Trapping of gold nanoparticle and polystyrene beads by dynamic optical tweezers

Gold nanoparticles and polystyrene beads are very important to use in advanced nanoscopic optical trapping techniques to probe any biological system of interest. Multiple trapping of these particles with different diameters can be performed by an optical tweezers system employing dark soliton controlled by Gaussian pulse within a particular configuration of microring resonators. By controlling some parameters and input power of the system, dynamics of the tweezers can be tuned. Radiation pressure acting on the particles including gradient and scattering forces were theoretically measured as a function of normalized position from the center of the laser beam. In this work, the highest output signal in the form of potential well is recorded at 112.80 W corresponding to 1.6 pm wavelength. Sizes of the tweezers are found within the range of 20 nm and the highest value of the optical force is recorded at 895.70 pN. We have demonstrated that the gradient force component is dominant over particle size within Rayleigh regime, thus a good agreement with theory is found

Responses of tropical fruit bats to monoculture and polyculture farming in oil palm smallholdings

The oil palm industry is one of the main economic drivers in Southeast Asia. The industry has caused tropical deforestation on a massive scale in producing countries, and this forest conversion to oil palm agriculture has decimated the habitat of numerous native species. Monoculture and polyculture practices are two distinctive oil palm production systems. We hypothesize that polyculture farming hosts a greater diversity of species than monoculture farming. Habitat complexity in smallholdings is influenced by multiple farming practices (i.e. polyculture and monoculture). However, little is known about the effects of such farming practices in smallholdings on mammalian biodiversity, and particularly frugivorous bats. Our study aimed to find the best farming practice to reconcile oil palm production with biodiversity conservation. Mist-nets were used to trap frugivorous bats at 120 smallholdings in Peninsular Malaysia. We compared species richness and the abundance of frugivorous bats between monoculture and poly-culture smallholdings. We investigated their relationships with vegetation structure characteristics. Our results revealed that species richness and abundance of frugivorous bats were significantly greater in polyculture smallholdings than monoculture smallholdings. We also found that 28.21% of the variation in species richness was explained by in situ habitat characteristics, including the number of dead standing oil palms and immature oil palms, non-grass cover, height of non-grass cover, and farming practices. Thein situ habitat quality was closely associated with oil palm farming management. Commercial growers should implement polyculture rather than monoculture farming because polyculture farming has positive effects on the abundance and species richness of bats in oil palm production landscapes

Trypanosomosis in a Sambar deer

A five years old Sambar deer was presented to the University Veterinary Hospital of Universiti Putra Malaysia. The deer was physically diagnosed with clinical signs of depression, lethargy, teeth grinding, pallor of mucous membranes, the vital parameters showed pyrexia (40.90C), increase in pulse (197beats/min.) and respiratory rates (42 circles/min.). Laboratory examination of the Buffy coat by micro haematocrit centrifugation technique revealed the presence of motile flagellates. Buffy coat smear examination confirmed the presence of Trypanosome spp. The disease was diagnosed based on clinical signs and laboratory finding. Diminazene Aceturate at a dose rate of 3.5mg/kg bodyweight was administered intramuscularly, coupled with multivitamin and fluid therapy proves effective in treating the condition. This report shows the significance of wild ruminants in maintaining the transmission cycle of this parasite and timely treatment could resolve the disease condition

Monopole Antenna with Dual Band Capabilities for WiFi Application

In this paper, a monopole antenna with rectangular elements for dual band capabilities was presented. This design was an improvement from the traditional monopole patch antenna by adding slits and truncated ground plane. The proposed antenna was designed for dual band operations for Wireless Local Area Network (WLAN) at 2.4 GHz and 5.2 GHz. The design improved the return loss and bandwidth for these two frequency bands. Calculation and measurement showed that the return loss exceeded the minimum design specification and the bandwidths for those bands were covered completely

Rectangular Microstrip Patch Antenna with Different Location of Minkowski Island Split Ring Resonator (MI-SRR) Structure

In this project, different locations of the Minkowski Island split ring resonator (MI-SRR) structure are embedded in the basic rectangular patch antenna. It started with a basic rectangular microstrip patch antenna that were simulated in CST Microwave Studio software. After that, four different locations (Location A, Location B, Location C and Location D) of MI-SRR were chosen to compare the performance of return loss, resonant frequency, surface current radiation pattern, and gain. Location A represented the antenna with the MI-SRR at the center part of the patch, while Location B had the MI-SRR at the upper part of the FR-4 substrate. Location C and Location D represented the antenna with MI-SRR at the ground at antenna with MI-SRR at the other layer, respectively. The return loss performances of Design of Location A, Location B, Location C, and Location D were - 26.546 dB, - 23.892 dB, -43.842 dB, - 51.506 dB at resonant frequency of 2.432 GHz, 2.510 GHz, 2.438 GHz and 2.542 GHz, respectively

