**Author details**

Naurú Idalia Vargas-Maya\* and Bernardo Franco

\*Address all correspondence to<EMAIL_ADDRESS>
Biology Department, Division of Natural and Exact Sciences. University of Guanajuato, México


**2.4. Distributed energy efficient clustering algorithm for heterogeneous wireless sensor networks**

(Qing et al, 2006) proposed a distributed energy efficient clustering scheme for heterogeneous wireless sensor networks, which is called DEEC. In DEEC, the cluster heads are elected by a probability based on the ratio between residual energy of each node and the average energy of the network. The epochs of being cluster heads for nodes are different according to their initial and residual energy.

316 Energy Efficiency – The Innovative Ways for Smart Energy, the Future Towards Modern Utilities

own data and transmits a new data packet to the next node in the chain.

the same procedure to bypass the dead node.

**Figure 3.** Token passing approach in PEGASIS

**2.3. A Stable Election Protocol (SEP)**

energy of each node assuring a uniform use of the nodes energy.

transmits the sensed data to BS.

of the first node.

**sensor networks**

In Fig.2, the algorithm starts with node 0 that connects to node 3. Then, node3 connects to node 1 and node 1 connects to node 2, which is the closest one to the base station ܤܵ. Because nodes already in the chain cannot be revisited, the neighbor distance will increase gradually. When a node dies (out of battery), the chain will be reconstructed by repeating

In one round of transmission, a randomized node is appointed to be the leader to transmit data to ܤܵ. If the ܤܵ locates outside the range of this node, multi-hop transmission will be employed. The leader will be changed randomly in every round, so that overall energy dissipation is balanced out. For transmitting a packet in each round, a token is used that passing from the one end of the chain to the other end of the chain. Only node that has a token can transmit a data packet to its intermediate node in the chain. When intermediate node receives data from one neighbor along with a token, it fuses the data packet with its

In fig.3, C0 will pass its data and token to C1. C1 fuses a data packet with its own data and pass a new data packet to the leader C2. C2 does not transmit a data packet to BS yet, but rather it passes a token to C4. When C2 receives a data from C4 and C3, it fuses and

A Stable Election Protocol (SEP) (G. Smaragdakis et al, 2004) is improved version of LEACH protocol. Main aim of it was used heterogeneous sensor in wireless sensor networks. This protocol have operation like LEACH but with this difference that, in SEP protocol sensors have two different level of energy. SEP based on weighted election probabilities of each node to become cluster head according to their respective energy. This approach ensures that the cluster head election is randomly selected and distributed based on the fraction of

In SEP, two types of nodes (normal and advanced) are considered. It is based on weighted election probabilities of each node to become cluster head according to the remaining energy in each node. This prolongs the stability period i.e. the time interval before the death

**2.4. Distributed energy efficient clustering algorithm for heterogeneous wireless**

(Qing et al, 2006) proposed a distributed energy efficient clustering scheme for heterogeneous wireless sensor networks, which is called DEEC. In DEEC, the cluster heads are elected by a The authors have assumed that all the nodes of the sensor network are equipped with different amount of energy, which is a source of heterogeneity. DEEC is also based on LEACH protocol, it rotates the cluster head role among all nodes to expend energy uniformity.

Two levels of heterogeneous nodes are considered in the algorithm and after that a general solution for multi-level heterogeneity is obtained. To avoid that each node needs to know the global knowledge of the networks, DEEC estimates the ideal value of network lifetime, which is used to compute the reference energy that each node should expend during a round. Simulation results show that DEEC achieves longer lifetime and more effective messages than LEACH, SEP and LEACH -E.

#### **2.5. Improved and balanced LEACH for heterogeneous wireless sensor networks**

(S. Ben alla et al. 2010) proposed Improved and Balanced LEACH (IB-LEACH), in which some high energy nodes elect themselves to be gateway at any given time with a certain probability. Base station confirms that whether those nodes suit to be gateway. These nodes broadcast their status to the other sensors in the network using advertisement message (ADV). The non -gateway nodes elect themselves to be cluster heads with a certain probability. These cluster head nodes broadcast their status to the other sensors in the network using advertisement message (ADV). The non-cluster head nodes wait the cluster head announcement from other nodes. Each sensor node determines to which cluster it wants to belong by choosing the cluster head that requires the minimum communication energy, and send the join -request (Join- REQ) message to the chosen cluster head, and the cluster head nodes wait for join-request message from other nodes.

Each cluster head collect and aggregate the data of their cluster members and transmit it to the chosen gateways that requires the minimum communication energy to reduce the energy consumption of cluster head and decrease probability of failure nodes. Simulation results show that this protocol performs better than LEACH and SEP in terms of network lifetime.

#### **2.6. Cluster head relay routing protocol for heterogeneous sensor networks**

(Du & Lin, 2005) proposed a cluster head relay (CHR) routing protocol for heterogeneous sensor networks. This protocol uses two types of sensors to form a heterogeneous network with a single sink: a large number of low-end sensors, denoted by L-sensors, and a small number of powerful high-end sensors, denoted by H-sensors. Both types of sensors are static and aware of their locations using some location service. Moreover, both L-sensor and H-sensors are uniformly and randomly distributed in the sensor field.

The CHR protocol partitions the heterogeneous network into clusters, each being composed of L-sensors and led by an H-sensor. Within a cluster, the L-sensors are in charge of sensing the underlying environment and forwarding data packets originated by other L-sensors toward their cluster head in a multi-hop transmission. The H-sensors, on the other hand, are responsible for data fusion within their own clusters and forwarding aggregated data packets originated from other cluster heads toward the sink in a multi-hop transmission using only cluster heads. While L-sensors use short-range data transmission to their neighboring H -sensors within the same cluster, H-sensors perform long-range data communication to other neighboring H-sensors and the sink. Simulation results demonstrate that CHR performs better than directed diffusion and SWR.

Hierarchical Adaptive Balanced Routing Protocol

for Energy Efficiency in Heterogeneous Wireless Sensor Networks 319

**Computational heterogeneity** means that the heterogeneous node has a more powerful microprocessor and more memory than the normal node. With the powerful computational resources, the heterogeneous nodes can provide complex data processing and longer-term

**Link heterogeneity** means that the heterogeneous node has high bandwidth and longdistance network transceiver than the normal node. Link heterogeneity can provide a more

**Energy heterogeneity** means that the heterogeneous node is line powered or its battery is

Among above three types of resource heterogeneity, the most important resource heterogeneity is the energy heterogeneity because both computational heterogeneity and

If there is no energy heterogeneity, computational heterogeneity and link heterogeneity will bring negative impact to the whole sensor network, i.e ., decreasing the network lifetime.

**Decreasing latency of data transportation**: Computational heterogeneity can decrease the processing latency in immediate nodes and link heterogeneity can decrease the waiting time in the transmitting queue. Fewer hops between sensor nodes and sink node also mean fewer

**Prolonging network lifetime**: The average energy consumption for forwarding a packet from the normal nodes to the sink in heterogeneous sensor networks will be much less than

**Improving reliability of data transmission**: It is well known that sensor network links tend

With heterogeneous nodes, there will be fewer hops between normal sensor nodes and the sink. So the heterogeneous sensor network can get much higher end-to-end delivery rate

Some performance measures that are used to evaluate the performance of clustering

**Network lifetime (stability period):** It is the time interval from the start of operation (of the

**Number of cluster heads per round**: Instantaneous measure reflects the number of nodes which would send directly to the base station, information aggregated from their cluster

to have low reliability and each hop significantly lowers the end-to-end delivery rate.

Placing few heterogeneous nodes in the sensor network can bring following benefits:

storage.

replaceable.

forwarding latency.

reliable data transmission.

link heterogeneity will consume more energy resource.

the energy consumed in homogeneous sensor networks.

protocols are listed below(R. Sheikhpour et al., 2011).

sensor network) until the death of the first alive node.

than the homogeneous sensor network.

**3.3. Performance measures**

members.

**3.2. Impact of heterogeneity on wireless sensor networks**


**4.2 Bifurcation lesion techniques**

Bifurcation of lesions in general is one of the most technically complex coronary interventions. Multiple classifications for bifurcation coronary lesions are available. The most common one is Medina classification which has three digits depending on true lesion involvement of vessels around bifurcation.

