**3. Ca-aluminate – general description and property profile**

Ca-aluminates comprise double oxides of CaO and Al2O3. Several intermediate phases exist and these are - using the cement chemistry abbreviation system - C3A, C12A7, CA, CA2 and CA6, where C=CaO and A=Al2O3. See Fig. 1 above. Table 5 presents typical property data.

The interval is primarily related to the c/w ratio used, and the highest values are achieved with c/w ratio close to that of complete hydration with no excess of water

Table 5. Mean property data of dental Ca-aluminate based materials (Kraft 2002, Lööf 2008, Lööf et al 2004,2005, Hermansson et al 2008)

Due to reduced porosity based on the huge water uptake ability, the Ca-aluminate material exhibit the highest strength among the chemically bonded ceramics. The inherent flexural strength is above 100 MP based on measurement of the fracture toughness, which is about 0.7 - 0.8 MPam1/2. The actual flexural strength is controlled by external defects introduced during handling and injection of the material. The thermal and electrical properties of Caaluminate based materials are close to those of hard tissue, the reason being that Caaluminate hydrates chemically belong to the same group as Ca-phosphates, the hard tissue

Nanostructural Chemically Bonded Ca-Aluminate Based Bioceramics 53

24 h. The test starts after 24 h hydration. The test probe accuracy was 0.01 mm. Values below

Determination of Ca and Al in the solution during the hydration process of the Caaluminate based material was performed using atomic absorption spectrometry (Liu et al 2002). Standard solutions of different concentrations of Ca and Al were prepared according to the manual. Samples were prepared with a size of 10mm x 2mm height using a wet-press method, corresponding to a surface area of 224 mm2. The test pieces were placed in plastic bottles in inorganic saliva solution of pH 7. The amount of liquid was 10 ml in each bottle. The temperature selected was 37 oC. The inorganic saliva solution contained calcium chloride, magnesium chloride, sodium chloride, a phosphate buffer, hydro-carbonate and citric acid. The Ca-content in the saliva solution corresponded to 68 ppm. 1 ml solution was removed at 1, 7 and 28 days for analyses, and saliva was exchanged at 1, 7 and 28 days after every measurement. For the 28 days test additional samples were also taken 1 h after new

Measurement of pH development during hydration of the material was conducted using a standard pH-meter. Samples were prepared according to the procedure for atomic absorption described above. The pH-testing was conducted in two separate ways. First the samples were immersed in saliva solution (pH =7) at 37 oC, and pH was measured continually over the whole experiment period (Test 1). 1 ml solution was removed at 1, 7, 14 and 28 days for pH measurement. The second type of measurement comprised immersion in 10 ml saliva solution at 37 oC, where the saliva was exchanged at 1, 7, 14 and 28 days. pH was measured at the time of observation and also after one hour in new saliva (data within

Specimens at different setting stages were subjected to cytotoxicity testing by using primary cultures of human oral fibroblasts. A tissue culture insert retaining tested materials was assembled into a 12-well plate above the fibroblast monolayers. The cytotoxicity was determined by MTT reduction assay after various curing times. Specimens were set and hydrated at 37 oC for different periods of time, i.e. 0, 5, 30, 60 min, 24 h and 1 week and were then placed on tissue culture netwell for a cytotoxicity test. Both acute (1 and 24 h) and long

Summarized below are the results from several biocompatibility and bioactivity studies (Engqvist 2004, 2005, Faris 2006) where Ca-aluminate is used as a biomaterial in orthopaedic and dental applications. *In vitro* bioactivity studies show apatite formation on the surface of the Ca-aluminate materials exposed to phosphate buffer solution, an example shown in

No height reduction at all was observed for two tested Ca-aluminate materials. Thus, according to the acid corrosion test, Ca-aluminate materials are judged as stable materials. The total absence of material loss, measured as height reduction in the acid corrosion test, is related to the general basic nature of the material, with possibility of neutralization of the

term (1 week) in vitro toxicity tests were conducted with MTT assay.

**3.1.1 Biocompatibility including bioactivity of Ca-aluminate bioceramics**

acid in the contact zone – especially in the earlier stage of the hydration process.

0.05 mm per 24 h solution impinging are judged as acid resistant.

solution was added.

brackets), Test 2.

**Biocompatibility evaluation**

Figure 2 below.

