**Byung-Jik Kim and Se-Youn Jung**

The Mediating Role of Job Strain in the Transformational Leadership–Safety Behavior Link: The Buffering Effect of Self-Efficacy on Safety Reprinted from: *Int. J. Environ. Res. Public Health* **2019**, *16*, 1425, doi:10.3390/ijerph16081425 . . . **197**


*3.1. Compressive Strength (CS)*

In this part, to carry through the compressive strength test (CST), concrete examples were arranged without any adulteration. Figure 4 expresses the CST consequences at 28 days period for low w/c ratio combinations formed with 100% reference and numerous ratios of recycled aggregate substituting reference aggregates, with and lacking waste glass. The CS values of the reference concrete without waste glass series at 28 days were found as 18.9 MPa, respectively. The lowest CS values were also found to be 7.10 MPa in the concrete produced with cement including 50% waste glass for 28 days periods, respectively. As observed in Figure 4, it has been detected that the CS of concrete combinations including waste glass utilization as a fractional replacement for cement were lesser than those of the corresponding concrete mixes lacking waste glass. As observed in Figure 4, statistical investigation of test values shows the noteworthy impact of waste glass (as a fractional replacement for cement) on the CS of concrete.

**Figure 4.** Results of CS.

In the comparison of the cement that was changed with waste glass powder, the CS of C10% (10% cement replaced with waste glass) is 6% greater than that of C20%. Correspondingly, the CS of C20% (20% cement replaced with waste glass) is 60% greater than that of C30%. Comparing the CS of C30% (30% of the cement was replaced with waste glass powder) it can be observed that the value is 15% greater than that of C40%. Finally, the comparison of CS of C40% (40% of the cement was substituted with waste glass powder) is 31% greater than that of C50%. Consequently, it is observed that the CS of C10% (10% cement was replaced with waste glass powder) is similar to that of reference concrete. As shown in Figure 4, while fine and coarse aggregate for 10%, 20%, and 30% (MIX10%, MIX20%, and MIX30%) were exchanged with waste glass, this trend was reversed as fractional replacement of cement with waste glass promoted the CS of concrete. On the other hand, at the comparison of CS of MIX10%, MIX20%, and MIX30%, the CST consequences for the great waste glass ratio continue trends comparable to those for the small waste glass ratio. In this situation too, the CS of MIX10% is 24% greater than the corresponding mix (MIX30%). While waste glass is used instead of cement, fine and coarse aggregate, remarkable improvements in strength are observed when compared with the reference concrete. Therefore, it was observed that by replacing cement with glass powder, a significant reduction in CS will be obtained.


*Review* **Sulfur-Containing Compounds from Endophytic Fungi: Sources, Structures and Bioactivities**

**Yaqin Fan 1,†, Zhiheng Ma 1,†, Yan Zhang 1 , Yufei Wang 2 , Yousong Ding 3 , Cong Wang 2,\* and Shugeng Cao 4,\***

**Abstract:** Endophytic fungi have attracted increasing attention as an under-explored source for the discovery and development of structurally and functionally diverse secondary metabolites. These microorganisms colonize their hosts, primarily plants, and demonstrate diverse ecological distribution. Among endophytic fungal natural products, sulfur-containing compounds feature one or more sulfur atoms and possess a range of bioactivities, e.g., cytotoxicity and antimicrobial activities. These natural products mainly belong to the classes of polyketides, nonribosomal peptides, terpenoids, and hybrids. Here, we reviewed the fungal producers, plant sources, chemical structures, and bioactivities of 143 new sulfur-containing compounds that were reported from 1985 to March 2022.

**Keywords:** sulfur; plant endophyte; endophytic fungi


**Hydrogels Applied for Conformance-Improvement Treatment of Oil Reservoirs Treatment of Oil Reservoirs**

**Hydrogels Applied for Conformance-Improvement**

DOI: 10.5772/intechopen.73204

Fernanda G. C. Tessarolli, Ailton S. Gomes and Claudia R. E. Mansur Claudia R. E. Mansur Additional information is available at the end of the chapter

Fernanda G. C. Tessarolli, Ailton S. Gomes and

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.73204

#### **Abstract**

This chapter aims at presenting a review of gelling polymer systems that are commercially available or under academic development with potential to control the anisotropic permeability profile of heterogeneous oil reservoirs. In these reservoirs, the oil recovery and sweep efficiency tend to be low, even after applying secondary and enhanced oil recovery methods, because the injected fluid flows preferably through the matrix's most permeable regions leaving behind part of the displaceable oil retained at the nonswept volume. For that, cross-linked polymers can be used to plug the high-permeability main paths by means of: (i) the formation of an *in situ* hydrogel or (ii) the adsorption or swelling of pre– cross-linked hydrogel within the reservoir pores, thus causing the diversion of the subsequently injected fluid to low-permeability zones and/or preventing the channeling and early breakthrough of the injected fluid (water or gas) in production wells. The selection of the most suitable hydrogel for the reservoir conformance-improvement treatment should take into account the nature of the conformance problem, the reservoir's lithology, mineralogy, temperature, pH value, salinity, and hardness of the formation water, as well as the gelling system toxicity and cost.

