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Measuring organic carbon, nutrients and heavy metals in rivers receiving leachate from controlled and uncontrolled municipal solid waste (MSW) landfills

Yusof N, Haraguchi A, Hassan MA, Othman MR, Wakisaka M, Shirai Y

Waste Manag, 2009 Oct;29(10):2666-80.
PMID: 19564103 DOI: 10.1016/j.wasman.2009.05.022

Since landfilling is the common method of waste disposal in Malaysia, river water is greatly exposed to the risk of contamination from leachate unless proper leachate management is carried out. In this study, leachates from three different types of landfills, namely active uncontrolled, active controlled and closed controlled, were characterized, and their relationships with river water chemistry were examined monthly for a year. The influence of leachate on river water chemistry from each type of landfill depended on many factors, including the presence of a leachate control mechanism, leachate characteristics, precipitation, surface runoff and the applied treatment. The impact of leachate from an active uncontrolled landfill was the highest, as the organic content, NH(4)(+)-N, Cd and Mn levels appeared high in the river. At the same time, influences of leachate were also observed from both types of controlled landfills in the form of inorganic nitrogen (NH(4)(+)-N, NO(3)(-)-N and NO(2)(-)-N) and heavy metals (Fe, Cr, Ni and Mn). Improper treatment practice led to high levels of some contaminants in the stream near the closed controlled landfill. Meanwhile, the active controlled landfill, which was located near the coastline, was exposed to the risk of contamination resulting from the pyrite oxidation of the surrounding area.
Nitrification of high-strength ammonium landfill leachate with microbial community analysis using fluorescence in situ hybridization (FISH)

Yusof N, Hassan MA, Yee PL, Tabatabaei M, Othman MR, Mori M, et al.

Waste Manag Res, 2011 Jun;29(6):602-11.
PMID: 21447612 DOI: 10.1177/0734242X10397581

Nitrification of mature sanitary landfill leachate with high-strength of N-NH(4) + (1080-2350 mg L(-1)) was performed in a 10 L continuous nitrification activated sludge reactor. The nitrification system was acclimatized with synthetic leachate during feed batch operation to avoid substrate inhibition before being fed with actual mature leachate. Successful nitrification was achieved with an approximately complete ammonium removal (99%) and 96% of N-NH(4) + conversion to N-NO(-) (3) . The maximum volumetric and specific nitrification rates obtained were 2.56 kg N-NH(4) (+) m(-3) day(-1) and 0.23 g N-NH(4) ( +) g(-1) volatile suspended solid (VSS) day(-1), respectively, at hydraulic retention time (HRT) of 12.7 h and solid retention time of 50 days. Incomplete nitrification was encountered when operating at a higher nitrogen loading rate of 3.14 kg N-NH(4) (+) m(-3) day(-1). The substrate overloading and nitrifiers competition with heterotrophs were believed to trigger the incomplete nitrification. Fluorescence in situ hybridization (FISH) results supported the syntrophic association between the ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria. FISH results also revealed the heterotrophs as the dominant and disintegration of some AOB cell aggregates into single cells which further supported the incomplete nitrification phenomenon.
Bacillus licheniformis BT5.9 Isolated from Changar Hot Spring, Malang, Indonesia, as a Potential Producer of Thermostable α-amylase

Ibrahim D, Zhu HL, Yusof N, Isnaeni, Hong LS

Trop Life Sci Res, 2013 Aug;24(1):71-84.
PMID: 24575243 MyJurnal

A total of 34 bacterial isolates were obtained from soil samples collected from Changar Hot Spring, Malang, Indonesia. Of these, 13 isolates produced a zone of hydrolysis in starch-nutrient agar medium and generated various amylases in liquid medium. One isolate was selected as the best amylase producer and was identified as Bacillus licheniformis BT5.9. The improvement of culture conditions (initial medium pH of 5.0, cultivation temperature of 50°C, agitation speed of 100 rpm and inoculum size of 1.7 × 10(9) cells/ml) provided the highest amylase production (0.327 U/ml).
An action research on promotion of healthy ageing and risk reduction of chronic disease: a need assessment study among rural elderly Malays, care givers and health professionals

Nur Asyura Adznam S, Shahar S, Rahman SA, Yusof NA, Arshad F, Yassin Z, et al.

