Fatty acid composition and antioxidant activity of oils from two cultivars of Cantaloupe extracted by supercritical fluid extraction

The effect of supercritical fluid extraction (SFE) fractionation of three oil fractions (1st, 2nd, 3rd fraction) on the fatty acid composition and antioxidant activity of oils from two cultivars of cantaloupe were investigated. Rock melon oil (RMO) and Golden Langkawi oil (GLO) were extracted using SFE and the major fatty acids for both cultivars were linoleic, oleic, palmitic, and stearic acid. The SFA decreased from 15.78 to 14.14% in RMO 1st fraction, and MUFA decreased from 18.30 to 16.56% in RMO 2nd fraction, while PUFA increased from 65.9 to 69.30% in RMO 3rd fraction. On the other hand SFA decreased from 16.35 to 13.91% in GLO 1st fraction, and MUFA decreased from 17.50 to 15.57% in GLO 2nd fraction, while PUFA increased from 66.15 to 70.52% in GLO 3rd fraction. The different fractions of the two oils showed high antioxidant activity in reducing the oxidation of pi-carotene in beta-carotene bleaching assay (BCB) and the quenching of 1,1-diphenyl-2-picrylhydrazyl (DPPH)

Structural Modeling and Biochemical Characterization of Recombinant KPN_02809, a Zinc-Dependent Metalloprotease from Klebsiella pneumoniae MGH 78578

Klebsiella pneumoniae is a Gram-negative, cylindrical rod shaped opportunistic pathogen that is found in the environment as well as existing as a normal flora in mammalian mucosal surfaces such as the mouth, skin, and intestines. Clinically it is the most important member of the family of Enterobacteriaceae that causes neonatal sepsis and nosocomial infections. In this work, a combination of protein sequence analysis, structural modeling and molecular docking simulation approaches were employed to provide an understanding of the possible functions and characteristics of a hypothetical protein (KPN_02809) from K. pneumoniae MGH 78578. The computational analyses showed that this protein was a metalloprotease with zinc binding motif, HEXXH. To verify this result, a ypfJ gene which encodes for this hypothetical protein was cloned from K. pneumoniae MGH 78578 and the protein was overexpressed in Escherichia coli BL21 (DE3). The purified protein was about 32 kDa and showed maximum protease activity at 30 °C and pH 8.0. The enzyme activity was inhibited by metalloprotease inhibitors such as EDTA, 1,10-phenanthroline and reducing agent, 1,4-dithiothreitol (DTT). Each molecule of KPN_02809 protein was also shown to bind one zinc ion. Hence, for the first time, we experimentally confirmed that KPN_02809 is an active enzyme with zinc metalloprotease activity

Actividad antioxidante y composición de ácidos grasos de aceites de semilla de melón de dos variedades extraídos mediante extracción con fluido supercrítico

The effect of supercritical fluid extraction (SFE) fractionation of three oil fractions (1st, 2nd, 3rd fraction) on the fatty acid composition and antioxidant activity of oils from two cultivars of cantaloupe were investigated. Rock melon oil (RMO) and Golden Langkawi oil (GLO) were extracted using SFE and the major fatty acids for both cultivars were linoleic, oleic, palmitic, and stearic acid. The SFA decreased from 15.78 to 14.14% in RMO 1st fraction, and MUFA decreased from 18.30 to 16.56% in RMO 2nd fraction, while PUFA increased from 65.9 to 69.30% in RMO 3rd fraction. On the other hand SFA decreased from 16.35 to 13.91% in GLO 1st fraction, and MUFA decreased from 17.50 to 15.57% in GLO 2nd fraction, while PUFA increased from 66.15 to 70.52% in GLO 3rd fraction. The different fractions of the two oils showed high antioxidant activity in reducing the oxidation of β-carotene in beta-carotene bleaching assay (BCB) and the quenching of 1,1-diphenyl-2-picrylhydrazyl (DPPH).El efecto del fraccionamiento mediante extracción con fluido supercrítico de tres fracciones (fracción 1ª, 2ª y 3ª) sobre la composición de ácidos grasos y actividad antioxidante de aceites de dos variedades de melón fué investigado. Aceites de melón de los cultivares Rock (RMO) y Golden Langkawi GLO) fueron extraídos usando SFE y los principales ácidos grasos en cada cultivar fueron ácido linoleico, oleico, palmítico y esteárico. Los ácidos grasos saturados (SFA) disminuyeron desde 15.78 a 14.14% en la 1ª fracción de RMO y los ácidos grasos monoinsaturados (MUFA) disminuyeron desde 18.30 a 16.56% en la 2ª fracción de RMO, mientras que los ácidos grasos poliinsaturados (PUFA) aumentaron de 65.9 a 69.30% en la 3ª fracción de RMO. Por otra parte, SFA disminuyo de 16.35 a 13.91% en la primera fracción de GLO y MUFA disminuyo de 17.50 a 15.57% en la 2ª fracción de GLO, mientras que PUFA aumento de 66.15 a 70.52% en la 3ª fracción de GLO. Las diferentes fracciones de los dos aceites mostraron una alta actividad antioxidante al reducir la oxidación del β-caroteno en el ensayo de decoloración de beta-carotene (BCB) y en la eliminación del radical 1,1-difenil-2-picrilhidrazilo (DPPH)

