Synthesis of titanium dioxide nanoparticles via sucrose ester micelle-mediated hydrothermal processing route

Titanium dioxide nanoparticles were synthesized via low-temperature sucrose ester micelle-mediated hydrothermal processing route using titanium isopropoxide as the precursor. X-ray diffractometer revealed that the samples possessed a mixed crystalline phases consisting of anatase and brookite in which anatase was the main phase. Upon increasing the hydrothermal reaction temperature, the degree of crystallinity of the nanoparticles improved and their morphology transformed from bundles of needles to rods and to spheres. Photocatalytic behaviour of the as-synthesized nanoparticles was investigated by photodegradation of methylene blue solution in an ultraviolet A irradiating photoreactor. The as-synthesized nanoparticles exhibited higher photocatalytic performance as compared to the commercial counterpart

Micro-hydrokinetic turbine potential for sustainable power generation in Malaysia

Micro-hydrokinetic turbine (μ-HKT) technology is considered a viable option for sustainable, green and low cost power production. In recent years, there is growing number of research and development on this technology to replace conventional power production systems such as fossil fuel as well as to provide off-grid electrification to communities in remote areas. This paper provides an overview of μ-HKT system, the implementation of the technology and the potential of using μ-HKT in Malaysia. A review on the climate in Malaysia shows that its average annual rainfall is higher than the world's average annual rainfall. It contributes to the total hydropower resource of about 29,000 MW which is available all year-round. Currently, hydropower resource contributes only 7.4% of the total electrical power production in Malaysia but is expected to increase with the main contribution coming from μ-HKT. However, the μ-HKT technology has not been adopted in Malaysia due to some challenges that hinder the development of the system. This paper reviews the μ-HKT technology and its potential for application in Malaysia, particularly in remote areas

Height-diameter allometry of tropical forest trees

Copyright © 2011 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/8/1081/2011/bg-8-1081-2011.html doi:10.5194/bg-8-1081-2011Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account

Preparation and characterization of calcium phosphate nanorods using reverse microemulsion and hydrothermal processing routes

Brushite (BR) and hydroxyapatite(HA) nanoparticles were fabricated through reverse microemulsion and hydrothermal processing route, respectively. The processing routes influenced nucleation and crystal growth although both methods resulted in nanorods formation. The calcium-to-phosphate ratio was 1.67, similar to that of natural bone and teeth. X-ray diffraction patterns revealed that the nanorods possessed almost pure crystal phase with negligible second phase. The ratio of particle length-to-width of BR and HA were approximately 3 and 4, respectively. To mimic the natural bone, chitosan/brushite(CTS/BR) and chitosan/hydroxyapatite (CTS/HA) nanocomposite scaffolds were prepared through rapid freeze-drying technique. The compressive strength of CTS/BR and CTS/HA nanocomposite scaffolds was compared for the first time. The compression test revealed that both the nanocomposite scaffolds exhibited reasonably high compressive strength of approximately 7 MPa. This value falls in the high-end range of cancellous bone’s compressive strength, with the compressive strength of CTS/HA 0.88 MPa more than CTS/BR

The influence of attraction on internet banking: An extension to the trust-relationship commitment model

Purpose - This research in this paper aims to investigate and extend the trust-relationship commitment model to an internet banking setting by adding attraction as a new factor. Design/methodology/approach - The paper shows that in testing whether attraction might be related to belief in and use of the internet banking, this research sampled 276 bank customers' responses via a cross-sectional survey in Doha, Qatar. Findings - The findings in the paper indicate that both trust and attraction have significant positive impact on relationship commitment with attraction having a strong positive effect, with communication representing the most important determinant of attraction and having a significant positive relationship with both trust and attraction. Practical implications - The paper shows that, from the managerial perspective, it is necessary for bankers and policy makers to know the relationship between trust and attraction because their influence on the actual commitment is different The findings of this study suggest that, in order to develop trust and to attract more users to internet banking, it is not going to be enough to make the system easy to interact with. It is of paramount importance for banks to develop secured and private internet banking systems that are trustworthy, for their users. Thus, management attention might be fruitfully focused on the development of such beliefs on the part of the users. Thus, the internet banking authorities should employ training and promotion approaches to develop customers' beliefs of shared value, communication, and opportunistic behavior, which in turn will influence or attract the customers' behavioural intention to utilize internet banking services. Similarly, banks may consider offering a low-cost service by passing on some of their gains from reduced operating cost to customers. This may lead to better customer loyalty towards the service. Originality/value - The paper finds that attraction as an additional factor in a trust-relationship commitment model has not been examined before. Thus, researchers should include attraction in online relationship banking models along with other relationship effects. Also, bankers and policy makers need to develop trust among the customers and to realize that more favorable communication environments must be created to attract customers and to make them more committed to using online banking transactions over the internet

Assessment of pubertal development in juvenile male rats after sub-acute exposure to bisphenol A and nonylphenol

The effects of bisphenol A and nonylphenol on pubertal development in the intact juvenile/peripubertal male Sprague-Dawley rats was observed in this study from PND23-52/53. Two groups of rats were administered orally with either 100 mg/kg body weight of nonylphenol or bisphenol A. Another group of rats were administered orally with a mixture of 100 mg/kg body weight of nonylphenol and bisphenol A. Control group was administered with the vehicle of Tween-80 with corn oil (1:9 v/v). Observations made in this study included growth, age at preputial separation, thyroid, liver, testis and kidney weight and histology, epididymal and seminal vesicle plus coagulation gland weight. Nonylphenol and bisphenol A have been observed to cause delay in puberty onset as well as testicular damage in the treatment groups when compared to the control; spermatogenesis was affected in most treated rats. Bisphenol A also caused the enlargement of the kidney and hydronephrosis. Administration of nonylphenol and bisphenol A as a mixture has caused less than additive effects. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved

Does the Cranial Suspensory Ligament Have a Role in Cryptorchidism?

The cranial suspensory ligament (CSL) is a fibromuscular structure anchoring the embryonic gonad to the posterior abdominal wall in male and female mammals. Its persistence in females is believed to be responsible for retaining the ovaries within the abdomen, while its regression in males permits testis descent. Embryonic loss of the CSL in males is believed to be an androgen-dependent event, and failure of this process has been proposed as a cause of cryptorchidism. The present study demonstrates that the nuclei of mesenchymal cells in the caudal part of the CSL are immunoreactively positive for androgen receptor. We examined the effects of exposure of the non-steroidal antiandrogen flutamide during the period from gestational day 10 to birth on the development of the CSL and on testis descent. Exposure of male Albino Swiss rats to the antiandrogen flutamide during this period resulted in feminization of the external genitalia and the suppression of growth of the testes and male reproductive tracts. In adulthood, testes were found to be located in diverse positions including normal scrotal (50%), intra-abdominal (10%) and ectopic suprainguinal (40%). The CSL of the testis persisted into adulthood in all flutamidetreated males, regardless of testis location. In all cases, the ligament consisted of bundles of smooth muscle fibres in the retroperitoneal fat of the posterior abdominal wall. These findings suggest that androgen blockade during embryonic development interferes with testicular descent, but that maldescent cannot be correlated with either the persistence of the CSL of the testis or its structure. Copyright (C) 2009 S. Karger AG, Base