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  1. Fulltext Enhanced caffeine degradation by immobilised cells of Leifsonia sp. strain SIU
    Ibrahim S, Shukor MY, Syed MA, Johari WL, Shamaan NA, Sabullah MK, et al.
    J Gen Appl Microbiol, 2016;62(1):18-24.
    PMID: 26923127 DOI: 10.2323/jgam.62.18
    In a previous study, we isolated Leifsonia sp. strain SIU, a new bacterium from agricultured soil. The bacterium was tested for its ability to degrade caffeine. The isolate was encapsulated in gellan gum and its ability to degrade caffeine was compared with the free cells. The optimal caffeine degradation was attained at a gellan gum concentration of 0.75% (w/v), a bead size of 4 mm diameter, and 250 beads per 100 mL of medium. At a caffeine concentration of 0.1 g/L, immobilised cells of the strain SIU degraded caffeine within 9 h, which is faster when compared to the case of free cells, in which it took 12 h to degrade. The immobilised cells degraded caffeine completely within 39 and 78 h at 0.5 and 1.0 g/L, while the free cells took 72 and 148 h at 0.5 and 1.0 g/L, respectively. At higher caffeine concentrations, immobilised cells exhibited a higher caffeine degradation rate. At concentrations of 1.5 and 2.0 g/L, caffeine-degrading activities of both immobilised and free cells were inhibited. The immobilised cells showed no loss in caffeine-degrading activity after being used repeatedly for nine 24-h cycles. The effect of heavy metals on immobilised cells was also tested. This study showed an increase in caffeine degradation efficiency when the cells were encapsulated in gellan gum.
    Matched MeSH terms: Caffeine*
  2. Fulltext Caffeine and theobromine levels in chocolate couverture and coating products
    Ramli N, Abdul Rahman S, Hassan O, Mohd Yatim A, Said M, Lim LS, et al.
    Malays J Nutr, 2000 Mar;6(1):55-63.
    PMID: 22692392
    Thirty-two samples of chocolate products were analysed by HPLC for caffeine and theobromine contents. Defatted residues of samples were extracted with 80% aqueous acetone. After extraction into boiling water, the methylxanthines were identified and quantified with the use of μ-Bondapak column and mobile phase of methanol:water:acetic acid (20:79:1). Levels of caffein and theobromine in 32 samples of chocolate products averaged 0.62-1.14 mg/g and 0.026-0.153 mg/g respectively. Mean values for theobromine and caffeine content for chocolate coating were 0.82 and 0.07 mg/g respectively. The chocolate coating made from fat substitute had theobromine and caffeine levels ranging from 0.36-0.70 mg/g and 0.027-0.061 mg/g respectively, with mean values of 0.49 mg theobromine/g and 0.039 mg caffeine/g. In local chocolate, the mean theobromine and caffeine levels respectively were 0.72 mg/g and 0.04 mg/g in milk chocolate, and 0.85 mg/g and 0.06 mg/g in dark chocolate. Meanwhile, for imported chocolate, the mean theobromine and caffeine levels respectively were 1.05 mg/g and 0.12 mg/g in dark chocolate; 0.76 mg/g and 0.04 mg/g in milk chocolate; and 0.74 mg/g and 0.03 mg/g in white chocolate. Compared with the local chocolates, imported chocolates had higher levels of theobromine and caffeine at 1.141 mg/g and 0.1533mg/g. The average theobromine and caffeine concentrations in local chocolate were 0.082mg/g and 0.066mg/g. Theobromine concentration in chocolate samples is within the range of 0.62mg/g-1.141mg/g and the range of caffeine concentration is 0.026mg/g-0.153mg/g respectively. Bittersweet chocolates were found to have higher theobromine and caffeine concentrations than normal sweet chocolates and milk chocolates.
