The effect of drugs on heart rate: Research experiment

The effect of drugs on heart rate: Research experiment The water flea Daphnia pulex (see figure 1) is a small (1.1-3.5mm long ) crustacean commonly found in ponds in the United Kingdom. The full taxonomy of Daphnia pulux is as follows: Kingdom – Branchiopoda Phylum – Diplostraca Class – Cladocera Order – Anomopoda Family – Daphniidae Genus – Daphnia Subgenus pulex Figure 1. Daphnia pulex, showing the clear exoskeleton and inside the body (Cladoceran website 2005) Whilst being crustaceans and having an exoskeleton Daphnia are easy to study as their exoskeleton is actually clear so it is possible to see through it and study the working of the inside of their body. In particular it is possible to see the flow of the circulatory system and the heart beating. Therefore they are useful to test the effects of specific drugs on heartbeat, as it is easy to see the changes via an obvious change in heartbeat. Daphnia have been used in the present experiment as they are readily available and it is simple to study the effects of drugs on their systems. They are also robust to a variety of chemicals being present in their environment so can be used to assess the effects of these chemicals without fear that the chemicals will kill them instantly. Aspirin (acetylsalicylic acid), alcohol (ethanol), and caffeine are drugs that all commonly used by people. All 3 drugs have an effect on the human heart, mostly through indirect effects on the circulation and factors that affect circulation – eg platelet clotting. Alcohol causes a lowering of heart beat due to expanding the veins through vasodilatation. Aspirin also lowers the heart rate via its effects on platelets and the way that they cause veins to constrict. Caffeine, however, acts to increase heart beat. It is unfortunately not practical to test the effect of any of the drugs on the heartbeat of people as the drugs have a lot of other effects within the body as well. Instead Daphnia are used as they have a small body so the drug effects are less widespread and the effect on the heart is easy to assess. The effects are also evident very quickly so it is possible to carry out a large number of investigations in a relatively short space of time. Hypothesis The experimental hypotheses for each of the three drugs are as follows: Aspirin will cause the heart rate of Daphnia to lower in a concentration dependent manner. Alcohol will cause the heart rate of Daphnia to lower in a concentration dependent manner. Caffeine will cause heart rate of Daphnia to increase in a concentration dependent manner. The null hypothesis in all cases is that each of the drugs will have no effect on the concentration rate of Daphnia. Variables In order to see whether it is actually the drugs that are causing the change in the heart rate of Daphnia the only variable that can change is the concentration of the drug. As well as this each drug will have to be tested separately to make sure that it is only the effect of that drug which is causing the change, if any. A fourth set of results also needs to be taken, which is the heart rate of daphnia without any of the drugs added at all. For this experiment the independent variable will be the drug concentration. An independent variable is one that is chosen and set specifically by the experimentor. For this experiment the dependent variable – the one that changes as a result of the independent variable changing – will be the heart rate of the Daphnia. Constant variables will be: The number of Daphnia (approx 100) The volume of water (100ml) The temperature (same room temperature of approx 21  °C in all cases) The species of Daphnia (Daphnia pulux) The amount of water transferred to microscope slide for each test (1ml) The same length of time the Daphnia would be left in the chemical (1 hour) Method Daphnia will be collected from a pond, using a fine mesh sive and kept in a contained with pond water until they can be counted and the correct number can be transferred to a petri dish containing 100ml of distilled water for each experiment. Distilled water will be used so that there are no other chemicals present which might have an effect on heart rate. Approximately 100 Daphnia will be used for each experiment, although it would not be possible to count exactly that number so an approximate number will be used in each case. Aspirin will come in a readily available over the counter soluble form (Boots 300mg soluble aspirin) Caffeine will also come in a readily available over the counter form of ProPlus (50 mg Caffeine) Alcohol will come from vodka (Smirnoff Blue label 45% vol). The drug will be added to the distilled water in the petri dish before adding the daphnia and stirred with a clean glass rod to make sure that it is fully dissolved and spread throughout the liquid. Then the daphnia will be transferred to the petri dish using a pipette. Drugs will be in the quantities shown in tables 1-3 Table 1. A table showing the number of caffeine tablets used in each experiment and the resulting caffeine concentration Table 2. A table showing the number of aspirin tablets used in each experiment and the resulting aspirin concentration Table 3. A table showing the amount of vodka used in each experiment and the resulting alcohol concentration There would actually