#### *Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

Engaging challenges: after selecting appropriate guide shape, engaging severe lesions most likely would cause dampening, possibly ischemia, dangerous arrhythmias, and subsequent hemodynamic effect. To avoid these issues or in cases with challenging coronary take offs, operators can use one or more of the

*Cardiac Diseases - Novel Aspects of Cardiac Risk, Cardiorenal Pathology and Cardiac Interventions*

Using a GC with side holes. Again, side holes can cause a false sense of

Quick engagement and wiring followed by disengagement to minimize

Calcified ostial lesions that requires adjunct plaque modification such as atherectomy carries risk of causing aortic dissections. This can occur with simple angioplasty. The inflations time while performing angioplasty or stenting should be short as these vessels might be the only perfusion source of

inside the ascending aorta. A lot of operators recommend flaring the

protruding part with large balloon and high pressure to make the stent take the shape of the internal aorta. This step is important especially when future interventions are anticipated. Without this step, future engagement of the stent and PCI becomes a very difficult mission and almost impossible. There are special designed balloons that can help with achieving this step. A catheter with two balloons, two inflating ports, and three markers that identify the edges of the two balloons. Operators should use caution while using these double balloons as inflating proximal balloon inside the vessel can cause vessel injury. Sbazo technique is a unique technique where another wire is passed through the proximal stent cell and while advancing the stent the wire stops the advancement while assuring covering the ostium. The same technique can be used at a bifurcation ostium lesion while avoiding jailing the

Bifurcation of lesions in general is one of the most technically complex coronary interventions. Multiple classifications for bifurcation coronary lesions are available. The most common one is Medina classification which has three digits depending on

Missing the target: as operators try to match the proximal end of the stent to the ostium, it is not uncommon to miss the target ostial lesions. Locating the ostium is challenging and appropriate imaging views are critical here. To assure best view of ostial lesion, orthogonal views should be used. For ostial left main, superficial LAO/cranial and for RCA steep RAO and even lateral views are required depending on its origin. It is essential to know where the stent ends in regard to its radiopaque markers in order not to miss the ostium as some stents ends at the distant end of the radiopaque marker and others at the proximal end of the marker. In order to achieve good lesion coverage, stents are deployed to protrude couple of millimeters out of the coronary and

Phishing technique: it involves having the tip of the guide few millimeters close to the ostium without engagement then attempting to wire the coronary. If the ostium lumen can accommodate a micro catheter, then micro catheter can be used to approach the ostium with long wire to facilitate wiring the coronary. Steerable micro catheters are the most helpful when using this technique. Using a small 4 or 5Fr diagnostic catheter to engage and wire the coronary with a long wire then exchange with the appropriate guide catheter over the long

following techniques:

assurance.

ischemia.

wire.

the heart.

branch vessel.

**232**

**4.2 Bifurcation lesion techniques**

true lesion involvement of vessels around bifurcation.

In order to make bifurcation stenting simpler, the first decision is to decide whether the single-stent (provisional stenting) or the two-stent approach is the appropriate technique. There are significant data comparing provisional stenting to other two stent techniques. Both are acceptable techniques with good outcome and the decision to choose one is related to several factors.

Several techniques are used for bifurcation lesions. Deciding the best technique to use depends on multiple factors: medina classification, the angle between main and branch vessels, size difference of main and branch vessels, difficulty to rewire the sent struts, expected plaques shifting/angle changes post stenting and need for branch stenting distal to the bifurcation lesion, size and territory size of branch vessel and presence of trifurcation or proximal lesion.

Proximal optimization technique POT is an important step while performing any PCI and especially in the setting of bifurcation stenting. It refers to performing angioplasty inside the proximal segment of the stent/stents (making sure the distal end of the balloon at the level of side branch) to make sure proximal stent are well apposed and dilated to match the proximal vessel size. Injecting contrast while the balloon is inflated can help assuring well stent apposition when no contrast leak to distal vessel. POT allows safe rewiring and further intervention of the SB when required. It is important to perform POT at the right level, repeat it or perform kissing balloons if the SB was ballooned to optimize any possible distortion of the stent and to remove the SB wire before repeating POT or performing kissing balloons to avoid wire trapping complications.

Final kissing balloon is recommended in all two stents techniques. Kissing balloons goal is to optimize the bifurcation carina and lumens of both vessel at this level without compromise one of the bifurcation lumens.

IVUS-assisted bifurcation stenting has better outcome especially in distal left main bifurcation lesion. Because fluoroscopy angiogram provides only twodimensional images, intravascular imaging with IVUS and/or OCT can be very helpful to understand the morphology of bifurcation stenosis if performed before and after to evaluate the results and need for further intervention.

For any bifurcation lesion, protecting both vessels, branch vessel (side branch SB) and main vessel (MV) by wiring them is recommended especially when branch vessel is 2 mm and larger in diameter. Even in Medina 0.1.0 lesions, wiring both vessel for protection is recommended. Acute vessel closure of large branch could occur when least expected especially in the setting of small bifurcation angle.

It is very important to pre-determine the best views that allow the operator to evaluate the bifurcations accurately and assess the changes in both branches and main vessel at the same time with each step. Orthogonal views are important during all steps.

There is no available guide catheter that allows simultaneous three balloon inflations or stent deployments. There are techniques that use two guide catheters one 7Fr and the other 6 or Fr to treat trifurcation lesion with the risk of inducing ischemia by completely obstructing the coronary ostium.

Bifurcation lesions that carry the highest risk are true bifurcation lesions Medina 1.1.1 of distal left main involving ostial LAD and LCX. Unprotected left main is referred to any left main with no bypass to the LAD or LCX. It is important to recognize that intervention on unprotected left main carries a higher risk especially in the setting of left dominant system. Although recent emerging data suggest a similar outcome comparing PCI to CABG in such lesions even in diabetic patients, CABG still has the best data [11–13]. Discussion of the data is beyond this chapter. However, a simple decision-making approach is that the more complex anatomy, the more benefit CABG can provide especially in diabetic patients with low left ventricular ejection fractions [14]. It is important to recognize that diabetic patients have higher risk of restenosis and tend to have smaller vessels' lumen due to diffuse

the bifurcation. The second lumen can be used to wire the branch safely within the stent and provide support in challenging SB rewiring cases. However, this technique

When SB stenting is required, reverse crush, T-stenting, TAP or Culottes tech-

After wiring both the main vessel and its branch. A stent sized to the SB is placed into the branch vessel. To assure complete coverage of the lesion, part of the stent protrudes insides the MV. As the goal is to cover the whole bifurcation, the length of the protruding segment of stent correlates with the angulation angle. The smaller the angle the longer this protruding segment inside the MV. If the SB is taking off at 80° then theoretically, no part of stent should be protruding inside the MV. After SB stenting, a balloon loaded on the wire of the MV is used to crush the protruding segment of stent followed by stenting of the MV. The goal of mini crush that protruding segment of the stent would not jail the SB completely so if post stenting intra vascular imaging is performed, the distal part of the SB takeoff lumen will have two layers of stent, the protruding crushed segment of the SB stent and the MV stent while the proximal part will have only the MV stent. Rewiring the branch through the main stent struts and performing kissing balloon creating new carina is recommended. The lesion under the carina will have two layers of stents. If the segment of stent protruding inside the MV is long enough that when it is crushed by angioplasty/stenting the MV, the technique turns to crush stenting technique.

After wiring both vessels, loading a balloon on the MV wire, stenting the SB with significant part of stent protruding inside the MV is performed. The MV balloon then used to crush the protruding segment of the SB stent jailing the lumen of the branch completely with two layers of stents. Stenting of MV is then performed jailing the SB with additional layer of stent struts. Before that the SB wire is withdrawn to avoid wire trapping complications. Now, the SB is covered with three layers of stent struts which most likely will affect the flow of the SB. Thus, rewiring across these layers of stents is required and used to perform angioplasty to dilate the

It is similar to the crush technique but in reverse sequences. After wiring both vessels, the MV is stented then the SB is rewired across the MV stent struts which maybe challenging especially in the setting of true SB severe stenosis, and rewiring becomes more difficult with plaque shifting/angulation angle changes after stenting

completely inside the MV is deployed. At this point, depending on the angiographic

It is the most complicated technique but has a good supportive data. After wiring both vessels. The vessel with the hardest to rewire is stented first. Then alternating

the MV. A balloon angioplasty followed by stent that protrude partially or

results and the covering of diseased, the operator might crush the SB stent performing angioplasty inside the MV stent (followed by the rest of crush technique) or perform kissing balloon leaving segment of the protruding stent hanging

requires long wire (or extension wires) to make exchanges.

niques could be used.

*4.2.2 Mini crush technique*

*Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

*4.2.3 Crush stenting technique*

*4.2.4 Reverse crush technique*

in the lumen of the MV.

