1,112 research outputs found
Chiral microstructures (spirals) fabrication by holographic lithography
We present an optical interference model to create chiral microstructures
(spirals) and its realization in photoresist using holographic lithography. The
model is based on the interference of six equally-spaced circumpolar linear
polarized side beams and a circular polarized central beam. The pitch and
separation of the spirals can be varied by changing the angle between the side
beams and the central beam. The realization of the model is carried out using
the 325 nm line of a He-Cd laser and spirals of sub-micron size are fabricated
in photoresist.Comment: 6 page
Ocean container transport in global supply chains: Overview and research opportunities
This paper surveys the extant research in the field of ocean container transport. A wide range of issues is discussed including strategic planning, tactical planning and operations management issues, which are categorized into six research areas. The relationships be- tween these research areas are discussed and the relevant literature is reviewed. Representative models are selected or modified to provide a flavour of their functions and application context, and used to explain current shipping practices. Future research opportunities bearing in mind the emerging phenomena in the field are discussed. The main purpose is to raise awareness and encourage more research into and application of operations management techniques and tools in container transport chains
Bacterial diversity and community structure of banana rhizosphere in Orang Asli fields and commercial plantations
Bacteria play an important roles in the soil ecosystem and in the rhizosphere, they are intricately linked to nutrient content
and its accessibility to plants, plant protection and sometimes pathogenicity. Banana grows well in the tropics and it is
popularly grown in Orang Asli (OA) (indigenous people) settlements. Banana is also grown in commercial plantations.
In traditional planting practices, the OA do not add pesticide nor fertilizer to their crops which are planted for selfsustenance
mainly. On the other hand, fertilizer and pesticide are added to commercial banana plantations to maximise
yield. Rhizosphere bacteria from the banana plant, Pisang Nipah, grown in OA fields and commercial plantations were
identified by clone library construction of the 16S rRNA gene. This was to determine whether farming practices influenced
the bacterial community in the banana plant rhizosphere. Acidobacteria, Proteobacteria and Actinobacteria were found in
all the soil. Other common phyla found in some soil (but not all) were Nitrospirae, Firmicutes, Bacteroidetes, Chloroflexi,
Verrumicrobia, Gemmatimonadetes and Cyanobacteria. The bacterial diversity was a little more diverse in the OA fields
than the commercial plantations. The latter had higher contents of nitrogen, phosphorus and potassium. These could
have exerted selective pressure to reduce the bacterial diversity in the commercial plantations
Sponges from North Borneo and their bioactivity against human colorectal cancer cells
Sponges are major source of numerous cytotoxic compounds that are used for defence as well as adaptation to the environment. Numerous studies have discovered compounds from sponge extracts that were effective against a wide range of cancer cells. In this study, a total of 23 sponges comprising of 19 species were collected from Northeast Borneo. Sponges were treated and extracted using modified Folch extraction method, followed by cytotoxicity assay to determine their effectiveness against different colorectal cancer cells. Our results demonstrate that Monanchora clathrata, Dysidea sp., and Jaspis sp. possess different degrees of cytotoxicity against a wide range of human colorectal cancer cells. Monanchora clathrata (KDT07), Dysidea sp. (KDT09), and Jaspis sp. (KDT18) are among the demosponges which possess significant cytotoxicity against colorectal cancer cell lines, including HCT116, LoVo, SW480, and SW620. KDT08 and KDT21 which fall under the same genus Dysidea, possess insignificant cytotoxicity against colorectal cancer cells suggested environmental factors (symbiotic organisms) play a role in biosynthesizing bioactive compounds. Presented results suggested the importance of intensifying research on isolating and purifying natural products from marine sponges for useful applications
Physicochemical and sensory analyses of high fibre bread incorporated with corncob powder
The primary objectives of the present work were to produce corncob powder (CCP) from corncobs and incorporate the CCP into bread formulation in order to develop high fibre bread, and to investigate the physicochemical and sensory properties of the produced high fibre bread (HFB). The corncobs were collected and washed before they underwent the grinding and drying processes. The obtained CCP was incorporated into the bread formulation in three different proportions (5, 10 and 20%) to partially substitute bread flour in the formulation. All three bread samples and the control (0% CCP in the formulation) were analysed to obtain their physicochemical and sensory properties. The incorporation of CCP significantly affected the texture, colour and volume attributes of the produced breads. Increasing the content of CCP in the formulation was found to be responsible for firmer, smaller and darker bread loaves as compared to the composite bread samples. The bread formulation incorporated with 10% CCP had the highest mean scores (7.00) of overall acceptability among all the other formulations, and it was comparable to the commercial breads in the current market