Effects of in situ habitat quality and landscape characteristics in the oil palm agricultural matrix on tropical understory birds, fruit bats and butterflies

The expansion of commercial oil palm crop has modified much of the natural landscape, subsequently leading to biodiversity loss in Southeast Asia. Aside from large-scale oil palm monoculture plantations, self-managed oil palm smallholdings are also becoming common in palm oil producing countries, but less is known about how management of the smallholdings affects faunal biodiversity. We argue that it is critically important to understand the role of habitat complexity at the local and landscape scales for maintaining faunal biodiversity in oil palm smallholdings. We used passive sampling methods to survey understory birds, fruit bats, and butterflies in oil palm smallholdings on the west coast of Peninsular Malaysia. We quantified the diversity in each taxon and measured in situ habitat quality and landscape metrics. We found that oil palm smallholdings located near rice fields supported fewer bird species. Proximity to roads can give rise to bird and fruit bat richness. Bird and fruit bat richness declined at sites with high crop density. Fruit bat richness declined, but butterfly richness increased, with the height of oil palm stands. Butterfly richness declined with distance from riparian habitats. Decreased coverage and height of ground vegetation also negatively affected butterfly species richness. We also found that the number of farm houses is positively related to bird, fruit bat, and butterfly species richness. Of the three taxa, only butterfly richness was positively influenced by crop diversity. We found that habitat complexity enables smallholdings to support a diverse community of birds and butterflies, but not fruit bats. These findings imply that oil palm smallholdings can be managed in a conservation agricultural matrix, as the smallholdings were able to maintain farmland biodiversity

In situ measurement of gold nanoparticle production

The closeness of the experimental and theoretical values enables the development of an in situ characterization technique to monitor and analyze the production of gold nanoparticles (NPs), overcoming the use of high-end and expensive instrumentation. Gold NPs below the radius size of 10 nm were successfully synthesized in accordance with a few working parameters of pulse laser ablation in a liquid technique. In this report, the size, shape, concentration, and aggregation properties of gold NPs were estimated by the Mie-Gans model based on a reliable and interactive real-time absorption spectroscopy. The major features can be an important means toward determination of efficient process measures, productivity of gold NPs generated, and efficiency of the mass ablation rate. The accuracy in the measurement is confirmed via transmission electron microscopy analysis

Simultaneous action of surfactant modified clinoptilolite: adsorbent of dyes and antibacterial agent

In this study, the simultaneous action of surfactant modified clinoptilolite (SMC) as adsorbent for dyes and its antibacterial activity was investigated. Methylene blue (MB) and acid orange 7 (AO7) represent cationic and anionic dyes, respectively were used as adsorbate in this study and the antibacterial activity was studied against Gram-negative (Escherichia coli ATCC 11229) and Gram-positive bacteria (Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 2921). Initially, natural zeolite clinoptilolite was modified with 3 different concentrations (0.1, 1.0 and 4.0 mM) of cationic surfactant hexadecyltrimethyl ammonium bromide (HDTMA-Br). The SMC samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), amount of HDTMA adsorbed and dispersion behaviour. Result from XRD shows that the HDTMA-Br molecules caused no effect on primary structure of the clinoptilolite since the clinoptilolite structure remained the same after modification with HDTMA-Br. Compared to the unmodified clinoptilolite, FTIR spectra of the SMC shows peak corresponds to C-H stretches which proved the attachment of HDTMA onto the clinoptilolite surfaces. In the dispersion behaviour study, SMC samples were located at the adjacent phase between the water and oil mixture. The amount of HDTMA-Br adsorbed onto the clinoptilolite increased with the increasing concentrations of the surfactant. The use of SMC as adsorbent and antibacterial agent were further studied against the ionic dyes and bacteria simultaneously. The results show that the adsorption capacity of SMC towards both ionic dyes increase with the increasing HDTMA-Br concentration. While for the antibacterial activity, the number of colony forming unit of bacteria seem to be highly reduced at the highest concentration of the HDTMA (4.0 mM) attached on the clinoptilolite. Hence, this study had shown that SMC has high adsorption capacity towards the ionic dyes at the same time reducing the growth of both Gram positive and negative bacteria in aquoes solution