Temperature Stress on Physiological and Morphological Traits in Rhizophora apiculata

الاحتباس الحراري له تأثيرات كبيرة على النظم البيئية الحيوية، والتي تسببت أيضًا في ارتفاع درجات الحرارة وثاني أكسيد الكربون الذي يتبعه تغيرات في العوامل اللاأحيائية المختلفة، والتي تشكل تهديدات لبيئة غابات المنغروف. تم إجراء هذا البحث لفحص الخصائص الفسيولوجية والمورفولوجية لأشجار القرم Rhizophora apiculata فيما يتعلق بارتفاع درجة حرارة الهواء لأنواع الأشجار المتنوعة التي تستجيب لتغير المناخ. حيث تم زراعة الشتلات لمدة ثلاثة أشهر في غرف نمو منظمة بثلاث درجات حرارة متفاوتة 38 درجة مئوية، 21 درجة مئوية تحت ثاني أكسيد الكربون عند 450 جزء في المليون، والمنطقة المحيط بتركيز ثاني أكسيد الكربون 450 ± 20 جزء في المليون تحت متوسط درجة الحرارة عند 28 درجة مئوية كشرط تحكم. تمت معالجة النباتات كل 48 ساعة بـ 3 لترات من الماء المالح بتركيز 28 جزء من المليون. بعد أسبوعين عند درجة حرارة عالية، أظهرت أشجار المانغروف نتائج إيجابية لجميع المعلمات. أدت التغيرات في درجات الحرارة إلى اختلافات كبيرة، مثلاً سلبية لزيادة درجة الحرارة مما أدى إلى تلف شديد للعديد من العينات بينما كانت إيجابية لانخفاض درجة الحرارة مما أدى إلى نمو بطيء. أظهرت النتائج الفسيولوجية انخفاضًا في معدلات التمثيل الضوئي مقارنةً بالعينات الخاضعة للرقابة. تشير هذه النتائج إلى أن مستويات القدرة على التمثيل الضوئي المنخفضة يمكن أن تكون قد حدثت بسبب انخفاض آلية تفاعل تثبيت ثاني أكسيد الكربون، ومواد أصباغ التمثيل الضوئي، والتباين بين معدل التنفس والتمثيل الضوئي.Global warming has had considerable effects on vital ecosystems, which has also been caused by increased temperatures and CO2 that follow changes in different abiotic factors, which poses threats to mangrove forests environment. This research was conducted to examine the physiological and morphological characteristics of the Rhizophora apiculata mangrove regarding higher air temperature for the variety of tree species that respond to climate change. Seedlings were cultivated for three months in regulated growth chambers with three varying temperatures of 38°C, 21°C under CO2 at 450 ppm, and ambient CO2 concentration i.e., 450 ± 20 ppm under average temperature at 28°C as the control condition. The plants were treated every 48 hours with 3 L of saline water of 28 ppt. After two weeks at high temperature, the mangrove showed positive results for all parameters. The temperature variations resulted in major variations, such as negative for increased temperature resulting in extreme damage to many samples while positive for decreased temperature resulting in slow development. The physiological results show decreased photosynthesis rates compared to controlled samples. These findings indicate that low photosynthetic capability levels could have occurred due to reduced CO2 fixative reaction mechanism, photosynthetic pigment material, and the discrepancy between respiratory and photosynthesis rate

Stocking and species composition of second growth forests in Peninsular Malaysia.