**Keywords:** hydrogel, polymer, conformance improvement, reservoir, oil and gas


**Shinichi Takaichi**

Department of Biology, Nippon Medical School, Kosugi-cho, Nakahara, Kawasaki 211-0063, Japan; E-Mail<EMAIL_ADDRESS>Tel.: +81-44-733-3584; Fax: +81-44-733- 3584

*Received: 2 May 2011; in revised form: 31 May 2011 / Accepted: 8 June 2011 / Published: 15 June 2011*

**Abstract:** For photosynthesis, phototrophic organisms necessarily synthesize not only chlorophylls but also carotenoids. Many kinds of carotenoids are found in algae and, recently, taxonomic studies of algae have been developed. In this review, the relationship between the distribution of carotenoids and the phylogeny of oxygenic phototrophs in sea and fresh water, including cyanobacteria, red algae, brown algae and green algae, is summarized. These phototrophs contain division- or classspecific carotenoids, such as fucoxanthin, peridinin and siphonaxanthin. The distribution of ΅-carotene and its derivatives, such as lutein, loroxanthin and siphonaxanthin, are limited to divisions of Rhodophyta (macrophytic type), Cryptophyta, Euglenophyta, Chlorarachniophyta and Chlorophyta. In addition, carotenogenesis pathways are discussed based on the chemical structures of carotenoids and known characteristics of carotenogenesis enzymes in other organisms; genes and enzymes for carotenogenesis in algae are not yet known. Most carotenoids bind to membrane-bound pigment-protein complexes, such as reaction center, light-harvesting and cytochrome *b*6*f* complexes. Watersoluble peridinin-chlorophyll *a*-protein (PCP) and orange carotenoid protein (OCP) are also established. Some functions of carotenoids in photosynthesis are also briefly summarized.

**Keywords:** algal phylogeny; biosynthesis of carotenoids; distribution of carotenoids; function of carotenoids; pigment-protein complex


**Figure 10.** Molecular structures of the building units for the **ANW** materials and time course of H2 production through **ANW** networks from water containing 10vol. % triethanolamine as electron donor (λ>300 nm). Reproduced with permission from RSC; see Ref. [10].

(**P1**-**P7**) are also exhibited excellent visible light-induced H2 evolution activities even without depositing any co-catalysts, whereas methanol and triethylamine mixture were used as the sacrificial electron donors. Out of all planar co-polymers, **P7** showed the highest photocatalytic activity with HER of 92 μmol h−1, while the rate was further found to be increased up to 116 μmol h−1 in the presence of Pt-nanoparticles as a co-catalyst. The AQY of hydrogen generation for **P7** was measured as 2.3% at 420 nm (**Figure 11**).

#### **3.6. Polymer dots (Pdots)**

Till discussed all materials behaved as heterogeneous catalyst because these all have poor dispersibility in water, to run the photocatalytic experiment in absolutely aqueous condition and the organic/water mixed solvent were commonly used to make good dispersibility. Another drawback is that majority materials were worked under UV light and also in the presence of a co-catalyst such as Pt. In the absence of co-catalyst and visible light, all show very unsatisfactory performances. Tian et al. used the conjugated polymer dots (Pdots), which is nicely dispersible in aqueous solution for photocatalytic proton reduction [47]. The Pdots of hydrophobic conjugated polymer (**PFBT**) were prepared through nanoprecipitation method by mixing with an amphiphilic co-polymers (**PS-PEG-COOH**). Typically, **PFBT** was dissolved in THF together with the co-polymer **PS-PEG-COOH** and then was poured into water. THF was removed later by continuously sonicating and Ar purging. The well-dispersed nanoparticles in water were obtained. Particle size of the nanoparticles was around 30–50 nm measured by dynamic light scattering (DLS). The optical band gap of PFBT Pdots was 2.38 eV. Without any co-catalyst in the presence of ascorbic acid as sacrificial donor, Pdots showed excellent photocatalytic activity with a HER of 8.3±0.2 mmol h−1 g−1. Pdots configuration is very important because the pristine polymer itself did not show activity under the same test condition. The AQY of hydrogen evolution was 0.5% at 445 nm. However, after 1.5 h, the Pdots deactivated and precipitated out from the aqueous medium by forming bigger particle (**Figure 12**).

respect to **Pdots 1**, **Pdots 2** shows even more stability and works for more than 4 hour. The

three injections of the headspace gas in the reaction flask. Reproduced with permission from Wiley-VCH; see Ref. [47].

**Figure 12.** Preparation of PFBT Pdots and the diagram for light-driven hydrogen generation; visible light-driven hydrogen generation from water at room temperature. Conditions: **PFBT** Pdots, ca. 16.8 mg/mL; ascorbic acid: 0.2 M; pH 4.0 (adjusted with 1 M NaOH); LED lamp: white light (l>420 nm); the kinetic curve is monitored by a hydrogen sensor

of **Pdots 2**, suggests that the evolving hydrogen is mainly coming from the water. Since this kind of conjugated polymers is prepared by Pd-catalysed copolymerization method, where the residual Pd is known to be a good catalyst for proton reduction and it could behave as co-catalyst for this photocatalytic reaction. However, from the Pd poisoning experiments with carbon monoxide (CO) and ethylenediaminetetraacetic acid (EDTA), it suggests that the Pdots

**Figure 13.** Molecular structures of three organic D–A polymers (**1**, **2** and **3**) and a co-polymer PS-PEG-COOH; lightdriven hydrogen generation of Pdots **1** (17 μg/ml), **2** (13 μg/ml) and **3** (19 μg/ml) in water at ambient temperature. Conditions: ascorbic acid: 0.2 M; pH 4.0 (adjusted with 1 M NaOH); white LED light (420 nm, 17 W, 5000 K). Inset: H2

bubbles observed during photocatalysis. Reproduced with permission from RSC; see Ref. [48].

