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پایان نامه رشته زبان انگلیسی :تاثیراصلاحات صریح وضمنی برعملکرد دستوری فراگیران زبان انگلیسی پسر

نیاز به تصحیح ایرادهای ساختاری فراگیران زبان درحرفه آموزش امری بدیهی است، اما معلمان اغلب از مقدار ویاحتی چگونگی تصحیح کردن مطمئن نیستند.به رغم اینکه تحقیقات گوناگونی مبنی بر تأثیرگذاری انواع شیوه های گوناگون تصحیح خطاهای دستوری صورت گرفته، عملا پژوهشهای کمی دراین زمینه وجوددارندکه نقش تصحیح خطاهای دستوری را ازطریق عملکرد متوالی فراگیران موردبررسی قرارداده باشند. هدف اصلی این تحقیق این بودکه آیا دو شیوه  تصحیح، ضمنی یا رفع اشکال مستقیم، میتواند یادگیری دستور زبان انگلیسی برای فراگیران فارسی زبان در سطح متوسط را افزایش دهد. هدف دیگر تحقیق حاضر این بود که کدامیک از شیوه های تصحیح، ضمنی یا رفع اشکال مستقیم، به پیشرفت دانش دستوری زبان آموزان ایرانی مقطع متوسط کمک می کند. علاوه براین، دوروش رفع اشکال ضمنی، اعلانی وپرسشی، تحت بررسی قرارگرفتند بدین منظور که زبان آموزان ایرانی مقطع متوسط کدامیک از شیوه های رفع اشکال ضمنی را ترجیح می دهند توسط معلم استفاده شود  .پنجاه نفر از دانش آموزان پسر زبان انگلسی مقطع متوسط کانون زبان ایران در شعبه یزد در این تحقیق شرکت کردند. آنها به دوگروه رفع اشکال مستقیم و غیرمستقیم تقسیم شدند. قبل ازاینکه فرایند متوالی ارائه بازخورد تصحیحی آغاز شود در ابتدا یک پیش آزمون اجرا شد وسپس در پایان دوره آموزش، یک پس آزمون اجراگردید. روش اجرای آزمون ومحتوای آن برای هردو گروه رفع اشکال مستقیم و غیر مستقیم یکسان بود. تنها تفاوت  درانجام تصحیح اشکالات گرامری دانش آموزان درحین آموزش بود. بدین صورت که اشتباهات گروه رفع اشکال مستقیم بصورت آشکارا، اما اشتباهات گروه رفع اشکال ضمنی بطور ضمنی اصلاح شد. نتایج حاصل از این تحقیق نشان داد که اولا هر دو شیوه تصحیح، ضمنی و رفع اشکال مستقیم، به پیشبرد دانش دستوری فراگیران به یک نسبت کمک نموده اند و مقایسه بین عملکرد دستوری دو گروه نشان داد که تفاوت معنی داری  بین استفاده از رفع اشکال مستقیم وغیرمستقیم وجودندارد. بررسی درصدهای دوروش رفع اشکال ضمنی، اعلانی وپرسشی، نشان داد که فراگیران رفع اشکال پرسشی را بر اعلانی ترجیح داده اند. یافته های این تحقیق نشان می دهد که استفاده از بازخورد تصحیحی آشکار وضمنی مفیدبوده و فرایند یادگیری قواعد دستوری یک زبان جدیدراآسان تر می کند.

 

 

 

کلمات کلیدی:  بازخوردتصحیحی, دانش دستوری, رفع اشکال ضمنی اعلانی, رفع اشکال ضمنی پرسشی, رفع اشکال غیرمستقیم, رفع اشکال مستقیم

 

 

 

Table of Contents

 

Title                                                                                                                      Page

 

Chapter One: Introduction

 

Chapter Two: Review of the Literature

 

Chapter Three: Method

 

Chapter Four: Data Analysis and Results

 

Chapter Five: Summary, Discussion, and Conclusion

 

List of Tables

 

Title                                                                                                                      Page

 

Table 4.1 Descriptive Statistics for the Participants’ Homogeneity in the Pre-test..75

 

Table 4.8 Independent Samples t-test for the Overt Correction and Recast Groups79

 

 

 

 

 

 

 

 

 

 

 

List of Figures

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Abstract

 

The need to make corrections is inherent in the teaching profession, but teachers are often unsure as to how much to correct, or even how to go about it. Although a large body of research examined the effectiveness of certain

پایان نامه

 types of error treatment methods, there has been little research done to investigate the efficacy of different types of corrective feedback on EFL learners’ grammar accuracy through eliciting repeated performances. The main objective of the study was to see if two types of corrective feedback, overt correction and recast, could help Iranian EFL learners’ grammar achievement at the intermediate level. The study was also an attempt to see which of these two types of corrective feedback could lead to a better grammar achievement. In addition, two methods of recast, declarative and interrogative, were under investigation to figure out which method of recast Iranian EFL learners at the intermediate level preferred to be used by instructors. Fifty male EFL students studying at the intermediate level at the Iran Language Institute, Yazd branch, Iran, took part in this study. They were divided into two groups who received corrective feedback through overt correction and recast. A pre-test was administered at the beginning before the consecutive process of corrective feedback provision started, and a post-test was given at the end when the process finished. The procedure of test administration and the content was the same for both overt correction and recast groups. The only difference was in the treatment, in which the errors of the overt correction group were corrected overtly, but the errors of the recast group were corrected implicitly. The results of the study indicated that both overt correction and recast as two types of corrective feedback could help Iranian language learners at the intermediate level develop their grammar knowledge over the instruction. Between-groups comparison revealed that there was no significant difference between the overt correction and recast groups with regard to their grammar performance. Additionally, a survey was conducted to explore the participants’ preferable type of recast, declarative or interrogative. A careful consideration of the percentages of declarative and interrogative recast choices showed a significant preference for interrogative recasts by the group receiving recasts in their class. The findings of this study suggested that both overt correction and recast are equally beneficial and might facilitate the process of grammar acquisition by Iranian EFL learners at the intermediate level.

 

 

 

Keywords: Corrective Feedback, Declarative Recasts, Grammar Knowledge, Interrogative Recasts, Overt Correction, Recasts.

 

 

 

 

 

 

 

Chapter One

 

Introduction

 

 

 

 

 

 

 

 

 

Preliminaries

 

Error correction of both oral and written mistakes occupies a prominent place in English Language Teaching (ELT) literature and continues to be a divisive issue. In the past, the consensus was that errors of any kind were bad. While reading aloud in class, students would have every pronunciation mistake corrected on the spot. In written work, all mistakes would be shown, very seriously put in red ink. Offering an answer in class often risked losing face and sometimes being reprimanded for being lazy if the answer was incorrect. More recently, however, in English language classrooms, there has been a shift in attitude to errors. Errors are regarded as indicators that learners are experimenting with a language, or testing out a new language hypothesis, or progressing in general.