Management of the production forests in Malaysia is currently undergoing a major change as the total extent of undisturbed forest being harvested is diminishing. Currently most of the harvesting operations are being conducted in second growth (rotation) forests and in the near future all production forest will solely consist of only logged forests. This is expected to result in a significant reduction of the supply of raw materials to the industry because second growth forest stands are generally poorer and not so well-stocked with quality timber species. According to the forest management systems applied to these forests, namely the Selective Management System (SMS) and the Malayan Uniform System (MUS), the residual forests should be able to recover in the specified rotation cycle and there should be sufficient quality crop for the second and subsequent harvests. To understand the situation, a study was carried to assess the stocking and species composition of second rotation forests in two production forests located in Tekam Forests Reserve, Pahang and Cherul Forest Reserve, Terengganu. The study results indicated that the second rotation forests are not as productive as predicted but still able to produce an economic harvest in terms of total timber yield within the specified rotation cycle. However, based on inventory projections of existing stocks, it was found that in general the forests have not fully recovered in terms of stocking of commercial species. Species composition has been altered favouring higher dominance of non-dipterocarp species. Some of the major factors that could have contributed to this phenomenon are slower recovery of the forest after the first cut, higher mortality due to logging damage, and implementation of cutting limit prescriptions that favour high removal of dipterocarps as they are dominant in the upper diameter classes. It must be noted that the second growth forest assessed were those that were more than 20 years old. Currently, forest management practices have improved significantly and thus the recent second growth forests are expected to be in a much better condition. The information generated from this project on the status of the stocking and species composition of second growth forest will be essential for improving planning and management of the resource with the aim of enhancing future productivity

The evaluation of shear deformation for contact analysis with large displacement

A common problem encountered in the study of contact problem is the failure to obtain stable and accurate convergence result when the contact node is close to the element edge, which is referred as "critical area". In previous studies, the modification of the element force equation to apply it to a node-element contact problem using the Euler-Bernoulli beam theory [1]. A simple single-element consists two edges and a contact point was used to simulate contact phenomenon of a plane frame. The modification was proven to be effective by the convergeability of the unbalanced force at the tip of element edge, which enabled the contact node to "pass-through", resulting in precise results. However, in another recent study, we discover that, if shear deformation based on Timoshenko beam theory is taken into consideration, a basic simply supported beam coordinate afforded a much simpler and more efficient technique for avoiding the divergence of the unbalanced force in the "critical area". Using our unique and robust Tangent Stiffness Method, the improved equation can be used to overcome any geometrically nonlinear analyses, including those involving extremely large displacements

Characterisation of Aquilaria hirta based on morphology evaluation and volatile chemical compound

Aquilaria hirta is one of the agarwood tree species in Malaysia that produces a unique resinous wood and essential oil used in perfumery, medicinal, cosmetic and religious ceremonies. Currently, it has been listed as vulnerable (VU) and threatenad species in the IUCN Red List. This study aims to characterise the morphology of A. hirta via scanning electron microscopic analysis, and to identify the volatile chemical compounds of the wood and its essential oil using gas chromatography-flame ionisation detector and gas chromatography-mass spectrometry analyses. Aquilaria hirta was identified by the presence of hirsute on the abaxial side of leaves and midrib. The field emission scanning electron microscope analysis showed plant vessel pits can be seen in the healthy wood images compared with resinous wood images due to presence of resin and microorganisms. A total of 19 compounds were identified in resinous A. hirta wood consisting of 5.97% sesquiterpenes and 20.32% oxygenated sesquiterpenes. The major compounds are kessane, γ-cadinene, α-caryophyllene, β-caryophylene and caryophyllene oxide. There were 35 compounds found in A. hirta oil comprising 0.45% monoterpenes, 23.51% sesquiterpenes and 19.53% oxygenated sesquiterpenes. Major compounds detected were γ-cadinene, nor-ketoagarofuran, allo-aromadendrene, γ-gurjunene and β-gurjunene. This study provides a reference for the identification of A. hirta species based on morphology evaluation and volatile chemical compounds profile of the essential oil and wood

