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Fulltext Systematic Scoring Balloon Lesion Preparation for Drug-Coated Balloon Angioplasty in Clinical Routine: Results of the PASSWORD Observational Study

Bonaventura K, Schwefer M, Yusof AKM, Waliszewski M, Krackhardt F, Steen P, et al.

Adv Ther, 2020 05;37(5):2210-2223.
PMID: 32274746 DOI: 10.1007/s12325-020-01320-2

INTRODUCTION: Scoring balloon angioplasty (SBA) for lumen gain prior to stent implantations or drug-coated balloon angioplasty (DCB) is considered an essential interventional tool for lesion preparation. Recent evidence indicates that SBA may play a pivotal role in enhancing the angiographic and clinical outcomes of DCB angioplasty.
METHODS: We studied the systematic use of SBA with a low profile, non-slip element device prior to DCB angioplasty in an unselected, non-randomized patient population. This prospective, all-comers study enrolled patients with de novo lesions as well as in-stent restenotic lesions in bare metal stents (BMS-ISR) and drug-eluting stents (DES-ISR). The primary endpoint was the target lesion failure (TLF) rate at 9 months (ClinicalTrials.gov Identifier NCT02554292).
RESULTS: A total of 481 patients (496 lesions) were recruited to treat de novo lesions (78.4%, 377), BMS-ISR (4.0%, 19), and DES-ISR (17.6%, 85). Overall risk factors were acute coronary syndrome (ACS, 20.6%, 99), diabetes mellitus (46.8%, 225), and atrial fibrillation (8.5%, 41). Average lesion lengths were 16.7 ± 10.4 mm in the de novo group, and 20.1 ± 8.9 mm (BMS-ISR) and 16.2 ± 9.8 mm (DES-ISR) in the ISR groups. Scoring balloon diameters were 2.43 ± 0.41 mm (de novo), 2.71 ± 0.31 mm (BMS-ISR), and 2.92 ± 0.42 mm (DES-ISR) whereas DCB diameters were 2.60 ± 0.39 mm (de novo), 3.00 ± 0.35 mm (BMS-ISR), and 3.10 ± 0.43 mm (DES-ISR), respectively. The overall accumulated TLF rate of 3.0% (14/463) was driven by significantly higher target lesion revascularization rates in the BMS-ISR (5.3%, 1/19) and the DES-ISR group (6.0%, 5/84). In de novo lesions, the TLF rate was 1.1% (4/360) without differences between calcified and non-calcified lesions (p = 0.158) and small vs. large reference vessel diameters with a cutoff value of 3.0 mm (p = 0.901).
CONCLUSIONS: The routine use of a non-slip element scoring balloon catheter to prepare lesions suitable for drug-coated balloon angioplasty is associated with high procedural success rates and low TLF rates in de novo lesions.
Fulltext Comparing effectiveness of high-fidelity human patient simulation vs case-based learning in pharmacy education

Lee Chin K, Ling Yap Y, Leng Lee W, Chang Soh Y

Am J Pharm Educ, 2014 Oct 15;78(8):153.
PMID: 25386018 DOI: 10.5688/ajpe788153

To determine whether human patient simulation (HPS) is superior to case-based learning (CBL) in teaching diabetic ketoacidosis (DKA) and thyroid storm (TS) to pharmacy students.
Transmission dynamics and estimates of malaria vectorial capacity for Anopheles balabacensis and An. flavirostris (Diptera: Culicidae) on Banggi island, Sabah, Malaysia

Hii JL, Kan S, Vun YS, Chin KF, Tambakau S, Chan MK, et al.

