Pertanika Journal of Scholarly Research Reviews (PJSRR - Universiti Putra Malaysia, UPM)
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Ozone Application in Fresh Fruits and Vegetables
Get PDFThe demand of fruits and vegetables across the world had increased throughout the years which urge the need to have better and proper way to increase produce safety, quality and postharvest life. Traditionally pesticides or other chemicals had been used to encounter microbes related to postharvest diseases. Over time, consumers are concern towards health effect of consuming those produce treated with chemicals. Ozone is one of the approach that provide both of the needs to deal with pathogenic microbes and also give no harmful residue throughout the process. Several reports had proven that ozone can almost kill or inhibit all pathogenic microbes on treated commodity which promote higher quality and postharvest life during storage. This review focus and summarise the use of ozone in the form of aqueous and gaseous towards fresh produces, its benefits and also the precaution during ozone application
A Review on The Global Widespread of TTV Infection Among Humans Population
Get PDFTorque Teno Virus (TTV) is a human-infected virus that is present ubiquitously in nature. Globally, it infects up to 95% of the healthy individuals without any clinical manifestations. The widely used laboratory diagnosis of TTV infection is Polymerase chain reaction (PCR). Nevertheless, several other methods have been developed. The rapid growth of TTV variants over time has posed a challenge in estimating the global TTV infection as none of the PCR protocol has the ability to detect the entire spectrum of TTV variants. Multiple TTV epidemiological studies have been conducted among Asian population, whereas other continents showed a limited number of studies. The horizontal and vertical transmission of TTV among humans population, as well as interspecies transmission are potentially related to the global widespread of TTV infection
Flow in a Branching Open Channel: A Review
Get PDFBranching channel flow refers to any side water withdrawals from rivers or main channels. Branching channels have wide application in many practical projects, such as irrigation and drainage network systems, water and waste water treatment plants, and many water resources projects. In the last decades, extensive theoretical and experimental investigations of the branching open channels have been carried out to understand the characteristics of this branching flow, varying from case studies to theoretical and experimental investigations. The objectives of this paper are to review and summarise the relevant literatures regarding branching channel flow. These literatures were reviewed based on flow characteristics, physical characteristics, and modeling of the branching flow. Investigations of the flow into branching channel show that the branching discharge depends on many interlinked parameters. It increases with the decreasing of the main channel flow velocity and Froude number at the upstream of the branch channel junction. Also it increases with the increasing of the branch channel bed slope. In subcritical flow, water depth in the branch channel is always lower than the main channel water depth. The flow diversion to the branch channel leads to an increase of water depth at the downstream of the main channel. From the review, it is important to highlight that most of the study concentrated on flow characteristics in a right angle branch channel with a rigid boundary. Investigations on different branching angles with movable bed have still to be explored
Swiftlets and Edible Bird’s Nest Industry in Asia
Get PDFSwiftlets are small insectivorous birds which breed throughout Southeast Asia and the South Pacific. Among many swiftlet species, only a few are notable to produce edible bird’s nests (EBN) from the secreted saliva during breeding seasons. The taxonomy of swiftlets remains one of the most controversial in the avian species due to the high similarity in morphological characteristics among the species. Over the last few decades, researchers have studied the taxonomy of swiftlets based on the morphological trade, behavior, and genetic traits. However, despite all the efforts, the swiftlet taxonomy remains unsolved. The EBN is one of the most expensive animal products and frequently being referred to as the “Caviar of the East”. The EBN market value varies from US10,000.00 per kilogram depending on its grade, shape, type and origin. Hence, bird’s nest harvesting is considered a lucrative industry in many countries in Southeast Asia. However, the industry faced several challenges over the decades such as the authenticity of the EBN, the quality assurance and the depletion of swiftlet population. Furthermore, there is limited scientific evidence regarding EBN’s medical benefits as claimed by manufacturers. This paper reviews the taxonomy of swiftlets, its morphological characteristics, the challenges currently encountered by the industry, and finally the composition and medical benefits of EBN
Horizontal Gene Transfer: A Vehicle for the Dissemination of Resistance and Virulence Determinants during Colonization and Disease
Get PDFThe successful in vivo horizontal transfer of mobile genetic elements carrying resistance and virulence determinants have contributed immensely to a global dissemination of virulent and multi-drug resistant pathogens. In addition, the pathogenesis of MRSA infection is enhanced via initial colonization of the skin through the component of the microbial surface antigen recognizing adhesive matrix molecules and by their ability to evade host immune response. Furthermore, it was also observed that the genetic diversity of pathogenic MRSA is due to its’ ability to rapidly acquire resistance and virulence determinants. A characteristic feature that made it one of the most important nosocomial pathogen worldwide. Similarly, the expression of virulence gene in MRSA has been observed to be regulated by the accessory gene regulator system (agr). These system is made up of a series of genes whose product build up quorum-sensing regulatory mechanisms that is growth dependent. In addition, at a certain growth stage, the agr systems triggers a pronounced changes in the expression of genes called the quorum sensing. The findings of this review affirms the importance of horizontal gene transfer in the dissemination of resistance and virulence determinants and as well as the genetic diversity of MRSA