    Matched MeSH terms: Caffeine*
  3. A review on matcha: Chemical composition, health benefits, with insights on its quality control by applying chemometrics and multi-omics
    Phuah YQ, Chang SK, Ng WJ, Lam MQ, Ee KY
    Food Res Int, 2023 Aug;170:113007.
    PMID: 37316075 DOI: 10.1016/j.foodres.2023.113007
    This review discussed the origin, manufacturing process, chemical composition, factors affecting quality and health benefits of matcha (Camellia sinensis), and the application of chemometrics and multi-omics in the science of matcha. The discussion primarily distinguishes between matcha and regular green tea with processing and compositional factors, and demonstrates beneficial health effects of consuming matcha. Preferred Reporting Items for Systematic Reviews and Meta-Analyses was adopted to search for relevant information in this review. Boolean operators were incorporated to explore related sources in various databases. Notably, climate, cultivar, maturity of tea leaves, grinding process and brewing temperature impact on the overall quality of matcha. Besides, sufficient shading prior to harvesting significantly increases the contents of theanine and chlorophyll in the tea leaves. Furthermore, the ground whole tea leaf powder delivers matcha with the greatest benefits to the consumers. The health promoting benefits of matcha are mainly contributed by its micro-nutrients and the antioxidative phytochemicals, specifically epigallocatechin-gallate, theanine and caffeine. Collectively, the chemical composition of matcha affected its quality and health benefits significantly. To this end, more studies are required to elucidate the biological mechanisms of these compounds for human health. Chemometrics and multi-omics technologies are useful to fill up the research gaps identified in this review.
    Matched MeSH terms: Caffeine
  4. Fulltext Camellia sinensis solvent extract, epigallocatechin gallate and caffeine confer trophocidal and cysticidal effects against Acanthamoeba castellanii
    Fakae LB, Harun MSR, Ting DSJ, Dua HS, Cave GWV, Zhu XQ, et al.
    Acta Trop, 2023 Jan;237:106729.
    PMID: 36280206 DOI: 10.1016/j.actatropica.2022.106729
    We examined the anti-acanthamoebic efficacy of green tea Camellia sinensis solvent extract (SE) or its chemical constituents against Acanthamoeba castellanii by using anti-trophozoite, anti-encystation, and anti-excystation assays. C. sinensis SE (625-5000 µg/mL) inhibited trophozoite replication within 24-72 h. C. sinensis SE exhibited a dose-dependent inhibition of encystation, with a marked cysticidal activity at 2500-5000 µg/mL. Two constituents of C. sinensis, namely epigallocatechin-3-gallate and caffeine, at 100 μM and 200 μM respectively, significantly inhibited both trophozoite replication and encystation. Cytotoxicity analysis showed that 156.25-2500 µg/mL of SE was not toxic to human corneal epithelial cells, while up to 625 µg/mL was not toxic to Madin-Darby canine kidney cells. This study shows the anti-acanthamoebic potential of C. sinensis SE against A. castellanii trophozoites and cysts. Pre-clinical studies are required to elucidate the in vivo efficacy and safety of C. sinensis SE.
    Matched MeSH terms: Caffeine/pharmacology
  5. Caffeine-Supplemented Diet Prevents Fatigue-Like Behavior in Tumor-Bearing Mice
    Ferdaos N, Harada A, Masuda E, Kasai S, Horaguchi T, Yoshizawa K
    Nutr Cancer, 2023;75(3):1005-1013.