Ann Trop Med Parasitol, 1988 Feb;82(1):91-101.
PMID: 3041932

Holoendemic malaria transmission in two small isolated forest communities and a coastal village was studied by (1) all night human bait collections of Anopheles species from inside and outside houses and (2) buffalo-biting and CDC light-trapping catches during March and November 1984. During the same period thick and thin blood films were collected from the human population, and spleen rates were determined in children from two to nine years of age. Using both the immunoradiometric assay (IRMA) and the dissection technique, more sporozoite-positive infections were detected in An. balabacensis and An. flavirostris in November than in March. IRMA confirmed the presence of Plasmodium falciparum sporozoites. An average of 76.2% of the An. balabacensis population lived long enough to have reached a point where infectivity with P. falciparum was possible in November. Although fewer than five adult females bit humans per night at any time, a resident could theoretically have received more than 160 infective bites in one year. A high frequency of feeding on humans, coupled with increased anopheline life expectancy, contributed to high estimates of falciparum malaria vectorial capacity (number of infections distributed per case per day); for An. balabacensis (1.44-7.44 in March and 9.97-19.7 in November) and for An. flavirostris (0.19-5.14 in March and 6.27-15.8 in November). These high values may explain the increased malaria parasite rates obtained from at least two forest communities. Correlation between actual and calculated rates of gametocytaemia was poorest in Kapitangan due to inadequate sampling of the human population. In Banggi island, malaria is stable and holoendemic, and the population enjoys a high degree of immunity.
Fulltext The impact of routine histopathological examination on cholecystectomy specimens from an Asian demographic

Chin KF, Mohammad AA, Khoo YY, Krishnasamy T

Ann R Coll Surg Engl, 2012 Apr;94(3):165-9.
PMID: 22507719 DOI: 10.1308/003588412X13171221501708

INTRODUCTION: Most gallbladder carcinoma cases are suspected pre-operatively or intra-operatively. In Malaysia histopathological examination of cholecystectomy specimens has become routine practice. The aim of this study was to assess the impact of routine histological examinations on cholecystectomy specimens from an Asian demographic, which may differ from a Caucasian demographic.
METHODS: A retrospective study was performed of all histopathology reports for cholecystectomies (laparoscopic and open) undertaken over a period of 12 years (1997-2008) in a single teaching hospital.
RESULTS: A total of 1,375 gallbladder specimens were sent for histopathological analysis, with 7 (0.5%) being reported as malignant while only three (0.2%) were found to contain primary gallbladder carcinoma. Other premalignant findings included two specimens with dysplastic changes of the mucosa and one tubulovillous adenoma with a dysplastic epithelium. From the ten malignant and premalignant specimens, seven were diagnosed pre-operatively, two were suspected intra-operatively and one was diagnosed with dysplastic changes on the histopathology report post-operatively.
CONCLUSIONS: This study supports earlier research carried out in the UK and the demographic difference does not affect the impact of the histology examination on cholecystectomy specimens in diagnosing this disease. A selective policy is recommended in Malaysia.
Medium-term (5-year) comparison of the functional outcomes of combined anterior cruciate ligament and posterolateral corner reconstruction compared with isolated anterior cruciate ligament reconstruction

Cartwright-Terry M, Yates J, Tan CK, Pengas IP, Banks JV, McNicholas MJ

Arthroscopy, 2014 Jul;30(7):811-7.
PMID: 24794571 DOI: 10.1016/j.arthro.2014.02.039

To present a 5-year comparison of the functional outcomes of combined anterior cruciate ligament (ACL) and posterolateral corner (PLC) reconstruction with those of isolated ACL reconstruction.
Acute nonspecific carditis with advanced heart block in Malaysians

Chin K, Singham KT, Anuar M

Aust N Z J Med, 1983 Aug;13(4):374-5.
PMID: 6580862

Acute nonspecific carditis with advanced heart block is rare. We observed nine cases with complete heart block and one with Mobitz type II block over an eight and a half year period. Temporary cardiac pacing was instituted in all while permanent pacing was required in six patients. No death was recorded.
Optimization study of ethanolic fermentation from oil palm trunk, rubberwood and mixed hardwood hydrolysates using Saccharomyces cerevisiae

