Processing parallel-disk viscometry data in the presence of wall slip

Leong, Yee-Kwong,Campbell, Graeme R.,Yeow, Y. Leong,Withers, John W. The Korean Society of Rheology 2008 Korea-Australia rheology journal Vol.20 No.2

This paper describes a two-step Tikhonov regularization procedure for converting the steady shear data generated by parallel-disk viscometers, in the presence of wall slip, into a shear stress-shear rate function and a wall shear stress-slip velocity functions. If the material under test has a yield stress or a critical wall shear stress below which no slip is observed the method will also provide an estimate of these stresses. Amplification of measurement noise is kept under control by the introduction of two separate regularization parameters and Generalized Cross Validation is used to guide the selection of these parameters. The performance of this procedure is demonstrated by applying it to the parallel disk data of an oil-in-water emulsion, of a foam and of a mayonnaise.

Cervical Pneumatocele as Delayed Manifestation of Tracheal Injury after Thyroidectomy: Case Series and Literature Review

Jia Ern Leong,Wai Leong Kok,Yee Ling Tan,Balwinder Singh Mann,Sadhana Mahamad 대한갑상선-내분비외과학회 2021 The Koreran journal of Endocrine Surgery Vol.21 No.1

Delayed manifestation of surgical emphysema as cervical pneumatocele post thyroid surgery is rare and unexpected that which needs to be managed appropriately. Herein we report three cases of delayed tracheal injury presenting with persistent subcutaneous emphysema, without acute respiratory distress. All three cases were managed surgically. Possible risk factors were discussed alongside hypotheses on the mechanisms of delayed tracheal injury and recommendations to prevent such complications. The management algorithm was summarized after the literature review. While surgical management is definitive, the non-surgical approach can also be a reasonable option, but requires a longer hospital stay.

Processing parallel-disk viscometry data in the presence of wall slip

Yee-Kwong Leong,Graeme R. Campbell,Y. Leong Yeow,John W. Withers 한국유변학회 2008 Korea-Australia rheology journal Vol.20 No.2

This paper describes a two-step Tikhonov regularization procedure for converting the steady shear data generated by parallel-disk viscometers, in the presence of wall slip, into a shear stress-shear rate function and a wall shear stress-slip velocity functions. If the material under test has a yield stress or a critical wall shear stress below which no slip is observed the method will also provide an estimate of these stresses. Amplification of measurement noise is kept under control by the introduction of two separate regularization parameters and Generalized Cross Validation is used to guide the selection of these parameters. The performance of this procedure is demonstrated by applying it to the parallel disk data of an oil-in-water emulsion, of a foam and of a mayonnaise.

Prevalence of chloramphenicol-resistant gene in Escherichia coli from water sources in aquaculture farms and rivers of Kuching, Northwestern Borneo

Leong, Sui Sien,Lihan, Samuel,Toh, Seng Chiew The Korean Society of Fisheries and Aquatic Scienc 2022 Fisheries and Aquatic Sciences Vol.25 No.4

Antibiotic resistant Escherichia coli cases are increasing high especially in Southeast Asia. Illegal use of the antibiotic in the aquaculture farming may become the culprit of the outbreak and spread into environmental source. A study was conducted to: 1) detect the chloramphenicol (CAL)-resistant gene in E. coli isolated from three aquaculture farms and six rivers of northwestern Borneo and 2) investigate the correlation between cat gene with five common antibiotics used. Isolation of E. coli was done on Eosin methylene blue agar and characterized using indole, methyl red, Voges-Proskauer, citrate tests. E. coli isolates were subsequently tested for their susceptibility to five antibiotics commonly used in aqua-farming. The CAL-resistant E. coli were further analyzed for the presence of resistant genes (cat I, cat II, cat III, cat IV) using multiplex polymerase chain reaction. 42 bacterial colonies were isolated from a total of 80 individual water samples, 34 of which were identified as E. coli. Result showed 85.3% of the E. coli isolates were resistant to amoxicillin, 35.3% were resistant to tetracycline, 29.4% were resistant to CAL, 17.6% were resistant to nitrofurantoin and 8.8% were resistant to nalidixic acid. All of the 10 CAL resistant E. coli isolateswere detected with cat II genes; five isolates detected with cat IV genes; three isolates detected with cat III genes; and another two detected with cat I genes. Pearson correlation coefficient shows highly significant relationship between resistance pattern of CAL with amoxicillin; and CAL with tetracycline. Our findings provide the supplementary information of the CAL resistance gene distribution, thereby improving our understanding of the potential risk of antibiotic resistance underlying within this microbial ecosystem.