**235**

*4.2.5 Culottes' bifurcation stenting*

stent struts followed by performing kissing balloons.

disease which in turn increases the need for vessel revascularization due to more hemodynamically significant restenosis. The same percentage of stenosis could be tolerated better with less hemodynamic effect in larger non-diabetic vessels. If a patient is not a candidate for CABG, a hemodynamic support device should be considered depending on the severity of stenosis, calcification, the need for atherectomy or other lesion modification techniques, presence of aortic valve stenosis, and LV function. Even with normal LV function, operator should consider mechanical support with severe calcified lesions with high risk of acute vessel closure, low LVEF, prolonged ischemia or complication. Simultaneous kissing stents to minimize ischemia time is a good option especially in Medina 0.1.1 lesions. **Figure 4** shows a simple decision-making approach for bifurcation stenting.

#### *4.2.1 Provisional stenting*

Stenting from main vessel to main vessel or branch depends on size differences, angulation of the SB, and the easier vessel to rewire after jailing it in case further intervention is needed.

When the size difference is less between the SB and proximal MV compared to difference between distal lesion of MV and proximal vessel, then stenting from main vessel to the SB is a good option, otherwise, stenting from proximal to distal MV is most common especially in LAD bifurcation lesions. Stenting to SB like from proximal LCX to branch obtuse marginal is more common than stenting from proximal to distal LCX. Evaluating the SB flow is very important to make a decision whether it requires angioplasty or stenting. Before judging the branch flow, it is recommended to administer intracoronary nitroglycerin.

As long as SB has normal flow and is not at risk of closure, no further intervention is required. If SB flow is impaired, performing angioplasty of stent struts the next step. If the results of angioplasty weren't successful to improve the flow, or caused SB injury, stenting becomes required. For the same reason SB with normal flow or small lumen <2 mm should not be rewired unless poor flow is present as rewiring with or without angioplasty might cause more complications than benefits. When attempting to rewire the jailed SB through stent struts, there is always a concern of wiring under the stent or not able to wire the SB especially when POT is not performed. To avoid that, the MV wire can be used to rewire the SB as long as the operator does not withdraw the wire beyond the proximal edge of the stent. In this way, the operator can be assured that the wire is inside the stent. Another approach is to reverse wire the SB by wiring the MV stent with J tip wire and then the wire is withdrawn to the origin of SB. Lastly, a special twin pass micro-catheter loaded on the MV wire and passed till

**Figure 4.** *A simple decision-making approach for bifurcation stenting.*

#### *Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

the bifurcation. The second lumen can be used to wire the branch safely within the stent and provide support in challenging SB rewiring cases. However, this technique requires long wire (or extension wires) to make exchanges.

When SB stenting is required, reverse crush, T-stenting, TAP or Culottes techniques could be used.

## *4.2.2 Mini crush technique*

disease which in turn increases the need for vessel revascularization due to more hemodynamically significant restenosis. The same percentage of stenosis could be tolerated better with less hemodynamic effect in larger non-diabetic vessels. If a patient is not a candidate for CABG, a hemodynamic support device should be considered depending on the severity of stenosis, calcification, the need for atherectomy or other lesion modification techniques, presence of aortic valve stenosis, and LV function. Even with normal LV function, operator should consider mechanical support with severe calcified lesions with high risk of acute vessel closure, low LVEF, prolonged ischemia or complication. Simultaneous kissing stents to minimize ischemia time is a good option especially in Medina 0.1.1 lesions. **Figure 4** shows a simple decision-making approach for bifurcation stenting.

*Cardiac Diseases - Novel Aspects of Cardiac Risk, Cardiorenal Pathology and Cardiac Interventions*

Stenting from main vessel to main vessel or branch depends on size differences, angulation of the SB, and the easier vessel to rewire after jailing it in case further

When the size difference is less between the SB and proximal MV compared to difference between distal lesion of MV and proximal vessel, then stenting from main vessel to the SB is a good option, otherwise, stenting from proximal to distal MV is most common especially in LAD bifurcation lesions. Stenting to SB like from proximal LCX to branch obtuse marginal is more common than stenting from proximal to distal LCX. Evaluating the SB flow is very important to make a decision whether it requires angioplasty or stenting. Before judging the branch flow, it is

As long as SB has normal flow and is not at risk of closure, no further intervention is required. If SB flow is impaired, performing angioplasty of stent struts the next step. If the results of angioplasty weren't successful to improve the flow, or caused SB injury, stenting becomes required. For the same reason SB with normal flow or small lumen <2 mm should not be rewired unless poor flow is present as rewiring with or without angioplasty might cause more complications than benefits. When attempting to rewire the jailed SB through stent struts, there is always a concern of wiring under the stent or not able to wire the SB especially when POT is not performed. To avoid that, the MV wire can be used to rewire the SB as long as the operator does not withdraw the wire beyond the proximal edge of the stent. In this way, the operator can be assured that the wire is inside the stent. Another approach is to reverse wire the SB by wiring the MV stent with J tip wire and then the wire is withdrawn to the origin of SB. Lastly, a special twin pass micro-catheter loaded on the MV wire and passed till

recommended to administer intracoronary nitroglycerin.

*4.2.1 Provisional stenting*

intervention is needed.

**Figure 4.**

**234**

*A simple decision-making approach for bifurcation stenting.*

After wiring both the main vessel and its branch. A stent sized to the SB is placed into the branch vessel. To assure complete coverage of the lesion, part of the stent protrudes insides the MV. As the goal is to cover the whole bifurcation, the length of the protruding segment of stent correlates with the angulation angle. The smaller the angle the longer this protruding segment inside the MV. If the SB is taking off at 80° then theoretically, no part of stent should be protruding inside the MV. After SB stenting, a balloon loaded on the wire of the MV is used to crush the protruding segment of stent followed by stenting of the MV. The goal of mini crush that protruding segment of the stent would not jail the SB completely so if post stenting intra vascular imaging is performed, the distal part of the SB takeoff lumen will have two layers of stent, the protruding crushed segment of the SB stent and the MV stent while the proximal part will have only the MV stent. Rewiring the branch through the main stent struts and performing kissing balloon creating new carina is recommended. The lesion under the carina will have two layers of stents. If the segment of stent protruding inside the MV is long enough that when it is crushed by angioplasty/stenting the MV, the technique turns to crush stenting technique.

### *4.2.3 Crush stenting technique*

After wiring both vessels, loading a balloon on the MV wire, stenting the SB with significant part of stent protruding inside the MV is performed. The MV balloon then used to crush the protruding segment of the SB stent jailing the lumen of the branch completely with two layers of stents. Stenting of MV is then performed jailing the SB with additional layer of stent struts. Before that the SB wire is withdrawn to avoid wire trapping complications. Now, the SB is covered with three layers of stent struts which most likely will affect the flow of the SB. Thus, rewiring across these layers of stents is required and used to perform angioplasty to dilate the stent struts followed by performing kissing balloons.

#### *4.2.4 Reverse crush technique*

It is similar to the crush technique but in reverse sequences. After wiring both vessels, the MV is stented then the SB is rewired across the MV stent struts which maybe challenging especially in the setting of true SB severe stenosis, and rewiring becomes more difficult with plaque shifting/angulation angle changes after stenting the MV. A balloon angioplasty followed by stent that protrude partially or completely inside the MV is deployed. At this point, depending on the angiographic results and the covering of diseased, the operator might crush the SB stent performing angioplasty inside the MV stent (followed by the rest of crush technique) or perform kissing balloon leaving segment of the protruding stent hanging in the lumen of the MV.

#### *4.2.5 Culottes' bifurcation stenting*

It is the most complicated technique but has a good supportive data. After wiring both vessels. The vessel with the hardest to rewire is stented first. Then alternating

applied after the MV stent has been deployed and kissing balloon inflation has been performed. In particular, TAP stenting was developed to ensure full SB ostium coverage by DES struts. To achieve this, the SB stent is delivered with intentional minimal protrusion inside the MV with an uninflated balloon positioned in the MV across the SB take-off. After SB stent deployment, kissing balloons inflation is immediately performed with the stent's balloon and the MV balloon. Further kissing balloon inflations with noncompliant balloons may be advisable in the case of suboptimal stent expansion. During the practice of TAP stenting, the operator should pay attention to and try to limit as much as possible the protrusion inside the MV which influences the length of the neo-carina. Nevertheless, similar to crush techniques, two main determinants of neo-carina length should be recognized: the SB take-off angle and the "quality" of pre-TAP kissing inflation. The impact of the SB take-off angle is quite intuitive: when the SB has a "T" shape take-off, small or absent SB stent protrusion inside the MV is needed to cover the SB ostium successfully. On the other hand, acute SB angles (Y-shapes) are associated with longer, oval-shaped SB ostia. Such an anatomic configuration implies the need for wider protrusion of the SB stent inside the MV, resulting in a longer neo-carina.