Chin KL, H'ng PS, Wong LJ, Tey BT, Paridah MT

Bioresour Technol, 2010 May;101(9):3287-91.
PMID: 20056407 DOI: 10.1016/j.biortech.2009.12.036

Ethanolic fermentation using Saccharomyces cerevisiae was carried out on three types of hydrolysates produced from lignocelulosic biomass which are commonly found in Malaysia such as oil palm trunk, rubberwood and mixed hardwood. The effect of fermentation temperature and pH of hydrolysate was evaluated to optimize the fermentation efficiency which defined as maximum ethanol yield in minimum fermentation time. The fermentation process using different temperature of 25 degrees Celsius, 30 degrees Celsius and 40 degrees Celsius were performed on the prepared fermentation medium adjusted to pH 4, pH 6 and pH 7, respectively. Results showed that the fermentation time was significantly reduced with the increase of temperature but an adverse reduction in ethanol yield was observed using temperature of 40 degrees Celsius. As the pH of hydrolysate became more acidic, the ethanol yield increased. Optimum fermentation efficiency for ethanolic fermentation of lignocellulosic hydrolysates using S. cerevisiae can be obtained using 33.2 degrees Celsius and pH 5.3.
Prospective, large-scale multicenter trial for the use of drug-coated balloons in coronary lesions: The DCB-only All-Comers Registry

Rosenberg M, Waliszewski M, Chin K, Ahmad WAW, Caramanno G, Milazzo D, et al.

Catheter Cardiovasc Interv, 2019 02 01;93(2):181-188.
PMID: 30280482 DOI: 10.1002/ccd.27724

OBJECTIVES: This prospective, observational all-comers registry assessed the safety and efficacy of a Drug Coated Balloon-only strategy (DCB-only) in patients with coronary lesions.
BACKGROUND: Data regarding the performance of a DCB-only approach, especially in patients with previously untreated de-novo coronary artery disease (CAD), are still limited.
METHODS: This study was conducted as an international, multicenter registry primarily enrolling patients with de-novo CAD. However, it was also possible to include patients with in-stent restenosis (ISR). The primary endpoint was the rate of clinically driven target lesion revascularization (TLR) after 9 months.
RESULTS: A total of 1,025 patients with a mean age of 64.0 ± 11.2 years were enrolled. The majority of treated lesions were de-novo (66.9%), followed by drug-eluting-stent ISR (DES-ISR; 22.6%) and bare-metal-stent ISR (BMS-ISR; 10.5%). The TLR rate was lower in the de-novo group (2.3%) when compared to BMS- (2.9%) and DES-ISR (5.8%) (P = 0.049). Regarding MACE, there was a trend toward fewer events in the de-novo group (5.6%) than in the BMS- (7.8%) and DES-ISR cohort (9.6%) (P = 0.131). Subgroup analyses revealed that lesion type (95% CI 1.127-6.587); P = 0.026) and additional stent implantation (95% CI 0.054-0.464; P = 0.001) were associated with higher TLR rates.
CONCLUSIONS: Our results show that DCB-only angioplasty of de-novo coronary lesions is associated with low MACE and TLR rates. Thus, DCBs appear to be an attractive alternative for the interventional, stentless treatment of suitable de-novo coronary lesions.
An Approach to Ostial Lesion Management

Chin K

Current interventional cardiology reports, 2001 May;3(2):87-89.
PMID: 11322911
Preferential Use of Carbon Sources in Culturable Aerobic Mesophilic Bacteria of Coptotermes curvignathus's (Isoptera: Rhinotermitidae) Gut and Its Foraging Area

Wong WZ, H'ng PS, Chin KL, Sajap AS, Tan GH, Paridah MT, et al.

