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Fulltext Parcellation of the Hippocampus According to Its Connection Probability with Prefrontal Cortex Subdivisions in a Malaysian Malay Population: Preliminary Findings

Abdullah AN, Ahmad AH, Zakaria R, Tamam S, Abdullah JM

Malays J Med Sci, 2021 Jun;28(3):65-76.
PMID: 34285645 DOI: 10.21315/mjms2021.28.3.6

Background: Lesion studies have shown distinct roles for the hippocampus, with the dorsal subregion being involved in processing of spatial information and memory, and the ventral aspect coding for emotion and motivational behaviour. However, its structural connectivity with the subdivisions of the prefrontal cortex (PFC), the executive area of the brain that also has various distinct functions, has not been fully explored, especially in the Malaysian population.
Methods: We performed diffusion magnetic resonance imaging with probabilistic tractography on four Malay males to parcellate the hippocampus according to its relative connection probability to the six subdivisions of the PFC.
Results: Our findings revealed that each hippocampus showed putative connectivity to all the subdivisions of PFC, with the highest connectivity to the orbitofrontal cortex (OFC). Parcellation of the hippocampus according to its connection probability to the six PFC subdivisions showed variability in the pattern of the connection distribution and no clear distinction between the hippocampal subregions.
Conclusion: Hippocampus displayed highest connectivity to the OFC as compared to other PFC subdivisions. We did not find a unifying pattern of distribution based on the connectivity-based parcellation of the hippocampus.
Fulltext Outcomes of Prostate Artery Embolisation in Patients with Severe Symptoms of Benign Prostate Hyperplasia

Abdul Rahim R, Eng Hong G, Nik Ismail NA, Zakaria R

Malays J Med Sci, 2021 Dec;28(6):55-63.
PMID: 35002490 DOI: 10.21315/mjms2021.28.6.6

Background: Benign prostatic hyperplasia (BPH) is associated with severe lower urinary tract symptoms (LUTS). The severity of LUTS is assessed by the International Prostate Symptoms Score (IPSS). Prostate artery embolisation (PAE) is a newly available method for combating LUTS. This study aims to assess the outcomes of PAE in reducing LUTS and prostate volume in patients with BPH.
Methods: Patients diagnosed with BPH with severe LUTS who had undergone PAE were included. Their IPSS score was ≥ 20 despite medical therapy. PAE was performed via the unilateral femoral artery using various types of embolic material. Bilateral or unilateral embolisation of the prostate artery was considered a technical success. The severity of LUTS pre- and post-PAE were assessed using IPSS while prostate volume pre- and post-PAE were assessed by ultrasound and magnetic resonance imaging (MRI).
Results: Ninety percent of patients had technical success and one required transurethral resection of the prostate (TURP). The mean IPSS reduction at the final follow-up was 12.9 (P < 0.028). The mean reduction of prostate volume at the last follow-up by ultrasound was 114.99 mL (P < 0.028) and by MRI was 29.17 mL (P < 0.028).
Conclusion: PAE is safe and effective in reducing severe LUTS and prostate gland volume in BPH patients.
The role of mTOR signalling pathway in hypoxia-induced cognitive impairment

Abdo Qaid EY, Zulkipli NN, Zakaria R, Ahmad AH, Othman Z, Muthuraju S, et al.

Int J Neurosci, 2021 May;131(5):482-488.
PMID: 32202188 DOI: 10.1080/00207454.2020.1746308

Hypoxia has been associated with cognitive impairment. Many studies have investigated the role of mTOR signalling pathway in cognitive functions but its role in hypoxia-induced cognitive impairment remains controversial. This review aimed to elucidate the role of mTOR in the mechanisms of cognitive impairment that may pave the way towards the mechanistic understanding and therapeutic intervention of hypoxia-induced cognitive impairment. mTORC1 is normally regulated during mild or acute hypoxic exposure giving rise to neuroprotection, whereas it is overactivated during severe or chronic hypoxia giving rise to neuronal cells death. Thus, it is worth exploring the possibility of maintaining normal mTORC1 activity and thereby preventing cognitive impairment during severe or chronic hypoxia.
Minocycline protects against lipopolysaccharide-induced glial cells activation and oxidative stress damage in the medial prefrontal cortex (mPFC) of the rat