O and NaOD instead of H2

generation of **Pdots 2** was measured as 0.6% at 550 nm. The isotopic labelling

O and NaOH in a photocatalytic experiment

generation confirmed by GC-MS, the three peaks are signals from

Visible Light–Driven Hydrogen Production by Carbon based Polymeric Materials

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149

AQY for H2

experiment, using D2

(see details in the Supporting Information). Inset: H2

In order to further improve the system and study the reactivity sites of photocatalysis, Tian et al. subsequently investigated structures insight for highly efficient Pdots by both experimental and theoretical prospect. Pdots prepared from **1** and **2** (**Figure 13**) with benzothiadiazole (BT) units showed photocatalytic activity with a HER of 8.3±0.2 mmol h−1 g−1 and 50±0.5 mmol h−1 g−1, whereas Pdots of **3** without such a unit did not show any photocatalytic activity. It suggests that the BT unit has crucial role in proton reduction reaction [48]. The theoretical study suggests that proton adsorption is facilitated due to the presence of N sites in the electron withdrawing BT unit which in fact enhances the photocatalytic activity. With

**Figure 11.** Schematic representation of reactions for the synthesis of planarized conjugated polymers. Reproduced with permission from Wiley-VCH; see Ref. [46].

Visible Light–Driven Hydrogen Production by Carbon based Polymeric Materials http://dx.doi.org/10.5772/intechopen.70444 149

(**P1**-**P7**) are also exhibited excellent visible light-induced H2

eration for **P7** was measured as 2.3% at 420 nm (**Figure 11**).

**3.6. Polymer dots (Pdots)**

148 Visible-Light Photocatalysis of Carbon-Based Materials

permission from Wiley-VCH; see Ref. [46].

depositing any co-catalysts, whereas methanol and triethylamine mixture were used as the sacrificial electron donors. Out of all planar co-polymers, **P7** showed the highest photocatalytic activity with HER of 92 μmol h−1, while the rate was further found to be increased up to 116 μmol h−1 in the presence of Pt-nanoparticles as a co-catalyst. The AQY of hydrogen gen-

Till discussed all materials behaved as heterogeneous catalyst because these all have poor dispersibility in water, to run the photocatalytic experiment in absolutely aqueous condition and the organic/water mixed solvent were commonly used to make good dispersibility. Another drawback is that majority materials were worked under UV light and also in the presence of a co-catalyst such as Pt. In the absence of co-catalyst and visible light, all show very unsatisfactory performances. Tian et al. used the conjugated polymer dots (Pdots), which is nicely dispersible in aqueous solution for photocatalytic proton reduction [47]. The Pdots of hydrophobic conjugated polymer (**PFBT**) were prepared through nanoprecipitation method by mixing with an amphiphilic co-polymers (**PS-PEG-COOH**). Typically, **PFBT** was dissolved in THF together with the co-polymer **PS-PEG-COOH** and then was poured into water. THF was removed later by continuously sonicating and Ar purging. The well-dispersed nanoparticles in water were obtained. Particle size of the nanoparticles was around 30–50 nm measured by dynamic light scattering (DLS). The optical band gap of PFBT Pdots was 2.38 eV. Without any co-catalyst in the presence of ascorbic acid as sacrificial donor, Pdots showed excellent photocatalytic activity with a HER of 8.3±0.2 mmol h−1 g−1. Pdots configuration is very important because the pristine polymer itself did not show activity under the same test condition. The AQY of hydrogen evolution was 0.5% at 445 nm. However, after 1.5 h, the Pdots deactivated and precipitated out from the aqueous medium by forming bigger particle (**Figure 12**).

In order to further improve the system and study the reactivity sites of photocatalysis, Tian et al. subsequently investigated structures insight for highly efficient Pdots by both experimental and theoretical prospect. Pdots prepared from **1** and **2** (**Figure 13**) with benzothiadiazole (BT) units showed photocatalytic activity with a HER of 8.3±0.2 mmol h−1 g−1 and 50±0.5 mmol h−1 g−1, whereas Pdots of **3** without such a unit did not show any photocatalytic activity. It suggests that the BT unit has crucial role in proton reduction reaction [48]. The theoretical study suggests that proton adsorption is facilitated due to the presence of N sites in the electron withdrawing BT unit which in fact enhances the photocatalytic activity. With

**Figure 11.** Schematic representation of reactions for the synthesis of planarized conjugated polymers. Reproduced with

evolution activities even without

**Figure 12.** Preparation of PFBT Pdots and the diagram for light-driven hydrogen generation; visible light-driven hydrogen generation from water at room temperature. Conditions: **PFBT** Pdots, ca. 16.8 mg/mL; ascorbic acid: 0.2 M; pH 4.0 (adjusted with 1 M NaOH); LED lamp: white light (l>420 nm); the kinetic curve is monitored by a hydrogen sensor (see details in the Supporting Information). Inset: H2 generation confirmed by GC-MS, the three peaks are signals from three injections of the headspace gas in the reaction flask. Reproduced with permission from Wiley-VCH; see Ref. [47].

respect to **Pdots 1**, **Pdots 2** shows even more stability and works for more than 4 hour. The AQY for H2 generation of **Pdots 2** was measured as 0.6% at 550 nm. The isotopic labelling experiment, using D2 O and NaOD instead of H2 O and NaOH in a photocatalytic experiment of **Pdots 2**, suggests that the evolving hydrogen is mainly coming from the water. Since this kind of conjugated polymers is prepared by Pd-catalysed copolymerization method, where the residual Pd is known to be a good catalyst for proton reduction and it could behave as co-catalyst for this photocatalytic reaction. However, from the Pd poisoning experiments with carbon monoxide (CO) and ethylenediaminetetraacetic acid (EDTA), it suggests that the Pdots

**Figure 13.** Molecular structures of three organic D–A polymers (**1**, **2** and **3**) and a co-polymer PS-PEG-COOH; lightdriven hydrogen generation of Pdots **1** (17 μg/ml), **2** (13 μg/ml) and **3** (19 μg/ml) in water at ambient temperature. Conditions: ascorbic acid: 0.2 M; pH 4.0 (adjusted with 1 M NaOH); white LED light (420 nm, 17 W, 5000 K). Inset: H2 bubbles observed during photocatalysis. Reproduced with permission from RSC; see Ref. [48].

are the real photocatalysts. The DFT computation also suggests the unique structure of the Pdots from aggregated polymers benefits for lowering the energy barrier of proton reduction process via N atoms in BT units.