 

Correction is called for in any ELT class since learners consider correction as a source of improvement (Chaudron, 1988, as cited in Celce-Murcia, 2001), but it is the teacher who determines the most proper time for correction, the best type of it and whether to correct or not. Teachers can exploit the errors that a learner makes to show him the current state of his English and to determine the content of future practice. There are different types of correction (Celce-Murcia, 2001; Brown, 2007): overt/ explicit/ direct (Brown, 2007), implicit/ indirect (Richards & Schmidt, 2002), peer-correction (Paulston & Bruder, 1976), self-correction (Swain, 1985), clarification request, repetition, recast, metalinguistic feedback, elicitation (Brown, 2007). According to Brown (2007, p. 379), “corrective feedback includes responses to learners’ produced utterances which repair or call attention to their errors”.

 

Although there are different points of view towards error correction and the type of feedback we can give to treat errors, teachers are responsible to provide learners with feedback on even the most persistent of errors, but if they do not, fossilization becomes inevitable.

 

It is also known that the acquisition of grammar is a gradual process. What teachers teach and what students learn are not always directly linked. So, we cannot put our expectations too high about the complete disappearance of learners’ errors soon after receiving our feedback.

 

The current study focuses on two correction methods: overt correction (explicit correction) and recasts (reformulation). In addition, two types of recasts (i.e. declarative and interrogative) will be examined. Declarative recasts are the ones based on which the recast is provided with falling intonation as a declarative statement, and interrogative recasts is a recast provided with rising intonation as a question.

 

 

 

Statement of Problem

 

There is disagreement among second and foreign language researchers over the extent and the type of feedback that maybe useful in second language acquisition. It has long been assumed by foreign language teachers and by researchers working in the area of corrective feedback that corrective feedback provision by teachers helps students to acquire correct linguistic forms and structures. As a result, they are concerned with discovering the most effective ways of providing corrective feedback so that students improve their grammar knowledge. Therefore, a lack of total agreement on the type of feedback given to students by teachers can be observed in English language classes. Additionally, language learners usually have different viewpoints on the type of feedback they receive from their teachers. While some students prefer to be corrected directly by their teachers, others are more comfortable with indirect corrections done by teachers. That is why language instructors sometimes face the dilemma of how to correct their students’ language problems.

 

Although a great body of research has been done on corrective feedback (Russell, 2009; Sauro, 2009; Büyükbay & Dabaghi, 2010; Lyster & Saito, 2010; Abadikhah & Ashoori, 2012; Lyster & Ranta, 2013; Lyster, Saito, & Sato, 2013 ) and its role on learning a new language, only a few studies have attempted to directly investigate whether learners who receive overt correction on their errors are able to improve their grammar performance compared with those who receive recasts (Dabaghi, 2006; Shirazi & Sadighi, 2012).

پایان نامه رشته زبان انگلیسی:The present study was conducted to compare the effect of synchronous and asynchronous Computer Mediated Communication (CMC) on EFL learners’ Speaking and Autonomy

متن کامل پایان نامه مقطع کارشناسی ارشد رشته :زبان انگلیسی

 

 

 

عنوان : پایان نامه رشته زبان انگلیسی:The present study was conducted to compare the effect of synchronous and asynchronous Computer Mediated Communication (CMC) on EFL learners’ Speaking and Autonomy.

 

 

 

 

 

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Abstract

 

 

 

 

 

 

 

 

 

 

 

CHAPTER I

 

Background and Purpose

 

 

 

1.1 Introduction

 

The emergence of internet offers an effective means of opening new horizons for Foreign Language (FL) learning and teaching. Two different dimensions of computer-mediated communication (CMC) which has an important role in educational settings are asynchronous exchange (e.g., emails and discussion boards) and synchronous interaction in real time (e.g., chat rooms and video conferences) give unique learning conditions for FL learners to expand the use of the target language and thus develop their communicative language skills (Abrams, 2003; Blake, 2000). A number of studies have documented the advantages of online technologies (Smith, 2003; Warschauer, 2000), online learning creates a friendly and low-anxiety learning environment that allows “all” rather than “some” students to participate (Kern, 1995; Lee, 2002, Magnan, Farrell, Jan, Lee, Tsai, & Worth, 2003) and make students   improve their communicative skills faster than ever before.

 

Although web-based language learners might choose to limit their online connection times, or they may not have access at all due to the connection problems, computers have a variety of offline software such as e-books and audio books which mostly lack the interactional factors but conquer this problem. They can be used by learners on their computers without any necessity for connection to the internet. In so many developing countries where the internet connections have a very low speed, these offline materials look so invaluable since they can prevent students from wasting their time.

 

The impact of Computer Mediated Communication (CMC) on FL learning has been approved by so many researches (Kelm, 1992; Ker1995; Ortega, 1997).

 

Given the characteristics of computer assisted language learning (CALL) as a medium of education, there seems to be a need to consider learners’ characteristics as an indivisible part of learning.  In Ozlem Bayat (2011, p.107) words

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 “EFL learners are responsible for finding settings outside school where the target language is used, for example: the internet, participation in certain activities and using self-access canters”.

 

Autonomous learners are those who seek the opportunities to learn outside classroom setting and create their own instructional settings freed from the teacher (Breen & Mann, 1997). It is critical for learners to take advantage of as many opportunities as they can to learn and use the target language. Computers as a prominent part of these opportunities can help learners to foster their autonomy but the way in which they can be used is controvertible.

 

In area of language learning, speaking  skills  have  a  privileged  status  in  the  language-learning  world (Egan,  1999).  Both  educators  and  language  learners  consider  speaking  a fundamental  communicative  skill  in  which  development  is  often  expected. However, evidence reveals  that foreign  language educators regularly experience difficulties  in  fostering  speaking  activities  due  to  multiple  reasons  –  some  of which  are  beyond  their  control. Understanding these difficulties and finding solution for improving students’ speaking thorough using different type of CMC is one of the aims of this study.

 

Another influential factor in language learning situation is learner autonomy. Autonomy is generally defined as the capacity to take charge of, or responsibility for one’s own learning (Holec, 1981, p. 3). It is both a social and an individual construct, which involves the personal development of each student and, at the same time, interaction with others (La Ganza, 2001). Research findings have provided evidence that autonomy is of general concern in second or foreign language learning (Dafei, 2007; Wenden, 1998; Zhang & Li, 2004). As a result, the trends in language teaching has recently moved toward making learners more autonomous and shifting the responsibility toward the learner (Wenden, 1998).

 

Considering the above facts, it seems that in spite of the numerous studies which have tried to understand different aspects of CALL, still there are so many aspects which are intact.  It seems it is becoming crystal clear for learners and teachers that using computer in educational settings is so advantageous but the novelty of this phenomenon and its complexity has a huge potential for further studies.