Characterization of fabricated optical fiber for food irradiation dosimetry

Food irradiation is a process carried out in order to improve hygienic quality and germination control, retarding sprouting, also enhancing physical attributes of the food product. In order to provide for food safety, radiation dosimetry in irradiated foods is required. In present studies use is made of germanium doped (Ge-doped) optical fibres of various form and dimensions. The fibres are irradiated using a gamma source irradiator (Gamma Cell 220 Excel), with doses from 1 kGy up to 10 kGy. For the particular Ge-doped optical fibres, investigation has been made of linearity with dose, reproducibility, and fading, intercomparisons being made. The fibres all exhibit TL yields that are linear with dose from 1 kGy up to 10 kGy, exceeding the dose range of all commercial high dose dosimeters used in the food irradiation industry. In respect of the flat fibre dosimeters, the mean reproducibility was found to be within 0.53% to 4.96%, also offering low signal loss (fading), within 13.41% (for fibres of cross-sectional dimensions 60 x 180 μm) to 20.12% (for fibres of cross-sectional dimensions 200 x 750μm), after 22 days of storage

Dimensional Accuracy And Surface Roughness Of Part Features Manufactured By Open Source 3D Printer

This paper investigates the effectiveness and the accuracy of open source 3D printer of Mendel Max and Kossel Mini which the additive manufacturing technique of Fused Filament Fabrication (FFF) was implemented.A benchmark of the 3D printer test model was designed based on critical features of AM process i.e. hemispheres, cube,cylindersand slots.The benchmark was produced by both machines using variation FFF parameters of layer height and infill density.In addition,the material of FFF was varied between PLA and ABS for each test.The dimensional accuracy of the part features were measured by the nominal dimension of the part using Profile Projector DS600.In addition,TR200 roughness tester was used to measure the surface roughness.The result shows that for dimensional accuracy results,Mendel Max machine has a lower deviation result compared to Kossel machine. Furthermore,PLA filament gives better result compare to ABS filament in term of surface quality finishing for both machines.The result shows that for both 3D printer machines,the quality and accuracy of the part features are better when the layer thickness is 0.178 and 20% of infill density

Physico-chemical properties, carbon dioxide emissions and carbon stock in peat soil used for turmeric cultivation at Kuala Langat Selatan, Selangor, Malaysia

Measurement of carbon dioxide emissions in peat soil was done in a turmeric cultivation area on August 2009 and January 2010 at Kampung Tumbuk Darat, Kuala Langat Selatan, Selangor. The objective of this research was to determine the quantity of CO2 emissions from peat soil as well as the carbon stock that is stored in the peat soil. Other parameters that were investigated included soil pH, soil temperature, soil bulk density, soil organic carbon, soil fresh water content, organic matter, humic acid and fulvic acid content. A total of 30 carbon dioxide emission sampling points in rectangular grid arrangement was prepared in a survey plot of 1 hectare. The survey plot was further divided into sub-plots of size 20 m x 25 m. Soil samples were randomly taken at the depth of 0-15 cm to 50-65 cm using an auger. Sampling of CO2 emissions was done using the static alkali absorption method (Kirita Method). The organic carbon content was determined using the Walkley-Black method, while the humic and fulvic acid content was determined using the basic molecule isolation method. Other soil properties were determined using standard methods of determination. The surface temperature of peat soil was between 28oC and 30oC. The bulk density of the area was as low as 0.20 g cm-3. On the other hand, the soil fresh water content, soil organic matter, and peat soil humic acid was very high. The minimum quantity of CO2 emissions in the peat soil on August 2009 and January 2010 was 40.92±21.62 t CO2 ha-1 yr -1 (467.10±246.86 mg CO2 m-2 hr-1) and 41.51±13.41 t CO2 ha-1 yr -1 (473.86±153.12 mg CO2 m-2 hr -1), respectively. Carbon stock for the month of August 2009 and January 2010, respectively was 297.70 t ha-1 and 456.60 t ha-1. T test showed that there were significant (p<0.05) differences in many of the soil parameters such as the pH, water content and organic carbon. Correlation analysis showed that CO2 is influenced by the organic matter, water content and temperature

Distribution, biomass and dynamics of Burseraceae trees in the 50-HA plot at Pasoh Forest Reserve, Negeri Sembilan, Malaysia