Abdo Qaid EY, Abdullah Z, Zakaria R, Long I

Int J Neurosci, 2024 Jun;134(1):56-65.
PMID: 35638219 DOI: 10.1080/00207454.2022.2084092

PURPOSE/AIM: Neuroinflammation and oxidative stress have been encountered in neurodegenerative diseases such as Alzheimer's disease (AD). However, the neuroprotective effects of minocycline against lipopolysaccharide (LPS)-induced glial cells activation and oxidative stress damage in the medial prefrontal cortex (mPFC) of rats are still elusive. The purpose of this study is to investigate the effects of minocycline and memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist, on the microglia and astrocytes expression, as well as oxidative stress levels in the mPFC of LPS injected rats.
MATERIALS AND METHODS: Fifty adult Male Sprague Dawley rats were divided into five groups: control, LPS (5 mg/kg), LPS treated with minocycline (25 mg/kg), LPS treated with minocycline (50 mg/kg) and LPS treated with memantine (10 mg/kg). The immunohistochemistry and western blotting were used to analyse the expressions and densities of microglia marker (Iba-1) and astrocyte marker, (GFAP) while enzyme-linked immunosorbent assay (ELISA) was used to measure the protein carbonyl (PCO), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) levels.
RESULTS: In comparison to the control group, the expression and density of Iba-1 and GFAP were significantly enhanced in the LPS group (p
Fulltext Image-guided chemoport insertion by interventional radiologists: A single-center experience on periprocedural complications

Yaacob Y, Nguyen DV, Mohamed Z, Ralib AR, Zakaria R, Muda S

Indian J Radiol Imaging, 2013 Apr;23(2):121-5.
PMID: 24082475 DOI: 10.4103/0971-3026.116543

To report our early experience in image-guided chemoport insertions by interventional radiologists.
Short report: differences in dihydrofolate reductase but not dihydropteroate synthase alleles in Plasmodium falciparum isolates from geographically distinct areas in Malaysia

Cox-Singh J, Zakaria R, Abdullah MS, Rahman HA, Nagappan S, Singh B

Am J Trop Med Hyg, 2001 6 27;64(1-2):28-31.
PMID: 11425158

Dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr) alleles were typed in 67 Malaysian Plasmodium falciparum isolates. The isolates were collected from two geographically distinct locations: 51 from Sabah, Malaysian Borneo, where sulfadoxine/pyrimethamine (SDX/PYR) is used to treat uncomplicated malaria and 16 from Peninsular Malaysia where in vivo resistance to SDX/PYR has been reported. A total of seven dhps alleles were identified with no significant difference in allele frequency between the 2 populations. Two of the dhps alleles described here have not been previously reported. Four dhfr alleles were detected in 67 P. falciparum isolates. Eighty-seven percent of the isolates from the Peninsula, where clinical SDX/PYR failure has been reported, had dhfr alleles with triple point mutations while all of the isolates from Sabah had dhfr alleles with 2 or less point mutations. The difference in dhfr allele frequency between the two populations was highly significant. There was no correlation between in vitro PYR response and accumulation of dhfr point mutations.
Fulltext A Case of Persistent Urogenital Sinus: Pitfalls and challenges in diagnosis

Tan HH, Tan SK, Shunmugan R, Zakaria R, Zahari Z

Sultan Qaboos Univ Med J, 2017 Nov;17(4):e455-e459.
PMID: 29372089 DOI: 10.18295/squmj.2017.17.04.013