Engaging, performing angiogram and interventions on RIMA/LIMA carries higher risk for multiple reasons. LIMA is a vessel with high risk for dissection during any instrumentation. Most patients that requires LIMA interventions have significant underlying native vessel a baseline with possible occlusion of other bypass grafts. In a lot of clinical scenarios, LIMA could be the only source of

Grafts/LIMA interventions could be performed via any approach. Left radial or distal left radial has the advantage of avoiding complications of femoral approaches and avoid left subclavian issues. Most common LIMA interventions are related to anastomosis at the LAD, left subclavian pseud or true stenosis, and ostial lesions at the takeoff from left subclavian. Lesions in the body of LIMA are less common. When using femoral approach, a lot of operators prefer to use a short LIMA guide which allows for more wire to reach distally to distal LAD after the anastomosis. Short GC usually is not required when using left radial approaches and if needed,

Distal anastomosis interventions: in early post-operative days, grafts angiogram (especially arterial grafts LIMA, RIMA, radial) might appear concerning for a dissection or spasm and this could be related to the post-operative shock or vasoactive medication. Most of the times, graft has not yet matured, and later imaging would confirm that. Stenosis at the anastomosis is mostly related to operative technical issues during post-operative period vs. true progression of CAD during the months or years after. Intervention if truly indicated should be performed quickly but safely specially in fresh LIMA-LAD anastomosis. Operator should minimize occluding the target grafts with the guide catheter as much as safely possible. Direct stenting is a good option if a stent could be passed without ballooning. Fresh anastomosis and sutures might be frail and over inflation of the balloon or stent should be avoided. Stent is sized based on the size of the bypassed vessel. One of the challenges in SVG anastomosis interventions is sizing the stent. It is very common that SVG is much larger than the target bypassed vessel. Proximal optimization technique using balloon diameter sized to SVG to dilate the segment of stent inside SVG. Data suggests good outcome post PCI of LIMA-LAD if performed by experience operator. Proximal optimization technique to the size of the LIMA has a lower risk especially in

shortening the guide catheter is a technique that can be used.

**4.3 Grafts interventions**

*Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

perfusion for the heart.

early days post bypass.

**237**

wires positions to wire the SB through stent struts followed by performing angioplasty to dilate struts to the nonstented vessel. This step might require several balloons' angioplasty with escalating sizes. Then, stenting the SB jailing the first stented vessel. Again, here alternating wire positions are performed followed by final kissing balloon. The advantage of this technique is complete coverage of the lesions with stents. However, double coverage of proximal MV with two layers of stents and new carina have been controversial and suspected to increase risk of thrombosis. Most recent evidence suggests no difference between this technique and other two stents techniques in terms of stent thrombosis. Culottes' technique is best used when the branched vessels are close in diameter to the MV to avoid stent size mismatch and the angulation angle is acute below 70°.

#### *4.2.6 V stenting*

This technique is best used in bifurcation lesion Medina class 0.1.1 where the proximal MV is not involved or when the lesion is barely involving the proximal MV. After wiring both vessels, angioplasty of both vessels might be required regardless to pass stents followed by simultaneous kissing stenting. Stenting is step wise fashion with deploying one stent at time is feasible using 6F GC as long as it is followed by kissing balloons. Otherwise, performing kissing stent requires 7F GC.

#### *4.2.7 Double barrel kissing stents technique*

As in the case of V stenting, this technique requires 7F GC. It can be quick minimizing ischemia time and thus useful for large left main vessel with bifurcation disease involving LAD and LCX. After wiring both vessels, simultaneous stenting is performed creating double barrel in the proximal MV. Clearly, the stents in the proximal MV are not fully deployed and they are crushed against each other and the relationship between these barrels are not as simple it might appear. They are mostly twisted around each other and the size difference might affect the morphology of each stent within that part, i.e., one stent could be circle, the other is D shaped where in perfect scenario they both should have D shaped appearance with full apposition against the vessel. Clearly, re-accessing can be very challenging, which makes this technique less suitable for small vessel bifurcation lesions and for patients with expected need for further revascularization.

#### *4.2.8 T-stenting technique*

Bifurcation lesions that are appropriate for T stenting are lesions where the angulation angle is between 70 and 90°. The steps include wiring both vessels, performing necessary pre ballooning if needed, and then stenting the SB followed by stenting MV jailing the SB stent. A helpful technique to assure full coverage of bifurcation lesion is to leave inflated balloon inside the MV first then pulling he stent of the SB till it faces the resistance from the inflated MV balloon and then deflating that balloon followed by deploying the SB stent and finally stenting the MV. Depending on the results, rewiring through the MV stent struts might be necessary, followed by performing kissing balloons. When the angulation angle is less than 70, this approach is called TAP.

#### *4.2.9 T-stenting and small protrusion technique TAP*

It is a modification of the T-stenting technique aimed at optimizing "bail-out" SB stent implantation after MV treated by the "provisional" approach. Thus, it is

#### *Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

wires positions to wire the SB through stent struts followed by performing angioplasty to dilate struts to the nonstented vessel. This step might require several balloons' angioplasty with escalating sizes. Then, stenting the SB jailing the first stented vessel. Again, here alternating wire positions are performed followed by final kissing balloon. The advantage of this technique is complete coverage of the lesions with stents. However, double coverage of proximal MV with two layers of stents and new carina have been controversial and suspected to increase risk of thrombosis. Most recent evidence suggests no difference between this technique and other two stents techniques in terms of stent thrombosis. Culottes' technique is best used when the branched vessels are close in diameter to the MV to avoid stent

*Cardiac Diseases - Novel Aspects of Cardiac Risk, Cardiorenal Pathology and Cardiac Interventions*

This technique is best used in bifurcation lesion Medina class 0.1.1 where the proximal MV is not involved or when the lesion is barely involving the proximal MV. After wiring both vessels, angioplasty of both vessels might be required regardless to pass stents followed by simultaneous kissing stenting. Stenting is step wise fashion with deploying one stent at time is feasible using 6F GC as long as it is followed by kissing balloons. Otherwise, performing kissing stent requires 7F GC.

As in the case of V stenting, this technique requires 7F GC. It can be quick minimizing ischemia time and thus useful for large left main vessel with bifurcation disease involving LAD and LCX. After wiring both vessels, simultaneous stenting is performed creating double barrel in the proximal MV. Clearly, the stents in the proximal MV are not fully deployed and they are crushed against each other and the relationship between these barrels are not as simple it might appear. They are mostly twisted around each other and the size difference might affect the morphology of each stent within that part, i.e., one stent could be circle, the other is D shaped where in perfect scenario they both should have D shaped appearance with full apposition against the vessel. Clearly, re-accessing can be very challenging, which makes this technique less suitable for small vessel bifurcation lesions and for

Bifurcation lesions that are appropriate for T stenting are lesions where the angulation angle is between 70 and 90°. The steps include wiring both vessels, performing necessary pre ballooning if needed, and then stenting the SB followed by stenting MV jailing the SB stent. A helpful technique to assure full coverage of bifurcation lesion is to leave inflated balloon inside the MV first then pulling he stent of the SB till it faces the resistance from the inflated MV balloon and then deflating that balloon followed by deploying the SB stent and finally stenting the MV. Depending on the results, rewiring through the MV stent struts might be necessary, followed by performing kissing balloons. When the angulation angle is

It is a modification of the T-stenting technique aimed at optimizing "bail-out" SB stent implantation after MV treated by the "provisional" approach. Thus, it is

size mismatch and the angulation angle is acute below 70°.

patients with expected need for further revascularization.

*4.2.7 Double barrel kissing stents technique*

*4.2.8 T-stenting technique*

**236**

less than 70, this approach is called TAP.

*4.2.9 T-stenting and small protrusion technique TAP*

*4.2.6 V stenting*

applied after the MV stent has been deployed and kissing balloon inflation has been performed. In particular, TAP stenting was developed to ensure full SB ostium coverage by DES struts. To achieve this, the SB stent is delivered with intentional minimal protrusion inside the MV with an uninflated balloon positioned in the MV across the SB take-off. After SB stent deployment, kissing balloons inflation is immediately performed with the stent's balloon and the MV balloon. Further kissing balloon inflations with noncompliant balloons may be advisable in the case of suboptimal stent expansion. During the practice of TAP stenting, the operator should pay attention to and try to limit as much as possible the protrusion inside the MV which influences the length of the neo-carina. Nevertheless, similar to crush techniques, two main determinants of neo-carina length should be recognized: the SB take-off angle and the "quality" of pre-TAP kissing inflation. The impact of the SB take-off angle is quite intuitive: when the SB has a "T" shape take-off, small or absent SB stent protrusion inside the MV is needed to cover the SB ostium successfully. On the other hand, acute SB angles (Y-shapes) are associated with longer, oval-shaped SB ostia. Such an anatomic configuration implies the need for wider protrusion of the SB stent inside the MV, resulting in a longer neo-carina.

