Major issues in SISP: Insights into the main reason of SISP failure

Blogs are increasingly being used as collaboration tools in organizations. However the quality and accuracy of the posted messages in them are still causes for concern. This study proposes a research model to investigate the factors affecting trust in posted messages and the influence of such trust on knowledge use. It suggests that users’ intention to use trusted messages can act as a moderator variable in the relationship between trust and use of the collaboration tool

An Information Diffusion-Based Recommendation Framework for Micro-Blogging

Micro-blogging is increasingly evolving from a daily chatting tool into a critical platform for individuals and organizations to seek and share real-time news updates during emergencies. However, seeking and extracting useful information from micro-blogging sites poses significant challenges due to the volume of the traffic and the presence of a large body of irrelevant personal messages and spam. In this paper, we propose a novel recommendation framework to overcome this problem. By analyzing information diffusion patterns among a large set of micro-blogs that play the role of emergency news providers, our approach selects a small subset as recommended emergency news feeds for regular users. We evaluate our diffusion-based recommendation framework on Twitter during the early outbreak of H1N1 Flu. The evaluation results show that our method results in more balanced and comprehensive recommendations compared to benchmark approaches

Hepatic Carboxylesterase 1 Is Induced by Glucose and Regulates Postprandial Glucose Levels

Metabolic syndrome, characterized by obesity, hyperglycemia, dyslipidemia and hypertension, increases the risks for cardiovascular disease, diabetes and stroke. Carboxylesterase 1 (CES1) is an enzyme that hydrolyzes triglycerides and cholesterol esters, and is important for lipid metabolism. Our previous data show that over-expression of mouse hepatic CES1 lowers plasma glucose levels and improves insulin sensitivity in diabetic ob/ob mice. In the present study, we determined the physiological role of hepatic CES1 in glucose homeostasis. Hepatic CES1 expression was reduced by fasting but increased in diabetic mice. Treatment of mice with glucose induced hepatic CES1 expression. Consistent with the in vivo study, glucose stimulated CES1 promoter activity and increased acetylation of histone 3 and histone 4 in the CES1 chromatin. Knockdown of ATP-citrate lyase (ACL), an enzyme that regulates histone acetylation, abolished glucose-mediated histone acetylation in the CES1 chromatin and glucose-induced hepatic CES1 expression. Finally, knockdown of hepatic CES1 significantly increased postprandial blood glucose levels. In conclusion, the present study uncovers a novel glucose-CES1-glucose pathway which may play an important role in regulating postprandial blood glucose levels

Information Diffusion and Influence Propagation on Social Networks with Marketing Applications

Web and mobile technologies have had such profound impact that we have witnessed significant evolutionary changes in our social, economic and cultural activities. In recent years, online social networking sites such as Twitter, Facebook, Google+, and LinkedIn have gained immense popularity. Such social networks have led to an enormous explosion of network-centric data in a wide variety scenarios, posing unprecedented analytical and computational challenges to MIS researchers. At the same time, the availability of such data offers major research opportunities in various social computing and analytics areas to tackle interesting questions such as: - From a business and marketing perspective, how to mine the novel datasets of online user activities, interpersonal communications and interactions, for developing more successful marketing strategies? - From a system development perspective, how to incorporate massive amounts of available data to assist online users to find relevant, efficient, and timely information? In this dissertation, I explored these research opportunities by studying multiple analytics problems arose from the design and use of social networking services. The first two chapters (Chapter 2 and 3) are intended to study how social network can help to derive a better estimation of customer lifetime value (CLV), in the social gaming context. In Chapter 2, I first conducted an empirical study to demonstrate that friends' activities can serve as significant indicators of a player's CLV. Based on this observation, I proposed a perceptron-based online CLV prediction model considering both individual and friendship information. Preliminary results have shown that the model can be effectively used in online CLV prediction, by evaluating against other commonly-used benchmark methods. In Chapter 3, I further extended the metric of traditional CLV, by incorporating the personal influences on other customers' purchase as an integral part of the lifetime value. The proposed metric was illustrated and tested on seven social games of different genres. The results showed that the new metric can help marketing managers to achieve more successful marketing decisions in user acquisition, user retention, and cross promotion. Chapter 4 is devoted to the design of a recommendation system for micro-blogging. I studied the information diffusion pattern in a micro-blogging site (Twitter.com) and proposed diffusion-based metrics to assess the quality of micro-blogs, and leverage the new metric to implement a novel recommendation framework to help micro-blogging users to efficiently identify quality news feeds. Chapter 5 concludes this dissertation by highlighting major research contributions and future directions

USE OF BLOGS FOR COLLABORATION IN ORGANIZATIONS

Blogs are increasingly being used as collaboration tools in organizations. However the quality and accuracy of the posted messages in them are still causes for concern. This study proposes a research model to investigate the factors affecting trust in posted messages and the influence of such trust on knowledge use. It suggests that users’ intention to use trusted messages can act as a moderator variable in the relationship between trust and use of the collaboration tool

Reputation management in an open source developer social network: An empirical study on determinants of positive evaluations

Successful development of open source software (OSS) projects requires a steady supply of self motivated software developers. Thus a large body of OSS studies focuses on studying the developers' participation motivations. One important motivation is an OSS developer's desire to gain good community reputation which is largely based on positive evaluations from his peers. Therefore, to better motivate developers' project participations through their reputation needs, our empirical analysis adopted a social network perspective to study what factors may affect a developer's decision to positively evaluate one other in a large online open source community called Ohloh. The results surprisingly show that a developer's positive evaluation decision does not depend on his evaluatee's level of OSS-related experience, but rather based on 1) his past reputation (i.e. existing number of positive evaluations), 2) their shared affiliations such as mutual acquaintances, as well as 3) their homophily in location (city), nationality, programming language preference, and community status. We then discuss these findings and their implications for inducing more positive evaluations and better reputation management among open source project members. To the best of our knowledge, this paper is the first research that investigates issues of reputation building and relationship management in an open source development context

CES1 regulates postprandial levels.