J Nutr Health Aging, 2009 Dec;13(10):925-30.
PMID: 19924355

OBJECTIVE: Prior to the development of a healthy ageing and risk reduction of chronic diseases intervention package for older people in Malaysia, a need assessment study was conducted to identify nutritional knowledge status and information needs, as part of an action research process.
DESIGN: A cross sectional study was conducted among 267 elderly people, 54 care givers and 66 health professionals in two rural areas of Peninsular of Malaysia (i.e Sabak Bernam, Selangor and Kuala Pilah, Negeri Sembilan). Information on nutritional knowledge was obtained from an interview based questionnaire for older subjects and caregiver and through self administered questionnaire from the health professionals. Anthropometric and functional measurements were also conducted among elderly subjects.
RESULTS: It was found that the elderly subjects had poor nutritional knowledge with 43.8% of them classified as having unsatisfactory nutritional knowledge, followed by moderately satisfactory (33.7%), very unsatisfactory (15.7%) and good (6.7%). Talks, counselling sessions with health professionals and electronic media such as television and radio were the most preferred nutrition education sources among elderly subjects and their care givers. The majority of health professionals studied (98.5%) had good nutritional knowledge. Although most of them (93.6%) were involved in management of the elderly, only 45.5% incorporated nutritional information component in this activity. Most of the health professionals used the guidelines for management of elderly patients (63.6%). However, nutritional knowledge was very minimal in these guidelines. Multiple regression analysis indicated that 'level education', involvement in 'social activities', presence of 'hearing problems', the Instrumental Activities of Daily Living (IADL) score, having previous 'nutritional information' and 'participation in healthy eating programme' were the major predictors of nutritional knowledge score among elderly subjects.
CONCLUSION: Based on the above findings it is thus, imperative that an appropriate nutritional intervention package and programme be developed so as to help improve nutritional knowledge and subsequently the nutritional status of the rural elderly Malays.
Prevalence of Absence of Palmaris Longus and Its Association with Gender, Hand Dominance and Absence of FDS Tendon to Little Finger Among Malay Population

Yong MW, Yusof N, Rampal L, Arumugam M

J Hand Surg Asian Pac Vol, 2017 Dec;22(4):484-489.
PMID: 29117832 DOI: 10.1142/S021881041750054X

BACKGROUND: Palmaris Longus is being widely used in reconstructive, plastic and cosmetic surgeries due to its long tendon. It is the most readily available source for tendon grafting. The objective of this study was to determine the prevalence of absence of Palmaris Longus and its association with gender, hand dominance and absence of FDS (flexor digitorum superficialis) tendon to little finger among Malay population.
METHODS: An analytical cross sectional study design was used and a self-administered proforma was distributed for data collection. 1239 Malay secondary school children in Putrajaya were tested for absence of Palmaris Longus using Schaffer's test. 4 additional tests namely Thompson's test, Mishra's test I, Mishra's test II and Pushpakumar's 'two-finger sign' method were used to confirm its absence in respondents with negative Schaffer's test. Function of Flexor Digitorum Superficialis tendon to little finger was determined by flexing PIP of little finger while hyperextend the other fingers.
RESULTS: The prevalence of absence of Palmaris Longus was 11.7%. Left side absence of Palmaris Longus was much common. There was a significant association between absence of Palmaris Longus with gender in which female had higher prevalence of absence of Palmaris Longus than male.
CONCLUSIONS: In conclusion, the prevalence of absence of Palmaris Longus in Malay population was lower than Indian but higher than Chinese population. Females had higher prevalence of absence of Palmaris Longus and no association can be found with hand dominance and absence of Flexor Digitorum Superficialis tendon to little finger.
Glycerol preserved bovine pericardium for abdominal wall reconstruction: experimental study in rat model