Environ Entomol, 2015 Oct;44(5):1367-74.
PMID: 26314017 DOI: 10.1093/ee/nvv115

The lower termite, Coptotermes curvignathus, is one of the most prominent plantation pests that feed upon, digest, and receive nourishment from exclusive lignocellulose diets. The objective of this study was to examine the utilization of sole carbon sources by isolated culturable aerobic bacteria among communities from the gut and foraging pathway of C. curvignathus. We study the bacteria occurrence from the gut of C. curvignathus and its surrounding feeding area by comparing the obtained phenotypic fingerprint with Biolog's extensive species library. A total of 24 bacteria have been identified mainly from the family Enterobacteriaceae from the identification of Biolog Gen III. Overall, the bacteria species in the termite gut differ from those of foraging pathway within a location, except Acintobacter baumannii, which was the only bacteria species found in both habitats. Although termites from a different study area do not have the same species of bacteria in the gut, they do have a bacterial community with similar role in degrading certain carbon sources. Sugars were preferential in termite gut isolates, while nitrogen carbon sources were preferential in foraging pathway isolates. The preferential use of specific carbon sources by these two bacterial communities reflects the role of bacteria for regulation of carbon metabolism in the termite gut and foraging pathway.
Lead levels in new enamel household paints from Asia, Africa and South America

Clark CS, Rampal KG, Thuppil V, Roda SM, Succop P, Menrath W, et al.

Environ Res, 2009 Oct;109(7):930-6.
PMID: 19656507 DOI: 10.1016/j.envres.2009.07.002

In 2006 a report on the analysis for lead in 80 new residential paints from four countries in Asia revealed high levels in three of the countries (China, India and Malaysia) and low levels in a fourth country (Singapore) where a lead in paint regulation was enforced. The authors warned of the possible export of lead-painted consumer products to the United States and other countries and the dangers the lead paint represented to children in the countries where it was available for purchase. The need for a worldwide ban on the use of lead in paints was emphasized to prevent an increase in exposure and disease from this very preventable environmental source. Since the earlier paper almost 300 additional new paint samples have been collected from the four initial countries plus 8 additional countries, three from Asia, three from Africa and two from South America. During the intervening time period two million toys and other items imported into the United States were recalled because the lead content exceeded the United States standard. High lead paints were detected in all 12 countries. The average lead concentration by country ranged from 6988 (Singapore) to 31,960ppm (Ecuador). One multinational company sold high lead paint in one country through January 2007 but sold low lead paint later in 2007 indicating that a major change to cease adding lead to their paints had occurred. However, the finding that almost one-third of the samples would meet the new United States standard for new paint of 90ppm, suggests that the technology is already available in at least 11 of the 12 countries to produce low lead enamel paints for domestic use. The need remains urgent to establish effective worldwide controls to prevent the needless poisoning of millions of children from this preventable exposure.
Compost feedstock characteristics and ratio modelling for organic waste materials co-composting in Malaysia

Chai EW, H'ng PS, Peng SH, Wan-Azha WM, Chin KL, Chow MJ, et al.

Environ Technol, 2013 Sep-Oct;34(17-20):2859-66.
PMID: 24527651

In Malaysia, large amounts of organic materials, which lead to disposal problems, are generated from agricultural residues especially from palm oil industries. Increasing landfill costs and regulations, which limit many types of waste accepted at landfills, have increased the interest in composting as a component of waste management. The objectives of this study were to characterize compost feedstock properties of common organic waste materials available in Malaysia. Thus, a ratio modelling of matching ingredients for empty fruit bunches (EFBs) co-composting using different organic materials in Malaysia was done. Organic waste materials with a C/N ratio of < 30 can be applied as a nitrogen source in EFB co-composting. The outcome of this study suggested that the percentage of EFB ranged between 50% and 60%, which is considered as the ideal mixing ratio in EFB co-composting. Conclusively, EFB can be utilized in composting if appropriate feedstock in term of physical and chemical characteristics is coordinated in the co-composting process.
In-stent restenosis: the gold standard has changed