Harmonic Reduction of a Single-Phase Multilevel Inverter Using Genetic Algorithm and Particle Swarm Optimization

Power inverter play an important role in power system especially with its capability on reducing system size and increase efficiently. The recent research trends of power electronic system are focusing on multilevel inverter topics in optimization on voltage output, reducing the total harmonics distortion, modulation technique, and switching configuration. The research emphasizes the optimization with a fundamental switching frequency method that is the optimized harmonic stepped waveform (OHSW) modulation method. The selective harmonic elimination (SHE) calculation has adapted with genetic algorithm (GA) and particle swarm optimization (PSO) in order to speed up the calculation. Both bioinspired algorithms are compared in terms of total harmonic distortion (THD) and selective harmonic elimination for both equal and unequal sources. The overall result showed that both algorithms have high accuracy in solving the nonlinear equation. However, the genetic algorithm showed better output quality in terms of selective harmonic elimination which overall no exceeding 0.4%. Particle swarm optimization shows strength in finding the best total harmonic distortion where in seven-level cascaded H-bridge multilevel inverter (m=0.8) shows 6.8% only as compared to genetic algorithm. Simulation for three-level, five-level, and seven-level for each multilevel inverter at different circumferences had been done in this research. The result draws out a conclusion where the possibility of having a filterless high-efficient inverter can be achieved

Improved outcome of acute lymphoblastic leukaemia treated by delayed intensification in Hong Kong children: HKALL 97 study

Objective. To study the outcome of children with acute lymphoblastic leukaemia who were treated using a protocol including one or two delayed intensifications. Design. Prospective single-arm multicentre study. Setting. Five designated children cancer units of the Hospital Authority of Hong Kong. Patients. Children aged between 1 and 17.9 years with newly diagnosed acute lymphoblastic leukaemia seen from November 1997 to December 2002. Intervention. Chemotherapy was modified from a German Berlin-Frankfurt-Muenster 95 (BFM95) protocol that included a delayed intensification similar to the induction phase repeated 5 months after diagnosis. High-risk patients were given double delayed intensification. Main outcome measures. Overall survival and event-free survival of the whole group and the three risk groups (standard-, intermediate-, and high-risk groups), and comparison with historical controls. Results. A total of 171 patients were recruited with a median age at diagnosis of 5.57 years (range, 1.15-17.85 years). The induction remission rate was 95.3% and non-leukaemia mortality during remission was 2.3%. At 4 years, the relapse rate of this (HKALL97) study was significantly lower than that of the HKALL93 study (15.7 vs 37.3%; P<0.001). The 4-year overall survival of HKALL97 and HKALL93 studies were 86.5% and 81.8%, respectively (P=0.51). The 4-year event-free survival for HKALL 97 and HKALL93 studies were 79% and 65%, respectively (P=0.007). Nonetheless the difference of event-free survival was most remarkable in the intermediate-risk group: 75.6% and 53.1% for HKALL97 and HKALL93 studies, respectively (P=0.06). Conclusion. A more intensive delayed consolidation phase improved the outcome for children with acute lymphoblastic leukaemia by reducing relapses at 4 years. The early treatment complications were manageable and non-leukaemia mortality during remission remained low.published_or_final_versio

A synopsis of current care of thalassaemia major patients in Hong Kong

OBJECTIVE: To provide a synopsis of current thalassaemia major patient care in Hong Kong. DESIGN: Retrospective study. SETTING: All haematology units of the Hospital Authority in Hong Kong. PATIENTS: All patients with thalassaemia major with regular transfusion. RESULTS: To date, there were 363 thalassaemia major patients under the care of the Hospital Authority. Prenatal diagnosis has helped to reduce the number of indigenous new cases, but in recent years immigrant cases are appearing. The patients have a mean age of 23 (range, 1-52) years, and 78% of them are adults. In 2009, they received 18 782 units of blood. This accounted for 9.5% of all blood consumption from the Hong Kong Red Cross. In the past, cardiac iron overload was the major cause of death (65%) and few patients survived beyond the age of 45 years. The availability of cardiac iron assessment by magnetic resonance imaging (T2 MRI) to direct the use of oral deferiprone chelation has reduced the prevalence of heart failure and cardiac haemosiderosis, which should reduce mortality and improve life expectancy. CONCLUSION: The future for thalassaemia care in Hong Kong is bright. With better transfusion and chelation, it should be possible to avoid growth and endocrine deficiencies in younger patients.published_or_final_versio