[2] Liu C, Wang K, Gong X, Heeger AJ. Chemical Society Reviews. Low bandgap semicon-

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### **4. Perspective**

Library of carbon-based organic photocatalysts are very few in comparison to the inorganic photocatalysts. The performance of these materials are still unsatisfactory but these organic materials have several advantages such as light-weight, easily processable and better reproducibility upon batch-to-batch variation. The organic photocatalysts are of great interest because there is a wide opportunity to introduce several new materials with different optical and electrochemical properties by small structural modification. By proper structural modification, the performance of these materials can be tuned and would be comparable with the inorganic materials. The major drawback of all of these organic carbon-based material is water dispersibility because of very poor solubility in water. The polymer dot encounters the solubility issue by some extent whereas rather need optimization to solve the associated problem such as unwanted aggregation along with light illumination, which causes deactivation and so on.

### **Acknowledgements**

The authors thanks the financial support from KA Wallenberg Foundation, Swedish Energy Agency, Sweden VR-Korea NRF joint climate change project, Stiftelsen Olle Engkvist Byggmästare and Göran Gustafssons Stiftelse.

### **Author details**

Palas Baran Pati1 , SU-IL In2 and Haining Tian1 \*

\*Address all correspondence to<EMAIL_ADDRESS>
1 Physical Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden

2 Department of Energy Systems Engineering, DGIST, Daegu, Republic of Korea

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are the real photocatalysts. The DFT computation also suggests the unique structure of the Pdots from aggregated polymers benefits for lowering the energy barrier of proton reduction

Library of carbon-based organic photocatalysts are very few in comparison to the inorganic photocatalysts. The performance of these materials are still unsatisfactory but these organic materials have several advantages such as light-weight, easily processable and better reproducibility upon batch-to-batch variation. The organic photocatalysts are of great interest because there is a wide opportunity to introduce several new materials with different optical and electrochemical properties by small structural modification. By proper structural modification, the performance of these materials can be tuned and would be comparable with the inorganic materials. The major drawback of all of these organic carbon-based material is water dispersibility because of very poor solubility in water. The polymer dot encounters the solubility issue by some extent whereas rather need optimization to solve the associated problem such as unwanted aggregation along with light illumination, which causes deactiva-

The authors thanks the financial support from KA Wallenberg Foundation, Swedish Energy Agency, Sweden VR-Korea NRF joint climate change project, Stiftelsen Olle Engkvist

\*

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[44] Li LW, Cai ZX, Wu QH, Lo WY, Zhang N, Chen LX, Yu LP. Journal of the American Chemical Society. Rational design of porous conjugated polymers and roles of residual

[45] Chu S, Wang Y, Wang CC, Yang JC, Zou ZG. International Journal of Hydrogen Energy. Bandgap modulation of polyimide photocatalyst for optimum H2 production activity

[46] Sprick RS, Bonillo B, Clowes R, Guiglion P, Brownbill NJ, Slater BJ, Blanc F, Zwijnenburg MA, Adams DJ, Cooper AI. Angewandte Chemie International Edition. Visible-lightdriven hydrogen evolution using planarized conjugated polymer photocatalysts.

[47] Wang L, Fernández-Terán R, Zhang L, Fernandes DLA, Tian L, Chen H, Tian H. Angewandte Chemie International Edition. Organic polymer dots as photocatalysts for visible light-

[48] Pati PB, Damas G, Tian L, Fernandes DLA, Zhang L, Pehlivan IB, Edvinsson T, Araujo CM, Tian H. Energy & Environmental Science. An experimental and theoretical study of

an efficient polymer nano-photocatalyst for hydrogen evolution. 2017;**10**:1372

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under visible light irradiation. 2013;**38**:10768

154 Visible-Light Photocatalysis of Carbon-Based Materials

driven hydrogen generation. 2016;**55**:12306-12310

2016;**55**:1792

## *Edited by Yunjin Yao*

Carbon-based photocatalysis has been considered as an economic, safe, renewable, and clean technology, for various applications. However, the pristine carbon material is usually restricted by unsatisfactory photocatalytic efficiency and practical applications due to the insufficient solar light absorption, the low-surface area, and the fast recombination of photogenerated electron-hole pairs. Various modification strategies, such as elemental and molecular doping, preparation of mesoporous carbon materials, and combination of conductive materials, are adopted to enhance the photocatalytic activity of carbon materials. In this book, we intend to describe the great potential of efficient and low-cost carbon-based materials in various realms, such as photodegradation of organic compounds, water splitting, and selective organic transformations.

Published in London, UK © 2018 IntechOpen © Arsgera / iStock

Visible-Light Photocatalysis of Carbon-Based Materials

Visible-Light Photocatalysis

of Carbon-Based Materials

*Edited by Yunjin Yao*


**5. Human-derived models of MM**

#### **5.1. 3D** *in vitro /ex-vivo* **human-derived models of MM**

Due to inter-species differences, animal models have incomplete predictive value for human MM disease and drug response. New models are, therefore, needed that more closely re‐ semble the *in vivo* situation in patients. Reliable, human-derived *in vitro* models, able to re‐ produce myelomagenesis within the specificity of BM microenvironment, are therefore of extreme value.