be only 1 control experiment, to check for differences caused by the drug, so the top row of each table actually corresponds to the same experiment, where there is just water in the petri dish and no added chemicals. As the daphnia are small organisms with a relatively permeable exoskeleton they would be able to absorb the caffeine present in the water and it could have its effect upon the body. In each case the Daphnia would be left in the water and drug for a time of 1 hour to ensure that the drug has had any effect. As the Daphnia are only going to be used for a short period of time they would receive no food as it would not be necessary. Whilst whole Daphnia are visible to the naked eye, a microscope is necessary to see the actually heart beats. Therefore a clean pipette will be used to transfer a droplet of the treated water and daphnia onto a microscope slide. This would then be covered using a cover slip to prevent the liquid from moving. This will then be looked at under the microscope and the number of times the Daphnia’s heart beats per minute recorded. Each time that the heart beat is counted it will be repeated 3 times to obtain an average. Different microscope slides would be used in each case to avoid cross contamination by different drugs or drug concentrations. Equipment list Fine mesh sieve Plastic container to store daphnia in Distilled water (13 x 100 ml) 13 clean plastic pipettes 13 clean petri dishes 13 microscope slides and cover slips Light microscope Caffeine tablets (ProPlus) Aspirin tablets (Boots soluble aspirin) Alcohol (Smirnoff blue label vodka) Measuring cylinder Risk assessment There are a number of specific areas which involve risk within this experiment. These are the initial collection of daphnia, the handling of daphnia and the handling of chemicals. Specific risk assessment are as follows: If alcohol / drug is ingested then rinse out mouth immediately and seek medical advice. If alcohol / drug solution is spilt on clothes rinse affected area and remove clothes if necessary. If alcohol / drug solution gets into eyes then rinse out immediately and seek medical advice. An adult (over 18) must purchase the vodka and be present during its use. Care should be taken when obtaining the daphnia from a pond and an adult should ideally do the collecting. If pond water is ingested then rinse out mouth immediately and seek medical advice. Results It was found that, as Daphnia heart beat was very fast it was easier and more reliable to count in 15 second sections and then convert this to beats per minute. So this was done in all cases. The heart rate of daphnia under control conditions was found to be an average of 350 beats / minute. The results for each of the 3 drugs are considered separately below. Caffeine The results from the experiment to investigate the effect of caffeine upon the heart rate of Daphnia are shown in figure 2 below. Figure 2. The effect of caffeine on the heart rate of Daphnia Pulex (average of 3 counts) It can be seen that there is a positive correlation between caffeine concentration and Daphnia heart rate. The percentage increase in heart rate, when compared to control, is shown in table 4 below. Table 4. A table showing the effect of increasing caffeine concentration on daphnia heart rate Aspirin Unfortunately the concentrations of aspirin used actually killed the daphnia whilst they were in the solution for the required hour. Therefore it was necessary to alter the concentrations and repeat the experiment. As the daphnia died at all concentrations of aspirin even 30 mg / litre must have been too concentrated for them. Therefore the concentration was reduced to 10% of original values, and the experiment repeated. The new concentrations were obtained by diluting the dissolved tablets in more distilled water, eg 10 times the amount to obtain concentrations of 1/10. unfortunately, due to time constraints, the counts could not be repeated 3 times so the figure are for a single count at each concentration. The results from these new concentrations are shown in figure 3 below. Figure 3. The effect of aspirin on the heart rate of Daphnia It can be seen from figure 3 that there is no particular pattern to the results, other than the fact that aspirin is linked to a reduction in heart rate. However this reduction does not appear to be concentration dependent, or at least not at the concentrations used in this experiment. Alcohol The effect of increasing alcohol concentration is shown in figure 4. Figure 4. The effect of alcohol on the heart rate of Daphnia (average of 3 counts) It can be seen that alcohol had quite a large effect on the heart rate of daphnia and there was an inverse correlation between alcohol concentration and heart rate. The percentage decrease in heart rate, when compared to control, is shown in table 5 below. Table 5. A table showing the effect of increasing alcohol concentration on daphnia heart rate Statistical analysis of results It was not possible to undertake accurate statistical analysis of the aspirin results as only 1 count was taken at each concentration level on the repeated experiment. However it was possible to undertake a t test analysis on the alcohol and caffeine results, using the original data as opposed to the mean results shown in the graphs. Statistical analysis was carried out