Persistent urogenital sinus (PUGS) is a rare anomaly whereby the urinary and genital tracts fail to separate during embryonic development. We report a three-year-old female child who was referred to the Sabah Women & Children Hospital, Sabah, Malaysia, in 2016 with a pelvic mass. She had been born prematurely at 36 gestational weeks via spontaneous vaginal delivery in 2013 and initially misdiagnosed with neurogenic bladder dysfunction. The external genitalia appeared normal and an initial sonogram and repeat micturating cystourethrograms did not indicate any urogenital anomalies. She therefore underwent clean intermittent catheterisation. Three years later, the diagnosis was corrected following the investigation of a persistent cystic mass posterior to the bladder. At this time, a clinical examination of the perineum showed a single opening into the introitus. Magnetic resonance imaging of the pelvis revealed gross hydrocolpos and a genitogram confirmed a diagnosis of PUGS, for which the patient underwent surgical separation of the urinary and genital tracts.
Fulltext Coping Strategies for Sexual Problems and Sexual Dysfunction Amongst Malay Women With Breast Cancer. A Qualitative Study

Che Ya SN, Muhamad R, Mohd Zain N, Zakaria R, Ishak A, Hassan II, et al.

Sex Med, 2021 Jun;9(3):100336.
PMID: 33794448 DOI: 10.1016/j.esxm.2021.100336

INTRODUCTION: Women' sexuality becomes complex after breast cancer diagnosis and sexual health is highly neglected in the management of the illness.
AIMS: To explore the coping and strategies to overcome sexuality problems and sexual dysfunction among women with breast cancer.
MATERIAL AND METHODS: Using the in-depth and photo-elicitation interview methods, this qualitative study following phenomenological analysis was conducted on fourteen married female respondents with breast cancer and had the positive result for female sexual dysfunction (FSD) screened by Female Sexual Function Index (FSFI-6 items) from Kelantan, Malaysia. The interviews data were audio-recorded, transcribed verbatim and managed in analytic computer software NVivo11 Pro. The transcriptions were analyzed using thematic analysis by referring to the meaning-making theory.
MAIN OUTCOME MEASURES: We identified overlapping themes of coping and strategies among women with breast cancer to overcome sexual problems and sexual dysfunction which correspond with meaning-making theory.
RESULTS: Three themes have emerged. Women with breast cancer that developed sexuality problem and sexual dysfunction strived to accept the illness using religious belief and conform by altering sexual practices. These individuals positively look for a solution by seeking formal healthcare advice, modify their physical appearance, active discussion with the husband and support from other survivors. A few of them passively struggle with the subject by averting the intimacy and receptive toward polygamy.
CONCLUSION: This study highlighted the various mechanisms that emphasized the pivotal role of religious belief and relationship context as key factors in the coping strategies among women with breast cancer in Malaysia. The finding may not be generalized to other countries. Che Ya SN, Muhamad R, Zain NM, et al. Coping Strategies for Sexual Problems and Sexual Dysfunction Amongst Malay Women With Breast Cancer. A Qualitative Study. Sex Med 2021;9:100336.
Fulltext Taste, smell and food-related nausea and vomiting responses in hyperemesis gravidarum: A case-controlled study

Tan PC, Kartik B, Thanendran P, Zakaria R, Win ST, Omar SZ

Sci Rep, 2020 03 10;10(1):4445.
PMID: 32157169 DOI: 10.1038/s41598-020-61114-y

A case-controlled study was performed to evaluate taste and smell impairment, nausea or vomiting (NV) response to taste and smell and toleration to food texture, item and cooking method in hyperemesis gravidarum patients (HG) compared to gestation-matched controls from a university hospital and primary care clinic in Malaysia. Taste strips (4 base tastes), sniff sticks (16 selected smells) and a food-related questionnaire were used. 124 participants were recruited. Taste impairment was found in 13%(8/62) vs. 0%(0/62) P = 0.003 and the median for correct smell identification was 5[4-6] vs. 9[7-9] P
Fulltext Plasmon-enhanced reduced graphene oxide photodetector with monometallic of Au and Ag nanoparticles at VIS-NIR region

