq. The authors acknowledge the Ministry of Sciences and Technology in Iraq for providing them with the isolates of arbuscular mycorrhizal (AM) fungi to complete their research.

2 Department of Soil Science and Water, College of Agriculture, University of

\*Address all correspondence to<EMAIL_ADDRESS>
*Assessment of Biocontrol Potential of Arbuscular Mycorrhizal (*Glomus *spp.)…*

**10 days**

*DOI: http://dx.doi.org/10.5772/intechopen.93313*

**5 days**

*Evaluation of AM fungi on the growth parameters of cucumber plants.*

*Assessment of Biocontrol Potential of Arbuscular Mycorrhizal (*Glomus *spp.)… DOI: http://dx.doi.org/10.5772/intechopen.93313*

**Table 1.**

*Mycorrhizal Fungi - Utilization in Agriculture and Forestry*

Mycorrhizal fungi are considered as ideal biocontrol agents due to some characteristics such as the ability to form a mutualistic symbiosis relationship with the roots of most vascular plant species [20]. Moreover, the plant-mycorrhiza relationship benefits the plant not only to control soil-borne pathogens but also to enhance the plant's resistance to various abiotic stresses and increases the nutrients' absorption [21]. In the present study, inoculated plant with mycorrhizal fungi reduces significantly the disease severity of *R. solani* pathogen, which may be attributed to increase the nutrients' status, reduce the direct competition for root space and resources with the pathogen, induce the plant's immunity to involve certain systemic mechanisms such as the systemic acquired resistance (SAR) and cell wall defenses, and enhance the production of defense compounds such as phenolics, -1,3-glucanase, and chitinolytic enzymes [9]. Additionally, inoculated plants with mycorrhizal fungi (*G. mosseae*) showed a lower disease severity than *G. clarum*, which may lead to a potential active control tool. Furthermore, the inoculation with mycorrhizal fungi increases both the root dry weight and shoot dry weight, which

*Evaluation of arbuscular mycorrhizal (AM) fungi on the disease severity of damping-off diseases on cucumber. Each column represents the mean of four replicates. Bars on the pillars represent standard error and LSD*

*Pathogenicity test for isolated pathogens against damping-off diseases on cucumber. Each column represents the*

*mean of five replicates. Bars on the pillars represent standard error and LSD = 5.73 (P = 0.01).*

Mycorrhizal fungi play a main part in plant defense against pathogens and form a mutual relationship with plants. In summary, both mycorrhiza species could be

**72**

**Figure 1.**

**Figure 2.**

*(P = 0.01).*

supports our hypothesis.

*Evaluation of AM fungi on the growth parameters of cucumber plants.*

an important tool to control soil-borne pathogens, increase plant nutrient absorption, and increase resistance to abiotic stresses. In future research, specific systemic mechanisms of mycorrhiza fungi against pathogens should be investigated more.