 

1.2 Statement of the Problem and Purpose of the Study

 

Previous studies have documented a number of benefits that learners have gained by using online technologies (e.g., Chun & Wade, 2003; Darhower, 2002; Lee, 2002, 2004; Sengupta, 2001; Smith, 2003; Warschauer, 2000). Online leaning creates a friendly and low-anxiety learning environment that allows “all” rather than “some” students to participate (e.g., Kern, 1995; Lee, 2002; Magnan, Farrell, Jan, Lee, Tsai, & Worth, 2003) and encourages affective support among peers to increase students’ motivation toward L2 leanrning (Lee, 2003; Weasenforth, Biesenbach-Lucas& Meloni, 2002).

 

Given the above mentioned factors it should be considered that most studies compared the advantageous or disadvantageous of using or not using CALL. Few studies, if not any, compared different aspects of CALL. As the technology advanced, people began to see more interactive uses of CALL as well as an increase in the integration of various media into the computer system (Otto, 1990) but Synchronous Computer Mediated Communication (SCMC) and Asynchronous Computer Mediated Communication (ACMC) which are two types of CALL can be studied for enriching the nature of this phenomena and deciding which of them should be chosen in different educational settings.

 

The aim of this study, therefore, was to investigate the comparative view of the effect of asynchronous and synchronous CMC on the development of speaking skill and on learners’ autonomy. Currently,  there  is  a wide  range  of  services  and  tools  that  can accommodate  CMC  speaking  practices  which have  the  potential  to  significantly  contribute  to  learners’  levels  of  oral sophistication. It seems reasonable to suggest that whereas previous studies mostly considered language learning with the presence of a CALL medium with a situation in which the traditional language learning happens, it seems so important to scrutinize learning situations which contextualize different aspects of CALL with each other to find out functionality of these aspects. As Schütte (2000) emphasizes, within CMC communicative norms have not yet been established and are still in the process of being negotiated, more studies are trying to find the capacity of two types of CMC.

 

In view of the preceding, use of CMC in classrooms as other studies mentioned can be so effective (James 2013). Technological advances in recent years demonstrate that the digital medium has become more and more popular in developing oral skills (e.g., Abuseileek, 2007; Vinther, 2011; Jauregi et al., 2012). Many of these studies show that CMC in its synchronous manifestation facilitates the acquisition of oral competence (James, 2013). The most important factor that these studies emphasize on is the interaction which exists in Synchronous CMC. On the other hand some recent studies show that the practicality of synchronous CMC does not exceed those of asynchronous CMC. Actually,  emergent  research  in  the  field  of CMC  shows  that  a  significant  number  of  technology-based  speaking  activities take place asynchronically  (e.g., Huang & Hung, 2009; Sun, 2009;Hung,  2011).

 

In view of what was mentioned, the present study seeks to shed light on, firstly,   the type of CMC which is more suitable for improving learners speaking skill and secondly the type of CMC better affecting learners’ autonomy.

پایان نامه رشته زبان انگلیسی:Reading William Gibson’s Trilogy; Neuromancer, Count Zero, and Mona Lisa Overdrive, In the Light of Jean Baudrillard’s Theo

متن کامل پایان نامه مقطع کارشناسی ارشد رشته :زبان انگلیسی

 

 

 

عنوان : پایان نامه رشته زبان انگلیسی:Reading William Gibson’s Trilogy;  Neuromancer, Count Zero, and Mona Lisa Overdrive,    In the Light of Jean Baudrillard’s Theo

 

 

 

Islamic Azad University-Central Tehran Branch

 

                                 Faculty of Foreign Languages

 

                           Department of Postgraduate Studies

 

 

 

            A Thesis Submitted to the Department of Postgraduate Studies in Partial           Requirements for the Degree of Master of Arts in English Language and Literature

 

 

 

                                                          Subject:

 

                                Reading William Gibson’s Trilogy;  

 

                  Neuromancer, Count Zero, and Mona Lisa Overdrive,

 

                         In the Light of Jean Baudrillard’s Theories

 

 

 

                                                Thesis Advisor:

 

                                             Dr. Farid Parvaneh

 

 

 

                                                Thesis Reader:

 

                                            Dr. Razieh Eslamieh

 

                                                  Summer 2014

 

 

 

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تکه هایی از متن پایان نامه به عنوان نمونه :

 

(ممکن است هنگام انتقال از فایل اصلی به داخل سایت بعضی متون به هم بریزد یا بعضی نمادها و اشکال درج نشود ولی در فایل دانلودی همه چیز مرتب و کامل است)

 

Abstract

 

This thesis is an attempt to investigate William Gibson’s Trilogy; Neuromancer (1984), Count Zero (1986), and Mona Lisa Overdrive (1988), in the light of Jean Baudrillard’s critical theories which are categorized under two main headings; “simulation” and “disappearance.” Indeed, this study aims to divulge the specific kinds of ‘simulation’ and ‘disappearance,’ such as ‘the simulation of power’ and ‘the disappearance of the human (body) and the other(‘s body) in Gibson’s Trilogy. Therefore, the researcher elucidates the argument in three main chapters besides the chapters of introduction and conclusion. The second chapter provides a theoretical framework for this study through delineating Baudrillard’s key concepts, such as “hyperreality,” “simulacrum,” “simulation,” “disappearance,” etc. Baudrillard believes that power no longer exists except as “the simulation of power.” He demonstrates “the simulation of power” through expanding on “the hallucination of power,” “the circularization of power/the end of panopticon,” and “the simulation of terror.” With having recourse to these theories, the third chapter seeks to reveal the instances of “the simulation of power” in Gibson’s technological world. The fourth chapter, with an emphasis on the central notion of “disappearance,” attempts to indicate the metamorphosis of the human (body) to the post-human (body) and the recognition of the other(‘s body) which are caused by cyber- technologies, “cyborg” and “cyberspace.” Thus, the main focus of this chapter is to scrutinize the different types of hybrid characters that are continuously merging with ‘cyber- technologies’ and the different kinds of ‘cybertechnologies’ in order to delineate “the disappearance of the human (body) and the other(‘s body)” in light of Baudrillard’s theories in Gibson’s novels. Chapter five presents the findings. As this study concludes, Gibson’ novels depict the technological world in which everything might be simulated/disappeared, or rather redefined through merging with ‘cybertechnologies.’

 

Keywords: Hyperreality, Simulacrum, Simulation of power, Disappearance of the human (body), Disappearance of the other(‘s body), Jean Baudrillard, William Gibson

 

 

 

 

 

 

 

List of Abbreviations

 

C Z             Gibson, William. Count Zero. N.p.: Arbor House Pub Co, 1986.

 

 

 

F F              Baudrillard, Jean. Forget Foucault. Trans. Nicole Dufresne. Los Angeles: Semiotext(e),  2007.