Hafeez YM, Zuki AB, Loqman MY, Yusof N, Asnah H, Noordin MM

Med J Malaysia, 2004 May;59 Suppl B:117-8.
PMID: 15468846

The aim of this study was to evaluate bovine pericardium surgical patch in rat model. Bovine pericardial sacs collected from local abattoir were cleaned, disinfected and cut into pieces of 3 by 2.5cm and preserved in 99.5% glycerol. Full thickness abdominal wall defects of 3 by 2.5 cm were created in 30 adult male Sprague Dawley rats and repaired with glycerol preserved pieces. The rats were serially sacrificed in a group of six rats at 1,3,6,9 and 18 weeks post-surgical intervals for morphological and tensometeric study. Macroscopically, no mortality or postoperative surgical complications was encountered except slight adhesions between implanted grafts and some visceral organs in 10% of the rats. Microscopically no calcification or foreign body giant cell formation was found in the explanted grafts. The implanted grafts were replaced gradually with recipient tissue, which made mainly of dense collagenous bundles. The healing strength between the implanted grafts and the recipient abdominal wall was gradually increased with time. The results of this study showed that glycerol preserved bovine pericardium act as scaffold for transformation into living tissue without clinical complications such as that associated with prostheses.
Fulltext Acute vascular complications (flap necrosis and congestion) with one stage and two stage distally based sural flap for wound coverage around the ankle

Yusof NM, Fadzli AS, Azman WS, Azril MA

Med J Malaysia, 2016 04;71(2):47-52.
PMID: 27326940 MyJurnal

INTRODUCTION: The understanding of the skin's vascular anatomy has improved in the last decade. It has lead to technique modification such as the staged procedure in performing sural flaps and improvement in the flap survival rate. The aim of this study was to evaluate the acute vascular complications (flap necrosis or congestion) of 29 patients who underwent distal base sural flap for coverage of wound around the ankle.

METHODS: Twenty-four males and five females with a mean age of 37.1 years old underwent sural flap surgery to cover wounds at around the ankle. There were 12 cases of open fracture, five infected fractures, four spoke injuries, four degloving injuries and four diabetic foot ulcers. Twentythree cases were done as a single stage procedure while six as a two-stage procedure. The flaps were tunnelled under the skin in three cases.

RESULTS: Twenty one flaps healed uneventfully, seven acute vascular complications occur in a single stage group: five developed partial necrosis, one had congestion with epidermolysis, and one had complete flap necrosis. Complications were treated by dressing or skin grafting and only one required a repeat flap surgery.

CONCLUSIONS: Acute vascular complications may be minimised when sural flap is done in stages for elderly, diabetic, smokers and/or patients with large wound around the ankle. Even if the flap appears necrotic, the underlying structure may still be covered as the fasciosubcutaneous layer of the flap may still survive.
Fulltext Co-inheritance of compound heterozygous Hb Constant Spring and a single -alpha(3.7) gene deletion with heterozygous deltabeta thalassaemia: a diagnostic challenge

Azma RZ, Othman A, Azman N, Alauddin H, Ithnin A, Yusof N, et al.

Malays J Pathol, 2012 Jun;34(1):57-62.
PMID: 22870600

Haemoglobin Constant Spring (Hb CS) mutation and single gene deletions are common underlying genetic abnormalities for alpha thalassaemias. Co-inheritance of deletional and non-deletional alpha (alpha) thalassaemias may result in various thalassaemia syndromes. Concomitant co-inheritance with beta (beta) and delta (delta) gene abnormalities would result in improved clinical phenotype. We report here a 33-year-old male patient who was admitted with dengue haemorrhagic fever, with a background history of Grave's disease, incidentally noted to have mild hypochromic microcytic red cell indices. Physical examination revealed no thalassaemic features or hepatosplenomegaly. His full blood picture showed hypochromic microcytic red cells with normal haemoglobin (Hb) level. Quantitation of Hb using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) revealed raised Hb F, normal Hb A2 and Hb A levels. There was also small peak of Hb CS noted in CE. H inclusions was negative. Kleihauer test was positive with heterocellular distribution of Hb F among the red cells. DNA analysis for alpha globin gene mutations showed a single -alpha(-3.7) deletion and Hb CS mutation. These findings were suggestive of compound heterozygosity of Hb CS and a single -alpha(-3.7) deletion with a concomitant heterozygous deltabeta thalassaemia. Co-inheritance of Hb CS and a single -alpha(-3.7) deletion is expected to result at the very least in a clinical phenotype similar to that of two alpha genes deletion. However we demonstrate here a phenotypic modification of alpha thalassemia presumptively as a result of co-inheritance with deltabeta chain abnormality as suggested by the high Hb F level.
Mixed phenotype acute leukaemia with t(9,22), BCR-ABL1: A case report

Yong WL, Yusof N, Ithnin A, Shuib S, Tumian R, Yousuf R, et al.