Chin K

EuroIntervention, 2011 May;7 Suppl K:K43-6.
PMID: 22027726 DOI: 10.4244/EIJV7SKA7

In-stent restenosis remains an important issue even in the drug-eluting stent (DES) era today. In recent years, drug-eluting balloons (DEB) have emerged as a potential alternative to the treatment of in-stent restenosis. Paclitaxel was identified as the primary drug for DEB because of its rapid uptake and prolonged retention. Non-stent-based local drug delivery using DEB maintains the antiproliferation properties of DES, but without the limitations of DES such as subacute stent thrombosis, stent fractures, prolonged antiplatelet therapy and more importantly, avoiding a "stent-in-a-stent" approach. The first major impact of drug-eluting balloon (DEB) in the management of bare metal instent restenosis was the "PACCOCATH ISR I" randomised trial, comparing the efficacy of drug-eluting balloon versus uncoated balloon. The six months angiographic results showed a binary restenosis of 5% and 4% MACE in the drug-eluting balloon group, compared with 43% binary restenosis and 31% MACE, in the uncoated balloon group (p=0.002 and 0.02). The second major DEB trial is the "PEPCAD II Trial", comparing the efficacy of the SeQuent Please DEB with the Taxus drug-eluting stent in the treatment of bare-metal stent instent restenosis. At 6-month follow-up, in-segment late lumen loss was 0.38 ± 0.61 mm in the DES group versus 0.17 ± 0.42 mm (p=0.03) in the DEB group, resulting in a binary restenosis rate of 12/59 (20%) versus 4/57 (7%; p=0.06). At 12 months, MACE rates were 22% in the Taxus group and 9% in the DEB group (P=0.08). The TLR at 12 months was 15% in the Taxus group and 6% in the DEB group (p=0.15). Based on these two pivotal trials, the European Society of Cardiology Guidelines for Percutaneous Coronary Intervention (2010) recommended that DEB should be considered for the treatment of in-stent restenosis after prior bare-metal stent. This was accorded a class 2 IIa indication, with a level B evidence.
Total testosterone and sex hormone-binding globulin are significantly associated with metabolic syndrome in middle-aged and elderly men

Chin KY, Ima-Nirwana S, Mohamed IN, Aminuddin A, Ngah WZ

Exp. Clin. Endocrinol. Diabetes, 2013 Jul;121(7):407-12.
PMID: 23765753 DOI: 10.1055/s-0033-1345164

Testosterone and sex hormone-binding globulin (SHBG) have been shown to be associated with metabolic syndrome (MS) in men. This study aimed at validating these relationships in a group of middle-aged and elderly men and assessing their strength of association to MS. A cross-sectional study of 332 Malaysian men aged 40 years and above was conducted. The blood of subject was collected under fasting condition for determination of testosterone, SHBG, glucose and lipid levels. Their medical history, smoking and alcohol consumption status, waist circumference (WC), body mass index (BMI) and blood pressure (BP) were recorded. All testosterone and SHBG levels were significantly reduced in MS subjects compared to non-MS subjects (p<0.05). Testosterone and SHBG were correlated significantly with most of the MS indicators without adjustments. In multiple regression analysis, the triglyceride level was the only MS indicator that was significantly, inversely and independently associated with all testosterone measurements and SHBG (p<0.05). Waist circumference was significantly and negatively associated with SHBG level (p<0.05) though not independent of BMI. Total testosterone and SHBG were significantly and inversely associated with the presence of MS. Testosterone and SHBG are potential intervention targets for the prevention of MS in men.
Demography and clinical course of ulcerative colitis in a multiracial Asian population: a nationwide study from Malaysia

Hilmi I, Singh R, Ganesananthan S, Yatim I, Radzi M, Chua AB, et al.