Kirshner and her group have reconstructed, *in vitro,* human BM microenvironment, through the proper overlay of matrix components, on which isolated cells from BM aspirate of MM patients were seeded [63]. Cells spontaneously redistributed throughout the gel-matrix 3D substrate, mimicking human BM architecture and BM-MM interactions, thus providing a powerful tool for understanding the biology of MM [89]. Strikingly, reconstructed BM al‐ lowed the expansion of primary myeloma cells, including the putative stem cell fraction. Moreover, the model allowed the assessment of the impact of anti-MM drugs on distinct cel‐ lular compartments inside a 3D architecture [63].

#### **5.2. 3D culture of human MM isolated cells and tissue explants in the microgravity-based RCCSTM bioreactor**

It is well known that the metabolic requirements of complex 3D cell constructs are substan‐ tially higher than those needed for the maintenance of traditional cell monolayers (2D cul‐ ture) kept in liquid media under static conditions. Dynamic bioreactors were primarily developed to modulate mass transfer, a crucial element for guaranteeing gas/nutrient sup‐ ply and waste elimination, essential factors for maintaining cell viability within large 3D cell/tissue masses. Despite a wide array of fluid-dynamic bioreactors has been devised [47,90], the low-shear environment and optimal mass transfer, needed for the long-term cul‐ ture of functional 3D tissue constructs and explants, were attained only with the introduc‐ tion of the microgravity-based *Rotary Cell Culture System* (RCCS™, Synthecon Inc., USA) bioreactors (91,92; a vast literature is also available at http://www.synthecon.com). The rele‐ vance of this technology in enabling the long-term culture of complex tissue-like engineered 3D bio-constructs and tissue explants of various origin has been demonstrated also by our group, and, namely, in the case of bone [31,47.93].

On this basis, we successfully employed the microgravity-based RCCSTM technology for the generation (and long-term maintenance) of viable human-derived MM tissue explants and 3D cell constructs. Fig. 4 shows the culture chamber of the RCCS™ microgravity-based bio‐ reactor, and histo-morphological images of the *ex-vivo* models of human MM developed by our group. Isolated cells from the RPMI myeloma cell line, kept in Bioreactor, spontaneously self–aggregated forming spheroid-like structures which retained viability and were identifi‐ able with the specific anti-CD38 monoclonal antibody (Fig.4B).

tion from the spontaneous monoclonal gammopathy to a disease that fully recapitulate the biological and clinical features of human MM. In fact, Vk\*Myc mice are characterized by the accumulation of slowly proliferating plasma cells exclusively inside the BM. Moreover, high levels of monoclonal antibody are detectable and end-organ damage develops, including anemia, kidney failure and lytic bone disease [87]. The model was found to be highly predic‐ tive of the activity of anti-myeloma drugs [88], including those that target microenviron‐

Due to inter-species differences, animal models have incomplete predictive value for human MM disease and drug response. New models are, therefore, needed that more closely re‐ semble the *in vivo* situation in patients. Reliable, human-derived *in vitro* models, able to re‐ produce myelomagenesis within the specificity of BM microenvironment, are therefore of

Kirshner and her group have reconstructed, *in vitro,* human BM microenvironment, through the proper overlay of matrix components, on which isolated cells from BM aspirate of MM patients were seeded [63]. Cells spontaneously redistributed throughout the gel-matrix 3D substrate, mimicking human BM architecture and BM-MM interactions, thus providing a powerful tool for understanding the biology of MM [89]. Strikingly, reconstructed BM al‐ lowed the expansion of primary myeloma cells, including the putative stem cell fraction. Moreover, the model allowed the assessment of the impact of anti-MM drugs on distinct cel‐

**5.2. 3D culture of human MM isolated cells and tissue explants in the microgravity-based**

It is well known that the metabolic requirements of complex 3D cell constructs are substan‐ tially higher than those needed for the maintenance of traditional cell monolayers (2D cul‐ ture) kept in liquid media under static conditions. Dynamic bioreactors were primarily developed to modulate mass transfer, a crucial element for guaranteeing gas/nutrient sup‐ ply and waste elimination, essential factors for maintaining cell viability within large 3D cell/tissue masses. Despite a wide array of fluid-dynamic bioreactors has been devised [47,90], the low-shear environment and optimal mass transfer, needed for the long-term cul‐ ture of functional 3D tissue constructs and explants, were attained only with the introduc‐ tion of the microgravity-based *Rotary Cell Culture System* (RCCS™, Synthecon Inc., USA) bioreactors (91,92; a vast literature is also available at http://www.synthecon.com). The rele‐ vance of this technology in enabling the long-term culture of complex tissue-like engineered 3D bio-constructs and tissue explants of various origin has been demonstrated also by our

ment, and may potentially help to select new agents for evaluation in clinical trials.

**5. Human-derived models of MM**

50 Multiple Myeloma - A Quick Reflection on the Fast Progress

extreme value.

**RCCSTM bioreactor**

**5.1. 3D** *in vitro /ex-vivo* **human-derived models of MM**

lular compartments inside a 3D architecture [63].

group, and, namely, in the case of bone [31,47.93].

**Figure 4. RCCS TM-based 3D** *ex-vivo* **models of MM developed by our group. A:** Detail of the culture chamber of the RCCS™ microgravity-based bioreactor; **B**: Monotypic 3D multi-cellular spheroids (RPMI cell line) cultured for 1 week in the RCCS™ bioreactor (H&E staining, left panels; CD38 staining, right panels); **C:** 3D tissue culture of skin biop‐ sies (1 week) showing intact architecture and identifiable blood and lymphatic (D2-40+) vessels **D**: MM tissue explants cultured for 3 days in the RCCS™ bioreactor (H&E staining), in the absence or presence of Bortezomib, the latter show‐ ing plasma cells death. Arrows indicate bone lamellae.