A novel oxygen carrier 'YQ23' suppresses the liver tumor metastasis by decreasing circulating endothelial progenitor cells and regulatory T cells

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Native aggregation as a cause of origin of temporary cellular structures needed for all forms of cellular activity, signaling and transformations

According to the hypothesis explored in this paper, native aggregation is genetically controlled (programmed) reversible aggregation that occurs when interacting proteins form new temporary structures through highly specific interactions. It is assumed that Anfinsen's dogma may be extended to protein aggregation: composition and amino acid sequence determine not only the secondary and tertiary structure of single protein, but also the structure of protein aggregates (associates). Cell function is considered as a transition between two states (two states model), the resting state and state of activity (this applies to the cell as a whole and to its individual structures). In the resting state, the key proteins are found in the following inactive forms: natively unfolded and globular. When the cell is activated, secondary structures appear in natively unfolded proteins (including unfolded regions in other proteins), and globular proteins begin to melt and their secondary structures become available for interaction with the secondary structures of other proteins. These temporary secondary structures provide a means for highly specific interactions between proteins. As a result, native aggregation creates temporary structures necessary for cell activity

Clinical spectrum of Exophiala infections and a novel Exophiala species, Exophiala hongkongensis

Poster PresentationBackground: Exophiala species are saprophytic fungi which have been isolated from environments rich in hydrocarbons or from hot, humid, and oligotrophic environments. These fungi are considered as dematiaceous moulds; and due to their phenotypic characteristics at the beginning of colony formation, they are also often referred to as ‘black yeasts’, a misnomer which sometimes may mislead the choice of antifungal agents. When the cultures mature, brown hyphae are formed bearing conidiogenous cells referred to as annellides, a typical characteristic of this fungal genus. Although Exophiala species are environmental fungi, they should not be disregarded as contaminants when they are isolated from clinical specimens. These fungi are causative agents of skin and subcutaneous tissue infections and of systemic infections, such as prosthetic valve endocarditis, dialysis-associated peritonitis, and disseminated infections, especially in immunocompromised patients. Unfortunately, Exophiala species can often only be identified to the genus level by phenotypic characterisation. Objectives: The aims of this study were to study the clinical spectrum of Exophiala infections in Queen Mary Hospital, Hong Kong by a polyphasic approach, and to characterise a potentially novel Exophiala species, Exophiala hongkongensis (ex-type strain HKU32T). Methods: All Exophiala strains characterised in this study were isolated from patients during a 15-year period (1998-2012) and were retrieved from the collection in the clinical microbiology laboratory at Queen Mary Hospital, Hong Kong. The strains were characterised phenotypically by microscopic examination of fungal structure using the agar block smear preparation method and phylogenetically using the internal transcribed spacer (ITS) region and Rpb1 gene. In addition, a unique strain, HKU32T, was further characterised phenotypically by scanning electron microscopy, enzyme activity test using the API-ZYM system, and growth tests on different temperatures and culture media. HKU32T was also further phylogenetically characterised using β-tubulin and β-actin genes. All the phylogenetic analyses were performed by the maximum likelihood method using MEGA 5.0.5. Results: Microscopic examination of the young cultures of all the 12 strains showed subspherical, budding, yeast-like cells. Sequencing of the ITS region and partial Rpb1 gene showed 11 of the 12 strains were known Exophiala species, including E. oligosperma [n = 3], E. jeanselmei [n = 2], E. lecanii-corni [n = 2], E. bergeri [n = 1], E. cancerae [n = 1], E. dermatitidis [n = 1], and E. xenobiotica [n = 1]). As for HKU32T, it displayed unique morphological features and was positive for eight enzymes in the API-ZYM test. Optimal growth was observed at 30°C on potato dextrose agar or at 24°C on cornmeal agar. HKU32T also occupied unique phylogenetic positions in all the phylogenetic analyses, with Exophiala nishimurae being the most closely related species. Clinical spectrum of Exophiala infections in Hong Kong included chronic skin infection, colonisation of gastrointestinal tract, continuous ambulatory peritoneal dialysis (CAPD) peritonitis, onychomycosis, pneumonia, tinea pedis, and wrist or finger nodule. Conclusion: Exophiala species could cause a wide range of infections and the most frequent species isolated from patients in Hong Kong was Exophiala oligosperma. Exophiala hongkongensis sp. nov. is proposed to describe the unique strain HKU32T