using the software available from Graphpad quickcalcs. These statistically analysed results are shown in table 6 and 7 below. Table 6. A table to show the relative statistical significance of varying concentrations of caffeine upon the heart rate of daphnia Table 7. A table to show the relative statistical significance of varying concentrations of alcohol upon the heart rate of daphnia Discussion The results from this experiment indicate that both caffeine and alcohol affect heart rate of daphnia. Aspirin may affect heart rate but the results obtained here do not provide enough evidence to support this view fully. Why does caffeine affect heart rate? The results from this experiment show that caffeine causes heart rate to increase by around 0.05% per mg of caffeine. Whilst it cannot be known exactly why this happens there are various possible reasons. Caffeine if a methylxanthine which acts by inhibiting the enzyme (phosphodiesterase) that metabolises cAMP. The resulting rise in cAMP levels has the same effect as increasing levels of adenylate cyclase, which is one of the principal effects of adrenaline. Adrenaline is known to increase heart rate via its effects on the  Ã‚ ¢1 adrenoceptors so it is likely that caffeine has a similar effect. Whilst these effects are known about in humans, and daphnia are not the same organisms, it is likely that the effects are mediated for similar reasons – eg the involvement of enzymes and inhibition / stimulation of these. It is possible that the effects of caffeine were not as pronounced as might have occurred due to a reflex reaction. In humans an increase in heart rate is often rapidly followed by a reflexive compensatory mechanism to slow the heart rate again. This compensation can involve the veins dilating and a stimulation of enzymes such as phosphodiesterase in order to reduce cAMP levels. In the case of the daphnia it might have been the case that a more significant rise in heart rate occurred as soon as the caffeine was absorbed by the daphnia but then there was a compensatory mechanism to reverse this effect. However as the solution of caffeine was present around the daphnia for the whole duration of the experiment then this is unlikely as each time new caffeine was absorbed it would cause heart rate to increase, and the daphnia’s system would not be able to constantly undergo the reflexive compensations. How does aspirin affect heart rate Aspirin has its principal effects on an enzyme called cyclo-oxygenase. Aspirin acts by binding to the active site of the enzyme, thus preventing it from binding to the eiocosanoid and having its required effect. The inhibition is irreversible as aspirin binds permanently to the active site of the enzyme. Cyclo-oxygenase (COX) is the main enzyme involved in the conversion of eiocosanoids found in membrane fatty acids, into the inflammatory mediators prostaglandins and leuoktrienes. COX acts to convert arachadonic acid into the prostaglandin precursor prostaglandin G2 and also to convert this precursor into prostaglandin H2. It is from PGH2 that the main inflammatory mediators are generated. Therefore the prevention of COX prevents even the first part of the inflammatory cycle from taking place. Whilst it is not immediately obvious how the prevention of inflammatory mediators should reduce heart rate, it becomes obvious when the effect of the inflammation on heart rate is known. Whilst each individual prostanoid has slightly different effects, the overall one if to cause vasoconstriction and also an increase in myocardial contractility. This latter particularly results in heart rate being increased as the heart muscle in contracting more frequently. This means that decreases heart rate by preventing this increased heart muscle contraction, as well as preventing the vasculature from constricting so much. Again, it is the effects of aspirin in humans that is known about, but it could be expected that the effect is similar in daphnia. Why might alcohol affect heart rate It is not known exactly how ethanol acts to decrease heart rate, but it is believed to be a knock on effect from the changes in peripheral vasculature. Ethanol is known to cause vadodilatation – eg dilation of blood vessels. If blood vessels are dilated then there is more space thus a greater volume for blood so the heart has to beat fewer times to deliver the same amount of blood. It is also possible that ethanol has its effects on heart rate via a central nervous system effect. Ethanol initially increase catecholamine release, including dopamine. This acts to stimulate heart rate. However following this initial effect ethanol actually reduces the concentration of catecholamines, principally noradrenaline, by increasing the rate at which it is removed from cells. As the daphnia had been left in the ethanol containing water for an hour it would be expected that they had reached this second stage by the time heart rate was being measured. However it is possible that the conflict between the initial and subsequent effects of alcohol could be the reason why the results did not follow a particular pattern. Sources of error Whilst statistical significance appears to be present in a number of results it is very difficult to be certain with such a small population number. In order to be more certain of results, a much larger