The suitability of our method for the culture of human tissue samples was, firstly, proved by using skin biopsies, which retained intact epidermal and dermal architecture, including ker‐ atin stratum and skin annexes. Moreover, both blood and lymphatic vasculature was identi‐ fiable and exhibited normal morphology, in particular patent lumen and complete endothelial lining (Fig.4C). The 3D culture of thick sections of human MM tissue explants fully preserved tissue architecture and microenvironment integrity (Fig.4D) for extended pe‐ riods of time. Moreover, the system was suitable for the assessment of drug sensitivity, not only of tumor compartment, but also of angiogenic vessels (Fig.4D). Indeed, quantification of MVD in treated specimens could represent a unique method to assess the anti-angiogenic effect of a drug in human samples *ex vivo*. Finally, specialized functions of both MM cells and their microenvironment, including beta-2 microglobulin and cytokine release and met‐ alloproteases activities, could be also assessed (M. Ferrarini *et al*., *submitted*). Overall, these observations suggest that the 3D culture model in Bioreactor can be exploited as a novel translational tool, allowing prospective pre-clinical toxicity and drug efficacy testing in indi‐ vidual patients.

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**7.3** *Picralima nitida* **Stampf Th. et H. Dur.**

*Picralima nitida* is the only species of the genus Picralima and it is related to Hunteria and Pleiocarpa. it belongs to the apocynaceae family. *P. nitida* has widely varied applications in West Africa folk medicine. The indole alkaloid alstonine was identified as the major component of the fruit rind of *P. nitida*, a plant-based treatment administered to psychotic patients in Nigeria [34]. Alstonine was given prior to apomorphine/ amphetamine administration and observed for climbing behavior and stereotypy, the effect of the alkaloid on haloperidol-induced catalepsy was also assessed [89]. Further studies of alstonine showed a clear antipsychotic profile in rodents, closer to atypical than to typical antipsychotics. Apparently, apomorphine induced stereotypy and amphetamine-induced lethality were significantly reduced by alstonine, suggesting a decrease in mesolimbic dopamine, alstonine reversed haloperidol-induced catalepsy, indicating that nigrostriatal dopamine transmission is not lessened [89]. Alstonine was found to reduce negative symptoms, through a mechanism involving 5HT2A,C receptors, and reverses interaction deficits induced by MK801 [90]. Further studies by Linck et al. [35] indicated that alstonine indirectly modified DA receptors, precisely by modifying DA uptake. This unique mechanism for DA transmission modulation backs the antipsychoticlike effects of alstonine and is attuned with its behavioral profile in mice and apparent effects in patients. These findings may signify an innovation in the antipsychotic development field [35].


**4. Conclusion**

196 Chromatography and Its Applications

**Carbon (C) (H) δ Literature (CDCl3/CD3OD-5%)1 C H**  1 162.8 - 161.89 - 2 149.7 - 148.91 - 3 115.9 5.71 (dd, 2.0, 2.0) 116.76 5.76 (t, 2.0) 4 31.60 2.40 (m) 31.07 2.41 (ddq, 1.6,

5 45.70 1.82 (d, 2.0) 45.26 1.86 (ddd, 1.6,

6a 29.0 2.22 (dd, 2.0, 2.0) 28.80 2.27 (dt, 14.0, 2.0) 6b 1.76 (dd, 2.0, 2.0) 1.73 (dt, 14.0, 2.0) 7 83.6 4.85 (d, 2.0) 83.55 4.76 (d, 2.0) 8 47.5 - 46.74 - 9 39.6 2.52 (d, 2.0) 39.06 2.34 (brd, 4.0) 10 42.7 - 42.06 - 11 75.0 4.59 (d, 6.0) 73.60 4.56 (d, 4.0) 12 77.1 4.32 (d, 6.0) 76.00 4.23 (brs) 13 82.3 - 81.74 -

15 68.5 6.04 (d, 12.0) 67.00 6.09 16 167.5 - 168.24 - 18 170.5 - 171.25 - 19 18.6 1.64 (s) 18.12 1.60 (s) 29 19.9 1.18 (d, 6.0) 19.55 1.20 (d, 6.8) 30a 74.2 4.78 (d, 8.0) 73.6 4.78 (d, 8.0) 30b 3.81 (dd, 8.0, 2.0) 3.77 (d, 8.0) 1' 169.0 - 170.40 - 2' 20.6 1.98 (s) 20.49 2.09 (s) 3' 171.7 - 171.56 - 4' 113.4 6.26 (s) 113.17 6.26 (d, 2.0) OMe (5') 52.9 3.78 (s) 53.02 3,84 (s)

Table 2. Chemical shifts in NMR 1H (200 MHz, CDCl3) and NMR 13C (50 MHz, CDCl3) of

12.0) 49.63 3.24 (brd, 11.0)

14 51.1 3.29 (ddd, 15.0, 2.0, 2.0,

1 Vieira, et al. (2000)

neosergeolide (**2**).

2.0, 6.8)

12.4, 14.0)

The HPLC analysis of infusions (aqueous extracts) of stems and roots of *P. sprucei* revealed higher quantities of isobrucein B than neosergeolide, 40 fold, for both infusions. Considering this information and *in vitro* activity of both compounds, it is very likely that isobrucein B plays more important role for the antimalarial activity than neosergeolide.

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The high performance liquid chromatography has proved to be a powerful tool in the plant extract analysis. The possibility to perform qualitative and quantitative analysis, by HPLC, enables the development of new phytoterapeutical products from the Amazon biodiversity.