Rohizat NS, Ripain AHA, Lim CS, Tan CL, Zakaria R

Sci Rep, 2021 Oct 04;11(1):19688.
PMID: 34608217 DOI: 10.1038/s41598-021-99189-w

Hybrids plasmonic nanoparticles (NPs) and unique 2D graphene significantly enhanced the photoresponse of the photodetectors. The metallic NPs that exhibit localized surface plasmon resonance (LSPR) improves strong light absorption, scattering and localized electromagnetic field by the incident photons depending on the optimum condition of NPs. We report high-performance photodetectors based on reduced graphene oxide (rGO) integrated with monometallic of Au and Ag nanoparticles via a familiar fabrication technique using an electron beam evaporation machine. Under 680 nm illumination of light, our rGO photodetector exhibited the highest performance for Au-rGO with the highest responsivity of 67.46 AW-1 and the highest specific detectivity (2.39 × 1013 Jones). Meanwhile, Ag-rGO achieved the highest responsivity of 17.23 AW-1, specific detectivity (7.17 × 1011 Jones) at 785 nm. The response time are 0.146 µs and 0.135 µs for Au-rGO and Ag-rGO respectively for both wavelengths. The proposed photodetector with combining monometallic and graphene provide a new strategy to construct reliable and next-generation optoelectronic devices at VIS-NIR region.
Diabetes alters the mRNA expression of insulin-like growth factors and their receptors in the mouse fallopian tube and uterus during the preimplantation stages

Zakaria R, Rajikin MH, Yaacob NS, Nor NM

Reprod Biol, 2007 Mar;7(1):41-53.
PMID: 17435832

The possible role of insulin-like growth factors (IGFs) and their receptors (IGFRs) in the pathogenesis of diabetic embryopathy was investigated. Sexually mature female ICR mice of 6-8 weeks old were made diabetic by a single intraperitoneal injection with 200 mg/kg streptozotocin ten days prior to mating. Fallopian tubes and uterine tissues were obtained from the superovulated diabetic and normal mice 48, 72 and 96 hours following human chorionic gonadotropin (hCG) injection. The mRNA expression of IGF-1 and IGF-2 as well as their receptors was determined in the tissues using Real-time Polymerase Chain Reaction (Real-time PCR). The mRNA expression of IGF-1 in the fallopian tube and uterus of the diabetic mice was significantly lower 72 and 96 hours after hCG treatment, respectively, as compared to the controls. The mRNA expression of IGF-1R at 96 hours post-hCG treatment was significantly higher in the fallopian tube and lower in the uterus of the diabetic mice as compared to the controls. The mRNA expression IGF-2 in the fallopian tube was significantly higher 48 and 96 hours after hCG treatment, but was lower in the uterus of diabetic mice 96 hours after hCG treatment as compared to controls. The mRNA expression of IGF-2R in the diabetic mice was significantly higher 48 and 96 hours (the fallopian tube) and 48 hours (uterus) after hCG treatments as compared to the controls. In conclusion, an alteration in mRNA expression of IGFs and their receptors in the diabetic mice as observed in this study could possibly result in diabetic embryopathy.
Melatonin effects on Plasmodium life cycle: new avenues for therapeutic approach

