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Wood and Wood Modification
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
The structure of wood is a result of the requirements of the living tree. Xylem is the part of the tree that in everyday speech is called wood and consists of hollow tubes (cells) with a length of a few millimetres connected to each other (Figure 1.4). The majority of these cells within the living tree are dead, i.e., the protoplasm is absent, leaving hollow cells with rigid walls. Protoplasm is the living content of a cell that is surrounded by a plasma membrane, i.e., a biological membrane that protects the cell from its environment. The only living cells in a tree are located in the cambium, in the sapwood rays, and in the inner bark (phloem). Their functions are related to the growth of the tree (cambium cells) and to the storage of the nutrients produced by photosynthesis.
Cellular Level Water Distribution and Its Investigation Techniques
Published in M. Azharul Karim, Chung-Lim Law, Intermittent and Nonstationary Drying Technologies, 2017
Chung-Lim Law, Md. Imran H. Khan, R. Mark Wellard, Md. Mahiuddin, M. Azharul Karim
Food materials are a composite of different elements with cellular tissue. In plant-based food material, cells are the smallest structural units that are capable of functioning independently. According to biological analysis, a cell of a plant-based food material is composed of protoplasm surrounded by the plasma membrane (plasma lemma) and the cell wall. The protoplasm is an aqueous colloidal complex of proteins and other organic and inorganic substances. It comprises the living nucleus and the cytoplasm (or ground substance). The nucleus, cytoplasm and plasma membrane of a cell are called the protoplast and constitute a living unit, distinct from the inert walls and inclusions (Iglesias and Chirife 1982), as shown in Figure 9.1. However, in food processing research, researchers consider only three or four components, as needed. Vacuoles, cytoplasm, extracellular space, and the cell wall are the main physiological components in plant-based food material which predominantly consists of water. These four components have been considered by food researchers with a special interest in investigating post-harvest quality assurance, for instance, investigating core water (Cho et al. 2008; Clark et al. 1998; Melado-Herreros et al. 2013), internal browning (Cho et al. 2008; Clark and Burmeister 1999; Gonzalez et al. 2001) and microstructural heterogeneity (Defraeye et al. 2013; Winisdorffer et al. 2015).
Osmotic Dehydration of Fruits and Vegetables
Published in Arun S. Mujumdar, Handbook of Industrial Drying, 2020
Piotr P. Lewicki, Andrzej Lenart
The protoplast is composed of protoplasm enclosed in a membrane called plasma-lemma, vacuoles, and other structural elements such as the nucleus, plastids, and so on. The plasmalemma is a protein-lipid layer that regulates the contact between the protoplast and the environment. It is 7.5−10 nm thick (2), permeable to water, and selectively permeable to other substances. Protoplasm is a colloidal solution of proteins and lipoproteins in water. The vacuole is suspended in protoplasm and is enclosed in a membrane called the tonoplast. It contains a solution of minerals, sugars, and other organic compounds in water.
A review of microalgal cell wall composition and degradation to enhance the recovery of biomolecules for biofuel production
Published in Biofuels, 2023
Syafiqah Md Nadzir, Norjan Yusof, Norazela Nordin, Azlan Kamari, Mohd Zulkhairi Mohd Yusoff
Temperature influences the growth rate of microalgae, and there is an acceptable range of minimum and maximum temperatures for microalgal growth. According to a study conducted by Chokshi et al. [154], the cell size of Acutodesmus dimorphus varies with the culture temperature, with a 57% increase in cell size at 38 °C compared to 25 °C. Jiménez et al. [128] demonstrated that acute heat shock (40 °C) causes 96% of D. viridis cells to swell, and microscopic analysis indicates that the cells undergo nuclear expansion, mitochondrial disintegration, organelle membrane disruption, and eventually plasma membrane alteration. According to Barreto-Filho et al. [145], heat shock at 44 °C causes the cell of Ankistrodesmus densus to shrink, and microscopic examination revealed vacuolisation in the cytoplasm, damaged protoplasm with membrane detachment from the cell wall, and destruction of the thylakoid membrane.
Effects of pure oxygen aeration on organic pollutants removal performance and soluble microbial products characteristics of salt-tolerant activated sludge
Published in Environmental Technology, 2022
Hong-Ling Zhang, Ya-Qi Hu, Yong Zhang, Dan-Ning Qin, Hong Wang
Although the biological treatment of saline wastewater by far is the most popular method for organic removal [6], salinity would influence the degradation rate via the inhibition of microbial activity or enzyme activity. Besides, with the increase of salinity, the water density correspondingly increases, creating greater resistance to decantation through higher buoyant forces [7]. The high salt concentration and osmotic pressure would cause microorganism cell dehydration and cell protoplasm separation resulting in death of microorganism [8]. The utilization of salt-tolerant sludge in biological units seems to be a more possible approach for saline wastewater treatment [9,10]. Application of salt-tolerant sludge in hyper saline wastewater treatment could overcome the above stated problems. Cui et al. [11] found that domesticated activated sludge had good resistance to high salinity shock by comparing unacclimated and acclimated sludge. Salt-tolerant Halobacter-supplemented mixture by an activated sludge culture was found to be the best culture tested in terms of chemical oxygen demand (COD) removal efficiency [6]. Sivaprakasam et al. [12] also found that salt-tolerant bacterial consortia showed noticeable biodegradation at all tested saline concentrations (2%–10%) with 80% COD reduction.
Hydrogen sulfide mediated alleviation of cadmium toxicity in Phlox paniculata L. and establishment of a comprehensive evaluation model for corresponding strategy
Published in International Journal of Phytoremediation, 2020
Hong-Rui Wang, Yan-Hui Che, Dan Huang, Hong Ao
Atomic absorption experiment showed a negative correlation between H2S concentration and Cd enrichment (Figure 4). Meanwhile, the transfer factors of Cd showed a significant downward trend after H2S addition, which indicates that Cd is enriched in the root (Figure 4B). Cd in the root gets deposited on the cell wall to prevent excessive entry to the cell protoplasm and prevents cell damage (Yao et al.2014). In Athyrium yokoscense, an hyperaccumulator plant, 70–90% of Cd absorbed by the roots is accumulated on the cell wall of root tips (Yoshihara et al.2014). To conclude, when low concentration (0.3, 0.6, and 1.2 mg/kg) of Cd exists in soil, H2S significantly increase the absorption and decrease transfer of Cd (Figure 4) and simultaneously increases antioxidant enzymes to protect plants from Cd poisoning.