### **4.3 Grafts interventions**

Engaging, performing angiogram and interventions on RIMA/LIMA carries higher risk for multiple reasons. LIMA is a vessel with high risk for dissection during any instrumentation. Most patients that requires LIMA interventions have significant underlying native vessel a baseline with possible occlusion of other bypass grafts. In a lot of clinical scenarios, LIMA could be the only source of perfusion for the heart.

Grafts/LIMA interventions could be performed via any approach. Left radial or distal left radial has the advantage of avoiding complications of femoral approaches and avoid left subclavian issues. Most common LIMA interventions are related to anastomosis at the LAD, left subclavian pseud or true stenosis, and ostial lesions at the takeoff from left subclavian. Lesions in the body of LIMA are less common. When using femoral approach, a lot of operators prefer to use a short LIMA guide which allows for more wire to reach distally to distal LAD after the anastomosis. Short GC usually is not required when using left radial approaches and if needed, shortening the guide catheter is a technique that can be used.

Distal anastomosis interventions: in early post-operative days, grafts angiogram (especially arterial grafts LIMA, RIMA, radial) might appear concerning for a dissection or spasm and this could be related to the post-operative shock or vasoactive medication. Most of the times, graft has not yet matured, and later imaging would confirm that. Stenosis at the anastomosis is mostly related to operative technical issues during post-operative period vs. true progression of CAD during the months or years after. Intervention if truly indicated should be performed quickly but safely specially in fresh LIMA-LAD anastomosis. Operator should minimize occluding the target grafts with the guide catheter as much as safely possible. Direct stenting is a good option if a stent could be passed without ballooning. Fresh anastomosis and sutures might be frail and over inflation of the balloon or stent should be avoided. Stent is sized based on the size of the bypassed vessel. One of the challenges in SVG anastomosis interventions is sizing the stent. It is very common that SVG is much larger than the target bypassed vessel. Proximal optimization technique using balloon diameter sized to SVG to dilate the segment of stent inside SVG. Data suggests good outcome post PCI of LIMA-LAD if performed by experience operator. Proximal optimization technique to the size of the LIMA has a lower risk especially in early days post bypass.

second layer of stent depends on the results of angioplasty, size of the vessel, and long-term outcome. If the mechanism of restenosis is under expanded stent, fibrotic tissue, calcifications underneath the stent or hyper intimal hyperplasia, the treatment is targeting the underlying tissue. Available treatment options are those used for adjunct plaque modifications (brachytherapy, LASER, and intravascular lithotripsy).

Supra-annular valves like CoreValve bio prosthetic makes coronary access challenging. The goal is to a use a guide catheter to cross the cells of the bio prosthetic valve at the level of the coronary. Best approach is to use a 0.5 shorter guide catheter than usually used. Wire assisted technique to manipulate the GC to sit within the bio prosthetic and at the appropriate cell level to cross toward the coronary ostium. Manipulating the GC with a 0.035″ guide wire should be performed within the lumen of the aorta and away from the aortic wall to avoid aortic or coronary ostium injury. Guide wire makes the GC stiff and moving the GC quickly could cause the GC to jump quickly and damage the coronary ostium. Once the GC is in a good trajectory and directed toward the coronary ostium, GC should be advanced slowly

Percutaneous coronary interventions have always been crucial in medical care. Now more than ever, with rapidly evolving percutaneous interventions and less surgical interventions, coronary percutaneous interventions are priority. Developing required technical skills and mastering basic and complicated intervention techniques have never been as important as they are now. Before proceeding with any intervention, all necessary equipment and medications should be available. Other essential requirements for any successful intervention include planning, having competency in required techniques, early recognition, and being prepared to

Medicine (Interventional Cardiology), VA Medical Center, Indiana 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,

**4.5 Post aortic valve replacement coronary intervention**

*Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

toward the ostium.

manage complications.

**Conflict of interest**

**Author details**

Imran Khalil

**239**

The author declares no conflict of interest.

School of Medicine, Indianapolis, Indiana

provided the original work is properly cited.

\*Address all correspondence to<EMAIL_ADDRESS>
**5. Conclusion**

SVG are prone to thrombosis. Microvascular thrombosis can lead to bad outcomes. Using distal embolic protection (**Table 15**) in cardiac vessels interventions has showed benefits in interventions on SVGs especially with thrombotic lesions. The goal of distal embolic protection is to minimize/stop any thrombi from traveling distally to microvasculature. These devices cannot be used for all SVGs interventions. Distally to the target lesion, vessel should have about 4 cm safe landing segment where the device can be deployed. Severe stenotic lesions (especially aortoostial lesions) make using distal embolic protection technically challenging or impossible. Some operators advocate in such cases with difficulty passing the embolic protection device is to perform direct stenting if it allows. Fibrotic lesions (instent restenosis) with no friable thrombotic material, might not benefit from embolic protection. Direct stenting is another approach to minimize distal embolization and microvascular obstruction when feasible. Aneurysmal changes in SVG are very common which makes stent sizes difficult. Sizing should be based on the nonaneurysmal segment and post dilation can be used when needed. Proximal embolic protection devices are still available but are not used as much as the distal one during PCI on SVGs. The idea of these devices to reduce the thrombi that can travel upwards and cause organ ischemia specifically a stroke.

No reflow phenomena is common during any coronary or graft intervention. It is more common with thrombotic lesions and thought to be related to microvascular thrombosis and/or dysfunction. In addition to minimize clot burden with embolectomy, angioplasty and stenting to trap clots, administrating of microvascular active medications nitroprusside, verapamil and/or adenosine is necessary.

#### **4.4 Instent restenosis treatment**

Simple focal restenosis is usually treated with DES. The era of DES changed the approach of instent restenosis treatment. A second and a third layer of stents can be used to treat the lesion especially focal lesions in the body of the stent or edge of stent whether the prior used stent was a BMS or DES. Treatment of instent restenosis can be very challenging due to the variable potential underlying pathophysiology of stent restenosis: undersized, under expanded stent, presence of calcification, neoatherosclerosis, fibrotic tissue or presence of diffuse instent restenosis. Understanding the mechanism of restenosis is the main step to choose the appropriate treatment strategy. Intravascular imaging with IVUS or OCT if possible can be very helpful. However, most of the time these imaging catheters cannot cross the restenosis. In these setting, ballooning might be the only option.

In case of diffuse instent neoatherosclerosis cutting balloons is not a good option especially if the prior stents are well sized and fully apposed. The decision of adding a

#### **Table 15.** *Distal embolization protection devices.*

#### *Coronary Artery Intervention Techniques DOI: http://dx.doi.org/10.5772/intechopen.93458*

second layer of stent depends on the results of angioplasty, size of the vessel, and long-term outcome. If the mechanism of restenosis is under expanded stent, fibrotic tissue, calcifications underneath the stent or hyper intimal hyperplasia, the treatment is targeting the underlying tissue. Available treatment options are those used for adjunct plaque modifications (brachytherapy, LASER, and intravascular lithotripsy).


3. Summary

greater effect on the sugar yield. Also, Shi et al. [87] reported that efficiency in the mixed feedstocks pretreatments and densification demonstrated significant effect on sugar yields. Many studies without MW-assisted alkali pretreatment method using pelletization on different biomass have reported similar sugar yield, considering the biomass used in the conversion. Furthermore, conclusions made from these studies focused more on the effects of pelletization parameters on improving enzymatic hydrolysis process for biomass sugar conversion [85, 87–91]. The advantages of densifying biomass using different technologies to produce pellets are to

Technoeconomic analysis (TEA) involves technologies, system, and production processes evaluation. Different technoeconomic studies have classified the analysis into two major groups such as technical (maintenance requirement and service life, operation and maintenance skill requirement, the ease of transportation and installation, processing capacities available, material, esthetic and inherent risk for a system or product process) and economic (capital and operating costs, biomass cost, and profit revenues) depending on the process technology used [93, 94]. The TEA report also assists in understanding and providing additional information to the economic viability via production cost and market price [94], and the profitability and sensitivity analysis of a product or a process [95, 96]. To perform technical and economic evaluation, various software with in-built analysis tool to estimate capital and operational costs have been developed by different software developers, and the choice of software is dependent on the project evaluation. The available commercial TEA software includes Super-Pro designer, PRO/II and DYNSIM, Aspen Plus HYSYS, DESIGN II,

Life cycle assessment (LCA) involves the collection and evaluation of relevant input and output data of a product system including potential environment impacts within the process period [97]. Adams et al. [98] indicated that the main reason for using the LCA tool is to give a

improve handling, storage, and transportation efficiencies [92].