 

 

 

M L O        Gibson, William. Mona Lisa Overdrive. N.p:N.p, [1988].

 

 

 

               Gibson, William. Neuromancer. N.p:N.p, [1984].

 

 

 

S & S      Baudrillard, Jean. Simulacra and Simulation. Trans. Sheila Faria Glaser. Michigan:  University of Michigan Press, [1994?].

 

 

 

T T O E     Baudrillard, Jean. The Transparency of Evil: Essays on Extreme Phenomena. Trans. James Benedict. London and New York: Verso, 1993.

 

 

 

 

 

Table of Contents

 

 

 

Abstract   .. III

 

1.1   General Background……………………………………………………………………………………….. 1

 

1.2   Statement of the Problem………………………………………………………………………………… 9

 

1.3    Objectives and Significance of the Study………………………………………………………. 10

 

1.3.1  Hypothesis. 10

 

1.3.2  Significance of the Study. 11

 

1.3.3  Purpose of the Study. 13

 

1.3.4  Research Questions. 14

 

1.4    Review of Literature………………………………………………………………………………………. 15

 

  1. Materials and Methodology…………………………………………………………………………… 19

1.5.1  Definition of Key Terms. 19

 

1.5.2  Motivation and Delimitation. 20

 

  1. 6 Organization of the Study……………………………………………………………………………….. 21

Introduction. 23

 

2.2.1  Simulation of Power 31

 

2.3.1  Disappearance of the Human (Body) 37

 

2.3.2  Disappearance of the other 42

 

Conclusion. 46

 

Introduction. 47

 

. 52

 

. 60

 

Introduction. 67

 

4.1  The Metamorphosis of the Human (Body) to the Post-human (Body). 69

 

4.1.1   Cyborg (Technologies) 70

 

4.1.2   Cyberspace (Technologies) 76

 

4.2  The Recognition of the Other(‘s Body). 86

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4.2.1   The Transparency of the Other(’s Body) 86

 

4.2.2   Simulation of the Other(’s Body) 90

 

Conclusion. 92

 

5.1 Summing up. 96

 

5.2 Findings. 100

 

5.3 Suggestions for Further Research. 105

 

 

 

 

 

 

 

 

 

                                  Chapter One: Introduction

 

 

 

 

 

  • General Background

William Ford Gibson, an American author, was born in 1948 in South Carolina. He was interested in science fictions and used to read the biographies of most American science fiction writers, and also the writings of Allen Ginsberg, Jack Kerouac, and William S. Burroughs, thus, he was influenced by William S. Burroughs. Gibson “was among the first to explore the implication of virtual communities, reality television, nanotechnology, the digital divide, locative art, and ubiquitous computing” (Henthorne 4). His fictions represent a technological society in which the traits of street culture, such as crime, drug addiction, horror, and chaos are highlighted (Cavallaro 5). Indeed, Gibson was among the first authors who wrote cyberpunk fictions. Cyberpunk fictions “can be seen as an expansion of the tradition of science fiction” (Verhulsdonck 14), a genre which narrates new technological modes of being in “an era of blurred ontologies” (Russell 79). Gibson started his literary career by his short stories which were collected in Burning Chrome (1986). His short stories were followed by his Sprawl Trilogy; Neuromancer (1984), Count Zero (1986), and Mona Lisa Overdrive (1988). The following novels are the Bridge Trilogy; Virtual Light (1993), Idoru (1996), All Tomorrow’s Parties (1999), and the Bigend Trilogy; Pattern Recognition (2003), Spook Country (2007), Zero History (2010).

 

This study is focused on the Sprawl Trilogy; Neuromancer (1984), Count Zero (1986), and Mona Lisa Overdrive (1988). Neuromancer (1984) is a story of a console cowboy/ hacker, Henry Case, whose nervous system was damaged by his employers through Russian “mycotoxin,” so he cannot jack in cyberspace anymore. Case lives in a coffin in Cheap Hotel near Ninsei Street. He usually spends nights in Ninsei Street bars. Wage, Linda Lee (Case’s ex-girlfriend), and Julius Deane are the important characters in this period of Case’s life. After a year, one night when Case goes back to his coffin, a lady, Molly Millions, is waiting there. She was hired to help Case in a dangerous run which Armitage wants Case to do it. Indeed, Armitage wants to control Case through the glasses which were implanted into Molly’s eyes. After Case accepts to do the run, Armitage sends Case to a clinic to undergo a nervous system surgery in order to be able to jack in cyberspace again. Indeed, he feels alive when he is connected to cyberspace (Lloyd 8). And also, some “toxin sacs” are bonded to his arteries to control him.

 

After the surgery, Case and Molly live and work with each other. Whenever Molly goes to a place for work, Case controls the situation by jacking in cyberspace and connecting to her sensorium. He can see through her eyes and feel her feelings and sensations. Up to the middle of the story, they do not really know whom they are working for. Indeed, they are working for Wintermute, an Artificial Intelligence (AI) that persuades Case to help Wintermute to unite with another AI, Neuromancer, in order to increase their power. Meanwhile, Case searches about AIs, Tessier-Ashpool, and their daughter, Lady 3Jane through jacking in cyberspace and talking to Dixie-Flatline (a memory construct). Then, Molly is sent to Villa Straylight where she meets Lady 3Jane and her assistant, Peter Riveria. Molly gets hurt there. When Case sees Molly in danger, he jacks out cyberspace and goes to Villa Straylight in order to save her and complete the run. After their mission, Case goes to Chiba City and buys new parts of body, such as a pancreas and a liver. Then, he goes back to the Sprawl, and finds a job and a girlfriend. He continues his normal life in society and never sees Molly again.

 

Count Zero (1986), is divided into three stories which are connected to each other. One story focuses on Turner who had been survived from an accident by a Dutch surgeon. The Dutch surgeon with his team put Turner together by using prosthetics and cloning. “Turner represents the most physical breakdown of the opposition between man and machine” (Naidoo 97). He is hired by Conroy to find Christopher Mitchell and bring him to Hosaka. Conroy provides Turner with Christopher Mitchell’s dossier to know him. Turner and the members of a team called Site Team are supposed to control Mitchell’s jet through a biosoft, but there is an explosion before they can get Christopher Mitchell. Therefore, Turner finds Mitchell’s daughter, Angela, instead of Christopher. Angela, also known as Angie, explains everything about his father and herself to Turner. She tells him the members of Hosaka are after her because of her dreams. Then Turner decides to protect Angie, and he brings her to his brother’s, Rudy’s House. Rudy scans Angie and finds a biochip in her head. The biochip has been put in her head by her father in order to enable her to access cyberspace directly. Then, Turner and Angie go to the Sprawl. On their way, sometimes Angie jacks in cyberspace through the biochip and talks different languages. Then, they go to Jammer’s club.