Malays J Pathol, 2020 Dec;42(3):469-476.
PMID: 33361731

INTRODUCTION: Mixed phenotype acute leukaemia (MPAL) is a rare entity of acute leukaemia.
CASE REPORT: Here we report a case of a 39-year-old lady, with an incidental finding of hyperleukocytosis (white blood cells count: 139.2 x 109/L). Her peripheral blood film revealed 36% of blasts and a bone marrow aspiration showed 53% of blasts. Immunophenotyping showed a population of blasts exhibiting positivity of two lineages, myeloid lineage and B-lymphoid lineage with strong positivity of CD34 and terminal deoxynucleotidyl transferase (Tdt). A conventional karyotyping revealed the presence of Philadelphia chromosome. She was diagnosed with MPAL with t(9,22), BCR ABL1, which carried a poor prognosis. She was treated with acute lymphoblastic leukaemia (ALL) chemotherapy protocol coupled with a tyrosine kinase inhibitor and was planned for an allogeneic stem cells transplant.
CONCLUSION: This MPAL case was diagnosed incidentally in an asymptomatic patient during medical check-up. We highlight this rare case report to raise the awareness about this rare disease. Understanding the pathogenesis of the disease with the underlying genes responsible for triggering the disease, uniform protocols for diagnosis and targeted treatment will help for proper management of these patients.
Myelodysplastic syndrome with fibrosis and complex karyotype arising in a patient with essential thrombocythaemia

Mansor NA, Yusof N, Tang YL, Ithnin A, Azma RZ, Tumian NR, et al.

Malays J Pathol, 2018 Aug;40(2):191-197.
PMID: 30173238 MyJurnal

INTRODUCTION: Essential thrombocythaemia (ET) is a chronic myeloproliferative neoplasm (MPN) characterised by persistent thombocytosis. It is an indolent disorder but transformation to myelofibrosis (MF), acute myeloid leukaemia (AML) or myelodyplastic syndrome (MDS) has been reported.
CASE REPORT: We described a patient with ET whose disease evolved into MDS with fibrosis and complex karyotype after 15 years of stable disease. She was asymptomatic and was on hydroxyurea (HU) treatment until recently when she presented with worsening anaemia. Physical examination showed mild splenomegaly. Full blood picture showed leukoerythroblastic picture with presence of 3% circulating blasts and background of dysplastic features such as hypogranular cytoplasm and nuclear hyposegmentation of neutrophils. The bone marrow aspiration was haemodiluted but revealed presence of 6% blast cells, trilineage dysplasia and predominant erythroid precursors (60%). Trephine biopsy showed no excess of blast cells and normal quantity of erythroid precursors, but there was increased in fibrosis (WHO grade 2) and presence of dysmegakaryopoeisis such as nuclear hypolobation, multinucleation and micromegakaryocytes. Cytogenetic study showed complex karyotype; monosomy of chromosome 2, chromosome 5, chromosome 18 and presence of a marker chromosome (42~44, XX,-2,-5,-18,+mar). Fluorescence in situ hybridisation (FISH) showed 5q deletion (CSF1R and EGR1).
CONCLUSION: The findings were consistent with transformation of ET to MDS with fibrosis and complex karyotype. ET progression to MDS is considered rare. The presence of complex karyotype and fibrosis in MDS are associated with unfavourable outcome.
Fulltext Bilateral persistent sciatic arteries with unilateral complicating aneurysm

Aziz ME, Yusof NR, Abdullah MS, Yusof AH, Yusof MI

Singapore Med J, 2005 Aug;46(8):426-8.
PMID: 16049615

Persistent sciatic artery is a very uncommon embryological vascular variant. This case report highlights this rare vascular anomaly, diagnostic difficulty, complication and subsequent treatment in a 43-year-old man who presented with sudden onset of right leg pain for a few hours. He was unable to walk because of pain and numbness. Emergency right lower limb angiogram showed a large aneurysm that was initially thought to arise from the right common femoral artery, associated with thrombus formation within the right popliteal artery. A below knee amputation was performed due to worsening ischaemia of the right leg. The persistent right sciatic artery was later obliterated using percutaneous stenting and endovascular grafting, with deployment of two wallstents.
Fulltext A review of the potential of conventional and advanced membrane technology in the removal of pathogens from wastewater

Nasir AM, Adam MR, Mohamad Kamal SNEA, Jaafar J, Othman MHD, Ismail AF, et al.