Srinivasan V, Ahmad AH, Mohamed M, Zakaria R

Recent Pat Endocr Metab Immune Drug Discov, 2012 May;6(2):139-47.
PMID: 22537380

Malaria remains a global health problem affecting more than 515 million people all over the world including Malaysia. It is on the rise, even within unknown regions that previous to this were free of malaria. Although malaria eradication programs carried out by vector control programs are still effective, anti-malarial drugs are also used extensively for curtailing this disease. But resistance to the use of anti-malarial drugs is also increasing on a daily basis. With an increased understanding of mechanisms that cause growth, differentiation and development of malarial parasites in rodents and humans, new avenues of therapeutic approaches for controlling the growth, synchronization and development of malarial parasites are essential. Within this context, the recent discoveries related to IP3 interconnected signalling pathways, the release of Ca2+ from intracellular stores of Plasmodium, ubiquitin protease systems as a signalling pathway, and melatonin influencing the growth and differentiation of malarial parasites by its effects on these signalling pathways have opened new therapeutic avenues for arresting the growth and differentiation of malarial parasites. Indeed, the use of melatonin antagonist, luzindole, has inhibited the melatonin's effect on these signalling pathways and thereby has effectively reduced the growth and differentiation of malarial parasites. As Plasmodium has effective sensors which detect the nocturnal plasma melatonin concentrations, suppression of plasma melatonin levels with the use of bright light during the night or by anti-melatonergic drugs and by using anti-kinase drugs will help in eradicating malaria on a global level. A number of patients have been admitted with regards to the control and management of malarial growth. Patents related to the discovery of serpentine receptors on Plasmodium, essential for modulating intra parasitic melatonin levels, procedures for effective delivery of bright light to suppress plasma melatonin levels and thereby arresting the growth and elimination of malarial parasites from the blood of the host are all cited in the paper. The purpose of the paper is to highlight the importance of melatonin acting as a cue for Plasmodium faciparum growth and to discuss the ways of curbing the effects of melatonin on Plasmodium growth and for arresting its life cycle, as a method of eliminating the parasite from the host.
Gene and schizophrenia in the pregenome and postgenome-wide association studies era: a bibliometric analysis and network visualization

Zakaria WNA, Sasongko TH, Al-Rahbi B, Al-Sowayan N, Ahmad AH, Zakaria R, et al.

Psychiatr Genet, 2023 Apr 01;33(2):37-49.
PMID: 36825838 DOI: 10.1097/YPG.0000000000000336

This study aimed to perform a bibliometric analysis on genetic studies in schizophrenia in the pregenome-wide association studies (GWAS) and post-GWAS era. We searched the literature on genes and schizophrenia using the Scopus database. The documents increased with time, especially after the human genome project and International HapMap Project, with the highest citation in 2008. The top occurrence author keywords were discovered to be different in the pre-GWAS and post-GWAS eras, reflecting the progress of genetic studies connected to schizophrenia. Emerging keywords highlighted a trend towards an application of precision medicine, showing an interplay of environmental exposures as well as genetic factors in schizophrenia pathogenesis, progression, and response to therapy. In conclusion, the gene and schizophrenia literature has grown rapidly after the human genome project, and the temporal variation in the author keywords pattern reflects the trend of genetic studies related to schizophrenia in the pre-GWAS and post-GWAS era.
Emerging trends in gene and bipolar disorder research: a bibliometric analysis and network visualisation

Zakaria WNA, Wijaya A, Al-Rahbi B, Ahmad AH, Zakaria R, Othman Z

Psychiatr Genet, 2023 Jun 01;33(3):102-112.
PMID: 36825833 DOI: 10.1097/YPG.0000000000000338

This study aims to use a bibliometric technique to evaluate the scientific output of gene and bipolar disorder research. The search query related to gene and bipolar disorder from the Scopus database identified 1848 documents from 1951 to 2020. The growth in the publications increased since early 1990, peaked in 2011, and started to decline thereafter. High occurrence in author keywords suggests that some research topics, such as "polymorphism", "linkage" and "association study" have waned over time, whereas others, such as "DNA methylation," "circadian rhythm," "" and "meta-analysis," are now the emerging trends in gene and bipolar disorder research. The USA was the country with the highest production followed by the UK, Canada, Italy and Germany. The leading institutions were Cardiff University in the UK, the National Institute of Mental Health (NIMH) in the USA, King's College London in the UK and the University of California, San Diego in the USA. The leading journals publishing gene and bipolar literature were the American Journal of Medical Genetics Neuropsychiatric Genetics, Molecular Psychiatry and Psychiatric Genetics. The top authors in the number of publications were Craddock N, Serretti A and Rietschel M. According to the co-authorship network analysis of authors, the majority of the authors in the same clusters were closely linked together and originated from the same or neighbouring country. The findings of this study may be useful in identifying emerging topics for future research and promoting research collaboration in the field of genetic studies related to bipolar disorder.
Fulltext Phylogenetic classification of the world's tropical forests