 

The other story concerns Marly Krushkhova, a disgraced former operator of a gallery in Paris. She is hired by Joseph Virek to find the inventor of the mysterious boxes. Joseph Virek is a wealthy man who lives in a vat and wants to attain immortality. Paco, who works for Virek, helps Marly during her mission. After Marly finds her ex-boyfriend, Alain dead in an apartment, she decides to escape from Virek. In her flight to Japan, she jacks in Tally Isham’s Sensorium and sees Virek. He addresses Marly directly and tells her that he knows her destination. After that, Marly hires a woman to take Marly to the address which she had found in Alain’s room. The address is the address of Tessier-Ashpool’s old place. She goes to the place and meets Wigan Ludgate and Jones. She tells them that she should find the artist of the boxes and let him know that he is in danger. On their way to see the artist, Joseph Virek appears on a screen and tells Marly that she had fulfilled her contract and he had found what he wanted.

 

The third story centers on Bobby Newmark, also known as Count Zero, who lives near Barrytown. When he jacks in cyberspace to run the software which he bought from Two-a-Day, something happens. Then, he goes to find Two-a-Day to know what happened. On the way, some people attack him in the street and he becomes unconscious. After a while, he finds himself conscious in Two-a-Day’s apartment. He tells Bobby that the voodoo gods have saved his life. Then, he gets acquainted with Jackie; a priestess of Danbala (a voodoo god), Beauvoir, and Lucas. Lucas takes Bobby to a place to meet Finn whose job is selling computer software and programs. Finn explains that he had purchased all his decks, peripherals, and software from Wigan Ludgate. Then, Bobby and Jackie go to Jammer’s Club.

پایان نامه رشته زبان انگلیسی:بررسی راهبردهای درک شنیداری بکار گرفته شده توسط زبان آموزان ایرانی

متن کامل پایان نامه مقطع کارشناسی ارشد رشته :زبان انگلیسی

 

 

 

عنوان : پایان نامه رشته زبان انگلیسی:بررسی راهبردهای درک شنیداری بکار گرفته شده توسط زبان آموزان ایرانی

 

 

 

دانشگاه آزاد اسلامی

 

واحد گیلان

 

گروه زبان انگلیسی

 

پایان نامه برای دریافت درجه كارشناسی ارشد در رشته آموزش زبان انگلیسی

 

عنوان

 

بررسی راهبردهای درک شنیداری بکار گرفته شده توسط زبان آموزان ایرانی

 

استاد راهنما

 

دكتر رامین رحیمی

 

استاد مشاور

 

دكترفریدون وحدانی

 

شهریور 1393

 

 

 

(در فایل دانلودی نام نویسنده موجود است)

 

تکه هایی از متن پایان نامه به عنوان نمونه :

 

(ممکن است هنگام انتقال از فایل اصلی به داخل سایت بعضی متون به هم بریزد یا بعضی نمادها و اشکال درج نشود ولی در فایل دانلودی همه چیز مرتب و کامل است)

 

چكیده

 

 

 

هدف اصلی این تحقیق شناسایی راهبردهای مربوط به مهارت شنیداریست كه فراگیران مذكر و مونث زبان انگلیسی در ایران  انتخاب میكنندوهمچنین مقایسه این راهبردهابین دو گروه (مذكر و مونث).بنابراین با اجرای آزمون تعیین سطح آكسفورد 76  نفرازدانشجویان زبان انگلیسی با گرایشهای مختلف انتخاب شدند. در مرحله بعد به دو گروه ٣8 نفری تقسیم شدند تا به سوالات پرسشنامه ی راهبردهای شنیداری چنگ (٢٠٠2)  با سی سوال كه در مقیاس لیکرت، جهت تعیین راهبردهای انتخابیشان  پاسخ دهند. سپس داده های جمع آوری شده در آزمون های آماری شامل آزمون توصیفی و آزمون (Mann Whitney U)اجرا شد. بر اساس یافته ها ی تحقیق، شركت كنندگان از راهبردهای فراشناختی نسبت به راهبردهای شناختی و اجتماعی-عاطفی بیشتر استفاده میكردند. علاوه بر این چون متغیرجنسیت در انتخاب راهبردها موثر بوده،نتیجه تحقیق میتواند برای سیاستگذاران آموزشی، نویسندگان كتابها ی درسی زبان، مدرسان و استادان زبان خارجی در ایران موثر باشد بویژه اینكه فراگیران زبان خارجی  براساس جنسیت در كلاسهای درسی  جدا  از هم مینشینند.

 

کلید واژه ها: راهبردهای شنیداری، راهبردهای فراشناختی، شناختی و اجتماعی- عاطفی

 

Table of Contents

 

 

 

Title                                                                                                        Page

 

 

 

Chapter 1: Introduction

 

1.2 Significance of the Study……………………………………………………………………………………7

 

 

 

Chapter Two: Review of the Literature

 

2.3.1. What Is Listening?……………………………………………………………………………..28

 

 

 

Chapter Three: Methodology

 

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Chapter Four: Results

 

 

 

Chapter Five: Discussion

 

 

 

 

 

 

 

List of Tables

 

Table                                                                                                              Page

 

 

 

 

 

 

 

List of Figures

 

 

 

Table                                                                                                              Page

 

 

 

 

 

 

 

 

 

Abstract

 

The main goal of this investigation was to identify the listening strategies of Iranian male and female foreign (English) language learners and to compare the listening strategies of both groups of research participants. To investigate, 76 undergraduate students of different major of English were selected via administrating the Oxford Placement Test (OPT).Then, they were divided into two groups of 38asked to complete Cheng’ s (2002) 30-item Listening Strategyin the Likert-scale format to identify the listening strategies they  use. Then the data gathered were run through statistical tests, including descriptive test and Mann Whitney U-test. Based on the findings of the studythe listeners usedmore metacognitive strategies than cognitive and socio-affective strategies respectively.In addition, as gender influenced selecting the types of strategies for listening, it can be efficient for policy makers, syllabus designers, practitioners and instructors especially in Iran where classrooms are separated according to students’gender.

 

Key words:Listening Strategies, Metacognitive Strategies, Cognitive Strategies, Socio-affective Strategies

 

 

 

 

 

 

 

 

 

Chapter One

 

Introduction

 

 

 

 

 

 

 

 

 

1.0. Introduction

 

Listening has become an important part of manysecond or foreign language (L2)programs,as both it is a means to access various sources of knowledge and it is a criterion to determine whether an EFL learner is a competent language performancer or not. Teachers can help students improve their listening competence by equipping them with effective listening strategies and skills.In fact,its importance is influenced by the overwhelming amount of listening input in everyday life.

 

Despite its importance,listening is not an easy skill to master,especially listening in ESL or EFL contexts.Teachers look for the methods to find a way to enhance listening profeciency.Researchers and educaters know that learning strategies are necessary for  EFL learners to be a successsful one.Many reseachers have investigated on learning strategies to find which strategieas can improve learning and especially listening skill.