2.5. Economic evaluation of microwave pretreatment process

and CHEMCAD [93].

Feedstock Screen size (mm)

56 Renewable Resources and Biorefineries

Canola straw

Alkali Alkali

concentration (%)

MW time (min) Tensile strength (MPa)

1.6 NaOH 1.5 18 2.31 0.79 1370.27 110.05

3.2 NaOH 0.75 6 4.85 2.60 1324.75 55.78

3.2 NaOH 0.75 6 1.23 1.68 1205.73 72.22

Oat hull 1.6 NaOH 0.75 18 1.33 5.28 1221.99 99.10

Table 2. MW-assisted alkali pretreated canola straw and oat hull pellets and glucose yields results [3].

KOH 1.5 6 3.78 0.83 1392.21 53.42

KOH 1.5 6 5.19 0.83 1382.62 96.77

KOH 1.5 6 0.63 1.04 1185.69 97.53

KOH 1.5 18 1.17 5.95 1210.94 84.87

Dimensional stability (%)

Pellet density (kg/m3 ) Average glucose yield (mg/g)

> MW pretreatment technique has gained research attention and its future is growing. In spite of this, it is still under bench-scale development. Sufficient data generated from previous and recent studies can be used to quantify the dielectric properties of input biomass and to design and develop a continuous MW-assisted pretreatment and enzymatic saccharification process unit for commercial scale-up. Feedstock properties and reaction conditions are the two factors influencing microwave pretreatment characterization and yield of the final product.

The cost of MW pretreatment process is the main determinant associated with the adoption of this technology. Emphasis on the capital and operating cost investment will improve the pretreatment technique and hydrolysis process, thereby reducing the cost of the final product (bioethanol). Future research studies in MW-assisted biological pretreatment in improving lignocellulosic biomass digestibility, and techno-economic analysis and life cycle impact assessment of the process need to be considered. The concept is to develop a more economic pretreatment and hydrolysis techniques that can be environmentally sustainable and accepted by the bioenergy industry.

[2] Iroba KL, Tabil LG, Sokhansanj S, Meda V. Producing durable pellets from barley straw subjected to radio frequency-alkaline and steam explosion pretreatments. International Journal of Agricultural and Biological Engineering. 2014;7(3):68-82. DOI: 10.3965/j.

Pretreatment of Crop Residues by Application of Microwave Heating and Alkaline Solution for Biofuel…

http://dx.doi.org/10.5772/intechopen.79103

59

[3] Agu OS, Tabil LG, Dumonceaux T. Microwave-assisted alkali pretreatment, densification and enzymatic saccharification of canola straw and oat hull. Bioengineering. 2017;4(25):

[4] Yin C. Microwave-assisted pyrolysis of biomass for liquid biofuels production. Journal of Bioresource Technology. 2012;120:273-284. DOI: 10.1016/j.biortech.2012.06.016

[5] Bhaskar T, Bhavya B, Singh R, Naik DV, Kumar A, Goyal HB. Thermochemical conversion of biomass to biofuels. In: Pandey A, Gnansounou E, Dussap CG, Larroche C, Ricke SC, editors. Biofuels: Alternative Feedstocks and Conversion Processes. Oxford, UK:

[6] Aho A, Salmi T, Murzin DY. Catalytic pyrolysis of lignocellulosic biomass. In: Triantafyllidis KS, Lappas AA, Stocker M, editors. The Role of Catalyst for the Sustainable Production of Biofuels and Bio-Chemicals. Netherlands: Elsevier; 2013. pp. 137-145.

[7] Tong Z, Pullammanappallil P, Teixeira AA. How ethanol is made from cellulosic biomass [Internet]. 2012. Available from: http://edis.ifas.ufl.edu/pdffiles/AE/AE49300.pdf [Accessed:

[8] Karimi K, Shafiei M, Kumar R. Progress in physical and chemical pretreatment of lignocellulosic biomass. In: Gupta VK, Tuohy MG, editors. Biofuels Technologies. Berlin,

[9] Sarkar N, Ghosh SK, Bannerjee S, Aikat K. Bioethanol production from agricultural waste: An overview. Renewable Energy. 2012;37:19-27. DOI: 10.1016/j.renene.2011.06.045

[10] Kim S, Dale BE. Environmental aspects of ethanol derived from no-tilled corn grain: Non-renewable energy consumption and greenhouse gas emission. Biomass and

[11] Nomanbhay SM, Hussain R, Palanisamy K. Microwave-assisted alkaline pretreatment and microwave assisted enzymatic saccharification of oil palm empty fruit bunch fiber foe enhance fermentable sugar yield. Journal of Sustainable Bioenergy System. 2013;3:7-17.

[12] Quintero JA, Rincon LE, Cardona CA. Production of bioethanol from agro industrial residues as feedstocks. In: Pandey A, Gnansounou E, Dussap CG, Larroche C, Ricke SC, editors. Biofuels: Alternative Feedstocks and Conversion Processes. Oxford, UK: Aca-

[13] Van Zessen E, Weismann M, Bakker RRC, Elbersen HW, Reith JH, den Uil H. Lignocellulosic ethanol, a second opinion [Internet]. 2003. Available from: http://library.wur.nl/

Bioenergy. 2005;28:475-489. DOI: 10.1016/j.biombioe.2004.11.005

ijabe.20140703.009

1-33. DOI: 10.3390/bioengineering4020025

DOI: 10.1016/B978-0-444-56330-9.00005-X

Germany: Springer; 2013. pp. 53-96

DOI: 10.4236/jsbs.2013.31002

demic Press; 2011. pp. 253-260

WebQuery/wurpubs/339809 [2018/01/28]

Academic Press; 2011. pp. 51-77

March 17, 2018]


Staphylococcus and Streptococcus

*Edited by Sahra Kırmusaoğlu*

Published in London, United Kingdom

### *Supporting open minds since 2005*

Staphylococcus and Streptococcus http://dx.doi.org/10.5772/intechopen.77863 Edited by Sahra Kırmusaoğlu

#### Contributors

María Alejandra Bojanich, Mariano Daniel Orlietti, Valeria Velasco, Helia Bello, Mario Quezada-Aguiluz, Ming-Chu Hsu, Ying-Yuan Zhang, Li-Wen Chang, Manju Pai, Venkatesh S Pai, Pratima Gupta, Anuradha Chakraborti, Sahra Kırmusaoğlu, Ruby Hp Law, Adam J. Quek, James C. Whisstock, Razique Anwer, Khalid Alqumaizi

#### © The Editor(s) and the Author(s) 2020

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**Carmine Carmicino**

Department of Industrial Engineering—Aerospace Division, University of Naples "Federico II", Piazzale Tecchio, 80-80125 Naples, Italy<EMAIL_ADDRESS>
Received: 10 August 2020; Accepted: 13 August 2020; Published: 14 August 2020

Since the Editorial [1] of this Special Issue was published last 26 November 2019, I have had the pleasure to accept the submission of a couple of new articles which are now included in the Issue; moreover, for the sake of clarification, I want to mention that, over the revision process, the title of the paper [2]—which at that time was thought of as the last to be published—has been changed to more fairly comply with the revised topics.

The last two papers now appearing in the Special Issue deal, in the temporal order of publication, with the design and testing of a student hybrid rocket engine featuring an external carbon fiber composite structure [3], and with the development of an oxygen-methane torch ignition system designed for a hybrid rocket and later improved to be used in the testing of solid and liquid ramjet engines [4].

The former was developed in the framework of the German educational program Studentische Experimental-Raketen (STERN), by students of the Technische Universität Braunschweig, whereas the latter reports on a part of a research funded by the Foundation for the Scientific Research Support of the Brazilian Federal District at the University of Brasilia. I have particularly welcomed these two articles, in that, both being born in institutions recently involved in hybrids, they further prove the nice spread of the research activities in this subject across the world.

The aim of this short addendum is to give the final picture of the contents of the Special Issue, which collects 14 papers and 1 Editorial, 3 of which are review papers, 10 are original research papers, and 1 is a technical note.

The success of this experience has laid the groundwork for the "Hybrid Rocket (Volume II)", edited in collaboration with Toru Shimada and Arif Karabeyoglu [5], which, alongside articles addressing the advances in hybrid rocket technology and related analysis methodologies, will welcome papers dealing with novel space transportation systems, new flight systems, and mission concepts and optimization using hybrid rockets.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The author declares no conflict of interest.


