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Gig workers' psychological contracts and turnover intention: A mediated path analysis of organizational identification and job satisfaction

Yu J, Abdul Hamid R

Acta Psychol (Amst), 2024 Nov 06;251:104587.
PMID: 39509959 DOI: 10.1016/j.actpsy.2024.104587

This study, grounded in social exchange theory and social identity theory, aims to examine the influence of psychological contract fulfillment on turnover intention among gig workers. It employs mediated path analysis, specifically examining the mediating roles of organizational identification and job satisfaction. Structural equation modeling (SEM) was utilized to assess the goodness of fit of the proposed model and to test the proposed hypotheses. In Study 1, data collected from the ride-hailing industry in China (N = 374) proved that both transactional and relational contract fulfillment negatively impacted turnover intention, with this relationship mediated by organizational identification and job satisfaction. Study 2, employing time-lagged data (N = 426) collected at two different time points from the food delivery industry in China, also confirmed the negative relationship between transactional and relational contract fulfillment and turnover intention, as well as the mediating effects of organizational identification and job satisfaction. This research advances the current understanding within the psychological contract literature by providing insights into the dynamics of psychological contracts within the context of the gig economy. The findings have significant implications for the management.
Fulltext Promotion of HepG2 cell apoptosis by flower of Allium atroviolaceum and the mechanism of action

Khazaei S, Abdul Hamid R, Mohd Esa N, Ramachandran V, Aalam GT, Etemad A, et al.

BMC Complement Altern Med, 2017 Feb 10;17(1):104.
PMID: 28187719 DOI: 10.1186/s12906-017-1594-6

BACKGROUND: Liver cancer is a high incidence and fatal disease, the fifth most frequent cancer worldwide that is usually diagnosed at an advanced stage. The number of deaths from liver cancer has not declined even following various therapies. Plant secondary metabolites and their semi-synthetic derivatives play a principal role in anti-cancer drug therapy, since they are effective in the treatment of specific characteristics while also reducing side effects. Allium atroviolaceum, a plant of the genus Allium has been used in folk medicine to protect against several diseases. However, cytotoxicity and the anti-proliferative effect of Allium atroviolaceum remain unclear. This work aims to investigate the anticancer properties of Allium atroviolaceum and the mechanism of action.
METHODS: To evaluate the in vitro cytotoxicity of flower of Allium atroviolaceum, methanol extract at a dose range from 100 to 3.12 μg/ml was assessed against the HepG2 hepatocarcinoma cell line, and also on normal 3T3 cells, by monitoring proliferation using the MTT assay method. A microscopy study was undertaken to observe morphological changes of HepG2 cells after treatment and cell cycle arrest and apoptosis were studied using flow cytometry. The apoptosis mechanism of action was assessed by the level of caspase-3 activity and expression of apoptosis related genes, Bcl-2, Cdk1 and p53. The combination effect of the methanolic extract with doxorubicin was also investigated by determination of a combination index.
RESULTS: The results demonstrated growth inhibition of cells in both dose- and time-dependent manners, while no cytotoxic effect on normal cell 3T3 was found. The results revealed the occurrence of apoptosis, illustrated by sub-G0 cell cycle arrest, the change in morphological feature and annexin-V and propidium iodide staining, which is correlated with Bcl-2 downregulation and caspase-3 activity, but p53-independent. In addition, a combination of Allium atroviolaceum and doxorubicin led to a significant synergistic effect.
CONCLUSION: These findings suggest that Allium atroviolaceum flower extract has potential as a potent cytotoxic agent against HepG2 cell lines, as it has commendable anti-proliferative activities against human hepatocarcinoma and it can be considered as an effective adjuvant therapeutic agent after the clinical trials.
Fulltext Low dose triterpene-quinone fraction from Ardisia crispa root precludes chemical-induced mouse skin tumor promotion

Yeong LT, Abdul Hamid R, Saiful Yazan L, Khaza'ai H, Mohtarrudin N

BMC Complement Altern Med, 2015;15(1):431.
PMID: 26638207 DOI: 10.1186/s12906-015-0954-3

Drastic increment of skin cancer incidence has driven natural product-based chemoprevention as a promising approach in anticancer drug development. Apart from its traditional usages against various ailments, Ardisia crispa (Family: Myrsinaceae) specifically its triterpene-quinone fraction (TQF) which was isolated from the root hexane extract (ACRH) was recently reported to exert antitumor promoting activity in vitro. This study aimed at determining chemopreventive effect of TQF against chemically-induced mouse skin tumorigenesis as well as elucidating its possible pathway(s).
Synergistic action of compounds isolated from the hexane extract of Ardisia crispa root against tumour-promoting effect, in vitro

Yeong LT, Abdul Hamid R, Saiful Yazan L, Khaza'ai H, Awang Hamsin DE

Nat Prod Res, 2014;28(22):2026-30.
PMID: 24836304 DOI: 10.1080/14786419.2014.917415