Sep Purif Technol, 2022 Apr 01;286:120454.
PMID: 35035270 DOI: 10.1016/j.seppur.2022.120454

Consumption of pathogenic contaminated water has claimed the lives of many people. Hence, this scenario has emphasized the urgent need for research methods to avoid, treat and eliminate harmful pathogens in wastewater. Therefore, effective water treatment has become a matter of utmost importance. Membrane technology offers purer, cleaner, and pathogen-free water through the water separation method via a permeable membrane. Advanced membrane technology such as nanocomposite membrane, membrane distillation, membrane bioreactor, and photocatalytic membrane reactor can offer synergistic effects in removing pathogen through the integration of additional functionality and filtration in a single chamber. This paper also comprehensively discussed the application, challenges, and future perspective of the advanced membrane technology as a promising alternative in battling pathogenic microbial contaminants, which will also be beneficial and valuable in managing pandemics in the future as well as protecting human health and the environment. In addition, the potential of membrane technology in battling the ongoing global pandemic of coronavirus disease 2019 (COVID-19) was also discussed briefly.
Fulltext Enzymatic and genetic characterization of lignin depolymerization by Streptomyces sp. S6 isolated from a tropical environment

Riyadi FA, Tahir AA, Yusof N, Sabri NSA, Noor MJMM, Akhir FNMD, et al.

Sci Rep, 2020 05 08;10(1):7813.
PMID: 32385385 DOI: 10.1038/s41598-020-64817-4

The conversion of lignocellulosic biomass into bioethanol or biochemical products requires a crucial pretreatment process to breakdown the recalcitrant lignin structure. This research focuses on the isolation and characterization of a lignin-degrading bacterial strain from a decaying oil palm empty fruit bunch (OPEFB). The isolated strain, identified as Streptomyces sp. S6, grew in a minimal medium with Kraft lignin (KL) as the sole carbon source. Several known ligninolytic enzyme assays were performed, and lignin peroxidase (LiP), laccase (Lac), dye-decolorizing peroxidase (DyP) and aryl-alcohol oxidase (AAO) activities were detected. A 55.3% reduction in the molecular weight (Mw) of KL was observed after 7 days of incubation with Streptomyces sp. S6 based on gel-permeation chromatography (GPC). Gas chromatography-mass spectrometry (GC-MS) also successfully highlighted the production of lignin-derived aromatic compounds, such as 3-methyl-butanoic acid, guaiacol derivatives, and 4,6-dimethyl-dodecane, after treatment of KL with strain S6. Finally, draft genome analysis of Streptomyces sp. S6 also revealed the presence of strong lignin degradation machinery and identified various candidate genes responsible for lignin depolymerization, as well as for the mineralization of the lower molecular weight compounds, confirming the lignin degradation capability of the bacterial strain.
Immunophenotyping analysis of lymph node biopsies by flow cytometry

Raja-Sabudin RZ, Hamid AA, Yusof N, Alauddin H, Aziz SA, Kulaveerasingam S, et al.

Saudi Med J, 2012 Oct;33(10):1131-3.
PMID: 23047221
Fulltext Antimicrobial resistance in methicillin-resistant staphylococcus aureus

Ali Alghamdi B, Al-Johani I, Al-Shamrani JM, Musamed Alshamrani H, Al-Otaibi BG, Almazmomi K, et al.

Saudi J Biol Sci, 2023 Apr;30(4):103604.
PMID: 36936699 DOI: 10.1016/j.sjbs.2023.103604

In the medical community, antibiotics are revered as a miracle because they stop diseases brought on by pathogenic bacteria. Antibiotics have become the cornerstone of contemporary medical advancements ever since penicillin was discovered. Antibiotic resistance developed among germs quickly, placing a strain in the medical field. Methicillin-resistant Staphylococcus aureus (MRSA), Since 1961, has emerged as the major general antimicrobial resistant bacteria (AMR) worldwide. MRSA can easily transmit across the hospital system and has mostly gained resistance to medications called beta-lactamases. This enzyme destroys the cell wall of beta-lactam antibiotics resulting in resistance against that respective antibiotic. Daptomycin, linezolid and vancomycin were previously used to treat MRSA infections. However, due to mutations and Single nucleotide polymorphisms (SNPs) in Open reading frames (ORFs) and SCCmec machinery of respective antibody, MRSA developed resistance against those antibiotics. The MRSA strains (USA300, CC398, CC130 etc.), when their pan-genomes were analyzed were found the genes involved in invoking resistance against the antibiotics as well as the epidemiology of that respective strain. PENC (penicillin plus potassium clavulanate) is the new antibiotic showing potential in treatment of MRSA though it is itself resistant against penicillin alone. In this review, our main focus is on mechanism of development of AMR in MRSA, how different ORFs are involved in evoking resistance in MRSA and what is the core-genome of different antimicrobial resistant MRSA.
Potential of Malaysian Local Honey as an Antibacterial Agent (Potensi Madu Tempatan Malaysia sebagai Agen AntiBakteria)