Slik JWF, Franklin J, Arroyo-Rodríguez V, Field R, Aguilar S, Aguirre N, et al.

Proc Natl Acad Sci U S A, 2018 02 20;115(8):1837-1842.
PMID: 29432167 DOI: 10.1073/pnas.1714977115

Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world's tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.
Fulltext Soils on exposed Sunda shelf shaped biogeographic patterns in the equatorial forests of Southeast Asia

Slik JW, Aiba S, Bastian M, Brearley FQ, Cannon CH, Eichhorn KA, et al.

Proc Natl Acad Sci U S A, 2011 Jul 26;108(30):12343-7.
PMID: 21746913 DOI: 10.1073/pnas.1103353108

The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass. A dispersal barrier in the form of a dry savanna corridor during glacial maxima has been proposed to explain this disparity. However, the short duration of these dry savanna conditions make it an unlikely sole cause for the biogeographic pattern. An additional explanation might be related to the coarse sandy soils of central Sundaland. To test these two nonexclusive hypotheses, we performed a floristic cluster analysis based on 111 tree inventories from Peninsular Malaysia, Sumatra, and Borneo. We then identified the indicator genera for clusters that crossed the central Sundaland biogeographic boundary and those that did not cross and tested whether drought and coarse-soil tolerance of the indicator genera differed between them. We found 11 terminal floristic clusters, 10 occurring in Borneo, 5 in Sumatra, and 3 in Peninsular Malaysia. Indicator taxa of clusters that occurred across Sundaland had significantly higher coarse-soil tolerance than did those from clusters that occurred east or west of central Sundaland. For drought tolerance, no such pattern was detected. These results strongly suggest that exposed sandy sea-bed soils acted as a dispersal barrier in central Sundaland. However, we could not confirm the presence of a savanna corridor. This finding makes it clear that proposed biogeographic explanations for plant and animal distributions within Sundaland, including possible migration routes for early humans, need to be reevaluated.
Fulltext An estimate of the number of tropical tree species

Slik JW, Arroyo-Rodríguez V, Aiba S, Alvarez-Loayza P, Alves LF, Ashton P, et al.

Proc Natl Acad Sci U S A, 2015 Jun 16;112(24):7472-7.
PMID: 26034279 DOI: 10.1073/pnas.1423147112

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.
Fulltext Novel Mangosteen-Leaves-Based Marker Ink: Color Lightness, Viscosity, Optimized Composition, and Microstructural Analysis