*3.4. Modeling Studies*

The thermodynamic parameters of the SMT-BCD or SMT-RAMEB complexes were determined at 298 K as follows: The enthalpy change considered as the energy change calculated by subtracting the total energies of the reactants from the total energies of the products. Similarly, the entropy changes were calculated by subtracting the entropy terms of the reactants from the entropy terms of the products. The entropy terms of the species interacted were calculated applying Boltzmann statistics. The higher contribution to the entropy comes from the vibrational motions. Therefore, after calculating the vibrational frequencies using the harmonic approximation, the entropy was then determined as the following equation implemented in the HyperChem code:

$$S\_{vib} = R \sum\_{i} \left\{ \frac{h\nu\_i/kT}{e^{(h\nu\_i/kT)} - 1} - \ln[1 - e^{(-h\nu\_i/kT)}] \right\} \tag{2}$$

where the ν*i* is the frequency of vibration and *T* is the temperature (298.16 K).

The total energies of the species interacted have been calculated at semi-empirical MINDO/3 level using HyperChem 8 code. After the geometry optimization at MINDO/3 level the vibrational-rotational analysis was performed in harmonic approximation using AM1 approximation. Neutral aqueous environment was considered by the TIP3P solvation model implemented in HyperChem code [47]. Considering that in the present studies ionic species are interacted, the ionic strength of the buffer were considered by the additional PO4 3−, K+, Na+ and H3O+ ions as described in an earlier study [34]. Accordingly, the final cube for representing solvents has 30 Å × 30 Å × 30 Å sizes and contained water, PO4 3−, HPO4 2−, K+, Na+ and 9 H3O+ according to the composition of the buffer solution while the pH varied from 7, 5 and 2. After 10 ps MD simulation to equilibrate the system at room-temperature at MM+ level, the calculations for the complexes and the separated species interacted were performed at MINDO/3 level. To reduce the huge computational time, the random-methylated CD derivative (RAMEB, which have electron-rich cavity) was considered as negatively charged species of the native BCD [48,49].


3. Conclusions

Depending on the specific cases, the application of MTMs as the DGS of the antenna not only reduces the size but also increases the obtained bandwidth of the antenna. Figure 19 compares the sizes and bandwidths of two antennas before and after applying the MTMs with the same 2.413 GHz resonant frequency for WLAN system. The ratio of the decreased size and the

Antenna types Antenna size ratio, % Ratio of BW, % Type of radiation pattern

Without MTM 100 100 Directional With MTMs 78.7 141 Directional

Table 2. Comparison between parameters of two types of antennas for WLAN system.

The application of metamaterials in antenna design has enhanced its bandwidth. Depending on the technical requirements of the designed antenna, the different metamaterial structures and different application methods are selected to achieve the most appropriate antenna

From the need to integrate multiple functions (many communication systems operation) on single devices, multiband antennas are more interested. The use of metamaterials in antenna design is an attractive trend not only to reduce size, improve the power gain, enhance bandwidth, but also to design multifrequency-band antennas [46]. The unit cells of metamaterials can be used as radiation components, a part or loaded part of the ground plane of antenna. Because, MTMs can support negative refraction indexes at resonant frequencies and unit cell structures of symmetric pairs. This can be used to design multifrequency antennas with smaller dimensions than traditional one [46]. Metamaterial can be combined with a conventional or fractal microstrip antenna to create multiband antenna, in which the antenna size is determined by the lowest

Figure 20. The configuration of microstrip antenna for WLAN systems without loaded CSRR (a), fractal antenna with

increased bandwidth is shown in Table 2.

2.3.4. Use metamaterials to get multiband

loaded CSRR (b), and S11 parameters of them (c) [27, 48, 49].

bandwidth.

80 Metamaterials and Metasurfaces

In this chapter, the applications of metamaterials in design to enhance antenna parameters are presented. The metamaterials can be applied as an environment of the antenna or as part of the antenna. Depending on the parameters of the desired antenna to improve, the metamaterials can be applied in different methods. The metamaterials can be applied to improve bandwidth, power gain, or to create compact, multifrequency-band antennas. To apply metamaterials in an antenna, the first is to design their unit cells, which are considered as atoms, creating special properties of the metamaterial at the desired frequency. The size of the unit cells is calculated, simulated, and optimized, based on the HFSS software. Effectiveness of improving the parameters of the antenna depends on the structure, size, quantity, and method of use of the unit cell of the metamaterials. Application of metamaterials in antenna design can increase their power gain ≥2 dB, bandwidth ≥100%, reduce size ≥50% or to create additional frequency bands for multicommunication systems operated antennas.


**Nanomaterials for Ion Battery Applications**

Editor

**Jaehyun Hur**

MDPI ' Basel ' Beijing ' Wuhan ' Barcelona ' Belgrade ' Manchester ' Tokyo ' Cluj ' Tianjin

*Editor* Jaehyun Hur Department of Chemical and Biological Engineering Gachon University Gyeoggi Korea, South

*Editorial Office* MDPI St. Alban-Anlage 66 4052 Basel, Switzerland

This is a reprint of articles from the Special Issue published online in the open access journal *Nanomaterials* (ISSN 2079-4991) (available at: www.mdpi.com/journal/nanomaterials/special issues/nano battery).

For citation purposes, cite each article independently as indicated on the article page online and as indicated below:

LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. *Journal Name* **Year**, *Volume Number*, Page Range.

**ISBN 978-3-0365-4770-1 (Hbk) ISBN 978-3-0365-4769-5 (PDF)**

© 2022 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications.

The book as a whole is distributed by MDPI under the terms and conditions of the Creative Commons license CC BY-NC-ND.


*Edited by Vladimir Kalinin*

Although Obsessive-Compulsive Disorder (OCD) has been known since the ancient times, the exact etiology and pathogenesis of OCD unfortunately still remain unknown. In addition, the therapeutic approaches elaborated for the treatment of OCD as a whole are not perfect, and this disorder as a rule is characterized by unfavorable course and lack of full therapeutic response. In the current book some modern data on pathogenesis, phenomenology and treatment of OCD are presented. Besides, the data on co-morbidity of OCD with other neurological and psychiatric disorders are also included. This book is intended for broad circle of readers, but mostly for psychiatrists, psychologists and neurologists.

ISBN 978-953-51-1238-9

Obsessive-Compulsive Disorder - The Old and the New Problems

Photo by Zuberka / iStock

## Obsessive-Compulsive Disorder The Old and the New Problems

*Edited by Vladimir Kalinin*

**OBSESSIVE-COMPULSIVE**

**DISORDER - THE OLD**

**AND THE NEW**

Edited by **Vladimir Kalinin**

**PROBLEMS**


**3. Aerial robot system description**

Multirotor aircraft are mechanical systems that exist in 3D space with six degrees of freedom (DOF) consisting of N rotors. From the aspect of dynamics, they are considered as symmetrical rigid bodies, where the only moving parts are the rotors of the propulsion assembly on whose axes are mounted propellers with a fixed pitch angle. Propellers create aerodynamic forces and moments by their rotation, so it follows that the angular velocities of the rotor are the only variables that have a direct impact on flight dynamics. The development and design of multirotor UAVs depend on constraints in size and energy consumption, and a key parameter in system design is aircraft weight. Given that the multirotor type of UAV is characterized by high energy consumption, it is extremely important to correctly select the components and parameters of the system in order to reduce energy consumption and extend the flight duration. To ensure overall flight performance, it is necessary to determine the thrust-to-weight ratio (TWR), and as a rule, aircraft are designed with approximately twice the thrust of the weight.


**Abstract**

The hydrodynamic instabilities in a turbomachine can be divided into two main groups: periodic (or quasi-periodic) and nonperiodic. And the total instability, calculated from a statistical parameter with linear characteristics, such as variance, can be defined as the sum of periodic and nonperiodic instabilities. Based on the above, the main objective of the study was to estimate the periodic instabilities in a pump operating as a turbine. For this purpose, pressure fluctuation signals from sensors installed on the turbomachine volute and spaced 135° apart were used. The signals were analyzed in the time and frequency domain to identify, initially, the periodic instabilities and their relationship with the spectral components and, subsequently, to estimate the magnitude of these instabilities as the variance of the filtered series in the spectral band related to the periodic instability. In addition, the study aims to establish the contribution of periodic instabilities to total instability.

**Keywords:** pump as turbine, hydrodynamic instabilities, periodic instabilities, variance, phase analysis, Fourier analysis


*1.2. Employer Branding*

EB is not a new concept; back in 1996, Ambler and Barrow [14] (p. 8) described the employer brand as the 'functional, economical and psychological package given by a job matching the employer company'. Nevertheless, the concept has been growing to a more relevant role concerning talent management [5]. The designers of the first EB model (see Figure 2), Backhaus and Tikoo [15] point out three vital assets to create the employer brand: organisational culture, organisational identity, and differentiating value proposition.

