Ligand-Receptor Networks of TGF-beta plays essential role in transmitting a wide range of extracellular signals that affect many cellular processes such as cell growth. However, the modeling of these networks with conventional approach such as ordinary differential equations has not taken into account, the spatial structure and stochastic behavior of processes involve in these networks. Membrane computing as the alternatives approach provides spatial structure for molecular computation in which processes are evaluated in a non-deterministic and maximally parallel way. This study is carried out to evaluate the membrane computing model of Ligand-Receptor Networks of TGF-beta with model checking approach. The results show that membrane computing model has sustained the behaviors and properties of Ligand-Receptor Networks of TGF-beta. This reinforce that membrane computing is capable in analyzing processes and behaviors in hierarchical structure of cell such as Ligand-Receptor Networks of TGF-beta better than the deterministic approach of conventional mathematical models.
This paper presents a method to convert the deterministic, continuous representation of a biological system by ordinary differential equations into a non-deterministic, discrete membrane computation. The dynamics of the membrane computation is governed by rewrite rules operating at certain rates. That has the advantage of applying accurately to small systems, and to expressing rates of change that are determined locally, by region, but not necessary globally. Such spatial information augments the standard differentiable approach to provide a more realistic model. A biological case study of the ligand-receptor network of protein TGF-β is used to validate the effectiveness of the conversion method. It demonstrates the sense in which the behaviours and properties of the system are better preserved in the membrane computing model, suggesting that the proposed conversion method may prove useful for biological systems in particular.
Studies all over the world reported that smoking relapses occur during the first two weeks after a quit date. The current study aimed to assess the impact of the additional phone calls counselling during the first month on the abstinence rate at 3 and 6 months after quit date among smokers in Penang, Malaysia.
OBJECTIVES: Assessment of nicotine withdrawal symptoms is an essential part of tobacco dependence treatment. This study aimed to evaluate the psychometric properties of a Malay translated version of the Minnesota Nicotine Withdrawal Scale (MNWS).
METHODS: The original scale was translated into Malay following the standard guidelines proposed for translation studies. The reliability and validity of the Malay version scale were evaluated on the basis of data collected from 133 participants. The Cronbach's alpha coefficient was calculated to assess the reliability. To validate the psychometric properties of the scale, factor analysis and construct validity were used. This study was conducted at the Quit Smoking Clinic at Penang General Hospital, Penang, Malaysia.
RESULTS: The translated scale has excellent reliability, with total Cronbach's alpha of 0.91. The test-retest reliability for the scale presented an excellent reliability and stability of the translated scale with Spearman's rank correlation coefficient (r = 0.876; P < 0.001). There was a significant positive correlation between the exhaled carbon monoxide level, Fagerstrom Test for Nicotine Dependence total score, and number of cigarettes smoked per day and the MNWS total score (r = 0.72, 0.68, and 0.68, respectively; P < 0.001). A principal-components analysis with orthogonal rotation yielded a unidimensional model that includes all the items of the MNWS.
CONCLUSIONS: The Malay version of the MNWS is a reliable and valid measure of withdrawal symptoms as well as the smoking urge, and it is applicable to clinical practice and research study.
Study site: Quit Smoking Clinic at Penang General Hospital, Penang, Malaysia.
This study aimed to evaluate the psychometric properties of Malay translated version of the brief questionnaire of smoking urges (QSU-Brief). The translation procedure was done following the standard guidelines. The reliability and validity of the Malaysian version scale were evaluated based on the data collected from 133 Malaysian smokers. The internal consistency was calculated to assess the reliability. Factor analysis and construct validity were performed to validate psychometric properties of the scale. Total Cronbach's alpha of the scale was 0.806. The exploratory factor analysis revealed two factors that accounted for 66.15% of the explained total variance. The first component consisted of items 1, 3, 6, 7, and 10, while the second component included the rest. The QSU-Brief total score had a significant positive relationship with exhaled CO level (r=0.24; P=0.005), number of cigarettes smoked per day (r=0.30; P<0.001) and other clinical factors. Items 2 and 5 loaded strongly on factor 2, whereas both items loaded ambivalently on two factors in the previous studies. This discrepancy might be clarified by language differences. The Malaysian QSU-Brief is a good candidate for evaluating urge to smoke in both clinical practice and clinical trials.