**Corrosion resistance**

of bone. Another important property related to Ca-aluminate materials is the possibility to control the dimensional change during hardening. In contrast to the shrinkage behaviour of many polymer-based biomaterials, the Ca-aluminates exhibit a small expansion, 0.1-0.3 linear-% (Kraft 2002).

### **3.1 Biocompatibility including bioactivity**

#### **Definitions used**

The terms biocompatibility and bioactivity are used in different ways by different categories of scientists. Below are presented the definitions used in this paper, mainly agreeing with the definitions discussed in (Williams, 1987) Biocompatibility: "The ability of a material to perform with an appropriate host response in a specific application".

Bioactivity (bioactive material): "A material which has been designed to induce specific biological activity". Another definition according to (Cao and Hench,1996) "A bioactive material is one that elicits a specific response at the interface of the material which results in the formation of a bond between the tissues and the material".

Thus a material cannot in itself be classified as biocompatible without being related to the specific application, for which it is intended. Bioactivity from a materials viewpoint is frequently divided into *in vitro* and *in vivo* bioactivity. The *in vitro* bioactivity of a material is however only an indication that it might be bioactive in a specific *in vivo* application. Another aspect of bioactivity is that this term can be adequate only when the biomaterial is in contact with a cellular tissue. However, often a material is claimed to be bioactive if it also reacts with body liquids forming an apatite-phase. *In vitro* bioactivity is tested in phosphate buffer systems similar to that of saliva or body liquid, and apatite formation is the claimed sign of bioactivity. A further aspect of bioactivity and also biocompatibility deals with the different curing times and temperatures at which the observation (testing) is performed. This is important to issues such as initial pH-development, cohesiveness and initial strength. Finally the biocompatibility and bioactivity can only be confirmed in clinical situations, with the actual implant/biomaterial in the designed amount or content and shape. This is especially important for injectable biomaterials which are formed (hydrated) and cured *in vivo*, and for implants where movements, even micro-movement, can influence the outcome.

#### **Standards and methods**

Relating to the definition aspects above, the acceptance of a biomaterial is a crucial issue, and to some extent the question has been solved by relating to the following toxicological endpoints indicating biocompatibility as referred in the harmonized standard ISO 10993:2003, which comprises the following sections:

Cytotoxicity (ISO10993-5), Sensitization (ISO10993-10), Irritation/Intracutaneous reactivity (ISO10993-10), Systemic toxicity (ISO10993-11), Sub-acute, sub-chronic and chronic toxicity (ISO10993-11), Genotoxicity (ISO10993-3), Implantation (ISO10993-6), Carcinogenicity (ISO10993-3) and Hemocompatibility (ISO10993-4).

This will be the main guideline when presenting the status of the biocompatibility of the CASPH-system, but was complemented by corrosion testing, elementary analysis, pHchange and additional cytotoxicity testing.

The corrosion resistance test – using a water jet impinging technique - was conducted according to EN 29917:1994/ISO 9917:1991,where removal of material is expressed as a height reduction using 0.1 M lactic acid as solution, pH 2.7 . The duration time of the test is

of bone. Another important property related to Ca-aluminate materials is the possibility to control the dimensional change during hardening. In contrast to the shrinkage behaviour of many polymer-based biomaterials, the Ca-aluminates exhibit a small expansion, 0.1-0.3

The terms biocompatibility and bioactivity are used in different ways by different categories of scientists. Below are presented the definitions used in this paper, mainly agreeing with the definitions discussed in (Williams, 1987) Biocompatibility: "The ability of a material to

Bioactivity (bioactive material): "A material which has been designed to induce specific biological activity". Another definition according to (Cao and Hench,1996) "A bioactive material is one that elicits a specific response at the interface of the material which results in

Thus a material cannot in itself be classified as biocompatible without being related to the specific application, for which it is intended. Bioactivity from a materials viewpoint is frequently divided into *in vitro* and *in vivo* bioactivity. The *in vitro* bioactivity of a material is however only an indication that it might be bioactive in a specific *in vivo* application. Another aspect of bioactivity is that this term can be adequate only when the biomaterial is in contact with a cellular tissue. However, often a material is claimed to be bioactive if it also reacts with body liquids forming an apatite-phase. *In vitro* bioactivity is tested in phosphate buffer systems similar to that of saliva or body liquid, and apatite formation is the claimed sign of bioactivity. A further aspect of bioactivity and also biocompatibility deals with the different curing times and temperatures at which the observation (testing) is performed. This is important to issues such as initial pH-development, cohesiveness and initial strength. Finally the biocompatibility and bioactivity can only be confirmed in clinical situations, with the actual implant/biomaterial in the designed amount or content and shape. This is especially important for injectable biomaterials which are formed (hydrated) and cured *in vivo*, and for implants where movements, even micro-movement, can influence the outcome.

Relating to the definition aspects above, the acceptance of a biomaterial is a crucial issue, and to some extent the question has been solved by relating to the following toxicological endpoints indicating biocompatibility as referred in the harmonized standard ISO

Cytotoxicity (ISO10993-5), Sensitization (ISO10993-10), Irritation/Intracutaneous reactivity (ISO10993-10), Systemic toxicity (ISO10993-11), Sub-acute, sub-chronic and chronic toxicity (ISO10993-11), Genotoxicity (ISO10993-3), Implantation (ISO10993-6), Carcinogenicity

This will be the main guideline when presenting the status of the biocompatibility of the CASPH-system, but was complemented by corrosion testing, elementary analysis, pH-

The corrosion resistance test – using a water jet impinging technique - was conducted according to EN 29917:1994/ISO 9917:1991,where removal of material is expressed as a height reduction using 0.1 M lactic acid as solution, pH 2.7 . The duration time of the test is

perform with an appropriate host response in a specific application".

the formation of a bond between the tissues and the material".

linear-% (Kraft 2002).

**Definitions used**

**Standards and methods**

10993:2003, which comprises the following sections:

(ISO10993-3) and Hemocompatibility (ISO10993-4).

change and additional cytotoxicity testing.

**3.1 Biocompatibility including bioactivity**

24 h. The test starts after 24 h hydration. The test probe accuracy was 0.01 mm. Values below

0.05 mm per 24 h solution impinging are judged as acid resistant. Determination of Ca and Al in the solution during the hydration process of the Caaluminate based material was performed using atomic absorption spectrometry (Liu et al 2002). Standard solutions of different concentrations of Ca and Al were prepared according to the manual. Samples were prepared with a size of 10mm x 2mm height using a wet-press method, corresponding to a surface area of 224 mm2. The test pieces were placed in plastic bottles in inorganic saliva solution of pH 7. The amount of liquid was 10 ml in each bottle. The temperature selected was 37 oC. The inorganic saliva solution contained calcium

chloride, magnesium chloride, sodium chloride, a phosphate buffer, hydro-carbonate and citric acid. The Ca-content in the saliva solution corresponded to 68 ppm. 1 ml solution was removed at 1, 7 and 28 days for analyses, and saliva was exchanged at 1, 7 and 28 days after every measurement. For the 28 days test additional samples were also taken 1 h after new solution was added.

Measurement of pH development during hydration of the material was conducted using a standard pH-meter. Samples were prepared according to the procedure for atomic absorption described above. The pH-testing was conducted in two separate ways. First the samples were immersed in saliva solution (pH =7) at 37 oC, and pH was measured continually over the whole experiment period (Test 1). 1 ml solution was removed at 1, 7, 14 and 28 days for pH measurement. The second type of measurement comprised immersion in 10 ml saliva solution at 37 oC, where the saliva was exchanged at 1, 7, 14 and 28 days. pH was measured at the time of observation and also after one hour in new saliva (data within brackets), Test 2.

Specimens at different setting stages were subjected to cytotoxicity testing by using primary cultures of human oral fibroblasts. A tissue culture insert retaining tested materials was assembled into a 12-well plate above the fibroblast monolayers. The cytotoxicity was determined by MTT reduction assay after various curing times. Specimens were set and hydrated at 37 oC for different periods of time, i.e. 0, 5, 30, 60 min, 24 h and 1 week and were then placed on tissue culture netwell for a cytotoxicity test. Both acute (1 and 24 h) and long term (1 week) in vitro toxicity tests were conducted with MTT assay.

## **3.1.1 Biocompatibility including bioactivity of Ca-aluminate bioceramics**

#### **Biocompatibility evaluation**

Summarized below are the results from several biocompatibility and bioactivity studies (Engqvist 2004, 2005, Faris 2006) where Ca-aluminate is used as a biomaterial in orthopaedic and dental applications. *In vitro* bioactivity studies show apatite formation on the surface of the Ca-aluminate materials exposed to phosphate buffer solution, an example shown in Figure 2 below.

#### **Corrosion resistance**

No height reduction at all was observed for two tested Ca-aluminate materials. Thus, according to the acid corrosion test, Ca-aluminate materials are judged as stable materials. The total absence of material loss, measured as height reduction in the acid corrosion test, is related to the general basic nature of the material, with possibility of neutralization of the acid in the contact zone – especially in the earlier stage of the hydration process.

Nanostructural Chemically Bonded Ca-Aluminate Based Bioceramics 55

The results of the measurement of pH development during hydration of the Ca-aluminate based are shown in Table 7. The initial *in vitro*-pH is 10.5 in saliva. After 1 week, pH after 1 h

Test No. At start 1h 24 hrs 7 days 14 days 28 days 1 10.5 10.3 10.7 10.3 9.9 9.8 2 10.5 10.2 10.2 (7.7) 9.9 (7.8) 9.5 (8.1) 9.2 (8.1)

The pH is high during the early stage of the hydration, but decreases with time and approaches neutrality. The reason for the high pH in the beginning is the general basic

clinical situation saliva is produced in a dynamic way, creating an environment capable of buffering surrounding solution to neutrality. In the clinical studies performed so far no adverse reactions have been reported from a possible elevated pH during the early part of

When Ca-aluminate material is combined with glass ionomer system the pH-system becomes initially acidic. However after 10 min the pH is above neutral, but will not exceed

The *in vitro* MTT reduction test of the experimental Ca-aluminate dental filling material in human oral fibroblast culture showed no obvious cytotoxicity. The average level of MTT reduction of the experimental dental filling material was close to 100% of the control values. The maximal variation (SD) was less than 30%. Different curing times of the test material did not seem to affect the cytotoxicity test results although one week curing produced the most stable testing results both in the short and long term tests. After a week the material

Morphological changes were not observed in any of the test groups at different MTT reduction testing points. As shown in Figure 3, the cell culture was typically fibroblastic with a slender and elongated form in both the control group and the group exposed to the examined material.

Fig. 3. Morphological observation of human oral fibroblasts on an experimental Caaluminate based material. A: Normal control. B: After exposure to the experimental filling

during the hydration process. In the

Table 7. Change of pH during initial hydration of Ca-aluminate based materials

**Change in pH during hydration**

the hydration.

pH 9 (Jefferies et al 2009). **Cytotoxicity testing**

dissolution time in saliva is approx. 8.

character of the material and the formation of OH-

can be considered as fully cured, i.e. stable.

material for one week (Liu et al 2002).

Fig. 2. Cross section of the apatite-containing surface layer formed, SEM (Engqvist et al, 2004)

#### **Ion release measured by atomic absorption spectrometry**

The results of Ca and Al determination in the solution during the hydration process of the Ca-aluminate based material are presented in Table 6.

Table 6. Ca and Al dissolution during hardening of the Ca-aluminate material, (The 1h testing at 28 days within brackets)

The release of metal ions in water was below 5x10-2 ppm/(mm2 material) for aluminium and below 30x10-2 ppm/(mm2 material) for calcium, whereas somewhat higher aluminium content was measured in artificial saliva. The ion concentrations detected are generally not time-dependent during hydration. After the initial hydration time the ion concentration (molar) is determined by the solubility product of the phases formed (katoite = 5x10-26 and gibbsite = 3x10-24). Since the concentration of Ca in saliva is higher than what is obtained in the non-physiological aqueous solution (distilled water), it can be assumed that the filling material releases very limited amounts of Ca or Al once the material has hardened. The presence of Ca in saliva will decrease the solubility tendency of the calcium-aluminatehydrate phases.

Based on a search in the literature, the FAO/WHO Joint Expert Committee on Food Additives (JECFA) has provided a provisional figure for tolerable weekly aluminium intake of 7 mg/kg body weight. This corresponds to 1 mg/kg /day. The daily intake of aluminium via digestion/food is approximately 5 mg per day. For calcium the NIH Consensus Development Conference on Optimal Calcium Intake recommended an intake in the range 800 mg/day for young children to 1000 – 1500 mg/day for adults depending on gender and age. For many people there is a need to supply additional calcium in order to stay healthy. The ion concentrations measured and the amounts of Ca and Al released are far below the concentrations of the elements produced from food intake and should therefore not pose any safety concerns at all.


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198 Photonic Crystals – Innovative Systems, Lasers and Waveguides

interaction process involves resonant enhancements of all active molecular vibrational modes, in which the frequency differences of pump and Stokes fields equal the inherent vibrational frequencies of the molecular bonds respectively. The resonantly enhanced molecular vibrations exist in quantized forms which are called the phonons. Their numbers are equal to the numbers of generated Stokes photons respectively. When a probe field propagates through the matter, the photons of the probe interact with the generated phonons. The photons with

Based on the whole quantized picture of the CARS process, we presented a phonon depletion CARS (PD-CARS) technique by introducing an additional probe beam with the frequency different from the one of the probe beam in the center of the focus. When the pump and Stokes simultaneously reaches the focus, the phonons are generated. The additional probe beam, which is shaped into a doughnut profile at the focus with a phase mask, reaches the focus a little bit earlier than the probe beam in the center of the focus. Therefore the wavelengths of the generated anti-Stokes signals at the peripheral region differ from the ones at the center of the focus and can be easily separated with a proper interference filter. By this way, the spatial resolution of the ultra-broadband T-CARS

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Fig. 22. Simulation result of the PSF in the PD-CARS microscopy [132].

0.9 2

*r*

where Idep and max

reaches 41nm.

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

**6. Conclusions and prospects**

Intensity (arb.units)

*n*

sin 3 3 *P P*

probe field for phonon depletion in the annual region respectively. From equation (5.2), we can know that the spatial resolution of CARS microscopy will be improved by increasing the intensity of additional probe beam. The simulation result of PSF is shown in figure 22. When max *P*1 *I* is fiftyfold of Idet, the spatial resolution of the ultra-broadband T-CARS microscopy

41nm

distance(nm)

In this chapter, we mainly introduce a kind of noninvasive label-free imaging technique – the ultra-broadband T-CARS spectroscopy and microscopy with SC generated by PCF. We

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*I I n*

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**Part 3**

**Photonic Crystal Waveguides and Plasmonics**


**Abstract**

Parasitic infection is an intimate relationship between host and parasite with exchange of signal and complex signaling systems involved in these organisms' molecular crosstalk. With the advances of knowledge due to the genomic and transcriptomic projects in the last two decades, several genes and the molecular mechanism involved in the biological function of platyhelminths have been described. Cytokines, hormones, and other molecules from the host have influenced the growth, development, and reproduction of platyhelminths. We are going to review the effects of host cytokines (IL-1, IL-4, IL-12, IL-7, TGF-β, TNF-α) and hormones (T4, estrogen, progesterone, and androgens) that directly or indirectly affect parasites' development and reproduction, and the possible associated signaling pathway. These are excellent models for system biology studies, and the generated knowledge may be helpful in the development of new strategies to combat these helminthiases.

**Keywords:** platyhelminths, signaling pathways, molecular crosstalk, cytokines, hormones


**15. Central venous access**

The use of long-term venous access is now an integral component of treatment for patients receiving long-term antibiotic administration or hyperalimentation or undergoing chemotherapy. Externalized tunneled catheters were introduced almost 30 years ago, but required daily cleaning and frequent flushing190,191. On average, deep venous thrombosis (DVT) can complicate approximately 2%–6.7% of such port placements192 – 194, although literature reports have ranged from 0% to 26%195–198. In 1991, Monreal et al.199 observed that 4 of 30 consecutive patients with upper extremity deep venous thrombosis (DVT) had PE (13.3%), but more importantly, all these 4 occurred in 20 catheter related DVT patients (20%), while none of 10 patients with primary upper extremity DVT had PE.