Review on Progress and Application of Active Flow Control Devices - Coandă Effect on Unmanned Aerial Vehicles
Get PDFCoandă effect can be found in virtually all aerodynamic applications, and has drawn renewed interest for various applications, among others for generating lift and maneuvering impulses to be applied for unmanned air vehicles (UAV) and micro air vehicles (MAV). These air vehicles have the potential to revolutionize our sensing and information gathering capabilities, in homeland security and environmental areas. Sophisticated unmanned air vehicles for general applications have been developed rapidly across many different industries and interested researchers. In order to carry out a task, these air vehicles have to face many different challenges, due to the MAVs small size, flight regime, and modes of operation. This has led to the development of novel platforms that move away from traditional aircraft design in order to make them more capable. A good example is the Coandă MAV which uses the Active flow control–Coandă Effect. Improved aerodynamic performance of these air vehicles can lead to fast take off and slower landing speeds that can be related to reduce noise and crash survivability issues. The investigation and research in this field is rapidly rising and there are many concepts currently being considered around the world. This report provides an overview on the state of unmanned air vehicle and introduces the techniques of Active Flow Control ACF that could be potentially used for control of UAV. Furthermore, this paper may also focuses on the review research involved with the design modification and the generated flow phenomena of Micro air vehicle MAV
Quantum Dot-sensitized Solar Cell Based on nano-TiO2 Electrode
Get PDFQuantum dots-sensitized solar cell (QDSSC) is one of the third generation solar cell that is the most promising low cost, easy to manufacture and highly efficient solar cell. Compared to Dyesensitized solar cell (DSSC), quantum dots (QDs) of QDSSC has a narrow bandgap and possess excellent properties such as tunable band gaps, strong light absorption and high multiple electron generation. Titanium dioxide or titania (TiO2) is an oxides semiconductor material that is frequently used as a photoanode in this photovoltaic system due to high stability under visible light illumination. TiO2 is also known as a good photocatalyst and an excellent choice in environmental purification. The efficiencies of electron injection and light harvesting in QDSSC are affected by the nature, size morphology, and quantity of this nanomaterial. In this review, the concept and principles of the QDSSCs are reviewed. The preparation and fabrication method ofTiO2 electrode in QDSSC are also discussed. It is worthwhile to know the architecture of TiO2 in order to enhance the efficiency of QDSSC
A Review on Induced Mutagenesis of Stevia rebaudiana Bertoni
Get PDFStevia rebaudiana Bertoni in the Asteraceae family is commercially valuable and cultivated throughout the world due to the great demand for its steviol glycosides (SGs) contents particularly rebaudioside A. Previous studies confirmed that maximal content of SGs in stevia was achieved at or just before flowering, and delayed flowering with long days provide longer duration for steviol glycosides accumulation. However, there is no suitable stevia variety to be cultivated in Malaysia due to her short day length. Mutation induction, including gamma irradiation, had been shown to be useful for generating genetic variations as well as developing new plant varieties from which desired mutants were successfully selected. The use of mutagens, both physical and chemical, has helped in creating mutants that expressed the selected desirable traits. This paper presents some selected essential data available in extant scientific studies on stevia with the focus on application of gamma irradiation on stevia. Both established achievements and recent publications of gamma radiation on stevia were reviewed. Emphasis is on the exceptional potential of stevia through induced mutation approach especially by using gamma rays
Production of Essential Oil in Plants: Ontogeny, Secretory Structures and Seasonal Variations
Get PDFEssential oil production in plants is known to play crucial roles in attractive and defensive mechanism responses to environmental conditions. Various factors are known to determine the chemical variability and yields for specific essential oil bearing plants including genetic, physiology and environment. The purpose of this review is to summarize recent publications on the variation of essential oil and its composition with regards to physiological aspects of the plants
CsoR Metalloregulatory Protein: Function, Mechanism and Relevance
Get PDFTransition metals are required constituent in bacterial metabolism to assist in some enzymatic reactions. However, intracellular accumulations of these metal ions are harmful to the bacteria as it can trigger unnecessary redox reactions. To overcome this condition, metalloregulatory proteins assist organisms to adapt to sudden elevated and deprived metal ion concentration in the environment via metal homeostasis. CsoR protein is a copper(I) [Cu(I)] sensing operon repressor that is found to be present in all major classes of eubacteria. This metalloregulatory protein binds to the operator region in its apo state under Cu(I) limiting condition and detaches off from the regulatory region when it binds to the excess cytosolic Cu(I) ion, thus derepressing the expression of genes involved in Cu(I) homeostasis. CsoR proteins exist in dimeric and tetrameric states and form certain coordination geometries upon attachment with Cu(I). Certain CsoR proteins have also been found to possess the ability to bind to other types of metals with various binding affinities in some Gram positive bacteria. The role of this metalloregulatory protein in host pathogen interaction and its relation to bacterial virulence are also discussed