 

Chamot (2005) believes that Learning strategies are the thoughts and actions that individuals use to accomplish a learning goal. A lot of investigations in 1970s show the importance of learning strategies. The results mention that learners’ own creative and active participation play an important role in their success in spite of having much aptitude and motivation.

پایان نامه رشته زبان انگلیسی:Investigation on Rheological Behaviour of Dually Modified Cassava Starch/k-Carrageenan as Gelatin Alternative in Pharmaceutical Hard Capsules

متن کامل پایان نامه مقطع کارشناسی ارشد رشته :زبان انگلیسی

 

 

 

عنوان : پایان نامه رشته زبان انگلیسی:Investigation on Rheological Behaviour of Dually Modified Cassava Starch/k-Carrageenan as Gelatin Alternative in Pharmaceutical Hard Capsules

 

 

 

 

Islamic Azad University

 

Damghan Branch

 

Faculty of Agriculture

 

 

 

A Thesis Submitted in Partial Fulfillment of the Requirments For

 

the Degree of M.sc(Ph.D)in Food scienc and technology

 

 

 

Title

 

Investigation on Rheological Behaviour of Dually Modified Cassava Starch/k-Carrageenan as Gelatin Alternative in Pharmaceutical Hard Capsules

 

 

 

Supervisor:

 

 Abdorreza Mohammadi Nafchi, PhD

 

November 2013

 

 

 

(در فایل دانلودی نام نویسنده موجود است)

 

تکه هایی از متن پایان نامه به عنوان نمونه :

 

(ممکن است هنگام انتقال از فایل اصلی به داخل سایت بعضی متون به هم بریزد یا بعضی نمادها و اشکال درج نشود ولی در فایل دانلودی همه چیز مرتب و کامل است)

 

Table of Contents

 

Acknowledgement ii

 

Table of Contents. iii

 

List of Tables. vi

 

List of Figures. vii

 

Abstract 1

 

Chapter 1: Introduction. 2

 

1.1 Background. 3

 

1.2 Rational of study. 5

 

1.3 Objectives of the study. 5

 

1.4 Research Flowchart 6

 

Chapter 2: Literature Review.. 8

 

2.1 PHARMACEUTICAL CAPSULES. 9

 

2.1.1 Pharmaceutical hard capsules. 10

 

2.1.2 Manufacture of gelatin capsules. 11

 

2.1.3 Properties of gelatin capsules. 15

 

2.1.4 Alternatives to Gelatin. 17

 

2.2. POLYSACCHARIDES STUDY.. 20

 

2.2.1 Starch. 20

 

2.2.1.1 Composition and primary structure of starch. 21

 

2.2.1.2 Morphology and ultra-structure of starch grains. 24

 

2.2.1.3 Semi-crystalline structure of starch grains. 27

 

2.2.1.4 Thermal transitions. 30

 

2.2.1.5 Starch modification. 35

 

2.2.1.6 Cassava. 41

 

2.2.2 Carrageenan. 53

 

2.2.2.1 Chemical Structure. 53

 

2.2.2.2 Conformation of κ-carrageenan. 54

 

2.2.2.3 Gelation of κ-carrageenan. 60

 

2.2.2.4 Thermoreversibility of gels and rheological properties. 61

 

2.3 POLYSACCHARIDE MIXTURES. 65

 

2.3.1 Phase Behavior 65

 

2.3.2 Thermodynamic Incompatibility. 66

 

2.3.3 Gels based on mixtures polysaccharides. 68

 

2.3.3.1 Rheological properties. 69

 

2.3.3.2 Rheology of blends of starch. 70

 

Chapter 3: Materials and Methods. 72

 

3.1 Materials. 73

 

3.1.1 Gelatin. 73

 

3.1.2 κ-carrageenan. 73

 

3.1.3 Acid hydrolyzed hydroxypropylated cassava starch. 73

 

3.2 Methods. 74

 

3.2.1 Preparation of solutions. 74

 

3.2.1.1 Gelatin solutions. 74

 

3.2.1.2 Starch and κ-carrageenan solutions. 74

 

3.2.2 Rheological properties. 77

 

3.2.2.1 Flow properties. 77

 

3.2.2.2 Viscoelastic properties. 78

 

Chapter 4: Results and Discussions. 79

 

4.1 Rheological behavior of gelatin. 80

 

4.1.1 Gelatin solution at 50 °C.. 80

 

4.1.2 Sol-gel transitions. 82

 

4.1.3 Viscoelastic properties of gelatin gels at 20 °C.. 86

 

4.2 Rheological behavior of starch-κ-carrageenan blends. 90

 

4.2.1 Rheological behavior at 50 °C.. 90

 

4.2.1.1 Dually modified cassava starch (HHSS) 90

 

4.2.1.2 κ-carrageenan. 95

 

4.2.1.3 Dually modified cassava starch/κ-carrageenan blends. 96

 

4.2.2 Rheological behavior in sol-gel transitions (from 50 °C to 20 °C) 102

 

4.2.2.1 Influence of κ-carrageenan content 104

 

4.2.2.2 Influence of the different extents of starch hydrolysis. 106

 

4.2.3 Rheological properties of gels at 20 °C.. 107

 

4.2.3.1 κ-Carrageenan gels. 107

 

4.2.3.2 Composite gels. 108

 

Chapter 5: Discussion and Conclusion. 113

 

5.1 Synergy and gel state. 114

 

5.1.1 Dually modified cassava starch and κ-carrageenan. 114

 

5.1.2 Mixtures. 115

 

5.2 Comparison with gelatin. 120

 

5.2.1 Solution properties. 120

 

5.2.2 Jellification. 121

 

5.3 Conclusion and recommendation for future research. 123

 

References. 126

 

 

 

List of Tables

 

Table 2. 1: Properties and applications of modified starches. 35

 

Table 2. 2: Performance of starch slurry dewatering by a conventional centrifuge from a typical cassava starch factory. 51

 

Table 3.1: Compositions of the starch- κ-carrageenan solution. 76

 

Table 4.1: Changes in viscosity of gelatin as a function of concentration. Experiments were performed at 50 °C   81

 

(G’= G”) during cooling from 50 to 25 °C and heating from 25 to 50 °C. The rate of heating or cooling was 1°C/min. Frequency: 1 rad/s. Strain amplitude: 1%. 86

 

Table 4.3: Viscosity of κ-carrageenan in different concentrations. 95

 

) of κ-carrageenan alone and the mixture HHSS12-κ-carrageenan determined from cooling and heating ramps at 1 °C/min and 1 rad/s. 104

 

Table 4.5: Storage and loss moduli G’ and G” of κ-carrageenan alone and HHSS12-κC0.5 mixture determined from temperature ramps during cooling and heating at 1 °C/min by rheological measurements. Frequency: 1 rad/s. 111