    PMID: 36714982 DOI: 10.1080/01635581.2022.2163669
    Caffeine is a widely consumed stimulant, known for its positive effects on physical and mental performance. These effects are potentially beneficial for ameliorating cancer-related fatigue, which affects the quality of life of patients with cancer. This study aimed to determine the anti-fatigue and antitumor effects of caffeine in tumor-bearing mice. BALB/c mice were intravenously injected with C26 colon carcinoma cells and fed with normal or 0.05% caffeine-supplemented diet. Fatigue-like behavior was assessed by running performance using a treadmill test. Lung, blood, liver, muscle, and epididymal adipose tissue samples were collected on day 13 and examined. The antitumor effect of caffeine was assessed using subcutaneous tumor-bearing mice fed with 0.05% caffeine-supplemented diet, and the tumor volume was measured. C26 tumor-bearing mice showed fatigue-like behavior associated with hypoglycemia, depleted liver glycogen and non-esterified fatty acid (NEFA) levels. C26 tumor-bearing mice fed with 0.05% caffeine-supplemented diet showed improved running performance associated with restored NEFA levels. However, exacerbated hypoglycemia and liver glycogen levels after caffeine consumption may be due to tumor-induced catabolic signals, as the tumor volume was not affected. Collectively, caffeine may exert anti-fatigue effects through enhanced lipolysis leading to restored NEFA levels, which can be used as an alternative energy source.
    Matched MeSH terms: Caffeine/pharmacology
  6. Fulltext Spectrophotometric Analysis of Caffeine
    Ahmad Bhawani S, Fong SS, Mohamad Ibrahim MN
    Int J Anal Chem, 2015;2015:170239.
    PMID: 26604926 DOI: 10.1155/2015/170239
    The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometric methods have been developed. The monitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometric methods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. A range of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine.
    Matched MeSH terms: Caffeine
  7. Fulltext "Chap Kaki Tiga" a possible cause of upper gastrointestinal haemorrhage
    See IO
    Med J Malaysia, 1996 Mar;51(1):159-60.
    PMID: 10968003
    Matched MeSH terms: Caffeine/adverse effects*
  8. Synthesis and characterization of mixed ligand complexes of caffeine, adenine and thiocyanate with some transition metal ions
    Shaker SA, Yang Farina, Mahmmod S, Eskender M
    Sains Malaysiana, 2010;39.
    An ethanolic solution of caffeine was added to an aqueous solution of metal salts and followed by adding ethanolic solution of adenine and an aqueous solution of potassium thiocyanate to give complexes with general formula [M(CA)2(Ad)X2] where CA is caffeine, Ad is adenine, X is thiocyanate ion and M is Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The resulting products were characterized using UV-visible and infrared spectroscopies. Elemental analyses were performed using C, H, N analysis and atomic absorption techniques. The magnetic susceptibility and the conductivity were also measured. The results suggested that the complexes have octahedral geometry.
    Matched MeSH terms: Caffeine
  9. Advanced Dome cellulose/alginate/chitosan composite matrix design with gastric and intestinal co-targeting capacities
    Razali S, Bose A, Benetti C, Chong PW, Miller M, Colombo P, et al.
    Int J Pharm, 2022 Nov 25;628:122226.
    PMID: 36191818 DOI: 10.1016/j.ijpharm.2022.122226
    Dome matrix was designed with gastric and intestinal targeting capacities using melatonin and caffeine as model drugs, and alginate, chitosan and cellulose as composite materials. The melatonin, caffeine and intermediate hydroxypropylmethylcelluose-based dispersible modules were prepared through compaction. Caffeine piled module was capped at both ends with melatonin void modules via intermediate dispersible modules into Dome matrix. Dispersion of intermediate module detached melatonin module from Dome matrix and had it floated in stomach providing a more complete melatonin release due to favorable pH-pKa relationship of dissolution medium and drug. With reference to the caffeine module, the detachment of melatonin module facilitated its gastrointestinal transit as a reduced size matrix, with majority of caffeine delivered in colon. The dual site-targeted and -release Dome matrix is applicable as reference oral carrier for pharmaceutical, nutraceutical, functional food and veterinary medicine where a complex formulation and performancein vivoare required.
    Matched MeSH terms: Caffeine
  10. Enhancement of energy recovery from caffeine wastewater in constructed wetland-microbial fuel cell through operating conditions
    Teoh TP, Ong SA, Ho LN, Wong YS, Lutpi NA, Tan SM, et al.
