Solution:Sr. No. Scenarios Identification 1*5 Justification 3*5 1. Sara during the first year of her life feels pleasure that centers on the mouth. Things such as chewing, sucking, and biting are the sources of pleasure that reduces her anxiety. Oral This occurs during the first year of life and the erogenous zone during this stage is the mouth. At this stage, pleasures mainly come from mouth. According to Freud, an adult who is fixated at the early oral stage will engage in abundance of oral activities such as eating, drinking, or smoking. This person also will engage in activities that are symbolically equivalent to those oral activities such as collecting things, being a good listener etc. 2. During second year of life, Shazia feels pleasure on bowel and bladder elimination. The control she learns to exert over her bodily functions is manifested in toilet-training. Anal It starts during the second year of life, and the erogenous zone is the anus- buttocks region. It is the stage when the child has to gain control over his physiological processes so that they function in accordance with the demands of the society i.e. the child must be toilet trained. Fixation at this stage may result in physical problems. 3. Ali during the age span of 3 to 5 years feels pleasure for the genitals and coping with incestuous sexual feelings for his mother. He wants to possess his mother exclusively and get rid of his father to enable him to do so. On the other hand, Sana during 3 to 5 years of her age feels sexual attraction towards her father and hatred feelings towards her mother. Phallic This starts from the third year of life to about fifth year, and the erogenous area are the genital area. This is one of the most complicated and controversial of Freud’s stages. It is the stage of Oedipus and Electra complexes, the resolution of which has profound influence on an adult’s life. The male child experiences the Oedipus complex and the female experience Electra complex. 4. At the fifth to twelfth years of age, Ahmad feels that his sexuality is repressed into unconscious and he started focusing to identify himself with the same sex parent and interacts with same sex peers. Latency It lasts from about sixth year to about twelfth year. Here the sexual interests are displaced to substitute activities such as learning, athletics, and peer group activities. 5. When Rashid reached at the age of puberty, he feels that he reaches the physical sexual maturity and the genitals become the primary focus of pleasurable sensations, which he seeks to satisfy in the heterosexual relationships. Genital It is the final stage of development that occurs following puberty. It is the time at which the person emerges from pre genital stages as the adults as he/ she destined to become. Now the child has become a socialized adult with heterosexual interests leading to marriage and child- rearing. If, however, the experiences during the pre-genital stages cause fixation, they will manifests themselves throughout one’s adult life.
SOLVED BIO204 GDB1 Solution and discussion
Graded Discussion Board
BIO204 – Principles of Biochemical Engineering
GDB Date: 8 August to 9 August, 2019
Why freeze drying is preferred for the concentration and preservation of enzymes?
(You need to provide precise and to the point answer, avoid irrelevant details)
Your discussion must be based on logical facts and should be to the point
Your comments on the topic should be less than 60 words.
The GDB will remain open for 2 working days/48hours.
Do not copy or exchange your answer with other students.
Two identical / copied comments will be marked Zero (0) and may damage your grade in the course.
Obnoxious or ignoble answer should be strictly avoided.
Questions / queries related to the content of the GDB, which may be posted by the students on MDB or via e-mail, will not be replied till the due date of GDB is over.
Students need to post their answer on Graded discussion board (GDB) and not on MDB.
You cannot participate in the discussion after due date via email.
The GDB will remain open only during the specified time and date.
For Detailed Instructions please see the GDB Announcement.
Freeze drying (lyophilization) is a dehydration process which allows water to sublimate directly from solid phase to vapour phase at and below the freezing temperature of the material. Sub-atmospheric pressure (< 40 Pa) is maintained in most freeze-drying operations and the condensed water is immediately removed (Pikal, 2007). Freeze drying has been for decades one of the most preferred preservation methods for culture collection maintenance (Morgan et al., 2006). Due to high viability losses, an initial bacterial load of greater than 107 viable cells/mL has been recommended to ensure sufficient cells survive the freeze-drying process, thereby giving better success in storage, reconstitution and propagation (Bozoglu et al., 1987).
At commercial scale, operational and capital costs of freeze drying are very high. The freeze-drying process operates in batch mode and requires long drying times and large drying units to achieve mass production. Even so, freeze drying is currently the only drying method used at commercial scale for production of starter cultures intended for use as primary acid producers in dairy fermentations.
It is reported that the majority of bacterial death occurring during freeze drying happens during the freezing stage before the drying (sublimation) process commences. A slow freezing rate leads to higher bacterial death in the subsequent sublimation stage (Uzunova-Doneva and Donev, 2002). Rapid freezing, with formation of smaller ice crystals, favours better bacterial survival. On the other hand, formation of large ice crystals during slow freezing causes structural and physiological injury to the bacterial cells and causes damage to cell membranes that cannot be repaired upon subsequent drying or rehydration (Gardiner et al., 2000).
Many studies have exploited the addition of ‘protectant’ substances to enhance survival, and have investigated the use of low-cost food ingredients as protectants rather than substances such as glycine betaine (Cleland et al., 2004). Recent examples include work by Jagannath et al. (2010), who studied the survival of various probiotic bacteria after freeze drying. The survival obtained ranged from 67% to 70% depending on bacterial species. Zamora et al. (2006) compared the survival of twelve strains of lactic acid bacteria after freeze drying and reported a range from 3.3% to 100% depending on the bacterial type and protectant type used. For example, the survival of four strains of Lactococcus garviae was reported to be 100% when non-fat skim milk was used as the protectant (Zamora et al., 2006). Reddy et al. (2009) studied survival of three probiotic lactic acid bacteria with eleven different protectants (at various solids concentrations), and suggested that these protected not only the viability of the probiotic lactic acid bacteria but also their functional properties.