Data on Burseraceae in a 50-ha permanent plot at Pasoh Forest Reserve, Negeri Sembilan, Malaysia were obtained from the Forest Research Institute of Malaysia (FRIM) and used to assess the primary productivity and distribution of the family. Four censuses were conducted in 1985, 1990, 1995 and 2000 and data analyses were done on the later census, however comparisons were made between censuses of 1985, 1990 and 1995 to determine variabilities. From census in 2000, four genera and 22 species and varieties of Burseraceae were recorded in the plot. A total of 16,535 trees were enumerated of which the most abundant species was Dacryodes rugosa (4,972 trees). Total above ground biomass of the family was estimated at 207.14 tan ha-1, and the highest above ground biomass was represented by Triomma malaccensis, estimated at 34.31 tan ha-1. The biomass estimation for 20 years increased significantly (ANOVA, p<0.05) between the three censuses. The total population of the family had reduced by 5.92% within 20 years. A total of 3,408 (19.56%) trees were found dead, 3,165 (18.23%) trees were new recruits and 726 (4.17%) trees were damaged naturally and by animals. Distribution-wise, soil type is shown as an influential factor as well as the topography

Exploring the potential of biologically active phenolic acids from marine natural products as anticancer agents targeting the epidermal growth factor receptor

The epidermal growth factor receptor (EGFR) dimerizes upon ligand bindings to the extracellular domain that initiates the downstream signaling cascades and activates intracellular kinase domain. Thus, activation of autophosphorylation through kinase domain results in metastasis, cell proliferation, and angiogenesis. The main objective of this research is to discover more promising anti-cancer lead compound against EGRF from the phenolic acids of marine natural products using in-silico approaches. Phenolic compounds reported from marine sources are reviewed from previous literatures. Furthermore, molecular docking was carried out using the online tool CB-Dock. The molecules with good docking and binding energies scores were subjected to ADME, toxicity and drug-likeness analysis. Subsequently, molecules from the docking experiments were also evaluated using the acute toxicity and MD simulation studies. Fourteen phenolic compounds from the reported literatures were reviewed based on the findings, isolation, characterized and applications. Molecular docking studies proved that the phenolic acids have good binding fitting by forming hydrogen bonds with amino acid residues at the binding site of EGFR. Chlorogenic acid, Chicoric acid and Rosmarinic acid showed the best binding energies score and forming hydrogen bonds with amino acid residues compare to the reference drug Erlotinib. Among these compounds, Rosmarinic acid showed the good pharmacokinetics profiles as well as acute toxicity profile. The MD simulation study further revealed that the lead complex is stable and could be future drug to treat the cancer disease. Furthermore, in a wet lab environment, both in-vitro and in-vivo testing will be employed to validate the existing computational results

In silico evaluation of usnic acid derivatives to discover potential antibacterial drugs against DNA gyrase B and DNA topoisomerase IV

Due to the rising increase in infectious diseases brought on by bacteria and anti-bacterial drug resistance, antibacterial therapy has become difficult. The majority of first-line antibiotics are no longer effective against numerous germs, posing a new hazard to global human health in the 21st century. Through the drug-likeness screening, 184 usnic acid derivatives were selected from an in-house database of 340 usnic acid compounds. The pharmacokinetics (ADMET) prediction produced fifteen hit compounds, of which the lead molecule was subsequently obtained through a molecular docking investigation. The lead compounds, labelled compound-277 and compound-276, respectively, with the substantial binding affinity towards the enzymes were obtained through further docking simulation on the DNA gyrase and DNA topoisomerase proteins. Additionally, molecular dynamic (MD) simulation was performed for 300 ns on the lead compounds in order to confirm the stability of the docked complexes and the binding pose discovered during docking tests. Due to their intriguing pharmacological characteristics, these substances may be promising therapeutic candidate for anti-bacterial medication