J Dig Dis, 2009 Feb;10(1):15-20.
PMID: 19236542 DOI: 10.1111/j.1751-2980.2008.00357.x

To establish the clinical course of ulcerative colitis (UC) in the Malaysian population, comparing the three major ethnic groups: Malay, Chinese and Indian.
Fulltext Drug Coated Balloon-Only Strategy in De Novo Lesions of Large Coronary Vessels

Rosenberg M, Waliszewski M, Krackhardt F, Chin K, Wan Ahmad WA, Caramanno G, et al.

J Interv Cardiol, 2019;2019:6548696.
PMID: 31772539 DOI: 10.1155/2019/6548696

Objectives: We analyzed the efficacy of drug coated balloons (DCB) as a stand-alone-therapy in de novo lesions of large coronary arteries. DCBs seem to be an attractive alternative for the stent-free interventional treatment of de novo coronary artery disease (CAD). However, data regarding a DCB-only approach in de novo CAD are currently limited to vessels of small caliber.
Methods: By means of propensity score (PS) matching 234 individuals with de novo CAD were identified with similar demographic characteristics. This patient population was stratified in a 1:1 fashion according to a reference vessel diameter cut-off of 2.75 mm in small and large vessel disease. The primary endpoint was the rate of clinically driven target lesion revascularization (TLR) at 9 months.
Results: Patients with small vessel disease had an average reference diameter of 2.45 ± 0.23 mm, while the large vessel group averaged 3.16 ± 0.27 mm. Regarding 9-month major adverse cardiac event (MACE), 5.7% of the patients with small and 6.1% of the patients with large vessels had MACE (p=0.903). Analysis of the individual MACE components revealed a TLR rate of 3.8% in small and 1.0% in large vessels (p=0.200). Of note, no thrombotic events in the DCB treated coronary segments occurred in either group during the 9-month follow-up.
Conclusions: Our data demonstrate for the first time that DCB-only PCI of de novo lesions in large coronary arteries (>2.75 mm) is safe and as effective. Interventional treatment for CAD without permanent or temporary scaffolding, demonstrated a similar efficacy for large and small vessels.
Development of an immunochromatographic lateral flow dipstick for the detection of Mycobacterium tuberculosis 16 kDa antigen (Mtb-strip)

Mohd Amiruddin MN, Ang GY, Yu CY, Falero-Diaz G, Otero O, Reyes F, et al.

J Microbiol Methods, 2020 09;176:106003.
PMID: 32702386 DOI: 10.1016/j.mimet.2020.106003

Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that causes tuberculosis (TB). This contagious disease remains a severe health problem in the world. The disease is transmitted via inhalation of airborne droplets carrying Mtb from TB patients. Early detection of the disease is vital to prevent transmission of the infection to people in close contact with the patients. To date, there is a need of a simple, rapid, sensitive and specific diagnostic test for TB. Previous studies showed the potential of Mtb 16 kDa antigen (Ag16) in TB diagnosis. In this study, lateral flow immunoassay, also called simple strip immunoassay or immunochromatographic test (ICT) for detection of Ag16 was developed (Mtb-strip) and assessed as a potential rapid TB diagnosis method. A monoclonal antibody against Ag16 was optimized as the capturing and detection antibody on the Mtb-strip. Parameters affecting the performance of the Mtb-strip were also optimized before a complete prototype was developed. Analytical sensitivity showed that Mtb-strip was capable to detect as low as 125 ng of purified Ag16. The analytical sensitivity of Mtb-strip suggests its potential usefulness in different clinical applications.
Nanocrystalline forsterite for biomedical applications: synthesis, microstructure and mechanical properties

Ramesh S, Yaghoubi A, Lee KY, Chin KM, Purbolaksono J, Hamdi M, et al.