An isomeric mixture of α,β-amyrin (triterpene) and 2-methoxy-6-undecyl-1,4-benzoquinone (quinone) isolated from the Ardisia crispa root hexane (ACRH) extract was reported to possess anti-inflammatory properties in vivo. Considering the close association between inflammation and cancer, on top of the lack of antitumour study on those compounds, this study aimed to determine the potential of both compounds against tumour promotion in vitro, either as single agent or in combination. Triterpene and quinone compounds, as well as triterpene-quinone fraction (TQF) and ACRH were subjected to inhibition of Epstein-Barr virus-early antigen (EBV-EA) activation assay for that purpose. Compared with curcumin (positive control), inhibition against EBV-EA activation occurred in the order: ACRH>TQF ≥ curcumin>α,β-amyrin ≥ 2-methoxy-6-undecyl-1,4-benzoquinone. These findings reported, for the first time, the antitumor-promoting effect of α,β-amyrin and 2-methoxy-6-undecyl-1,4-benzoquinone from the roots of A. crispa, which was enhanced when both compounds act in synergy.
Flower extract of Allium atroviolaceum triggered apoptosis, activated caspase-3 and down-regulated antiapoptotic Bcl-2 gene in HeLa cancer cell line

Khazaei S, Ramachandran V, Abdul Hamid R, Mohd Esa N, Etemad A, Moradipoor S, et al.

Biomed Pharmacother, 2017 May;89:1216-1226.
PMID: 28320088 DOI: 10.1016/j.biopha.2017.02.082

Cervical cancer accounts for the second most frequent cancer and also third leading cause of cancer mortality (15%) among women worldwide. The major problems of chemotherapeutic treatment in cervical cancer are non-specific cytotoxicity and drug resistance. Plant-derived products, known as natural therapies, have been used for thousands of years in cancer treatment with a very low number of side effects. Allium atroviolaceum is a species in the genus Allium and Liliaceae family, which could prove to have beneficial effects on cancer treatment, although there is a lack of corresponding attention. The methanolic extract from the A.atroviolaceum flower displayed marked anticancer activity on HeLa human cervix carcinoma cells with much lower cytotoxic effects on normal cells (3T3). The A.atroviolaceum extract induced apoptosis, confirmed by cell cycle arrest at the sub-G0 (apoptosis) phase, characteristic morphological changes, evident DNA fragmentation, observed by fluorescent microscope, and early and late apoptosis detection by Annexin V. Furthermore, down-regulation of Bcl-2 and activation of caspase-9 and -3 strongly indicated that the mitochondrial pathway was involved in the apoptosis signal pathway. Moreover, combination of A.atroviolaceum extract with doxorubicin revealed a significant reduction of IC50and led to a synergistic effect. In summary, A.atroviolaceum displayed a significant anti-tumour effect through apoptosis induction in HeLa cells, suggesting that the A.atroviolaceum flower might have therapeutic potential against cervix carcinoma.
Fulltext The influence of job characteristics toward intention to pursue sales career mediated by feelings

Ab Hamid SN, Rosli N, Abdul Hamid R, Che Wel CA

Front Psychol, 2022;13:953645.
PMID: 36438356 DOI: 10.3389/fpsyg.2022.953645

The sales profession has suffered from negative perception and misconception. Despite a huge opportunity in this industry, several reasons have been highlighted as deterrents to job applicants from applying for a career in sales including the unethical practices, low prestige, and uncertainty of the job. This study examines the influence of job characteristics and feelings on intention to pursue a sales career among undergraduate and postgraduate students. A cross-sectional study was conducted with 251 questionnaires analyzed using Partial-Least Square-Structural Equation Modeling (PLS-SEM). The findings suggest that job characteristics and feelings have a favorable impact on intention. Job characteristics, on the other hand, influence feelings, and feelings mediate the relationship between job characteristics and intention. This study contributes to the body of knowledge by examining feelings as one of the constructs influencing sales career intention, and provides several implications to employers and business instructors to develop effective strategies to spark student interest in sales-related careers.
Fulltext Cytotoxicity and Proapoptotic Effects of Allium atroviolaceum Flower Extract by Modulating Cell Cycle Arrest and Caspase-Dependent and p53-Independent Pathway in Breast Cancer Cell Lines

Khazaei S, Abdul Hamid R, Ramachandran V, Mohd Esa N, Pandurangan AK, Danazadeh F, et al.

Evid Based Complement Alternat Med, 2017;2017:1468957.
PMID: 29250124 DOI: 10.1155/2017/1468957

Breast cancer is the second leading cause of cancer death among women and despite significant advances in therapy, it remains a critical health problem worldwide. Allium atroviolaceum is an herbaceous plant, with limited information about the therapeutic capability. We aimed to study the anticancer effect of flower extract and the mechanisms of action in MCF-7 and MDA-MB-231. The extract inhibits the proliferation of the cells in a time- and dose-dependent manner. The underlying mechanism involved the stimulation of S and G2/M phase arrest in MCF-7 and S phase arrest in MDA-MB-231 associated with decreased level of Cdk1, in a p53-independent pathway. Furthermore, the extract induces apoptosis in both cell lines, as indicated by the percentage of sub-G0 population, the morphological changes observed by phase contrast and fluorescent microscopy, and increase in Annexin-V-positive cells. The apoptosis induction was related to downregulation of Bcl-2 and also likely to be caspase-dependent. Moreover, the combination of the extract and tamoxifen exhibits synergistic effect, suggesting that it can complement current chemotherapy. LC-MS analysis displayed 17 major compounds in the extract which might be responsible for the observed effects. Overall, this study demonstrates the potential applications of Allium atroviolaceum extract as an anticancer drug for breast cancer treatment.