Mohd Basri MS, Liew Min Ren B, A Talib R, Zakaria R, Kamarudin SH

Polymers (Basel), 2021 May 14;13(10).
PMID: 34069259 DOI: 10.3390/polym13101581

Dry mangosteen leaves are one of the raw materials used to produce marker ink. However, research using this free and abundant resource is rather limited. The less efficient one-factor-at-a-time (OFAT) approach was mostly used in past studies on plant-based marker ink. The use of statistical analysis and the regression coefficient model (mathematical model) was considered essential in predicting the best combination of factors in formulating mangosteen leaf-based marker ink. Ideally, ink should have maximum color lightness, minimum viscosity, and fast-drying speed. The objective of this study to study the effect of glycerol and carboxymethyl cellulose (CMC) on the color lightness and viscosity of mangosteen-leaves-based marker ink. The viscosity, color lightness, and drying properties of the ink were tested, the significant effect of glycerol and CMC (responses) on ink properties was identified and the prediction model on the optimum value of the responses was developed by using response surface methodology (RSM). The microstructure of mangosteen leaves was analyzed to study the surface morphology and cell structure during dye extraction. A low amount of glycerol used was found to increase the value of color lightness. A decrease in CMC amounts resulted in low viscosity of marker ink. The optimum formulation for the ink can be achieved when the weight percents of glycerol, benzalkonium chloride, ferrous sulphate, and CMC are set at 5, 5, 1, and 3, respectively. SEM micrographs showed the greatest amount of cell wall structure collapse on samples boiled with the lowest amount of glycerol.
Fulltext Properties of Particleboard from Oil Palm Biomasses Bonded with Citric Acid and Tapioca Starch

Zakaria R, Bawon P, Lee SH, Salim S, Lum WC, Al-Edrus SSO, et al.

Polymers (Basel), 2021 Oct 12;13(20).
PMID: 34685253 DOI: 10.3390/polym13203494

The study investigated the effects of the addition of starch on the properties of oil palm biomass particleboard bonded with citric acid. Three kinds of oil palm biomasses were used in this study for the fabrication of particleboard, namely, oil palm frond (OPF), oil palm trunk (OPT), and empty fruit bunch (EFB) particles. Citric acid and tapioca starch at the mixing ratios of 100:0, 87.5:12.5, and 75:25 were prepared at a 60% solid content. A 30% resin content based on the oven-dried weight of the oil palm biomass particles was used. The sprayed particles were pre-dried at 80 °C for 12 h before being hot-pressed at 180 °C and 4 MPa pressure for 10 min. The physical and mechanical properties of the particleboard were evaluated. The mixtures of citric acid and tapioca starch were characterized by thermogravimetric analysis (TGA). Thermal stability of citric acid was reduced after the addition of tapioca starch. The addition of 12.5% tapioca starch improved the bending strength of the particleboard but increased the thickness swelling slightly. All UF-bonded particleboard exhibited significantly inferior performance than that of citric-acid-bonded particleboard. Citric-acid-bonded particleboard maintained its original shape after being subjected to a cyclic-aging treatment, while the UF-bonded particleboard disintegrated half way through the treatment. The performance of EFB particleboard was significantly inferior to its OPT and OPF counterparts.
Fulltext Autofluorescence study and selected cyanidin quantification in the Jewel orchids Anoectochilus sp. and Ludisia discolor

Poobathy R, Zakaria R, Murugaiyah V, Subramaniam S

PLoS One, 2018;13(4):e0195642.
PMID: 29649288 DOI: 10.1371/journal.pone.0195642

Anoectochilus sp. and Ludisia discolor are known as Jewel orchids. Both species are terrestrial wild orchids that grow in shaded areas of forests. The Jewel orchids are renowned for the beauty of their leaves, which are dark-green laced with silvery or golden veins. The orchids are used as a cure in various parts of Asia. Overharvesting and anthropogenic disturbances threaten the existence of the Jewel orchids in the wild, necessitating human intervention in their survival. An understanding of the structure and adaptations of a plant may assist in its survival when propagated outside of its habitat. In this study, ex vitro leaves of Anoectochilus sp. and L. discolor were subjected to freehand sectioning, and then inspected through brightfield and fluorescence microscopy. The study indicated that all parts of both plants presented typical monocotyledonous characteristics except the leaves. The leaves displayed dorsiventrality with distinct palisade and spongy mesophyll layers. The spongy mesophyll layer contained cells which fluoresced a bright red when exposed to ultraviolet, blue, and green light wavelengths, hinting at the presence of anthocyanins for photoprotection. Cyanidin was detected in the leaves of L. discolor, as enumerated through high performance liquid chromatography (HPLC). The observations indicated that Anoectochilus sp. and L. discolor are well-adapted to live under shaded conditions with minimal exposure to light.

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