J Mech Behav Biomed Mater, 2013 Sep;25:63-9.
PMID: 23726923 DOI: 10.1016/j.jmbbm.2013.05.008

Forsterite (Mg2SiO4) because of its exceptionally high fracture toughness which is close to that of cortical bones has been nominated as a possible successor to calcium phosphate bioceramics. Recent in vitro studies also suggest that forsterite possesses good bioactivity and promotes osteoblast proliferation as well as adhesion. However studies on preparation and sinterability of nanocrystalline forsterite remain scarce. In this work, we use a solid-state reaction with magnesium oxide (MgO) and talc (Mg3Si4(OH)2) as the starting precursors to synthesize forsterite. A systematic investigation was carried out to elucidate the effect of preparatory procedures including heat treatment, mixing methods and sintering temperature on development of microstructures as well as the mechanical properties of the sintered forsterite body.
The influence of permethrin-impregnated bednets and mass drug administration on the incidence of Plasmodium falciparum malaria in children in Sabah, Malaysia

Hii JL, Vun YS, Chin KF, Chua R, Tambakau S, Binisol ES, et al.

Med Vet Entomol, 1987 Oct;1(4):397-407.
PMID: 2979556

A small-scale trial was carried out in the Upper Kinabatangan district of Sabah, Malaysia, to determine the effect of using permethrin-impregnated bednets on malaria transmission. A total of 306 nylon bednets with cotton borders, impregnated at a dose estimated to have been 0.062 g permethrin/m2 of nylon netting, were distributed to 139 households in five villages. At the time of distributing bednets, mass drug administration with Fansidar plus primaquine was also administered to the human population to clear all parasitaemias due to Plasmodium falciparum Welch. In another village, for comparison, mass drug administration was the only intervention. After intervention measures in December 1984 and January 1985, the parasite rates in children declined in all villages during the first month, significantly more in the villages with impregnated bednets than in the control, thus proving that the nets had an impact on malaria. However, after about 2 months, parasite rates started to increase again. After 4-6 months, parasite rates in the villages with bednets approached the rate in the control village without nets. The increase in parasite rates was paralleled by a significant deterioration in the quality, physical condition and the degree of non-utilization of bednets. Entomological evaluation proved the efficacy of permethrin-impregnated nets for controlling Anopheles balabacensis Baisas and other anophelines. Bioassays (1 h exposure) of permethrin-impregnated bednets gave 100% mortality initially and 44-61% mortality after 85-106 days. Mosquito collections in treated bednets were significantly reduced for at least 217 days. The project failed to achieve prolonged suppression of malaria transmission for a combination of entomological, sociological and practical reasons which are discussed in relation to the objectives and implementation of future bednet studies.
Fulltext Physical properties and bonding quality of laminated veneer lumber produced with veneers peeled from small-diameter rubberwood logs

Khoo PS, Chin KL, H'ng PS, Bakar ES, Lee CL, Go WZ, et al.

R Soc Open Sci, 2019 Dec;6(12):191763.
PMID: 31903217 DOI: 10.1098/rsos.191763

The peeling of small-diameter rubberwood logs from the current short-rotation practices undoubtedly will produce lower grade veneers compared to the veneers from conventional planting rotation. Hence, this raises the question of the properties of the produced laminated veneer lumber (LVL) from veneers peeled from small-diameter rubberwood logs using the spindleless lathe technology. Different thicknesses of rubberwood veneers was peeled from rubberwood logs with diameter less than 20 cm using a spindleless lathe. Three-layer LVLs were prepared using phenol formaldehyde (PF) adhesive and hot pressed at different temperatures. During the peeling of veneer, lathe checks as deep as 30-60% of the veneer thickness are formed. Owing to deeper lathe check on 3 mm rubberwood veneer, higher pressing temperature significantly increased the gluebond shear strength of the PF-bonded LVL. In addition, lathe check frequency was also shown to influence the bond strength. The presence of higher lathe check frequency on 2 mm veneer increased the wettability, thus facilitating optimum penetration of adhesive for stronger bonding. These findings stress the importance of measuring and considering the lathe check depth and frequency during the lamination process to get a better understanding of bonding quality in veneer-based products.

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