 

 

 

 

 

List of Figures

 

Figure 1.1: Research flowchart 7

 

Figure 2. 1:  Formation of hard gelatin capsules by dip molding. 12

 

Figure 2. 2: Position fingers dipping during passage through the drying ovens. 13

 

Figure 2. 3: Steps removing (a) trimming (b), and assembly of capsules ©. 14

 

Figure 2. 4: Water content at equilibrium of pharmaceutical hard empty gelatin capsules in  relationship with the mechanical behavior. The capsules are stored at different relative humidities for two weeks at 20 ° C. 16

 

Figure 2. 5: Isothermal sorption-desorption capsules hard gelatin and HPMC at equilibrium at 25°C. 19

 

Figure 2. 6: Test for fragility of the capsules: the percentage of broken capsules according to their water content. a: resistance to pressure with capsules filled with corn starch. b: impact resistance with empty capsules. 19

 

Figure 2. 7: Structure of amylose. 22

 

Figure 2. 8: Structure of amylopectin. 23

 

Figure 2. 9: Grains of different starches observed in scanning electron microscopy SEM (magnification × 280) 24

 

Figure 2. 10: The different levels of grain starch. 25

 

Figure 2. 11: Organization of starch grains in “blocklets”. 27

 

Figure 2. 12: X-ray diffraction diagram for crystalline starch type A, B and C. 28

 

Figure 2. 13: Crystallinity of potato starch: influence of water content on the resolution of the diffraction pattern of X-rays. 29

 

Figure 2. 14: Crystalline arrangement of double helices of amylose type A and B.. 30

 

Figure 2. 15: Variation of classical transitions of the potato starch as a function of water content 33

 

Figure 2. 16: Hydroxypropylation reaction. 38

 

Figure 2. 17: Mass balance of cassava starch manufacturing process in a starch factory with a decanter. 47

 

Figure 2. 18: Mass balance of cassava starch manufacturing process in a starch factory without a decanter. 48

 

Figure 2. 19:  Starch granules trapped in discharged pulp of cassava starch process. 49

 

). 54

 

Figure 2. 18: Percentage of order of κ-carrageenan solution by polarimetry (0) and conductivity measurements (D) 55

 

. 57

 

Figure 2. 20: Phase diagram of κ-carrageenan representing the variation of transition temperature on cooling and heating according to the total concentration of potassium (Rochas, 1982; Rochas & Rinaudo, 1980). 59

 

Figure 2. 21: κ -Carrageenan gelation model, cation to promote gelation. (Morris et al., 1980) 60

 

: melting temperature. Cooling G’ (■), G” (¨). Heating G’ (□), G” (◊). (Fernandes, Gonçalves & Doublier, 1992). 63

 

Figure 2. 23: Kinetics of evolution of κ-carrageenan at a concentration of 1%. Temperature is 25 ° C. Frequency 1Hz. G’ (■), G” (¨). 64

 

Figure 2. 24: Phase diagram at 25 °C mixture of waxy hydroxypropyl starch/κ-carrageenan. 67

 

Figure 3.1: Phase diagram of κ-carrageenan representing the variation of transition temperature on cooling and heating according to the total concentration of potassium.. 75

 

Figure 4.1: Newtonian behavior of gelatin at 50 °C and 20% concentration. 80

 

Figure 4.2: Mechanical spectrum of 25% gelatin solution. G’: filled symbols, G”: empty symbols. Experiments were performed at 50 °C, strain amplitude was 1%.. 82

 

Figure 4.3: Storage and loss moduli G¢, G² for a 25% gelatin sample during a cooling ramp. Temperature was ramped from 50 to 20 °C at 1°C/min. Frequency: 1 rad/s. Strain amplitude: 1%.. 84

 

Figure 4.4: Storage and loss moduli G¢, G² as a function of temperature during a heating ramp of a 25% gelatin sample. Temperature was ramped from 25 °C to 50 °C at 1 °C/min. Frequency: 1 rad/s. Strain amplitude: 1%.. 85

 

Figure 4.5: Mechanical spectrum of 25% gelatin. G’: filled symbols, G”: empty symbols. The temperature was 20 °C. Strain amplitude: 1%. 87

 

Figure 4.6: Changes in modulus G’ and G” as a function of time for a 27% gelatin gel. Measurement temperature was 20 ° C. Frequency: 1 rad / s. Strain amplitude: 1%. 88

 

Figure 4.7: Changes in G’ as function of gelatin concentration. Data obtained after 6 h of time sweep measurement at 20 °C. Frequency: 1 rad/s. Strain amplitude: 1%. 89

 

Figure 4.8: Flow curves of hydrolyzed hydroxypropylated cassava starch dispersions at a concentration of 25% (g/g): HHSS6 (●), HHSS12 (■), HHSS18 (o), HHSS24 (€). Measurements were performed at 50 °C.. 91

 

Figure 4.9: Flow curves for dually modified cassava starch (HHSS12) dispersions at a concentration of 25% (g/g). Measurement was performed at 50 °C.. 92

 

Figure 4.10: Flow curves of dispersions of hydroxypropyl cassava starch HHSS12 at concentrations of 20% (■), 23% (●) and 25% (▲). Temperature was 50°C.. 93

 

Figure 4.11: Mechanical spectra of different dually modified cassava starches at concentrations of 25%: a) HHSS6, b) HHSS12, c) HHSS18, d) HHSS24. G’: filled symbols, G”: empty symbols. Measurement temperature was 50 °C and strain amplitude was 1%.. 94

 

Figure 4.12: Newtonian behavior of κ-carrageenan in the concentration range of 0.25% to 1% at 50 °C   96

 

Figure 4.13: Flow curves of the mixture HHSS12-κC0.5 (¨), 20%HHSS12 and 0.5% κ-carrageenan, κC0, 5 (×), and starch dispersions HHSS12 20% (□), 23% (○) and 25% (Δ). The temperature was 50 °C   97

 

filled symbols. 98

 

Figure 4.15: Flow curves of mixtures of 25% starch HHSS12 with κ-carrageenan at different concentrations. Measurements were taken at 50 °C.. 99

 

Figure 4.16: Flow curves for 0.5% κ-carrageenan and mixtures of 25% dually modified cassava starches/κC0.5. Measurement temperature was 50 °C. 100

 

Figure 4.17: Mechanical spectrum of κC0.5 (solid lines ■, □), HHSS12 (solid lines ●, ○), and the mixture κC0.5-HHSS12 (■, □). Concentration of HHSS12 alone was 25% and in combination total concentration was 25%. G’: filled symbols, G”: empty symbols. Measurement temperature: 50 ° C. Strain amplitude: 1%.. 101

 