Ainul Hafiza A.H., Yusof N., Maimon A.

Sains Malaysiana, 2005;34.

A laboratory study was carried out to study the microbiological quality of local honey and its potential as an antibacterial agent. Five local honeys namely, Belimbing, Gelam (Sample 1,2, and 3), Durian (Sample 1 and 2), Kelapa and Tualang were studied. Microbial colony count of each sample was determined using filtration method. Screening for antibacterial action against Staphylococcus aureus was carried out using agar diffusion method. The result showed that all samples had low colony counts ranging from 37 cfu/ml in Kelapa honey to 161 cfu/ml in Durian honey (Sample 2). All samples showed a very clear zone of inhibition for bacterial growth and there was significant difference (ANOVA, p<0.05) among the samples. Belimbing honey showed the biggest diameter (2.1cm) and Gelam honey â€“ Sample 3 had the smallest (1.7 cm).
[Kajian ini dijalankan untuk mengkaji kualiti mikrobiologi madu tempatan dan keupayaannya sebagai agen antibakteria. Lima madu tempatan iaitu Belimbing, Gelam (Sampel 1, 2, dan 3), Durian (Sampel 1 dan 2), Kelapa dan Tualang telah dikaji. Bilangan koloni mikrob ditentukan menggunakan kaedah turasan. Sifat antibakteria terhadap Staphylococcus aureus pula dikaji menggunakan kaedah serapan agar. Keputusan menunjukkan bahawa semua sampel mempunyai bilangan koloni yang rendah sekitar 37 cfu/ml dalam madu Kelapa hingga 161 cfu/ml dalam madu Durian â€“ Sampel 2. Semua sampel menunjukkan kesan rencatan pertumbuhan bakteria dan terdapat perbezaan ketara (ANOVA, p
Online commentaries of the sugar-sweetened beverages tax in Malaysia: Content analysis

Mohd Hanim MFB, Md Sabri BA, Yusof N

Public Health Nurs, 2024;41(1):139-150.
PMID: 37953703 DOI: 10.1111/phn.13262

INTRODUCTION: Implementing taxes on sugary drinks, or SSBs, has been a controversial topic in many countries, including Malaysia. This study aimed to examine how Malaysian Facebook users responded to the announcement and implementation of the SSBs tax through netnography.
METHODS: This cross-sectional study employed qualitative and quantitative methods and used an inductive approach and thematic content analysis to analyze online commentaries on news articles published on popular online news portals from November 2018 to August 2019. Data was collected by downloading the commentaries onto Microsoft Word and importing them into NVivo.
RESULTS: Of the commentaries analyzed, 60.9% rejected the SSBs tax, and 39.1% favored it. No association was found between the online news articles and the slants of the commentaries.
CONCLUSION: The results of this study demonstrate a clear divide in public opinion regarding the SSBs tax in Malaysia, with many online readers expressing opposition to the tax despite evidence of the harmful effects of sugar presented in the articles they are commenting on. These findings have implications for policymakers and public health advocates seeking to implement similar taxes in the future.
Mechanical properties and biocompatibility of co-axially electrospun polyvinyl alcohol/maghemite

Ngadiman NH, Mohd Yusof N, Idris A, Kurniawan D

Proc Inst Mech Eng H, 2016 Aug;230(8):739-49.
PMID: 27194535 DOI: 10.1177/0954411916649632