    Environ Sci Pollut Res Int, 2023 Jul;30(35):84397-84411.
    PMID: 37358771 DOI: 10.1007/s11356-023-28362-7
    The enhancement of up-flow constructed wetland-microbial fuel cell (UFCW-MFC) performance in energy retrieval from caffeine containing wastewater has been explored via various operating conditions (hydraulic retention time (HRT), multianode (MA), multicathode current collector (MC), external resistance). The anaerobic decaffeination and COD removal improved by 37 and 12% as the HRT extended from 1 to 5 d. The increment in contact time between the microbes and organic substrates promoted the degradation and contributed to higher power output (3.4-fold), CE (eightfold), and NER (14-16-fold). The MA and MC connections facilitated the electron transfer rate and the degradation rate of organic substrates in the multiple anodic zones, which enhanced the removal efficiency in the anaerobic compartment (Caffeine: 4.2%; COD: 7.4%) and led to higher electricity generation (Power: 4.7-fold) and energy recovery (CE: 1.4-fold; NER: 2.3-2.5-fold) compared to SA. The lower external resistance favored the growth of electrogens and induced higher electron flux, where the best treatment performance and electricity production was obtained when the external resistance approached the internal resistance. Overall, it was noteworthy that the optimum operating conditions were achieved with 5 d HRT, MA, and MC connection along with external resistance of 200 Ω, which significantly outperformed the initial conditions (1 d HRT, SA connection, and 1000 Ω) by 43.7 and 29.8% of caffeine and COD removal in the anaerobic compartment, respectively as well as 14-fold of power generation.
    Matched MeSH terms: Caffeine
  11. Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column
    Rahim AA, Nofrizal S, Saad B
    Food Chem, 2014 Mar 15;147:262-8.
    PMID: 24206716 DOI: 10.1016/j.foodchem.2013.09.131
    A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4 mL min(-1), the catechins and caffeine were isocratically separated in about 7 min. The limits of detection and quantification were in the range of 0.11-0.29 and 0.33-0.87 mg L(-1), respectively. Satisfactory recoveries were obtained (94.2-105.2 ± 1.8%) for all samples when spiked at three concentrations (5, 40 and 70 mg L(-1)). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas.
    Matched MeSH terms: Caffeine/analysis; Caffeine/isolation & purification*
  12. Effects of restricted caffeine intake by mother on fetal, neonatal and pregnancy outcome
    Jahanfar S, Sharifah H
    Cochrane Database Syst Rev, 2009 April 15.
    PMID: 19370665 DOI: 10.1002/14651858.CD006965.pub2
    BACKGROUND: Maternal caffeine consumption during pregnancy may have adverse effects on fetal, neonatal and maternal outcomes.
    OBJECTIVES: This review investigates the effects of restricting caffeine intake by mothers on fetal, neonatal and pregnancy outcomes.
    SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2008), scanned bibliographies of published studies and corresponded with investigators.
    SELECTION CRITERIA: Randomised controlled trials including quasi-randomised controlled trials (RCTs) investigating the effect of caffeine and/or supplementary caffeine versus restricted caffeine intake or placebo on pregnancy outcome.
    DATA COLLECTION AND ANALYSIS: The two review authors independently assessed trial quality and extracted data.
    MAIN RESULTS: One study met the inclusion criteria. Caffeinated instant coffee (568 women) was compared with decaffeinated instant coffee (629 women) and it was found that reducing the caffeine intake of regular coffee drinkers (3+ cups/day) during the second and third trimester by an average of 182 mg/day did not affect birthweight or length of gestation.
    AUTHORS' CONCLUSIONS: There is insufficient evidence to confirm or refute the effectiveness of caffeine avoidance on birthweight or other pregnancy outcomes. There is a need to conduct high-quality, double-blinded RCTs to determine whether caffeine has any effect on pregnancy outcome.