#### **5. Acknowledgment**

The autors wish to thank Dr Wanderli Pedro Tadei and CNPq/ FAPEAM - PRONEX, Rede Malária for financial support to the publication of this chapter, Massuo Kato for use of analytical HPLC apparatus and Profs. Norberto P. Lopes and Valquiria P. Jabor for helpful comments regarding this manuscript.

#### **6. References**

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**1. Introduction**

*Quantum computing* [1–3] is one of the hot topics in computer science in the last few decades. There are many problems where quantum algorithms outperform the best known classical algorithms [4–12].

One of these problems are problems for strings. Researchers show the power of quantum algorithms for such problems in [13–22].

In this paper, we consider three problems:

Our algorithms use some quantum algorithms as a subroutine, and the remaining part is classical. We investigate the problems in terms of query complexity. The query model is one of the most popular in the case of quantum algorithms. Such algorithms can do a query to a black box that has access to the sequence of strings. As a running time of an algorithm, we mean a number of queries to the black box.

In the paper, we suggested a quantum comparison procedure for two strings. We show that its quantum complexity is Θ(√*k*), where *k* is the length of strings. The classical complexity is Θ(*k*). Thus, the quantum algorithm has a quadratic speed-up compared to classical algorithms. We propose a quantum algorithm that is based on "the first one search" (The minimal element satisfying a condition) problem algorithm from [23–26]. This algorithm is a modification of Grover's search algorithm [27,28]. Another important

**Citation:** Khadiev, K.; Ilikaev, A.; Vihrovs, J. Quantum Algorithms for Some Strings Problems Based on Quantum String Comparator. *Mathematics* **2022**, *10*, 377. https:// doi.org/10.3390/math10030377

Academic Editors: Fernando L. Pelayo, Mauro Mezzini and Jan Sładkowski

Received: 12 November 2021 Accepted: 22 January 2022 Published: 26 January 2022

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

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

41

algorithm for the search is described in [29]. Using this idea, we obtain quantum algorithms for several problems.

The first problem is the String Sorting problem. Assume that we have *n* strings of length *k*. It is known [30] that no quantum algorithm can sort arbitrary comparable objects faster than *O*(*n* log *n*). At the same time, several researchers tried to improve the hidden constant [31,32]. Other researchers investigated the space bounded case [33]. We focus on sorting strings. In a classical case, we can use an algorithm that is better than arbitrary comparable objects sorting algorithms. It is radix sort that has *O*(*nk*) query complexity [34] for a finite size alphabet. It is also a lower bound for classical (randomized or deterministic) algorithms that is Ω(*nk*). Our quantum algorithm for the string sorting problem has query complexity *O*(*n*(log *n*) · √*k*) = *O*˜(*n* √*k*), where *O*˜ does not consider log factors. It is based on standard sorting algorithms [34] or Heapsort [34,35] and the quantum algorithm for comparing strings. Additionally, we use the idea of a noisy comparison procedure for sorting [36].

The second problem is the following. We have *n* strings of length *k*. We can assume that string symbols are letters from any constant size alphabet, for example, binary, Latin alphabet, or Unicode. The problem is finding the string that occurs in the sequence most often. The problem [37] is one of the most well-studied ones in the area of data streams [38–41]. Many applications in packet routing, telecommunication logging, and tracking keyword queries in search machines are critically based on such routines. The bestknown classical (randomized or deterministic) algorithms require Ω(*nk*) queries because an algorithm should at least test all symbols of all strings. The deterministic solution can use the radix sort algorithm [34] or the Trie (prefix tree) [42–45] that allow achieving the required complexity.

We propose a quantum algorithm that is based on the sorting algorithm from the first problem. Our algorithm for the most frequent string search problem has query complexity *O*(*n*(log *n*) · √*k*) = *O*˜(*n* √*k*). If log2 *n* = *o*( √*k*), then our algorithm is better than classical counterparts. Note that this setup makes sense in practical cases.

The third problem is the Intersection of Two String Sequences problem. Assume that we have two sequences of strings of length *k*. The size of the first set is *n*, and the size of the second one is *m*. The first sequence is given, and the second one is given in an online fashion, one by one. After each requested string from the second sequence, we want to check whether this string belongs to the first sequence. We propose a quantum algorithm for the problem with quantum query complexity *O*((*n* + *m*(log *m* + log log *n*)) · log *n* · √*k*) = *O*˜((*n* + *m*) √*k*). The algorithm uses a quantum algorithm for sorting strings. At the same time, the best-known classical (randomized or deterministic) algorithm requires Ω((*n* + *m*)*k*) queries, and this bound is achieved using the radix sort algorithm or the Trie data structure.

The paper is an extended version of a conference paper [46].

The structure of the paper is the following. Discussion on the computation model is situated in Section 2. We present the quantum subroutine that compares two strings in Section 3. Then, we discuss three problems: Strings Sorting problem in Section 4, the Most Frequent String Search problem in Section 5, and Intersection of Two String Sequences problem in Section 6. Section 7 contains the conclusions.


**Author details**

M. Chandra Surya Rao1 \*, B. Narsimha Rao2 , D.V. Swami3 , P. Ashok3 , G. Roja Ramani4 and B. Babu Rao3

1 MS Swaminathan School of Agriculture, Centurion University of Technology and Management, Odisha, India

2 ICAR-Indian Institute of Palm oil Research, Pedavegi, Andhra Pradesh, India

3 Dr. Y.S.R. Horticultural University, Venkataramannagudem, Andhra Pradesh, India

4 Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal, India

\*Address all correspondence to<EMAIL_ADDRESS>
© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Management and Processing of Palm Oil (*Elaeis guineensis *Jacq): The Crop for Future DOI: http://dx.doi.org/10.5772/intechopen.108579*


**9.2 Meningioma close to optical apparatus and skull base vital structures**

Management of meningioma at anterior skull base close or adhered to optical apparatus is always challenging in radiosurgery considerations (**Figure 5**).