**2.2 Peripheral vascular disease and ischemia**

Hypoperfusion (ischemia) resulting from peripheral vascular disease contributes to DFU development due to reduced oxygen supply to the diabetic foot [40]. The vascular disease in diabetic patients is mostly localized in arteries of the lower limb, with dismal prognosis [41, 42]. A major risk factor for the development of peripheral vascular disease is atherosclerosis [43, 44], a condition in which an artery become hardened or thickened due to a buildup of plaque in its inner lining. Atherosclerosis appears at a younger age in diabetic individuals and progresses more rapidly than in nondiabetic individuals [45, 46], thus making diabetes mellitus one of the risk factors for developing atherosclerosis. In the diabetic microcirculation, there is existence of structural changes, most notably, a thickening of the capillary basement membrane and endothelial dysfunction [47, 48]. As already mentioned, DPN reduces the production of neuropeptides which aid in wound healing [33–35]. These neuropeptides directly and indirectly (through mast cell release of histamine) cause increased permeability and vasodilation [49, 50]. The endothelium plays an important role in blood vessel wall function by synthesizing and releasing vasodilators such as prostaglandins and nitric oxide, which modulate vascular tone in pedal circulation [51, 52]. A host of mechanisms responsible for vascular dysfunction in diabetes have been identified to include over-production of reactive oxygen species, impaired nitric oxide pathway, abnormal production of vasoconstrictor prostanoids, intracellular signaling and advanced glycated end products [53–55]. This pathological vascular alteration in the diabetic foot contributes to DFU development, suggesting that diabetic patients must undergo a timely vascular examination for timely revascularization.

### **2.3 Infection**

The immune system of healthy people is much more robust and stronger than that of diabetic individuals [56, 57] and thus, foot infections in the latter group

need to be closely monitored and managed appropriately [58, 59]. Unsurprisingly, it is estimated that about 50% of patients with DFU present clinical signs of infection (either locally or systemically) [60, 61]. A foot infection is characterized by the presence of purulent secretions or at least two of the classic signs of inflammation (erythema, hyperemia, edema, or swelling and pain) [62, 63]. Patients with poor metabolic or uncontrolled diabetes are commonly afflicted with bacterial infection in which a lack of granulation tissue, delayed healing, appearance of necrotic tissue on wound surface and/or odor are prominent [64, 65]. Furthermore, these patients display a loss of sensitivity (i.e. diabetic peripheral neuropathy) in the affected foot due to damage caused to short and long fibers (A-beta and A-delta) secondary to hyperglycemia [66, 67]. Chronic hyperglycemia, a hallmark of diabetes mellitus, provides a suitable medium for bacterial growth, mainly aerobic Gram-positive cocci (e.g. *Staphylococcus aureus*), Gram-negative aerobes (e.g. *Pseudomonas aeruginosa*) and drug-resistant bacteria such as vancomycinresistant *S. aureus* and methicillin-resistant *S. aureus*, which were the common microorganisms identified in the diabetic foot [68–70]. In extreme situations, the bacterial infection of soft tissue spreads to the bones (causing osteomyelitis; an inflammation in the bone) and other surrounding tissues and organs. Unsuccessful attempts at halting the spread of the infection may lead to septicemia and amputation of the affected limb [65, 70]. Also, uncontrolled diabetes mellitus impairs the proliferation of fibroblasts and collagen synthesis while prolonging an inflammatory cascade [71, 72], a condition which compromises the wound healing abilities of diabetic patients. In summary, persistent hyperglycemia in diabetic individuals creates a suitable microenvironment for the growth of pathogenic bacteria, which contributes to DFU development and progression.


**About the Special Issue Editors**

**Feng Yu** received his B.S. degree in Applied Chemistry from the University of Jinan in 2003, and obtained his Ph.D. in physical chemistry from Technical Institute of Physics and Chemistry, Chinese Academy of Sciences (TIPC, CAS) in 2010. He then joined Nanyang Technological University (NTU) as a research fellow and Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (ICES, A\*STAR) as Scientist I. Then, he joined Shihezi University and worked as one scientist of the Recruitment Program of Global Experts (1000 Talent Plan). Now, Prof. Yu continues to undertake research in advanced functional materials for electrochemical catalysis and heterogeneous catalysis.

**Lanbo Di** received his Ph.D. in Plasma Physics from Dalian University of Technology in 2012. Since then, he has worked at the College of Physical Science and Technology at Dalian University. He has been a professor at Dalian University since 2019. He is a research professor in the Department of Chemistry and Chemical Engineering in Inha University, co-working with Professor Dong-Wha Park during 2016 to 2017, and a doctoral supervisor in Inha University since 2017. He won the first Dalian Youth Science and Technology award in 2014. He has been selected as being in the 1000-level of Liaoning BaiQianWan Talents and the candidate of the Eni Award in 2018. His research interests are focused on AP cold plasma for synthesizing supported metal catalysts and their energy and environmental applications, gas-liquid discharge, as well as plasma enhanced chemical vapor deposition (PECVD).