Electrospinning is a simple and efficient process in producing nanofibers. To fabricate nanofibers made of a blend of two constituent materials, co-axial electrospinning method is an option. In this method, the constituent materials contained in separate barrels are simultaneously injected using two syringe nozzles arranged co-axially and the materials mix during the spraying process forming core and shell of the nanofibers. In this study, co-axial electrospinning method is used to fabricate nanofibers made of polyvinyl alcohol and maghemite (γ-Fe2O3). The concentration of polyvinyl alcohol and amount of maghemite nanoparticle loading were varied, at 5 and 10 w/v% and at 1-10 v/v%, respectively. The mechanical properties (strength and Young's modulus), porosity, and biocompatibility properties (contact angle and cell viability) of the electrospun mats were evaluated, with the same mats fabricated by regular single-nozzle electrospinning method as the control. The co-axial electrospinning method is able to fabricate the expected polyvinyl alcohol/maghemite nanofiber mats. It was noticed that the polyvinyl alcohol/maghemite electrospun mats have lower mechanical properties (i.e. strength and stiffness) and porosity, more hydrophilicity (i.e. lower contact angle), and similar cell viability compared to the mats fabricated by single-nozzle electrospinning method.
Fulltext Novel Activated Carbon Nanofibers Composited with Cost-Effective Graphene-Based Materials for Enhanced Adsorption Performance toward Methane

Che Othman FE, Yusof N, Yub Harun N, Bilad MR, Jaafar J, Aziz F, et al.

Polymers (Basel), 2020 Sep 10;12(9).
PMID: 32927881 DOI: 10.3390/polym12092064

Various types of activated carbon nanofibers' (ACNFs) composites have been extensively studied and reported recently due to their extraordinary properties and applications. This study reports the fabrication and assessments of ACNFs incorporated with graphene-based materials, known as gACNFs, via simple electrospinning and subsequent physical activation process. TGA analysis proved graphene-derived rice husk ashes (GRHA)/ACNFs possess twice the carbon yield and thermally stable properties compared to other samples. Raman spectra, XRD, and FTIR analyses explained the chemical structures in all resultant gACNFs samples. The SEM and EDX results revealed the average fiber diameters of the gACNFs, ranging from 250 to 400 nm, and the successful incorporation of both GRHA and reduced graphene oxide (rGO) into the ACNFs' structures. The results revealed that ACNFs incorporated with GRHA possesses the highest specific surface area (SSA), of 384 m2/g, with high micropore volume, of 0.1580 cm3/g, which is up to 88% of the total pore volume. The GRHA/ACNF was found to be a better adsorbent for CH4 compared to pristine ACNFs and reduced graphene oxide (rGO/ACNF) as it showed sorption up to 66.40 mmol/g at 25 °C and 12 bar. The sorption capacity of the GRHA/ACNF was impressively higher than earlier reported studies on ACNFs and ACNF composites. Interestingly, the CH4 adsorption of all ACNF samples obeyed the pseudo-second-order kinetic model at low pressure (4 bar), indicating the chemisorption behaviors. However, it obeyed the pseudo-first order at higher pressures (8 and 12 bar), indicating the physisorption behaviors. These results correspond to the textural properties that describe that the high adsorption capacity of CH4 at high pressure is mainly dependent upon the specific surface area (SSA), pore size distribution, and the suitable range of pore size.
Fulltext Review on Nanocrystalline Cellulose in Bone Tissue Engineering Applications

Murizan NIS, Mustafa NS, Ngadiman NHA, Mohd Yusof N, Idris A

Polymers (Basel), 2020 Nov 27;12(12).
PMID: 33261121 DOI: 10.3390/polym12122818

Nanocrystalline cellulose is an abundant and inexhaustible organic material on Earth. It can be derived from many lignocellulosic plants and also from agricultural residues. They endowed exceptional physicochemical properties, which have promoted their intensive exploration in biomedical application, especially for tissue engineering scaffolds. Nanocrystalline cellulose has been acknowledged due to its low toxicity and low ecotoxicological risks towards living cells. To explore this field, this review provides an overview of nanocrystalline cellulose in designing materials of bone scaffolds. An introduction to nanocrystalline cellulose and its isolation method of acid hydrolysis are discussed following by the application of nanocrystalline cellulose in bone tissue engineering scaffolds. This review also provides comprehensive knowledge and highlights the contribution of nanocrystalline cellulose in terms of mechanical properties, biocompatibility and biodegradability of bone tissue engineering scaffolds. Lastly, the challenges for future scaffold development using nanocrystalline cellulose are also included.

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