    Matched MeSH terms: Caffeine/administration & dosage; Caffeine/pharmacology*
  13. Fulltext Systematic review and meta-analysis of clinical outcomes of early caffeine therapy in preterm neonates
    Kua KP, Lee SW
    Br J Clin Pharmacol, 2017 01;83(1):180-191.
    PMID: 27526255 DOI: 10.1111/bcp.13089
    AIMS: This study evaluated the therapeutic outcomes of early versus late caffeine therapy in preterm neonates.

    METHODS: We performed a systematic literature search in PubMed, Embase, CINAHL and CENTRAL from inception to 30 June 2016 to identify studies investigating the use of early caffeine therapy (initiated at less than 3 days of life) in preterm infants. Effect estimates were combined using random-effects meta-analysis. The primary outcomes for this study were bronchopulmonary dysplasia and mortality.

    RESULTS: The initial search found 4066 citations, of which 14 studies enrolling a total of 64 438 participants were included. The time of initiation of early caffeine therapy varied from the first 2 h to 3 days postnatal. Early caffeine therapy reduced the risk of bronchopulmonary dysplasia in both cohort studies (RR: 0.80, 95% CI: 0.66 to 0.96) and randomized controlled trials (RR: 0.67, 95% CI: 0.56 to 0.81). In cohort studies, neonates treated early with caffeine also showed decreased risks of patent ductus arteriosus, brain injury, retinopathy of prematurity and postnatal steroid use. However, the mortality rate was increased.

    CONCLUSIONS: The findings suggest that early caffeine therapy is associated with reduced incidence of bronchopulmonary dysplasia and may help decrease the burden of morbidities in preterm infants.

    Matched MeSH terms: Caffeine/administration & dosage*; Caffeine/therapeutic use*
  14. Fulltext Simultaneous coffee caffeine intake and sleep deprivation alter glucose homeostasis in Iranian men: a randomized crossover trial
    Rasaei B, Talib RA, Noor MI, Karandish M, Karim NA
    Asia Pac J Clin Nutr, 2016 Dec;25(4):729-739.
    PMID: 27702715 DOI: 10.6133/apjcn.092015.46
    Sleep deprivation and coffee caffeine consumption have been shown to affect glucose homeostasis separately, but the combined effects of these two variables are unknown.
    Matched MeSH terms: Caffeine/administration & dosage*; Caffeine/adverse effects*
  15. Caffeine prevents restenosis and inhibits vascular smooth muscle cell proliferation through the induction of autophagy
    Tripathi M, Singh BK, Liehn EA, Lim SY, Tikno K, Castano-Mayan D, et al.
    Autophagy, 2022 Sep;18(9):2150-2160.
    PMID: 35012409 DOI: 10.1080/15548627.2021.2021494
    Caffeine is among the most highly consumed substances worldwide, and it has been associated with decreased cardiovascular risk. Although caffeine has been shown to inhibit the proliferation of vascular smooth muscle cells (VSMCs), the mechanism underlying this effect is unknown. Here, we demonstrated that caffeine decreased VSMC proliferation and induced macroautophagy/autophagy in an in vivo vascular injury model of restenosis. Furthermore, we studied the effects of caffeine in primary human and mouse aortic VSMCs and immortalized mouse aortic VSMCs. Caffeine decreased cell proliferation, and induced autophagy flux via inhibition of MTOR signaling in these cells. Genetic deletion of the key autophagy gene Atg5, and the Sqstm1/p62 gene encoding a receptor protein, showed that the anti-proliferative effect by caffeine was dependent upon autophagy. Interestingly, caffeine also decreased WNT-signaling and the expression of two WNT target genes, Axin2 and Ccnd1 (cyclin D1). This effect was mediated by autophagic degradation of a key member of the WNT signaling cascade, DVL2, by caffeine to decrease WNT signaling and cell proliferation. SQSTM1/p62, MAP1LC3B-II and DVL2 were also shown to interact with each other, and the overexpression of DVL2 counteracted the inhibition of cell proliferation by caffeine. Taken together, our in vivo and in vitro findings demonstrated that caffeine reduced VSMC proliferation by inhibiting WNT signaling via stimulation of autophagy, thus reducing the vascular restenosis. Our findings suggest that caffeine and other autophagy-inducing drugs may represent novel cardiovascular therapeutic tools to protect against restenosis after angioplasty and/or stent placement.