sample size should be used in each case. When a result has been shown to be significant and is actually due to chance this is known as a type I statistical error. Temperature is another variable that affects the heart rate of daphnia, evident by the fact that daphnia can be preserved alive at low temperatures due to a slowing of heart rate. Therefore it is possible that the heat from the light microscope lamp caused an increase in the heart rate. However, as the light was present on each counting session this variable, whilst possibly affecting heart rate, would affect all counts by a similar amount. Therefore all counts would be raised from what they should be. This would serve to make the results from caffeine more significant and alcohol less significant. Given that the results from alcohol showed an inverse correlation then this source of error could have only made the results less significant. However in the case of the caffeine it is possible that they were responsible for the change in heart rate observed, rather than the caffeine, as the changes were rather small anyway. If the experiment were to be repeated this could be controlled by careful monitoring of temperature and ensuring that this remained constant throughout the experiment, a variable that was no measured in this experiment. The fact that alcohol had to be used from an initially diluted form, and in a non pure ethanol formulation may have caused the results to be affected. Whilst calculations were made to find the overall concentration of ethanol into which the daphnia were placed, it is not certain whether this was correct. The alcohol could have contained other chemicals in addition to ethanol which could have affected the daphnia and their heart rate. The formulation of caffeine used was in the form of proplus tablets. These are also not caffeine in a pure format and would contain other padding chemicals such as sugar and talcum powder to make up the tablet. Sugar may well affect the heart rate of daphnia as it is a food stuff for them, and their heart rate may change whilst feeding, or following a substantial amount of food. Whilst daphnia reproduce asexually they are present in male and female forms. It was not possible to ascertain which gender was being counted on each occasion. It is the females which actually give birth to young. However pregnant females have a lower heartbeat than non pregnant females and males. Therefore if some of the daphnia that were being counted were actually pregnant females then this could have artificially lowered the heart rate result. Without studying each daphnia and ensuring that all were of the same gender and pregnant / not it is not possible to tell whether this factor adversity affected the results. Whilst the daphnia were held in place loosely on the microscope slide they were not fixed in place. Therefore it was not always possible to check that it was the same daphnia that was being used for the repetitions of counts for each of the drug treatments. It is therefore possible that the variation within each of the 3 counts was due to different daphnia being used, rather than a different heart rate at different times. It was not possible to ascertain how old each daphnia was which may have had an effect on heart rate as juveniles usually have a higher heart rate than older organisms. It was assumed that all daphnia obtained from the pond were actually of the common daphnia pulex species. However it is possible that there were a mix of different species within the sample collected. If an organism from a different species was used for each of the counts then this could also give rise to altered results. Evaluation The How Did Whatsapp Become Popular? How Did Whatsapp Become Popular? How did WhatsApp overpower other chatting apps? A research on what reasons made WhatsApp the number 1 chatting app in the past 5 years. Abstract In this research, 15 random chat apps users who are from different ages, genders, countries, and educational status filled a survey about their usage and experience of chatting apps.   The analysis of the survey showed that 85.7 percent of chatting apps users are addicted to them as they use them for more than three hours per day. most of them prefer Whatsapp for different reasons. 57.1 percent of the users said that privacy is number one priority for them. They look for a chatting app by which they can remain anonymous and their personal information are safe. Another fifty percent of the users said that they prefer WhatsApp because it is easy to use. A friendy user interface make chatting simpler and easier. A chatting app is made to make peoples life easier so it must be, it self, simple. Only 42.9 percent of users care about the security of the chatting app they use. They look for a chatting app that had no vulnerabilities that hackers can exploit to hack into their phones. Wort h to mention that there is no 100 percent secure app or system so no matter how the system platform is protected and well built, still there is a way or another to hack into it. The last reason for choosing Whatsapp is that it is popular and most people use it. 35.8 percent of users said that no matter how good it is, a messaging app is nothing without plenty of users. They want a chatting app in which they can find their friends and communicate with them. Introduction We are in a time in which chatting apps and social media became of the needs of our daily life. Whether they agree or not, people depend on chatting apps so much on their life to the extent that they can not live without. They use them in all aspects of life eg. get in touch with their friends and relatives, to discuss matters of business, and to explain a lesson to a classmate. Beside the instant messaging, the group chats that people create with friends and colleagues help them to share their ideas, information, point of views, and feelings with each other.   