Figure 4.18: Variation of viscoelastic modulus G’ and G” as a function of temperature for κC0.5 and for the mixture of κC0.5 and HHSS12. a) Cooling from 50 °C to 20 °C. b) Heating from 20 °C to 50 °C. Heating/cooling rate: 1 °C/min. Frequency: 1 rad/s. Strain amplitude: 1%.. 103

 

Figure 4.19: Variations of modulus G’ and G” as a function of temperature during cooling from 50 °C to 20 °C for 25% HHSS24 alone and in combination with κ-carrageenan. G”: filled symbols; G’: empty symbols. Cooling rate: 1 °C/min. Frequency: 1 rad/s. Strain amplitude: 1%.. 105

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Figure 4.20: Variations of modulus G’ and G” as a function of temperature during cooling from 50 °C to 20 °C for 1% κ-carrageenan and 25% starch mixtures. G’: empty symbols; G”: filled symbols. Cooling rate: 1 °C/min. Frequency: 1 rad/s. Strain amplitude: 1%.. 106

 

Figure 4.21: Variations of modulus G’ and G” as a function of temperature during heating from 20 °C to 60 °C for 1% κ-carrageenan and 25% starch mixtures. G’: empty symbols; G”: filled symbols. Cooling rate: 1 °C/min. Frequency: 1 rad/s. Strain amplitude: 1%.. 107

 

Figure 4.22: Mechanical spectra of κC1 (■, □), κC0.75 (●, ○) and κC0.5 (▲, Δ). G’: filled symbols, G”: empty symbols. Temperature: 20 ° C. Strain amplitude: 1%. 108

 

Figure 4. 23: Mechanical spectrum of κC0.5 (●, ○), 25% HHSS12 (dashed line with ▲, Δ) and the mixture of κC0.5-HHSS12 (■, □) at 20°C. G’: filled symbols, G”: empty symbols. Strain amplitude: 0.1% for mixtures and 1% for constituents. 109

 

Figure 4.24: Mechanical spectrum of mixtures HHSS12-κC1(▲, Δ), HHSS12-κC0.5 (dashed line with ●, ○) and HHSS12-κC0.25 (■, □) at 20 °C. G’: filled symbols, G”: empty symbols. Strain amplitude: 0.1%   110

 

 

 

 

 

Abstract

 

With the goal of finding an alternative to gelatin in the processing of pharmaceutical capsules, the effects of k-carrageenans on dually modified cassava starch were investigated. While film forming and mechanical properties are important in all pharmaceutical capsules, solubility at high solid concentration and thermo-reversibility are important factors for hard capsule processing. Casava starches were modified first by hydrochloric acid (0.14 N for 6, 12, 18, and 24 h at 50 °C) and secondly by propylene oxide (10, 20, and 30% of solid for 24 h at 40°C).

 

To improve the gel setting property of the dually modified starch, dually modified cassava starches were combined with k-carrageenan (0.25, 0.5, 0.75, and, 1%). The concentration of the K+ ion in the composite mixture was adjusted appropriately to achieve the same sol-gel transition temperature. The rheological properties of the mixtures were measured and compared, with gelatin as the reference material. The solution viscosity, sol-gel transition, and mechanical properties of the films made from the mixtures at 50 °C were comparable to those of gelatin. The viscoelastic moduli (G’ and G”) for the gel mixtures were lower than those of gelatin. The composite gels had temperatures of gelation similar to that of gelatin. Both viscosity in solution and stiffness in gels could be adjusted using high levels of κ-carrageenan and was relatively independent of the molecular weight of the starch. These results illustrate that dually modified cassava starch in combination with k-carrageenan has properties similar to those of gelatin, thus these starches can be used in dip-molding processes, such as those used to make pharmaceutical hard capsules.

 

 

 

Chapter 1: Introduction

 

 

 

 

 

 

 

1.1 Background

 

The capsule is one of the formulations of the oldest pharmaceutical in history, known especially from the ancient Egyptians. In Europe, it was not until the nineteenth century that the first gelatin pharmaceutical capsule with the patent of Mr. Dublanc pharmacist and his student Mr. Mothes. Over the years, this invention has been so successful that the production of capsules has grown rapidly in many countries. This has led to many improvements including the invention of hard gelatin capsules in 1846 by Mr. Lehuby (Podczeck & Jones, 2004).

 

The development of pharmaceutical capsules, used for therapeutic purposes, originates in the keen interest shown by the numerous researches in pharmacology. This has greatly expanded the range of possible formulations using pharmaceutical capsules. Today, pharmaceutical capsules are mainly based on animal gelatin from porcine or bovine. Gelatin is an animal protein that is a traditional ingredient in many fields, including food. Gelation properties at temperatures close to room temperature and formation of homogeneous films, potable, gelatin as a choice for the manufacturing of pharmaceutical capsules.

 

However, the use of animal gelatin in the food and pharmaceutical industry is governed by regulations becoming more stringent. The precautionary principal applied, for example, the risk of transmission by animal gelatin; the bovine spongiform encephalopathy (BSE) has questioned its use. Even if today the rules on the origin of the gelatin are very strict and that gelatin is no longer a risk to health, development of alternative products of interest to pharmaceutical and food industries. The sources from which gelatin can also be problematic for ethical or religious populations. Many people around the world do not consume products made from pork (vegetarians, Hebrews, and Muslims) or beef base (vegetarian Hindus). It is therefore that the replacement of gelatin with other texturing agents of non-animal origin has been much research in recent years.

 

The most important properties that potable gelatin as capsule forming material are heat sealability of films for soft capsule processing and solubility in high concentration, film formability and thermo-reversibility for making hard capsules.

 

Starch as a plant based material is one of possible alternative for gelatin due to cost and accessibility. Native starches can form films, but the films have not heat sealability, also starches are non soluble biopolymer, and form non-reversible gels. So changes or supporting the structure likely improve the starch property to consider as gelatin replacement in some cases.

 

The proposed system is a mixture of starch and k-carrageenan. Starch would give the mixture of film-forming properties and solubility in aqueous and carrageenan bring its ability to gel. The selected starch has focused on the use of such modification(s) on starch that able it to dissolve at temperatures below 100 °C and form stable solutions at high concentrations (≈ 20-30%). The botanical origin of the cassava starch is due to its proper amylose content, which improves mechanical properties of films and availability of this starch in Southeast Asia. The gelling agent has been studied was κ-carrageenan/K+ for its ability to form thermo reversible gels and easily adjustable thermo-physical transition temperatures. The film-forming mixtures were prepared by casting method.

 

The main objective of this research project is to replace the gelatin with a composite cassava (tapioca) starch film for manufacturing of pharmaceutical capsules especially hard capsules. The idea for hard capsule processing is to develop a new system whose characteristics in the solution and solid state would be closer to existing formulations. The constraints imposed industrial development concentrated formulations (25-30%) prepared at temperatures below 100 °C capable of forming a gel by physical cooling and forming a film after drying.

 
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