Changes in Water and Sediment Quality of a River Being Impounded and Differences Among Functional Zones of the New Large Tropical Hydroelectric Reservoir
Though more large tropical reservoirs are being constructed to meet the increasing energy demand,
knowledge on the impact of damming a tropical river and the differences along the river after its impoundment is scarce. Thus, the present study aimed to increase our understanding of such differences both longitudinally and vertically. Water and sediment samples were collected at three different functional zones in the Murum River basin 10 months after impoundment began. Results show that
the impoundment has an impact on both the water and sediment. Longitudinal variations of water and sediment characteristics were observed at different functional zones. The upstream riverine zone subjected to anthropogenic activities serves as the main input of suspended solids and nutrients to the reservoir. The nitrogen changed from a high nitrate and low ammonia condition prior to impoundment to a low nitrate and high ammonia condition due to the accumulation of organic matter and slow nitrification rate after impoundment. In the transitional and lacustrine zones, vertical stratifications of dissolved oxygen and temperature were observed. The thickness of a well-oxygenated column for
sensitive aquatic organisms was only 2 m at some stations. Water quality in all zones showed impairment
during the filling phase as compared to the good water quality index before impoundment. The reduction
of suspended solids in the surface water column in the transitional and lacustrine zones is a positive
change for aquatic organisms. Sediment characteristics were found to be distinct in the transitional zone,
where it was lower in sand and higher in silt, clay, organic carbon and nutrients in contrast to the riverin
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Multiplex PCR System for Rapid Detection of Pathogens in Patients with Presumed Sepsis – A Systemic Review and Meta-Analysis
Background: Blood culture is viewed as the golden standard for the diagnosis of sepsis but suffers from low sensitivity and long turnaround time. LightCycler SeptiFast (LC-SF) is a real-time multiplex polymerase chain reaction test able to detect 25 common pathogens responsible for bloodstream infections within hours. We aim to assess the accuracy of LC-SF by systematically reviewing the published studies. Method Related literature on Medline, Embase, and Cochrane databases was searched up to October 2012 for studies utilizing LC-SF to diagnose suspected sepsis and that provided sufficient data to construct two-by-two tables. Results: A total of 34 studies enrolling 6012 patients of suspected sepsis were included. The overall sensitivity and specificity for LC-SF to detect bacteremia or fungemia was 0·75 (95% CI: 0·65–0·83) and 0·92 (95%CI:0·90–0·95), respectively. LC-SF had a high positive likelihood ratio (10·10) and a moderate negative likelihood ratio (0·27). Specifically, LC-SF had a sensitivity of 0·80 (95%CI: 0·70–0·88) and a specificity of 0·95(95%CI: 0·93–0·97) for the bacteremia outcome, and a sensitivity of 0·61 (95%CI: 0·48–0·72) and a specificity of 0·99 (95%CI: 0·99–0·99) for the fungemia outcome. High heterogeneity was found in the bacteremia outcome subgroup but not in the fungemia outcome subgroup. Conclusion: LC-SF is of high rule-in value for early detection of septic patients. In a population with low pretest probability, LC-SF test can still provide valuable information for ruling out bacteremia or fungemia
Baseline trace metals in water and sediment of the Baleh River—a tropical river in Sarawak, Malaysia
Quantitative indices are classically employed
to evaluate the contamination status of metals with
reference to the baseline concentrations. The baselines
vary considerably across different geographical zones. It
is imperative to determine the local geochemical baseline
to evaluate the contamination status. No study has
been done to establish the background concentrations in
tropical rivers of this region. This paper reports the
background concentrations of metals in water and sediment
of the Baleh River, Sarawak, derived based on the
statistical methods where the areas possibly disturbed
are distinguished from the undisturbed area. The baseline
levels of six elements in water determined were Al
(0.34 mg/L), Fe (0.51 mg/L), Mn (0.12 mg/L), Cu
(0.01 mg/L), Pb (0.03 mg/L), and Zn (0.05 mg/L).
Arsenic and selenium were below the detection limit.
For sediment, the background values were established
according to statistical methods including (mean + 2σ),
iterative 2σ, cumulative distribution frequency, interquartile,
and calculation distribution function. The background
values derived using the iterative 2σ algorithm
and calculated distribution function were relatively lower.
The baseline levels calculated were within the range
reported in the literatures mainly from tropical and subtropical
regions. The upper limits proposed for nine
elements in sediment were Al (100,879 mg/kg), Cr
(75.45 mg/kg), Cu (34.59 mg/kg), Fe (37,823 mg/kg),
Mn (793 mg/kg), Ni (22.88 mg/kg), Pb (27.26 mg/kg),
Zn (70.64 mg/kg), and Hg (0.33 mg/kg). Quantitative
indices calculated suggest low risk of contamination at
the Baleh River
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