The trend of instant messaging apps lead to the establishment of many chatting apps until it turned into a business in which many counterparts challenge each other to create an application that can attract the majority of users by offering them the features that they look for. One of these chatting applications is WhatsApp. It was established in 2009 by Brian Acton and Jan Koum with the slogan â€Å"Simple. Personal. Real time messaging.† The new app came with plenty of features like as the ability to make group chats, set broadcast contacts and send unlimited images, video and audio messages. Beside being full of features, easy to use, and a pioneer in its category, it helped people to save money by using it instead of the regular SMS messages (Short Message Service) so users do not have to pay extra fees for sending messages. Moreover, it helped make communication over barriers much easier and cheaper than it ever been. All of these features, and others, made WhatsApp the number one chatting app for the past 5 years. In this study, I will investigate how did WhatsApp become the number one chatting app in the world during the past 5 years, what people like on WhatsApp, and what circumstances lead to the failure of other chatting apps. I used a survey which is filled by 15 random people in different ages, genders, countries, and educational status to see what do they like on chatting apps, WhatsApp specifically,   what do they do not like, and what do they expect is the future of chatting applications. The survey is analyzed and its results and foundings are shown at the end of this research paper. Literature review Many studies are done about chatting apps, social media, Whatsapp. A study entitled â€Å"Smartphone application usage amongst students at a South African University†,done in the year 2012 by Walter U, Aadilah M, et.al assessed on the usage of smartphones and social media in between users in a South African University. The study showed that students remain online for 16 hours a day and spend about 5 hours per day on their smart phones interacting and communicating with other their friends, colleagues and relatives through social networking applications. This Application (WhatsApp) is highly addictive and can create a great impact on regular users, and apart from that it can leave a trace that becomes difficult to control and cure. Some of the most prominent technological innovations are smart phones, laptops and using the internet. They have greatly affected many aspects of our lives. Today the Internet continues to grow day by day at an incredible speed. About 32.7% of the world’s population has access to the internet. Howe, Yeboah J, Ewur G. (2014) The two researchers also said that the main purpose behind this application is to replace SMS with a crossplatform mobile messenger that works on an internet data plan. If you have unlimited text, it is still beneficial as it is a convenient way to avoid international fees that carriers may charge. Mayer, Davis, and Schoorman, (1995) define trust in chatting and social media as â€Å"the willingness of a party to be vulnerable to the actions of another party based on the expectation that the other will perform a particular action important to the trustor, irrespective of the ability to monitor or control that other party† (p. 712) Trust is also important for successful online interactions (Coppola, Hiltz, and Rotter, 2004, Jarvenpaa and Leidner, 1998, Meyerson, 1996, Piccoli and Ives, 2003). Trust is also a central component of social exchange theory (Roloff, 1981). â€Å"Millions of people have joined social networking sites, adding profiles that reveal personal information. The reputations of social networking sites has been diminished by a number of incidents publicized by the news media† (Chiaramonte and Martinez, 2006, Hass, 2006, Mintz, 2005, Read, 2006), This raise the question whether ot not it is â€Å"possible to join a network of millions of people and be able to trust all of them.