    Matched MeSH terms: Caffeine/metabolism; Caffeine/pharmacology
  16. Gas chromatographic method validation for the analysis of major components in illicit heroin seized in Malaysia
    Chan KW, Tan GH, Wong RC
    Sci Justice, 2012 Mar;52(1):9-16.
    PMID: 22325905 DOI: 10.1016/j.scijus.2011.07.005
    Apart from routine analysis of total morphine content required by the criminal justice system, quantification of other major components in illicit heroin has not been considered by the Malaysian enforcement laboratory. In order to quantify various other cutting agents in addition to alkaloids, a gas chromatographic (GC) method was developed to facilitate simultaneous quantification of eight target analytes commonly found in illicit heroin seized in Malaysia within a 12 min run time. The validation results demonstrated high selectivity with the use of an HP Ultra 2 capillary column. Different solvents were studied and methanol:chloroform (1:9) proved best for sample dissolution. The method was repeatable and reproducible. The study ranges covering 50-150% of the preferred concentrations of the eight analytes obtained r(2)>0.9997. Limits of detection up to 6μg/mL were also obtained and the method achieved 99-102% recovery. The capability of the method in heroin profiling was verified using samples from ten case samples.
    Matched MeSH terms: Caffeine/analysis; Caffeine/chemistry
  17. Fulltext Up Regulation of cystathione γ lyase and Hydrogen Sulphide in the Myocardium Inhibits the Progression of Isoproterenol-Caffeine Induced Left Ventricular Hypertrophy in Wistar Kyoto Rats
    Ahmad A, Sattar MA, Rathore HA, Abdulla MH, Khan SA, Azam M, et al.
    PLoS One, 2016;11(3):e0150137.
    PMID: 26963622 DOI: 10.1371/journal.pone.0150137
    Hydrogen sulphide (H2S) is an emerging molecule in many cardiovascular complications but its role in left ventricular hypertrophy (LVH) is unknown. The present study explored the effect of exogenous H2S administration in the regression of LVH by modulating oxidative stress, arterial stiffness and expression of cystathione γ lyase (CSE) in the myocardium. Animals were divided into four groups: Control, LVH, Control-H2S and LVH-H2S. LVH was induced by administering isoprenaline (5mg/kg, every 72 hours, S/C) and caffeine in drinking water (62mg/L) for 2 weeks. Intraperitoneal NaHS, 56μM/kg/day for 5 weeks, was given as an H2S donor. Myocardial expression of Cystathione γ lyase (CSE) mRNA was quantified using real time polymerase chain reaction (qPCR).There was a 3 fold reduction in the expression of myocardial CSE mRNA in LVH but it was up regulated by 7 and 4 fold in the Control-H2S and LVH-H2S myocardium, respectively. Systolic blood pressure, mean arterial pressure, pulse wave velocity were reduced (all P<0.05) in LVH-H2S when compared to the LVH group. Heart, LV weight, myocardial thickness were reduced while LV internal diameter was increased (all P<0.05) in the LVH-H2S when compared to the LVH group. Exogenous administration of H2S in LVH increased superoxide dismutase, glutathione and total antioxidant capacity but significantly reduced (all P<0.05) plasma malanodialdehyde in the LVH-H2S compared to the LVH group. The renal cortical blood perfusion increased by 40% in LVH-H2S as compared to the LVH group. Exogenous administration of H2S suppressed the progression of LVH which was associated with an up regulation of myocardial CSE mRNA/ H2S and a reduction in pulse wave velocity with a blunting of systemic hemodynamic. This CSE/H2S pathway exhibits an antihypertrophic role by antagonizing the hypertrophic actions of angiotensin II(Ang II) and noradrenaline (NA) but attenuates oxidative stress and improves pulse wave velocity which helps to suppress LVH. Exogenous administration of H2S augmented the reduced renal cortical blood perfusion in the LVH state.