**Figure 2.** Backhaus and Tikoo framework (2004). Source: Backhaus and Tikoo (2004) [15].

With the conceptualisation of this model, the authors intend to make the comprehension of the dynamics associated with the concept easier, as well as the importance of the narrow relationship between marketing and human resources to the implementation of an EB process.

Since the expression 'war for talent' was created by Mckinsey—one of the most important human resources consulting companies in the world—in 1997, EB processes have assumed a central role in organisational strategy because organisations realised that they would have to fight this 'war' on the following years if they wanted to attract and retain the talents relevant to their sustainability. Although brands and branding are not a recent topic, organisations are now applying the concepts to new management areas [16]. Branding, according to Kotler and Lee [17] (p. 215), is 'the identity developing process of an intended brand'. EB is the expression used to refer to the applicability of brand elements to human resources management. Sullivan [18] advocates that EB expresses the notion that designates a company as a good environment to execute functions.

It is of the utmost importance to clarify the concept and systematise its models due to the relevance the concept has been developing over the years, and because the introduction of EB within the organisation is becoming more and more a necessity and no longer an option. Therefore, one of the goals of the present systematic literature revision is the clarification of the concept and its dimensions.


3. Computing model and conditions

g ¼ ρuy ρuxuy ρuy

ductivity, the stress component and the total energy, respectively.

respectively; mi and ni are specific coefficients, no longer list.

The TVD Runge-Kutta discretization can be expressed as follows

n

¼ K1 Ljþ1 � Lj�1

Uð Þ1 ¼ a1Un þ b1f

Uð Þ3 ¼ a3Un þ b3 Uð Þ2 þ f

The spatial discretizations for viscous terms can be expressed as follow:

� � þ K2 Ljþ2 � Lj�2

2 Δt � �

2.2. Numerical method

24 Advances in Some Hypersonic Vehicles Technologies

used for time advance [20].

L 0

8 < :

and (8), respectively:

H0

Eqs. (7) and (8).

W0

gv ¼ 0 τxy τyy uxτxy þ uyτyy þ k

where ux, uy, P, ρ, T and E indicate the velocity in the x direction, the velocity in the y direction, pressure, density, temperature and total energy, respectively. k, τ and E are the thermal con-

In this paper, a high order finite difference method is used to solve the flowfield governing equation directly. The inviscid vector flux of the Navier-Stokes equation is divided into the positive and negative convection terms using S-W method [17]. The positive and negative convection terms are discretized by the 5th order upwind WENO scheme [18]. The viscous term is discretized by the 6th order central difference scheme [19]. In order to obtain the transient information of the flowfield and reduce computation time, the 3th TVD Runge-Kutta scheme is

The spatial discretization for positive and negative convection terms can be expressed as Eqs. (7)

¼ m1Wjþ3 þ m2Wjþ2 þ m3Wjþ1 þ m4Wj þ m5Wj�1 þ m6Wj�2 þ m7Wj�3 þ m8Wj�4 � �

¼ n1Hjþ4 þ n2Hjþ3 þ n3Hjþ2 þ n4Hjþ1 þ n5Hj þ n6Hj�1 þ n7Hj�2 þ n8Hj�3

where W and H are positive convection terms and negative convection terms, respectively; Δ is the grid spacing; W0 and H0 are the difference approximation of the derivative of W and H,

where L, L', Δ and Ki are viscous terms, the difference approximation of the derivative of viscous terms, the grid spacing and specific coefficients, respectively, which are similar to the symbols in

where Δt is time increment for time advance; L(U) is the partial derivative of U relative to time.

� �=Δ (8)

� � þ K3 Ljþ3 � Lj�3 � � � � =Δ (9)

Δt Uð Þ2 ¼ a2Un þ b2 Uð Þ1 þ f

Unþ1 ¼ Uð Þ3

1 Δt � �

� �T

2 þ p ρE þ p � �uy

� �T (5)

∂T ∂y

(6)

=Δ (7)

(10)

The model parameters and calculation conditions of flowfield calculation includes the freestream condition, model parameter, boundary conditions and meshing. For freestream conditions, the freestream temperature is equal to 69 K, and the Mach number is equal to 6. The Reynolds number, based on the nose radius, is equal to 10,000. The angle of attack is equal to 0. Figure 1 shows the computing model and schematic diagram. Calculation mode is a blunt wedge with the wedge angle of 16e; the nose radius r = 1 mm. the adiabatic wall, no-penetration and non-slip is introduced for wall condition; the symmetric boundary conditions is introduced for y = 0; the freestream conditions and exportation boundary conditions are introduced for the upstream of computing domain and the downstream of calculation domain, respectively. Figure 2 shows the computational grid. The local intensive grid method is carried out near the nose area and wall area, and the grid number is 300 120. The parameters of blunt wedge nose radius r, freestream velocity V∞, freestream temperature T∞, freestream viscosity coefficient μ∞, freestream conductivity coefficient k∞, freestream density ρ∞ are chosen as the normalized basic measure that is the characteristic variable.

In order to explore the influence of freestream pulse wave on hypersonic flow field, the interaction process between freestream pulse slow acoustic wave and hypersonic flowfield is direct numerical simulated. In present investigation, the stable flow over a blunt wedge at Mach 6 is calculated firstly, and then the simulation of hypersonic unsteady flowfield under the freestream pulse wave is conducted by introducing freestream pulse slow acoustic wave at the upstream boundary of computing domain.

The introducing time of the freestream pulse wave is recorded as t = 0. The form of pulse slow acoustic wave is expressed as follows:

Figure 1. Computational model and schematic diagram.

Figure 2. Mesh grid.

$$
\begin{bmatrix} u' \\ v' \\ p' \\ \rho' \end{bmatrix} = \begin{cases} \begin{bmatrix} 0 & 0 \ 0 & 0 \end{bmatrix}^T & (t < 0) \\ \begin{bmatrix} A & 0 & -\frac{A}{M\_{\bullet}} & -AM\_{\bullet} \end{bmatrix}^T e^{i\left(kx - \frac{R\alpha\_{\theta}}{10^{\theta}} + \frac{\pi}{2}\right)} & (0 \le t < 2) \\\ \begin{bmatrix} 0 & 0 & 0 \ 0 & 0 \end{bmatrix}^T & (t \ge 2) \end{cases} \tag{11}
$$

deformed and protruded outward, and the surrounding pressure is also significantly affected. Due to the deformation of the shock wave, the pressure of outward convex region near shock wave is significantly increased, and the flowfield pressure below the bow shock wave is greatly reduced. That is to say, from Figure 3(a)–(d), it shows that the freestream disturbance waves significantly interact with the bow-shaped shock waves, which greatly changes the

Figure 3. Contours of pressure under freestream pulse wave at different times. (a) t=2.0, (b) ) t=4.0, (c)t=6.0, (d) ) t=8.0.

Numerical Study of Hypersonic Boundary Layer Receptivity Characteristics Due to Freestream Pulse Waves

http://dx.doi.org/10.5772/intechopen.70660

27

Figure 4 shows the contours of density under freestream pulse wave at different times. Figure 4(a)–(f) correspond to t = 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0, respectively. Figure 5 shows the contours of temperature under freestream pulse wave at different times. Figure 5(a)–(f) correspond to t = 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0, respectively. As can be seen from Figure 4, the pulse wave disturbance has a great impact on the density. The density of the flowfield changes significantly under the action of freestream pulse wave, especially in the disturbance area between the pulse wave and the bow-shaped shock wave, where the density of the region is significantly smaller. Compared with the significant changes of flowfield density around the shock wave, the pulse wave has much smaller effect on the density in the boundary layer. Meanwhile, the closer to the nasal area, the greater the density changes and the effects are after the action of pulse wave. Obviously, this is because the closer the bowshaped shock wave is to the nose area, the stronger the action is. Therefore, it can be concluded that the stronger the intensity of the shock wave is, the more intense the effect of the pulse slow acoustic wave and the bow-shaped shock wave are. As can be seen from

shock standoff distance and the distribution of flowfield pressure in the active region.

Where u', v', P0 and ρ' indicate the velocity disturbance along x direction, the velocity disturbance along y direction, the pressure disturbance and the density disturbance, respectively; A indicates the amplitude, F indicates the generalized frequency, t indicates time. Here, A = 8 � 10�2 ; k = 3.1446 � 10�4 ; F = 50π; Ma∞ = 6.