An exploration of building up the quality of parent‐child relationship in residential childcare in Macao

Leong On Na Ribeiro,Liu Shu‐Wen 한국사회복지학회 2022 Asian Social Work and Policy Review Vol.16 No.2

Effect of Axial Restraints on Top-Seat Angle Connections at Elevated Temperatures

Leong Siong Hean,N.H. Ramli Sulong,Mohammed Jameel 대한토목학회 2016 KSCE Journal of Civil Engineering Vol.20 No.6

In this study, a finite element model of a top-seat angle connection at elevated temperature is developed to study the effect of axial restraints on the connection behavior. Models are first validated with existing fire test results of top-seat angle connection. Non-linear behavior of the materials was modeled with the definition of elastic-plastic multi-linear properties and frictional contact between surfaces is included to simulate actual conditions. Validation of the model behavior shows that the model is in good agreement with existing experimental results and therefore the model is used for further study on the effect of axial restraints towards connection behavior. Both isothermal and anisothermal conditions were analyzed considering the effect of axial restraints. Results from the model shows that an increase in axial restraints has increased connection capacity while the stiffness remains similar for low axial levels. On the other hand, the shrinkage of the beam, may lead to tensional axial loads, causing axial pulling on the connection, resulting in higher deformation and different deformation patterns of the component angle sections. Effect on the design guidelines for connection design with axial restraints provided by Eurocode 3:2005 (Part 1-8) is also discussed at the end.

Identification of the mechanism for dehalorespiration of monofluoroacetate in the phylum Synergistota

Leong Lex E. X.,Denman Stuart E.,Kang Seungha,Mondot Stanislas,Hugenholtz Philip,McSweeney Chris S. 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.2

Objective: Monofluoroacetate (MFA) is a potent toxin that blocks ATP production via the Krebs cycle and causes acute toxicity in ruminants consuming MFA-containing plants. The rumen bacterium, Cloacibacillus porcorum strain MFA1 belongs to the phylum Synergistota and can produce fluoride and acetate from MFA as the end-products of dehalorespiration. The aim of this study was to identify the genomic basis for the metabolism of MFA by this bacterium. Methods: A draft genome sequence for C. porcorum strain MFA1 was assembled and quantitative transcriptomic analysis was performed thus highlighting a candidate operon encoding four proteins that are responsible for the carbon-fluorine bond cleavage. Comparative genome analysis of this operon was undertaken with three other species of closely related Synergistota bacteria. Results: Two of the genes in this operon are related to the substrate-binding components of the glycine reductase protein B (GrdB) complex. Glycine shares a similar structure to MFA suggesting a role for these proteins in binding MFA. The remaining two genes in the operon, an antiporter family protein and an oxidoreductase belonging to the radical S-adenosyl methionine superfamily, are hypothesised to transport and activate the GrdB-like protein respectively. Similar operons were identified in a small number of other Synergistota bacteria including type strains of Cloacibacillus porcorum, C. evryensis, and Pyramidobacter piscolens, suggesting lateral transfer of the operon as these genera belong to separate families. We confirmed that all three species can degrade MFA, however, substrate degradation in P. piscolens was notably reduced compared to Cloacibacillus isolates possibly reflecting the loss of the oxidoreductase and antiporter in the P. piscolens operon. Conclusion: Identification of this unusual anaerobic fluoroacetate metabolism extends the known substrates for dehalorespiration and indicates the potential for substrate plasticity in amino acid-reducing enzymes to include xenobiotics. Objective: Monofluoroacetate (MFA) is a potent toxin that blocks ATP production via the Krebs cycle and causes acute toxicity in ruminants consuming MFA-containing plants. The rumen bacterium, <i>Cloacibacillus porcorum</i> strain MFA1 belongs to the phylum Synergistota and can produce fluoride and acetate from MFA as the end-products of dehalorespiration. The aim of this study was to identify the genomic basis for the metabolism of MFA by this bacterium.Methods: A draft genome sequence for <i>C. porcorum</i> strain MFA1 was assembled and quantitative transcriptomic analysis was performed thus highlighting a candidate operon encoding four proteins that are responsible for the carbon-fluorine bond cleavage. Comparative genome analysis of this operon was undertaken with three other species of closely related Synergistota bacteria.Results: Two of the genes in this operon are related to the substrate-binding components of the glycine reductase protein B (GrdB) complex. Glycine shares a similar structure to MFA suggesting a role for these proteins in binding MFA. The remaining two genes in the operon, an antiporter family protein and an oxidoreductase belonging to the radical S-adenosyl methionine superfamily, are hypothesised to transport and activate the GrdB-like protein respectively. Similar operons were identified in a small number of other Synergistota bacteria including type strains of <i>Cloacibacillus porcorum, C. evryensis</i>, and <i>Pyramidobacter piscolens</i>, suggesting lateral transfer of the operon as these genera belong to separate families. We confirmed that all three species can degrade MFA, however, substrate degradation in <i>P. piscolens</i> was notably reduced compared to <i>Cloacibacillus</i> isolates possibly reflecting the loss of the oxidoreductase and antiporter in the <i>P. piscolens</i> operon.Conclusion: Identification of this unusual anaerobic fluoroacetate metabolism extends the known substrates for dehalorespiration and indicates the potential for substrate plasticity in amino acid-reducing enzymes to include xenobiotics.