#### **Figure 5.**

*Treatment of anterior cranial fossa meningioma near bilateral optic nerves using LINAC 27.5 Gy in 5 fractions in our centre.*

Tumor control has to be balanced by risk of high-dose radiation exposure leading to optic neuritis and radiation-induced neuropathy. As mentioned, vision preservation can be achieved by confounding the maximum radiation exposure of optic pathway to 8–10 Gy per session. Su et al. in Taiwan treated 4 patients with large tumor volume by volume-staged Gamma Knife Radiosurgery. In stage I, the treatment was focused on the basal part of tumor (mean volume 13.2 cm3 , range 3.9–54.7 cm3 ) with marginal dose of 13.5 Gy (range 12–15 Gy), followed by smaller upper portion of tumor close to the optical apparatus (mean volume 4.3, range 1.5–16.2 cm3 ) with marginal dose of 9 Gy (range 9–10 Gy) in stage II. 34–46% tumor reduction was observed during the median follow-up period of 100.5 months with no new visual deterioration [35]. A study from Williams et al. on parasellar meningiomas treatment with Gamm Knife Radiosurgery had reviewed the tumor control together with any radiation induced neurological deficit. Totally 138 patients were reviewed from 1989 to 2006. The mean radiation volume was 7.5 cm3 (range 0.2–54.8 cm3 ). Radiographic progression free suvivial at 5 and 10 years were 95.4% and 69%. Only 4% of their patients had radiation related optic neuropathy [36].

Starke et al. had also similar promising findings in Gamma Knife Radiosurgery treatment for other skull base meningiomas. Around 10% of their cases had deterioration in neurological symptoms [37]. His group in another review specifically focus on posterior fossa cases in 152 patients. The radiographic progression free survival at 3, 5, and 10 years to b 98%, 96%, and 78% respectively. 9% of study patients showed deterioration in symptom. They concluded the predicative factors of new or worsening symptoms were clival or petrous-based location [38]. In Austria, Kreil et al. had a review of 200 patients with skull base meningimas with a follow up of 5–12 years. The tumor volume ranged from 0.38 to 89.8 cm3 (median 6.5 cm3 ), and the median dose was 12 Gy (7–25 Gy). They achieved actuarial progression free survival rate of 98.5% at 5 years and 97.2% at 10 years with only 1% radiation induced oedema and 4.5% neurological deterioration [39]. The promising tumor control with low new neurological deficit in Gamma Knife Radiosurgery can also be demonstrated in centres using LINAC system. Villavicencio et al. in Brigham and Women's Hospital had reviewed 56 patients with treatment for skull base meningiomas. The minimal peripheral dose ranged from 12 to 18.5 Gy (mean 15 Gy). The actuarial progression free rate was 95% in median follow-up of 26 months (range 6–66 months) [40].

In cases where skull base meningiomas had extension into the internal auditory meatus, the concern will be more towards the facial nerve function and hearing preservation after radiation. Pollock et al. had reviewed 16 patients from 1992 to 2002. The median tumor margin dose was 15 Gy. They achieved 63% tumor reduction in size at medial follow-up period of 36 months. No facial nerve palsy was reported, and 1 patient had worsened facial sensation. The actuarial incidences of hearing preservation was 93% at 1 year, 84% at 2 years and 42% at 5 years [41].

#### **9.3 Cavernous sinus meningioma**

Meningiomas at cavernous sinus are cases always have dilemma with clinical management due to its complex anatomy and its specific location in the antero-lateral skull base (**Figure 6**). Despite the advancement in microscopic and endoscopic surgical technique, still a complete radical excision with minimal anantomo-functional preservation remains very challenging. UCLA De Salles group had proposed a radiosurgery grading system for this specific group of tumor (**Table 5**) [42]. Pittsburgh group reviewed 79 patients with cavernous sinus meningioma between October 1987 and December 1995. The median marginal tumor dose was 15 Gy. The achieved actuarial tumor control rate was 95+/−2.8% at 5 years an 88.2+/−7% at 12 years with 12.7% patients experienced adverse radiation effects [43].

#### **Figure 6.**

*Meningioma involving cavernous sinus and petrosal apex was treated by LINAC stereotactic radiotherapy using 25 Gy in 5 fractions in our centre.*

#### **Table 5.**

*Radiosurgery grading system for cavernous sinus meningiomas by UCLA.*

Takanashi had reviewed 101 skull base meningioma patients with Gamma Knife Radiosurgery performed from 1991 to 2003. Among those cases, 38 cases are cavernous sinus in location with mean dose delivered to the tumor 14.5 to 15.2 Gy. The overall tumor control rate were 95.5% in the mean follow-up of 51.9 months (range 6–144 months) [44]. Fariselli et al. had proposed a multidisciplinary treatment algorithm involving microsurgery and stereotactic radiosurgery [45]:

### **9.4 Large tumor volume**

The consensus of tumor size in consideration of radiosurgery for meningioma is generally around 30–35 mm in diameter. Tumor volume greater than

#### *Overview of Radiosurgery for Intracranial Meningiomas DOI: http://dx.doi.org/10.5772/intechopen.100006*

8 cm3 is believed to have poor outcome compared. Starke et al. retrospectively reviewed the Gamma Knife Radiosurgery outcome of 75 patients with mean follow-up of 6.5 years (range 0.5–21 years) whom had tumor volume more than 8 cm3 . The actuarial rates of progression-free survival were 90.3% at 3 years, 88.6% at 5 years and 77.2% at 10 years. Factors associated with tumor progression included [46]: