Anthocyanin-containing extract (ACE) were prepared from the pericarp of Garcinia mangostana L. (mangosteen) and the inflorescence part of Etlingera elatior Jack (torch ginger) by using acidified methanol as extraction solvent. Our present study focuses on the antioxidant and cytotoxic activity and the effect of temperature, light and pH on stability of ACE derived from G. mangostana and E. elatior. The monomeric anthocyanin and total phenolic content in E. elatior was higher (43.42±0.01 mg/L dan 10.07±0.01 gGAE /100 g) compared to G. mangostana (15.03±0.01 mg/L and 3.29±0.01 gGAE/100 g). Both ACE of E. elatior and G. mangostana exhibited free radical scavenger activity, with IC50 value of14.90±1.02 mg/mL and 15.50±0.52 mg/mL, respectively, in 2,2’-diphenyl-1-picrylhydrazyl assay. ACE of E. elatior was also found to be a good reducing and possessed higher absorbance values at concentrations range from 1.25 to 20 mg/mL in FRAP assay. ACE of E. elatior exhibited mild cytotoxicity on human ovarian SKOV-3 cell line with IC50 values of 54.32 ± 4.60 μg/mL. The effects of light and temperature on ACE stability were performed in different environmental conditions, which promote the destabilization of anthocyanin molecules. ACE stability of G. mangostana were less resist to the effect of light but very susceptible to the prolonged effect of heat after 2 h exposure compared to the ACE in E. elatior. The different in pH highly influence the stability of both ACE which can be observed from the decrease in absorbance readings.
This paper presents the results for surface water quality parameters measured in the Setiu Wetland, on the east coast of Malaysia, which feeds into the southern part of the South China Sea. There are no previous studies dealing with the seasonal and spatial variation of water quality in this area, despite numerous anthropogenic inputs into this ecologically and economically important wetland. The parameters measured were salinity, temperature, dissolved oxygen (DO), pH, biological oxygen demand (BOD) and total suspended solids (TSS). These parameters were sampled monthly from October 2009 to September 2010, during both the wet and dry seasons, at ten sampling stations distributed throughout the area. The physical water quality parameters were measured in situ whilst TSS and BOD were determined using the standard methods. A deterioration of water quality in the Setiu Wetland was observed in areas near agriculture and aquaculture activities. This was expected to be as a result of the use of fertilisers, waste from fish farm food and the waste products of aquaculture. The parameters measured showed lower mean values of surface salinity, temperature, DO, pH and TSS during the wet season relative to the dry season. In contrast, the concentration of BOD was high during the wet season and lowest in the dry season. Results obtained from this study clearly showed the surface physical water quality for the Setiu Wetland was highly influenced by anthropogenic activities and seasonal variation. Therefore, both factors must be considered to move towards proper management of this wetland.
The growth form and condition of the tiger grouper × giant grouper (TGGG) hybrid were evaluated under four temperatures (22°C, 26°C, 30°C, and 34°C) and two diets (pellet and shrimp). The growth form of fish was determined over a 30 day experimental period using the length–weight relationship (LWR) method. The TGGG hybrid grouper exhibited a negative allometric growth (b < 3) at all temperatures and diets at the beginning of the experiment (0 day), which indicated that fish would become lighter as they increased in size. Conversely, toward the end of the experiment (30 d), the TGGG hybrid grouper showed a negative allometric growth (b < 3) at 22°C and 34°C on both pellet and shrimp diet as well as demonstrated an isometric growth (b = 3) at 26°C fed on both diet and 30°C on pellet diet only, which indicated that the shape of the fish would not change with increasing weight and length. However, a positive allometric growth (b > 3) was observed at 30°C when the fish were fed on shrimp diet, which indicated that fish weight would increase with increasing length and size. The condition factors (K and Kn) in the initial (0 d) and final (30 d) measurements were greater than 1, thereby indicating the wellbeing of the TGGG hybrid grouper, except for those fish fed on both pellet and shrimp diet under 22°C and 34°C. Therefore, diet did not have a significant effect (p > 0.05) on the growth and condition of TGGG hybrid grouper, whereas temperature significantly influenced the growth and condition of the fish. All in all, grouper farmers can culture TGGG hybrid grouper between 26°C and 30°C, whereas the best growth and condition could be observed by culturing the fish at 30°C fed on shrimp.
Oil palms (OP) in Sabah, Malaysia were studied to explore the relationship between canopy size and aboveground biomass (AGB). Four available allometric equations were used to calculate the dry AGB. Pearson’s correlation analysis was performed between crown diameter (CD) and crown area (CA) towards the variables of AGB, height and dbh. In this analysis, the transformation to natural log of variable resulted in better coefficient compared to the original one. The mean of various variables such as height (stem, total and height difference), biomass (crown, trunk and total), dbh (inner and outer) and number of petiole leaf were calculated based on 32 independent sample plots (N = 222 palms) across various age stages from 2 to 24 years. These variables were regressed against CD and age. AGB versus CD was a nonlinear with R2 ranging from 0.950 to 0.975. Random modelling and cross validation between AGB and CD was applied at the ratio of 70:30. Upon checking, the best estimation was achieved by using the allometric equation based on total height due to the lowest relative root mean square error (RMSE) (18.5%) and the least fluctuation between predicted and actual AGB. The other three models had relative RMSE that ranged between 23.9 and 68.8%. This study shows that AGB can be estimated using CD of OP consistently at all ages.
Pueraria javanica Benth. is one of the most common leguminous cover crop used in oil palm plantations of Malaysia. A study was conducted to determine the allelopathic potential of this plant, using the aqueous extract, sandwich and dish-pack methods, with the seed and leaf (of P. javanica) on three bioassay weed species namely, Eleusine indica, Cyperus iria and Chromolaena odorata. The aqueous extract experiment was conducted using 0 (control), 16.7, 33.3 and 66.7 g/L of the aqueous leaf and seed extracts while the sandwich method was carried out using 10 and 50 mg of each of the donour plant parts. Meanwhile, the dish-pack method was done using four different distances (41, 58, 82 and 92 mm) away from the donour plant. All experiments were replicated five times using the complete randomized design (CRD). The leaf extract exhibited 100% reduction on the fresh weight of E. indica and C. odorata while the seed extract exhibited 100% reduction on all parameters for E. indica and on the fresh weight of C. iria at 66.7 g/L concentration. The seed and leaf at 10 and 50 mg significantly reduced the radicle length of all the bioassay species. The dish-pack experiment also showed a reduction effect on the germination percentage and seedling growth parameters of all the bioassay species. However, the reduction effect was not totally in accordance to the distance from the donor species. More studies need to be conducted to determine the type of reduction mechanism involved in the allelopathic activity especially with respect to molecular and biochemical aspects.
Torch ginger (Etlingera elatior) is a herbaceous clumping plant. It is a multifunctional crop that has been used for culinary, medicinal, antibacterial agent, ornamental and floral arrangement purpose. However, from the literature, no work has been carried out to study its growth and development morphological characteristics. It is important to understand the developmental morphology of the torch ginger plant for research purpose, commercial usage and apply proper production practices by growers for higher yields and profits. Therefore, the aim of this study was to determine the time course of morphological changes during the growth and development of torch ginger. Results showed that it took 155 days from leafy shoot emerging from rhizome until senescence of inflorescence. The growth and development of torch ginger plant were divided into vegetative and reproductive phases. The vegetative phase mainly involved the growth activities of leafy shoot. The transition of vegetative to reproductive phase happened when the inflorescence shoot emerged from the rhizome. In the reproductive phase, the growth and development of the inflorescence were categorized into four phenological stages which were peduncle elongation, inflorescence emergence, flowering and senescence. The growth pattern of the leafy shoot and inflorescence demonstrated a monocarpic plant growth habit with the remobilization of photoassimilates from senescing plant parts to developing true flowers that caused whole-plant senescence. Further research is needed to study the mechanisms that regulate flowering and senescence in torch ginger plant.
Among abiotic stresses, salinity is the main abiotic stress limiting crop growth and yield worldwide. Improving agri-food production in salt-prone areas is the key to meet the increasing food demands in near future. A greenhouse experiment was conducted to investigate the effect of different soil conditioners, gypsum (GYP), citric acid (CA), ethylene diamine tetraacetic acid (EDTA) and polyvinyl alcohol (PVA), on growth and yield of wheat (Triticum aestivum L.) grown in salinesodic soil. Gypsum was applied at a rate of 100% soil gypsum requirement while other amendments were applied each at a rate of 5 g kg-1 of soil. The results showed that EDTA treatment increased pH and electrical conductivity (ECe) of soil while pH significantly decreased when treated with citric acid. Soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) decreased in all treatments following the order: CT > PVA > EDTA > CA > GYP. Addition of CA positively affected growth parameters as compared to other soil conditioners including plant height, number of tillers per plant, number of spikes per plant, plant dry weight and grain yield while EDTA negatively affected these parameters. Addition of CA also significantly increased photosynthetic rate, stomatal conductance, transpiration rate and chlorophyll contents while EDTA decreased these parameters. We conclude that increase in plant growth and yield with CA might be due to the effect of CA on soil properties which positively affected plant physiological parameters.
Induced mutagenesis using gamma ray has been proven applicable to improve varieties of many genotypes of crop species. The effects of 60Co gamma ray dosage on growth and callus induction of nucellus segments of Citrus reticulata cv. limau madu were investigated. The nucelli were exposed to gamma rays at doses of 10, 20, 40, 60, 80, 100 and 120 Gy, followed by embryogenic callus (EC) induction on Murashige and Skoog medium supplemented with 500 mg L-1 malt extract (ME), 146 mM sucrose, 0.8% (w/v) agar and 13.3 µM benzyl amino purine (BAP). Survival, callus type and colour, degree of callus formation, time of callus formation and total fresh weight of callus varied among the treatments. All untreated explants (controls) survived and produced friable EC in the 2nd or 3rd week of culture, whereas the irradiated nucelli showed delayed response. EC derived from the nucelli irradiated at 10, 20 and 40 Gy appeared in the 3rd week of culture, whereas EC from the 60 and 80 Gy doses appeared in the 4th week. Exposure to higher doses (100 and 120 Gy) completely suppressed callus formation. After 35 days of culture, an average of 697 and 660 mg of EC were harvested from the nucelli irradiated at 10 and 20 Gy, respectively, which was higher than those at 40 Gy (441 mg), 60 Gy (436 mg) and 80 Gy (380 mg). EC were initiated and proliferated and subsequently regenerated into plantlets. DNA of plantlets from the 20, 40 and 60 Gy exposure were individually amplified and compared to the control for early detection of mutagenesis using retrotransposon, inter simple sequence repeat and markers related to seedlessness. No variants were observed from the plantlets produced.
Aromatic grass species Cymbopogon citratus (‘serai biasa/serai makan’) and C. nardus (‘serai wangi’) can be commonly found throughout Peninsular Malaysia. C. citratus is used in traditional Malaysian cooking and brewed as tea, while C. nardus is used in traditional medicine for external application and in insect repellents. Due to similar morphologies, it can be difficult to tell apart the species at times. Based on DNA sequence alignments of three chloroplast DNA intergenic spacer regions, namely atpB-rbcL, trnH-psbA and trnL-trnF, we designed species-specific primers for multiplex PCR assays for rapid species discrimination between C. citratus and C. nardus. The method described here makes use of simple molecular techniques that are time- and cost-effective for large-scale application. Such an assay will be useful for the quality assurance of food and medicinal products.
A local Malnutrition Risk Screening Tool-Hospital (MRST-H) has been developed to identify the risk of malnutrition among hospitalized geriatric patients in Malaysia. The aims of this multicenter study were to evaluate the criterion validity of the MRST-H against the reference standard Subjective Global Assessment (SGA) and revise its scoring criteria among Malaysian geriatric patients. A cross-sectional study was conducted among 542 geriatric patients at eight general hospitals in Peninsular Malaysia from January 2011 to February 2013. The Malay version MRST-H and SGA were administered to all participants through face-to-face interviews. Sensitivity and specificity of MRST-H were established using the Receiver Operating Characteristic (ROC) curves and the optimal cut-off scores were determined. The MRST-H had area under the ROC curve (AUC) values of 0.84 and 0.88 when validated against the SGA-determined malnutrition (SGA B+C) and severe malnutrition (SGA C) status. These high AUC values indicated that the MRST-H has very good overall diagnostic accuracy. However, the original cut-off score of five points for MRST-H has undesirable sensitivity in identifying the malnutrition (sensitivity = 0.12) and severely malnutrition (sensitivity = 0.35) status. The optimal cut-off score of MRST-H in identifying malnourished and severely malnourished participants were both established at the cut-off score of two points. The sensitivity of MRST-H increased substantially at this point without compromising its specificity. Therefore, the established cut-off score of two points with optimal sensitivity and specificity was selected to replace to original cut-off score for screening of risk of malnutrition among hospitalized geriatric patients.
MeSH terms: Cross-Sectional Studies; Hospitals, General; Humans; Malaysia; Mass Screening; Risk; ROC Curve; Sensitivity and Specificity; Area Under Curve; Malnutrition
PLLA merupakan biodegrasi polimer yang mempunyai aplikasi yang meluas dalam pelbagai bidang industri dan perubatan. Dalam kajian ini, PLLA telah dicampurkan dengan triali isosianurat (TIAC) antara 1 hingga 6 v/v% bagi melihat perubahan sifat tegangan dan terikan filem PLLA. TIAC biasanya digunakan sebagai agen taut silang dan keplastikan untuk mengubah sifat polimer. Campuran PLLA-TIAC telah diiradiasi pada 10 kGy di bawah alur elektron (EB) dan gamma (γ). Keputusan menunjukkan kekuatan tegangan (tegasan maksimum) menurun dengan peningkatan kandungan TIAC di dalam PLLA tetapi meningkat sedikit pada 4 v/v% TIAC bagi PLLA iradiasi dan tanpa iradiasi. Manakala nilai terikan didapati meningkat pada TIAC 2 v/v% dan menurun apabila TIAC ditambah melebihi 2% v/v% terutamanya bagi PLLA yang diiradiasikan. Daripada keputusan DSC terdapat perubahan pada suhu peralihan kaca, Tg, suhu penghabluran sejuk, Tc, entalpi penghabluran sejuk, Hc dan suhu peleburan, Tm menunjukkan berlaku perubahan pergerakan rantaian PLLA dan fasa penghabluran dengan kehadiran TIAC dan sinaran mengion di dalam PLLA. Perubahan pada puncak penyerapan spektra infra merah jelmaan fourier (FTIR) menunjukkan berlaku penggantian atau kemasukkan molekul TIAC ke dalam rantian PLLA.
Protein antigen-i parasit ikan C. irritans berpotensi tinggi digunakan sebagai calon dalam pembangunan vaksin komersial terhadap C. irritans. Walau bagaimanapun, kewujudan variasi pada antigen-i serotip C. irritans yang berbeza mempengaruhi tahap perlindungan yang bakal diberikan terhadap varians C. irritans yang berbeza apabila antigen-i digunakan sebagai vaksin. Kajian ini dijalankan untuk membandingkan jujukan pelbagai antigen-i pencilan C. irritans di Malaysia berbanding antigen-i pencilan C. irritans yang pernah dilaporkan. Perbandingan filogenetik dijalankan untuk meramalkan potensi protein tersebut dalam usaha membangunkan calon serodiagnostik dan pemvaksinan terhadap pencilan C. irritans yang berlainan. Penjajaran jujukan berbilang bagi jujukan asid amino antigen-i dilakukan dengan perisian CLUSTALX dan analisis filogenetik antigen-i dilakukan menggunakan kaedah parsimoni maksimum (MP) dan kaedah Bayes. Sembilan transkrip unik (TU) C. irritans yang mempunyai padanan signifikan dengan antigen-i di pangkalan data protein NCBI didapati mempunyai peratus kesamaan antara 41% hingga 71%. Kedua-dua pohon MP dan Bayesian yang dijana menunjukkan varians antigen-i cn56 and cn57 terkelompok bersama dalam satu kumpulan manakala varians antigen-i yang lain terbahagi kepada dua kumpulan berasingan dan pengkelompokan ini disokong oleh kehadiran asid amino yang terpulihara dalam kumpulan masing-masing. Kajian lanjutan boleh dilakukan untuk mengenal pasti varians antigen-i yang sesuai sebagai calon serodiagnosis dan juga dapat memberi perlindungan silang terhadap pelbagai pencilan C. irritans di serata dunia.
MeSH terms: Bayes Theorem; Blood Group Antigens; Malaysia; Protein C; Serologic Tests
Penemuan sasaran dadah antikoksidia baharu merupakan antara usaha yang diperlukan untuk mengawal penyakit koksidiosis ayam yang disebabkan oleh spesies Eimeria. Dalam kajian ini, serpihan yang mengekodkan glikogen sintase kinase-3 (GSK-3) Eimeria tenella putatif telah diamplifikasi daripada cDNA E. tenella. Hasil pemadanan homologi menunjukkan jujukan GSK-3 E. tenella yang terjana mempunyai padanan yang tinggi dengan jujukan GSK-3 organisma lain. Domain terpulihara GSK-3 dan residu yang penting untuk aktiviti GSK-3 juga diramalkan hadir dalam jujukan GSK-3 E. tenella. Analisis struktur sekunder serta pemodelan homologi menunjukkan pembahagian struktur protein kepada domain bebenang beta pada hujung N dan domain heliks alfa pada hujung C, yang merupakan ciri enzim GSK-3. Kesemua hasil analisis ini menyokong bahawa jujukan yang dikaji mengekodkan protein GSK-3 dalam E. tenella. Walaupun darjah keterpuliharaan adalah tinggi, namun terdapat perbezaan yang bermakna diperhatikan antara GSK-3 E. tenella dan perumahnya. Residu Ser 9 yang dilaporkan penting untuk perencatan aktiviti GSK-3 didapati tidak terpulihara dalam GSK-3 E. tenella. Memandangkan Ser 9 merupakan tapak pemfosfatan bagi GSK-3β dalam haiwan vertebrata, ketiadaan residu ini dalam jujukan GSK-3 E. tenella mencadangkan bahawa pengawalaturan GSK-3 E. tenella melibatkan tapak pemfosfatan dan mekanisme yang berbeza. Tambahan pula, hasil analisis filogenetik menunjukkan bahawa GSK-3 E. tenella mempunyai pertalian yang rapat dengan protein GSK-3 tumbuh-tumbuhan. Analisis superposisi GSK-3 E. tenella dengan GSK-3β Homo sapiens pula menunjukkan bahawa perencat GSK-3 mampu berinteraksi dengan protein GSK-3 E. tenella. Keputusan kajian ini mencadangkan bahawa GSK-3 E. tenella mempunyai potensi untuk diperkembangkan sebagai sasaran dadah antikoksidia.
Penyelidikan dijalankan bagi menilai kesan penggunaan filem boleh makan dan filem polietilena (PE) sebagai bahan
penyalut untuk ubi keledek (Ipomoea batatas) goreng. Kepingan ubi keledek disalut dengan lapisan filem boleh makan
yang terdiri daripada 0.045 g/mL selulosa metil (MC), 0.045 g/mL selulosa hidroksipropil metil (HPMC) dan 0.16 g/mL
jagung zein (CZ) sebelum digoreng di dalam minyak sawit pada suhu 170-180°C selama 3 min. Manakala ubi keledek juga
disalut dengan filem tak boleh makan iaitu polietilena (PE) (nisbah PE kepada minyak 1:100 g/g) sebagai perbandingan.
Ubi goreng tanpa salutan filem digunakan sebagai sampel kawalan. Ciri fizikokimia ubi goreng bersalut dianalisa.
Keputusan menunjukkan semua filem melekat pada permukaan ubi setelah digoreng. Penggunaan filem CZ menjadikan
permukaan filem licin dan wujud tanpa sebarang retakan. Filem MC pula memberi lapisan permukaan yang tidak rata
tetapi menyaluti permukaan sampel dengan sekata. Tambahan pula, ubi bersalut MC menunjukkan peratusan lemak paling
sedikit (13.6%) selain kandungan kelembapan yang paling tinggi (17.5%) berbanding sampel lain. Secara keseluruhan,
MC merupakan filem yang terbaik untuk mengekalkan kelembapan bahan goreng dan mengurangkan penyerapan lemak.
Ketidaksuburan idiopati dalam kalangan lelaki telah dikaitkan dengan kesan psikostres. Walaupun begitu, hubungan langsung antara psikostres dan ketaknormalan kualiti semen masih samar. Maka, kajian ini dijalankan untuk menentukan kesan psikostres terhadap kualiti semen terutama kesan berdasarkan residu sitoplasma dan kerosakan DNA sperma. Dalam kajian ini, responden lelaki berumur antara 25-45 tahun dipilih secara rawak dalam kalangan pesakit yang mendapatkan rawatan di Pusat Kesuburan Lembaga Penduduk dan Pembangunan Keluarga Negara (LPPKN). Seramai 331 responden akhirnya telah dipilih daripada 628 responden selepas mengambil kira faktor penolakan. Setiap responden perlu menjawab borang keizinan dan soal selidik GHQ-12 bagi penentuan tahap stres sebelum pengambilan sampel semen mengikut piawaian WHO (2010). Tahap stres diukur berdasarkan keadaan semasa responden dalam tempoh 3-4 minggu sebelum kajian. Analisis semen, pewarnaan papanicolau dan asai komet neutral digunakan untuk penentuan kualiti semen dan kerosakan DNA sperma. Keputusan menunjukkan tidak terdapat hubungan yang signifikan antara psikostres dan ketaknormalan residu sitoplasma (U=895.50, p=0.08). Namun begitu, psikostres memberi kesan kepada peratus morfologi normal (U=6317.50, p<0.05) dan kerosakan DNA sperma (U=1047.00, p<0.01). Kesimpulannya, psikostres kronik boleh menjejaskan kualiti semen dan kerosakan DNA sperma serta mempengaruhi kesuburan.
MeSH terms: Body Fluids; DNA; Male; Semen; Spermatozoa; World Health Organization; Tetrahydroisoquinolines
Penyelidikan ini mengkaji tingkah laku cadmium (Cd) melalui tanah baki granit yang dipadatkan. Sampel tanah baki granit telah diambil di kawasan Broga, Selangor dan dikaji menggunakan tiga kaedah ujian utama iaitu; ujian fizikal (taburan saiz butiran, had-had Atterberg, graviti tentu, pemadatan dan kebolehtelapan), ujian kimia (pH, bahan organik, luas permukaan spesifik (SSA) dan kadar pertukaran kation (CEC) serta ujian mini kolum turasan. Melalui ujian kolum turasan, konsep kebolehtelapan turus menurun digunakan yang melibatkan tiga faktor iaitu halaju/daya-G, ketebalan sampel dan jenis larutan yang digunakan. Graf lengkung bulus menunjukkan kepekatan Cd dalam tanah baki granit semakin meningkat dengan peningkatan halaju. Urutan kapasiti penjerapan semakin meningkat terhadap kadar putaran alat emparan/daya tarikan graviti (G); 230G>520G>920G>1440G. Pergerakan logam berat melalui tanah baki juga meningkat dengan peningkatan halaju/daya-G. Lengkung bulus juga menunjukkan pergerakan Cd secara songsang dengan ketebalan lapisan tanah di dalam kolum. Masa penembusan bagi ketebalan 20 mm juga lebih lama berbanding ketebalan 15 dan 10 mm. Manakala jumlah Cd yang terjerap oleh tanah baki granit dalam larutan campuran adalah rendah berbanding larutan tunggal (masa yang singkat untuk menembusi lengkung bulus). Tanah baki granit juga mempunyai kapasiti penampanan yang rendah (pHfinal = 4 - 7). Kajian ini menunjukkan bahawa pencirian fiziko-kimia dan sifat penjerapan tanah dengan menggunakan ujian mini kolum turasan mempunyai kaitan yang kuat untuk mencirikan tanah baki granit untuk dijadikan pelapik lempung tereka bentuk.
Penyelidikan ini dijalankan untuk mengesan perubahan guna tanah dan litupan bumi (LULC) di daerah Gombak, Selangor melalui pendekatan penderiaan jauh. Perbandingan data siri masa antara tahun 1989-1999, 1999-2014 dan 1989-2014 telah dilakukan bagi melihat perubahan LULC. Data yang digunakan ialah imej satelit Landsat (TM dan OLI-TIRS) dan Peta Guna Tanah Selangor 1990 terbitan Jabatan Pertanian Malaysia. Guna tanah dibahagikan kepada lima kategori utama, iaitu badan air, hutan, getah, kelapa sawit dan tepu bina. Penilaian ketepatan antara LULC hasil daripada pengelasan imej penderiaan jauh dengan peta guna tanah 1990 dikira berdasarkan Koeffisien Kappa menerusi teknik ralat matrik dan nilai ketepatan adalah 74.5%. Analisis GIS ke atas imej pasca klasifikasi menunjukkan perubahan sebenar LULC bagi tahun perbandingan 1989-1999 ialah 13.69%, seterusnya meningkat kepada 18.65% bagi tahun 1999-2014 dan terus meningkat bagi tahun bandingan 1989-2014, iaitu 24.25%. Guna tanah getah mengalami perubahan sebenar paling tinggi berbanding guna tanah lain dengan -47.73% bagi tahun bandingan 1989-1999, manakala tahun bandingan 1999-2014 menunjukkan guna tanah tepu bina mengalami perubahan paling tinggi dengan +44.53% dan pada tahun 1989-2014 pula guna tanah getah mengalami perubahan sebenar paling tinggi sebanyak -34.6%. Kemerosotan guna tanah getah sangat ketara di daerah Gombak dan mempunyai kaitan dengan peningkatan kawasan guna tanah tepu bina. Secara umumnya, pola perubahan guna tanah dan litupan bumi di daerah Gombak selari dengan perkembangan dan pelaksanaan pembangunan semasa oleh pihak berkuasa.
MeSH terms: Acrylates; Malaysia; Methylglycosides; Propylene Glycols; Geographic Information Systems
Poli(etilena glikol) bermetoksi-ko-poli(β-amino ester) (MPEG-PbAE) telah disintesis dengan menggunakan poli(etilena glikol) bermetoksi yang mempunyai kumpulan hujung berfungsi akrilat (MPEG-ac), 1,6-heksanadiol diakrilat, heksilamina linear (A) dan heksilamina siklik (B) sebagai bahan reaktan. Kopolimer MPEG-PbAE A dan B dijangka akan membentuk misel dengan MPEG berfungsi sebagai bahagian luar yang hidrofilik dan PbAE yang mempunyai kumpulan heksil berfungsi sebagai bahagian dalam yang hidrofobik. MPEG-ac selepas diubah suai dan kopolimer MPEG-PbAE A dan B selepas disintesis telah dicirikan. Spektroskopi inframerah transformasi Fourier (FT-IR) dan spektroskopi resonans magnet nukleus jenis proton (1H-NMR) telah mengesahkan pengubahsuaian kumpulan hujung hidroksil di MPEG kepada kumpulan hujung akrilat. Didapati kopolimer A adalah lebih sesuai digunakan sebagai pembawa ubat berdasarkan perbandingan antara kopolimer A daripada heksilamina linear dan kopolimer B daripada heksilamina siklik. Kromatografi penelapan gel (GPC) menunjukkan bahawa nombor-purata berat molekul, Mn kopolimer A adalah 11216 dengan indeks kepoliserakan (PDI) 1.1925. Kepekatan misel kritikal (CMC) kopolimer A dalam larutan akueus pH7.4 adalah 84.6 mg/L. Purata saiz misel yang diperoleh daripada analisis penyerakan cahaya dinamik (DLS) adalah 26.25±0.149 nm.
Pemetaan dengan menggunakan kaedah pantulan bunyi telah menemukan satu permukaan lantai laut yang unik dengan ciri morfologi yang pelbagai bermula dari kawasan pesisir laut cetek Delta Sungai Kelantan hingga ke pelantar benua Laut China Selatan. Morfologi lantai laut menunjukkan peningkatan sehingga 38 m ke arah pelantar benua. Empat rentasan lantai laut menunjukkan kemiringan yang kurang daripada 1° dengan nilai antara 0.05° dan 0.57°, menunjukkan penurunan yang sekata sehingga pelantar benua. Suatu tindakan mekanisme pencetus telah menyebabkan fenomena lompatan hidraulik berlaku dan membentuk ketakseragaman morfologi lantai laut dan menghasilkan satu lohong hitam sedalam 26 m dari lantai laut sekitarnya dan pembentukan satu beting pasir yang mempunyai ketinggian sehingga 8 m dari permukaan laut dengan keluasan sekitar 9 km2. Penentuan fenomena yang terhasil dikukuhkan dengan penemuan empat kontur tertutup yang dikenal pasti sebagai kaviti kecil di tiga kawasan yang berbeza. Kesemua fitur dan perubahan morfologi yang berlaku di kawasan lantai laut ini terhasil daripada jatuhan air dari mulut Sungai Kelantan yang berterusan dengan kadar kelajuan berbeza bergantung kepada pelepasan air dan musim monsun.
Ancaman biokakisan akibat aktiviti bakteria penurun sulfat (SRB) pada saluran paip keluli karbon dalam industri petroleum boleh menjejaskan kelancaran aliran pengangkutan minyak mentah dan meningkatkan kos pengoperasian. Usaha bagi melindungi keluli karbon serta pengawalan SRB masih memerlukan kajian yang berterusan. Dalam kajian ini, keberkesanan tetrametilamonium bromida (TMB), karboksimetil trimetilamonium (BTN) dan benzalkonium klorida (BKC) bagi melindungi keluli karbon di dalam persekitaran yang mengandungi SRB diuji melalui kaedah pengutuban elektrokimia dinamik (PED) dan morfologi keluli karbon dianalisis menggunakan mikroskop elektron imbasan. Analisis PED mendapati penggunaan TMB, BTN dan BKC masing-masing berupaya mengurangkan kadar kakisan sehingga 0.13, 0.56 dan 0.17 mm/thn berbanding 8.91 mm/thn pada larutan kawalan yang mengandungi SRB. Morfologi permukaan biofilem mengesahkan kadar pertumbuhan SRB serta hasilan metabolisme bakteria ini turut mengalami penyusutan. Kajian ini menunjukkan dua mekanisme kawalan kakisan didapati berlaku iaitu mekanisme perencatan kakisan melalui penjerapan sebatian amonium kuaterner pada permukaan keluli karbon serta berlakunya proses tindak balas mitigasi sebatian ini dengan bakteria SRB. Kesimpulannya, TMB, BTN dan BKC didapati berupaya melindungi keluli karbon daripada mengalami kakisan akibat aktiviti SRB.