† Of course this does not look plgican. WWe can not trust strangers. Howver people still join networks and reveal their very personal information. what role does trust play in the use of social networking sites? Case study This study is based on a survey in which the responders answer some questions about what attracts him or her to a chatting app, what features does he or she want, and what aspects does he keep in mined when he choose a chatting app eg.security, privacy, ease to use and popularity of the application. This survey is published in a twitter page. 15 random people were engaged in it. They are from different ages, genders, countries, and educational status. The variety of the responders should help getting more accurate results and foundings for the study. A copy of the survey is attached. Research and survey results   The published survey got 15 responses from which I derived these analysis and answer the question of the paper, how did whatsapp overpower other chatting apps and be number one chatting application during the recent five years? The responses showed that 85.7% of users use different chatting apps more than three hours per day which is considered as addiction. Only 14.3 use instant messaging apps for only 1-3 hours per day. This is a regular usage. And nobody from the responders use chatting apps less than an hour a day. These results indicate that people are obviously in addiction with chatting apps no matter what do they use them for. When the responders were asked about the chatting apps they use, the all put WhatsApp at the top of the list, twitter comes second and Black Berry third. The reasons they all chose WhatsApp is clarified in the following figure 57.1% of the responders said that privacy is number one priority. They want to be anonymous and their personal information must be hidden to the eye’s of strangers. They ask for privacy options they can enable or disable by their choice. Since WhatsApp offer these options, it is their choice. However, children and even parents are rarely aware of the potential risks of information disclosure through mobile devices. Personal information, such as real-time locations, photos, and calendar, can be easily leaked via using mobile applications from mobile devices. (Chen Y et.al) They also claim that users’ personal information has been aggressively collected by different parities from mobile devices. 50 percent of the responders said that they prefer WhatsApp because it is easy to use. A friendy user interface make chatting simpler and easier. A chatting app is made to make peoples life easier so it must be, it self, simple. Security comes in rank 3 of the most important feature in a chatting application. 42.9% of people voted that whatsapp is secure enough to protect them against hackers’ attacks. Worth to mention that whatsapp was not encrypted, and though secure,   until April 2016 (Whatsapp.com). 35.8% said that the popularity of chatting app is the fourth most important feature. No matter how good it is, a messaging app is nothing without plenty of users. Keep in mind that because of the different protocols of chatting apps it is not possible to send a message from a certain app to another. A message must be sent and received by the same app. So 35.8 percent of people Conclusion Chatting apps and social media became parts of modern daily life. Nearly 85.7 percent of people are addicted to use their phones and chat more than 4 hours a day. People tend to look for a chatting app that respect their privacy and give them the choice to choose to what extent they are exposed to others. Security is also another important feature people look for. Ease to use and the popularity of chatting apps can make difference on peoples choices. A simple and popular chatting app is always listed as a good choice to use since it will allow the user to chat easily with a huge number of people. References Yeboah J, Ewur G. The Impact of whatsApp Messenger Usage on Student’s Performance in Tertiary Institutions in Ghana. In journal of Education and Practice. Vol.5 2014.Hindocha, N. Instant Insecurity: Security Issues of Instant Messaging. http://www.luisdelgado.es/seguridad/crypt4you/curso_comunicaciones_digitales/documentacion/im_security_issues.pdf . Accessed on 10]11\2016Chen, Y. Zhu, S. Zhou, Y. Xu, H. Protecting Children’s Personal Information: Using Contextual Integrity Theory to Examine Information Boundary on Mobile Devices. http://cs-sys-1.uis.georgetown.edu/~sz303/PIR2015/pir_submission/pir2015_submission_6.pdf. Accessed on 2016\11\10.Dwyer, C. Hiltaz, S. Passerini, K. Trust and Privacy Concern within Social Networking Sites: A Comparison of Facebook and MySpace. http://aisel.aisnet.org/cgi/viewcontent.cgi?article=1849context=amcis2007 Accessed on 10\11\2016Schrittwieser, S. Fruhwirt, P. et. al. Guess Who’s Texting You? Evaluating the Security of Smartphone Messaging Applications. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.681.9726rep=rep1type=pdf Accessed on 14\11\2016Jisha K, Jebakumar, Whatsapp: A Trend Setter in Mobile Communication among Chennai Youth. IOSR Journal Of Humanities And Social Science (IOSR-JHSS) Volume 19, Issue 9, Ver. VII (Sep. 2014), PP 01-06Smartphone Application Usage Amongst Students at a South African University, Walter UYS 1 , Aadilah MIA, Gary Jeffrey JANSEN, Haythem VAN DER SCHYFF, Michael Andre JOSIAS, Michelle KHUSU, Muzaffer GIERDIEN, Natacha Andrea LEUKES, Sulungeka FALTEIN, Tejas GIHWALA, Tracey-Lee THEUNISSEN, Yaseen SAMSODIEN. IST-Africa 2012 Conference Proceedings. Paul Cunningham and Miriam Cunningham (Eds) IIMC International Information Management Corporation , 2012Mayer, R. C., J. H. Davis, and F. D. Schoorman (1995) â€Å"An Integrative Model of Organizational Trust,† The Academy of Management Review (20) 3, pp. 709-734.Coppola, N., S. R. Hiltz, and N. Rotter (2004) â€Å"Building Trust in Virtual Teams,† IEEE Transactions on Professional Communication (47) 2, pp. 95-104.Roloff, M. E. (1981) Interpersonal communication: The social exchange approach. Beverly Hills, CA: Sage Publications, Inc.