Relooking "Look Back": A student`s Attempt at Problem Solving using Polya`s Model

( Leong Yew Hoong ),( Dindyal Jaguthsing ),( Toh Tin Lam ),( Quek Khiok Seng ),( Tay Eng Guan ) 한국수학교육학회 2011 수학교육 학술지 Vol.2011 No.1

Against the backdrop of half a century of research in mathematics problem solving, Polya`s last stage is especially conspicuous-by the scarcity of research on it! Much of the research focused on the first three stages (e.g., Francisco & Maher 2005; Taylor & Mcdonald, 2007), with little or no successful attempts at following through with the subjects. In this paper, we describe a case study of how the innovation of a "Practical Worksheet" within a new paradigm of a "Mathematics Practical" enabled a high-achieving student to push beyond getting a solution for a problem to extending, adapting and generalising his solution. The findings from this study indicate promise in achieving the learning of Polya`s model with notable success in the fourth stage, Look Back.

Ultrasound Breast Elastographic Evaluation of Mass-Forming Ductal Carcinoma-in-situ with Histological Correlation - New Findings for a Toothpaste Sign

Leong, Lester Chee Hao,Sim, Llewellyn Shao-Jen,Jara-Lazaro, Ana Richelia,Tan, Puay Hoon Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.5

Background: It is unclear as to whether the size ratio elastographic technique is useful for assessing ultrasound-detected ductal carcinoma-in-situ (DCIS) masses since they commonly lack a significant desmoplastic reaction. The objectives of this study were to determine the accuracy of this elastographic technique in DCIS and examine if there was any histopathological correlation with the grey-scale strain patterns. Materials and Methods: Female patients referred to the radiology department for image-guided breast biopsy were prospectively evaluated by ultrasound elastography prior to biopsy. Histological diagnosis was the gold standard. An elastographic size ratio of more than 1.1 was considered malignant. Elastographic strain patterns were assessed for correlation with the DCIS histological architectural patterns and nuclear grade. Results: There were 30 DCIS cases. Elastographic sensitivity for detection of malignancy was 86.7% (26/30). 10/30 (33.3%) DCIS masses demonstrated predominantly white elastographic strain patterns while 20/30 (66.7%) were predominantly black. There were 3 (10.0%) DCIS masses that showed had a co-existent bull's-eye sign and 7 (23.3%) other masses had a co-existent toothpaste sign, a strain pattern that has never been reported in the literature. Four out of 4/5 comedo DCIS showed a predominantly white strain pattern (p=0.031) while 6/7 cases with the toothpaste sign were papillary DCIS (p=0.031). There was no relationship between the strain pattern and the DCIS nuclear grade. Conclusions: The size ratio elastographic technique was found to be very sensitive for ultrasound-detected DCIS masses. While the elastographic grey-scale strain pattern should not be used for diagnostic purposes, it correlated well with the DCIS architecture.

Professional Development of Mathematics teachers: The Replacement Unit Strategy

( Leong Yew Hoong ) 한국수학교육학회 2016 수학교육 학술지 Vol.2016 No.3