    Matched MeSH terms: Caffeine/adverse effects*; Caffeine/pharmacology
  18. Statistical validation for the profiling of heroin by associating simulated postcut samples with the corresponding precut sample
    Chan KW, Tan GH, Wong RC
    J Forensic Sci, 2013 Jan;58 Suppl 1:S199-207.
    PMID: 23013257 DOI: 10.1111/j.1556-4029.2012.02285.x
    Statistical validation is crucial for the clustering of unknown samples. This study aims to demonstrate how statistical techniques can be optimized using simulated heroin samples containing a range of analyte concentrations that are similar to those of the case samples. Eight simulated heroin distribution links consisting of 64 postcut samples were prepared by mixing one of two mixtures of paracetamol-caffeine-dextromethorphan at different proportions with eight precut samples. Analyte contents and compositional variation of the prepared samples were investigated. A number of data pretreatments were evaluated by associating the postcut samples with the corresponding precut samples using principal component analysis and discriminant analysis. Subsequently, combinations of seven linkage methods and five distance measures were explored using hierarchical cluster analysis. In this study, Ward-Manhattan showed better distinctions between unrelated links and was able to cluster all related samples in very close distance under the known links on a dendogram. A similar discriminative outcome was also achieved by 90 unknown case samples when clustered via Ward-Manhattan.
    Matched MeSH terms: Caffeine
  19. Fulltext Cultural beliefs and caffeine-induced sleep disorder: the kopitiam man
    Leow M.Y., Russell V., Bharathy A.
    Malaysian Journal of Psychiatry, 2015;24(1):86-90.
    MyJurnal
    Objective: A case of caffeine-induced sleep disorder is reported to illustrate the clinical benefits of assessing culturally determined health beliefs in such presentations. Method: A middle-aged Malaysian Chinese male presented with caffeine-induced sleep disturbance arising from dietary modifications. Result: Assessing the contribution of cultural beliefs regarding hot and cold drinks led to successful management of the patient’s sleep disturbance. Conclusion: It is important for clinicians to explore health beliefs and associated dietary and lifestyle behaviours in caffeine-related sleep disorders.
    Matched MeSH terms: Caffeine
  20. Molecularly imprinted polymer synthesis using RAFT polymerisation
    Peter A.G. Cormack, Faizatul Shimal Mehamod
    Sains Malaysiana, 2013;42:529-535.
    In this paper, the synthesis and characterisation of caffeine-imprinted polymers are described. The polymers were prepared in monolithic form via both reversible addition-fragmentation chain-transfer (RAFT) polymerisation and conventional free radical polymerisation, using methacrylic acid and ethylene glycol dimethacrylate as the functional monomer and crosslinking agent, respectively. The potential benefits in applying RAFT polymerisation techniques towards the synthesis of molecularly imprinted polymers (MIPs) are explored and elucidated. The pore structures of the polymers produced were characterised by nitrogen sorption porosimetry and the molecular recognition properties of representative products were evaluated in high-performance liquid chromatography (HPLC) mode. Molecular imprinting effects were confirmed by analysing the relative retentions of analytes on imprinted and non-imprinted HPLC
    stationary phases. It was found that a caffeine-imprinted polymer synthesised by RAFT polymerisation was superior to a polymer prepared using a conventional synthetic approach; the imprinting factor and column efficiency were found to be higher for the former material.
    Matched MeSH terms: Caffeine
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