<p>(A–H) C57BL/6 mice were injected with Ad-shLacZ or Ad-shCes1. After 5 days, mice were fasted for 16 h followed by gavage with saline or glucose (8 g/kg) (n = 6 mice per group). Blood glucose levels were measured 1 h after gavage using a glucometer (A). Mice were then sacrificed 3 hours after gavage. Hepatic triglyceride (TG) (B) and free fatty acid (FFA) (C) levels were analyzed. Hepatic protein levels were assessed by Western blot assays (D) and then the ratio of p-AKT to total AKT was quantified (E). Hepatic mRNA levels of <i>Ces1</i> (F), <i>PEPCK</i> (G) and <i>G6Pase</i> (H) were determined by qRT-PCR. (I) Reciprocal regulation between plasma glucose and hepatic CES1. Elevated plasma glucose induces hepatic CES1, which in turn helps lower plasma glucose levels likely via increasing peripheral insulin sensitivity. AKT, protein kinase B. *<i>p</i><0.05 **<i>p</i><0.01.</p

Hepatic CES1 is regulated by nutritional status.

<p>(A–C) Hepatic mRNA levels in <i>ob/ob</i> (A) and <i>db</i>/<i>db</i> mice (B) mice were determined by qRT-PCR and protein levels determined by Western blot assays (C, top) (n = 4–6 mice per group). In (C, bottom), protein levels were also quantified by Image J. (D) C57BL/6 mice were treated with either vehicle (0.1 M sodium citrate, pH 4.5) or streptozotocin (STZ) (50 mg/kg/d) for 5 days. Seven days after STZ treatment, mice were euthanized and hepatic mRNA levels were quantified (n = 5 mice per group). (E) Wild-type mice were fed a chow or high fat/high cholesterol (HFHC) diet (21% fat, 1.5% cholesterol) for 3 weeks and hepatic mRNA levels were determined (n = 8 mice per group). (F) C57BL/6 mice were fed a chow diet, or fasted for 3, 8, 24 h, or fasted for 24 h followed by refed for 24 h (n = 5 mice per group). Hepatic protein levels were determined by Western blot assays (top) and then quantified (bottom). Pgc-1α, peroxisome proliferator-activated receptor gamma coactivator-1α. Abca1, ATP-binding cassette (ABC) transporter A1. Abcg5, ABC transporter G5. Pepck, phosphoenolpyruvate carboxykinase. *<i>p</i><0.05, **<i>p</i><0.01.</p

Hepatic CES1 is regulated by glucose but not insulin.

<p>(A–C) C57BL/6 mice were fasted for 16 h, followed by gavage with saline or glucose (8 g/kg) (n = 6 mice per group). Three hours after second oral gavage, hepatic mRNA levels (A) and protein levels (B) were determined. Hepatic CES1 protein levels were quantified (C). <i>L-PK</i> serves as a positive control in (A). (D) C57BL/6 mice were fasted for 16 h, followed by i.p. injection of either saline or insulin (0.8 units/kg) (n = 5 mice per group). After 3 h, mice were euthanized. <i>Srebp-1c</i> serves as a positive control. (E) Mouse primary hepatocytes were isolated and cultured in dulbecco's modified eagle medium (DMEM) plus 10% fetal bovine serum (FBS) overnight, followed by serum-free fasting for 8 h. Cells were then treated with either normal (5.5 mM) or high (27.5 mM) glucose for additional 24 h prior to quantification of mRNA levels. <i>Fas</i> serves as a positive control. (F) CES1 promoter-luciferase constructs were transfected into HepG2 cells, then treated with 5.5 mM or 27.5 mM glucose. After 36 h, luciferase activity was determined. Srebp-1c, sterol response element binding protein-1c. L-PK, liver type pyruvate kinase. Fas, fatty acid synthase. RLU, relative luciferase units. *<i>p</i><0.05, **<i>p</i><0.01.</p

ACL is required for glucose-induced hepatic CES1 expression.

<p>(A) C57BL/6 mice were injected i.v. with adenovirus expressing GFP or ChREBP. After 5 days, hepatic mRNA levels were determined by qPCR (n = 7 mice per group). (B–F) C57BL/6 mice were injected with adenovirus expressing shLacZ or shAcl (n = 6 mice per group). After 5 days, mice were gavaged with either saline or glucose (8 g/kg). Hepatic mRNA levels of <i>Acl</i> (B), <i>Ces1</i> (C) and <i>L-pk</i> (F) were determined. Hepatic protein levels were determined by Western blot assays <b>(D)</b> and CES1 protein levels quantified (E). *<i>p</i><0.05, **<i>p</i><0.01.</p