33 research outputs found

    Cryopreservation of Human Adipose Tissues and Adipose-Derived Stem Cells with DMSO and/or Trehalose: A Systematic Review.

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    Adipose tissue senescence is implicated as a major player in obesity- and ageing-related disorders. There is a growing body of research studying relevant mechanisms in age-related diseases, as well as the use of adipose-derived stem cells in regenerative medicine. The cell banking of tissue by utilising cryopreservation would allow for much greater flexibility of use. Dimethyl sulfoxide (DMSO) is the most commonly used cryopreservative agent but is toxic to cells. Trehalose is a sugar synthesised by lower organisms to withstand extreme cold and drought that has been trialled as a cryopreservative agent. To examine the efficacy of trehalose in the cryopreservation of human adipose tissue, we conducted a systematic review of studies that used trehalose for the cryopreservation of human adipose tissues and adipose-derived stem cells. Thirteen articles, including fourteen studies, were included in the final review. All seven studies that examined DMSO and trehalose showed that they could be combined effectively to cryopreserve adipocytes. Although studies that compared nonpermeable trehalose with DMSO found trehalose to be inferior, studies that devised methods to deliver nonpermeable trehalose into the cell found it comparable to DMSO. Trehalose is only comparable to DMSO when methods are devised to introduce it into the cell. There is some evidence to support using trehalose instead of using no cryopreservative agent

    An Evaluation of Consumers’ Perceptions Regarding “Modern Medicines” in Penang, Malaysia

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    The objective of this study was to evaluate consumers’ perceptions regarding “modern medicines” in Penang, Malaysia. To conduct this exploratory study, qualitative techniques were used. Consumers more than 19 years of age and could speak English, who had visited a pharmacy in the last 30 days, were included from the four major areas of Penang. Eighteen interviews were conducted until the point of saturation. The interviews were audio-taped and then transcribed verbatim for thematic content analysis. Many consumers correctly identified the major characteristics and properties of modern medicines; however, others raised doubts regarding the safety, quality and efficacy of “modern medicines”. There were many misconceptions such as “all modern medicines can cause dependence”, traditional medicines are completely “free of side-effects” and “Western medicines cure while Chinese medicines don’t”. Color was also considered a strong determinant of the safety and characteristics of a medicine. Regarding consumers’ “medicine information seeking behavior”, many consumers would seek information from doctors and pharmacists; however, there were others, who would look for books, or get it from the internet and friends. Of concern many consumers emphasized that while “self-searching for drug information” they would only look for side-effects. Misconceptions regarding medicine-taking behavior, medicine use and compliance were also identified. Though several consumers complied with the medicine-taking instructions, many reported that they would stop taking medicines, once they feel better. Though many consumers correctly identified the characteristics of “modern medicines”, misconceptions regarding "medicine information sources and “medicine-taking behavior” were rampant. The situation demands corrective actions including community-oriented educational campaigns to improve “medicine use” in the society

    A vision-based infrared decoy tracking algorithm for air conditioner spot cooling

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    Air conditioner has become one of the most common electrical appliances in every household. With the increase in their demand, the challenge to reduce the energy usage of air conditioner has become a subject of intense study in recent years. Spot cooling is one of the methods that can reduce the energy wastage. In this method, a control algorithm is implemented to actively track the location of users and direct the air conditioner's air flow to these targeted areas. This can make the cooling more efficient since the air conditioner does not need to cool down the entire room. By selectively directing the air flow, the users can still achieve the same cooling comfort. This paper proposed a technique of spot cooling for air conditioner using infrared (IR) camera and a decoy. The decoy is based on IR light emitting diodes arranged in a specific pattern. The IR camera captures the video of the room to locate the position of the decoy. Image processing techniques include thresholding and template matching are used for the decoy detection. Once the decoy is detected, the movement of the decoy is tracked by using a Kalman filter. To test the performance of the proposed method, a prototype system was implemented on a Raspberry Pi board and the accuracy of detection was evaluated. Experimental results showed that the system is able to detect the position of decoy with 98% accuracy in both day and night-time conditions

    Forecasting the unrevealed surface-controlled photocatalytic water splitting in two-dimensional Ag2Se with ultrafast carrier mobility: a first-principles study

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    It has been hypothesized that a thermodynamically feasible Ag2Se monolayer could be a potential candidate for photocatalytic water splitting. However, the present electronic structure knowledge is insufficient for forecasting and confirming the ultimate criterion of photocatalysis. Its wide band gap of around 2.70 eV is also non-ideal for photovoltaic conversion. These challenges are addressed herein using first-principles density functional theory (DFT) calculations to systematically probe the photocatalytic potential, light absorption coefficient, carrier mobility and carrier utilization efficiency of Ag2Se. To ascertain the spontaneity of the solar-to-hydrogen conversion, significant efforts have been made to calculate the energy barriers for the surface hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Fascinatingly, upon −6% compressive biaxial straining, the Ag2Se monolayer ingeniously combines all the desired characteristics for photocatalytic water-splitting activity, including a broader sunlight absorption region (∼105 cm−1), enhanced carrier mobility (∼105 cm2 V−1 s−1) and spontaneous catalytic pathways with relatively low triggering external potential, while retaining a direct band gap, good thermal stability and perfect band edge position. The corrected STH efficiency of ∼10% suggests commercial hydrogen production. This work provides valuable insights into the understanding of the catalytic mechanisms in the strain-modulated Ag2Se monolayer

    SLC17A3 rs9379800 and Ischemic Stroke Susceptibility at the Northern Region of Malaysia

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    Objectives: The relationships of Paired Like Homeodomain 2 (PITX2), Ninjurin 2 (NINJ2), TWIST-Related Protein 1 (TWIST1), Ras Interacting Protein 1 (Rasip1), Solute Carrier Family 17 Member 3 (SLC17A3), Methylmalonyl Co-A Mutase (MUT) and Fer3 Like BHLH Transcription Factor (FERD3L) polymorphisms and gene expression with ischemic stroke have yet to be determined in Malaysia. Hence, this study aimed to explore the associations of single nucleotide polymorphisms (SNPs) and gene expression with ischemic stroke risk among population who resided at the Northern region of Malaysia. Materials and methods: Study subjects including 216 ischemic stroke patients and 203 healthy controls were recruited upon obtaining ethical clearance. SNP genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism assays. Gene expression levels were quantified by real-time polymerase chain reaction assays. Statistical and genetic analyses were conducted with SPSS version 22.2, PLINK version 1.07 and multifactor dimensionality reduction software. Results: Study subjects with G allele, CG or GG genotypes of SLC17A3 rs9379800 demonstrated increased risk of ischemic stroke with the odds ratios ranging from 1.76-fold to 3.14-fold (p<0.05). When stratified study subjects according to the ethnicity, SLC17A3 rs9379800 G allele and CG genotype contributed to 2.14- and 2.96-fold of ischemic stroke risk among Malay population significantly, in the multivariate analysis (p<0.05). However, no significant associations were observed for PITX2, NINJ2, TWIST1, Rasip1, and MUT polymorphisms with ischemic stroke risk in the multivariate analysis for the pooled cases and controls as well as when stratified them according to the ethnicity. Lower mRNA expression levels of Rasip1, SLC17A3, MUT and FERD3L were observed among cases (p<0.05). After FDR adjustment, the mRNA level of SLC17A3 remained significantly associated with ischemic stroke among Malay population (q=0.034). Conclusion: In conclusion, this study suggests that SLC17A3 rs9379800 polymorphism and its gene expression contribute to significant ischemic stroke risk among Malaysian population, particularly the Malay who resided at the Northern Region of the country. Our findings can provide useful information for the future diagnosis, management and treatment of ischemic stroke patients.</p

    The epidemiology and clinical characteristics of myeloproliferative neoplasms in Malaysia

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    Abstract Background The evolution of molecular studies in myeloproliferative neoplasms (MPN) has enlightened us the understanding of this complex disease consisting of polycythaemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The epidemiology is well described in the western world but not in Asian countries like Malaysia. Materials and methods This retrospective national registry of MPN was conducted from year 2009 to 2015 in Malaysia. Results A total of 1010 patients were registered over a period of 5 years. The mean age was 54 years with male predominance. The ethnic distribution revealed that Chinese had a relatively high weighted incidence proportion (43.2%), followed by Indian (23.8%), Malay (15.8%) and other ethnic groups (17.2%). The types of MPN reported were 40.4% of ET (n = 408), 38.1% of PV (n = 385), 9.2% of PMF (n = 93), 3.1% of hypereosinophilic syndrome (HES) (n = 31) and 7.9% of unclassifiable MPN (MPN-U) (n = 80). Splenomegaly was only palpable clinically in 32.2% of patients. The positive JAK2 V617F mutation was present in 644 patients with 46.6% in PV, 36.0% in ET, 9.0% in PMF, and 7.4% in MPN-U, and had significantly lower haemoglobin (p < 0.001), haematocrit (p < 0.001) and white blood cells (WBC) (p < 0.001) than those with negative mutation. Significant differences in platelet and WBC count were detected in ethnic groups and MPN sub-types. There were more arterial thrombosis events seen in those with JAK2 V617F mutation as compared to venous thrombosis events (23.1% vs 4.4%). The bleeding rate was only 6.6%. Among the risk factors, previous thrombosis, old age (≥ 60 years) and hypertension were significantly correlated to positive JAK2 V617F mutation. The arterial thrombosis event is associated with higher presenting HB, HCT and PLT while the bleeding event is associated with lower presenting HB, HCT but higher PLT. The presence of JAK2 V617F mutation is associated with higher risk of arterial thrombosis. Conclusion Chinese ethnicity is associated with higher rates of MPN. The history of thrombosis, age ≥ 60 years and hypertension are risk factors that can be correlated to JAK2 V617F mutation. This study is instrumental for policy makers to ensure preventive strategies can be implemented in future
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