Minimal model for beta relaxation in viscous liquids

Contrasts between beta relaxation in equilibrium viscous liquids and glasses are rationalized in terms of a double-well potential model with structure-dependent asymmetry, assuming structure is described by a single order parameter. The model is tested for tripropylene glycol where it accounts for the hysteresis of the dielectric beta loss peak frequency and magnitude during cooling and reheating through the glass transition.Comment: Phys. Rev. Lett. (in press

Toxicity comparison of colloidal silver nanoparticles in various life stages of rainbow trout (Oncorhynchus mykiss)

Recognizing the significance of the life stage of fish for nano-eco-toxicological studies, the acute toxicity of colloidal silver nanoparticles (AgNPs) was tested in three different life stages of rainbow trout. Fishes were exposed to colloidal AgNPs at nominal concentrations of 100, 32, 10, 3.2, 1, 0.32, 0.1, and 0.032 mg/L. The estimated 96 hr LC50 values were 0.25, 0.71, and 2.16 mg/L for the eleutheroembryos, larvae and juveniles, respectively, revealing a higher sensitivity for the early life stages. In addition, a dose-dependent blood plasma reduction of chloride and potassium, also increase of cortisol and cholinesterase were observed in the juveniles to exposed AgNPs when compared to the controls. Thus, colloidal AgNPs should be classified as ‘very toxic’ and ‘toxic’ to the eleutheroembryo-larva and juvenile stages, respectively, meaning that the release of nanosilver into the aquatic environment or its direct application as an antimicrobial agent in aquaculture should no longer be allowed

Using Community-Owned Resource Persons to Provide Early Diagnosis and Treatment and Estimate Malaria Burden at Community Level in North-Eastern Tanzania.

Although early diagnosis and prompt treatment is an important strategy for control of malaria, using fever to initiate presumptive treatment with expensive artemisinin combination therapy is a major challenge; particularly in areas with declining burden of malaria. This study was conducted using community-owned resource persons (CORPs) to provide early diagnosis and treatment of malaria, and collect data for estimation of malaria burden in four villages of Korogwe district, north-eastern Tanzania.In 2006, individuals with history of fever within 24 hours or fever (axillary temperature ≥37.5°C) at presentation were presumptively treated using sulphadoxine/pyrimethamine. Between 2007 and 2010, individuals aged five years and above, with positive rapid diagnostic tests (RDTs) were treated with artemether/lumefantrine (AL) while under-fives were treated irrespective of RDT results. Reduction in anti-malarial consumption was determined by comparing the number of cases that would have been presumptively treated and those that were actually treated based on RDTs results. Trends of malaria incidence and slide positivity rates were compared between lowlands and highlands. Of 15,729 cases attended, slide positivity rate was 20.4% and declined by >72.0% from 2008, reaching <10.0% from 2009 onwards; and the slide positivity rates were similar in lowlands and highlands from 2009 onwards. Cases with fever at presentation declined slightly, but remained at >40.0% in under-fives and >20.0% among individuals aged five years and above. With use of RDTs, cases treated with AL decreased from <58.0% in 2007 to <11.0% in 2010 and the numbers of adult courses saved were 3,284 and 1,591 in lowlands and highlands respectively. Malaria incidence declined consistently from 2008 onwards; and the highest incidence of malaria shifted from children aged <10 years to individuals aged 10-19 years from 2009. With basic training, supervision and RDTs, CORPs successfully provided early diagnosis and treatment and reduced consumption of anti-malarials. Progressively declining malaria incidence and slide positivity rates suggest that all fever cases should be tested with RDTs before treatment. Data collected by CORPs was used to plan phase 1b MSP3 malaria vaccine trial and will be used for monitoring and evaluation of different health interventions. The current situation indicates that there is a remarkable changing pattern of malaria and these areas might be moving from control to pre-elimination levels

Prenylated flavonols from the Leaves of Macaranga gigantea (Rchb.f. & Zoll.) / M. Sulaiman M. Johari … [et al.]

The genus Macaranga comes from the family of Euphorbiaceae and it is the only genus in the subtribe Macaranginae that have a large genus with 300 species of which 27 species were found in Peninsular Malaysia. This plant grows as shrubs or trees that can grow up to 15 m tall and known for their mutual associations with ants. Fresh or dried leaves of some Macaranga species were used by traditional healers to treat swellings, cuts, sores, boils and bruises. The isolation of chemical constituent from this genus has been shown to produce numerous results of phenolic compounds, such as flavonoids and stilbenoids. In this paper, we report the isolation of a prenylated flavonol, glyasperinA (1), together with a simple flavone apigenin (2) from the methanolic extract of the leaves of Macaranga gigantea. The structure of both compounds has been elucidated based on its spectroscopic data, including mass spectroscopy (MS), infrared (IR), ultraviolet-visible (UV-Vis), 1D and 2D nuclear magnetic resonance (NMR) spectra and comparison with the previous literature

Contamination of Cd and Pb on Milkfish Chanos Chanos Cultured in Seribu Islands, Jakarta

Seribu Islands located in the north of Jakarta Bay; it is potentially polluted by heavy metal such as Cd and Pb. The aims of this study is to prove contamination presumption, by analyzing and determine correlation Cd and Pb concentration in the sediment, in the water and on milkfish Chanos chanos cultured in this area. On this study, we collected water quality data (pH, temperature, dissolve oxygen and salinity) and heavy metals contamination (Cd and Pb) in the sediment, in the water and on milkfish. We compare collected data with quality standar and correlate heavy metal concentration between in the water and in the sediment; in the water and on milkfish organ; and, in the sediment and on milkfish organ. In general, water quality is sufficient enough to support the life of farmed milkfish. Cd and Pb contamination level in the water lied below the quality standard of Ministry of Environment decree No. 51/2004 in the last April and July. However, the contamination exceeds the standard in the last October. The contamination in sediment lied below RNO (1981), EPA (1999) and IACD/CEDA (1997). Gills, viscera and the meat of the milkfish are contaminated with Cd and Pb, yet, still lied below the quality standard of Ministry of Environment Decree No. 51/2004. The results showed that farmed milkfish in Thousand Islands are safe to eat. We also found that the correlation of Cd and Pb contamination between water and sediment is positive. The correlation of Cd is much higher than Pb. The correlation of Cd between water and viscera as well as between sediment and viscera are the most closely related than any other organ

Graphical User Interface (GUI) Controlled Mobile Robot

The advanced design and development of robotic technology in producing multi task are increasingly. In this paper presents about designing and developing mobile robot model that can be controlled using Graphical User Interface (GUI) via wireless protocol. This paper focuses on the control mobile robot by using the GUI as navigation control and the user can get a view an image and real time video on visual basic software. To address the problem of sired based control, XBee wireless communication circuit was used in mobile robot through a computer command. The development of this mobile robot consists of a chassis, a graphical user interface (GUI), XBee module, DC gear motor, camera, track wheels and microcontroller type PIC18F4550. Differential driving method using L298 circuit was used to control movement of the robot. In mechanical design, the wheel track has been used instead of conventional wheels to enable the robot to travel through different types of surfaces or rough terrain. In addition, wireless cameras was attached to the robot as a system of monitoring function. Finally, the robot will be designed to control wireless remote control that can control robots. Wireless remote control allows the user of an environment that is unsafe or dangerous device and evades wires or cables interfere with the movement of the robot

The relationship between fragility, configurational entropy and the potential energy landscape of glass forming liquids

Glass is a microscopically disordered, solid form of matter that results when a fluid is cooled or compressed in such a fashion that it does not crystallise. Almost all types of materials are capable of glass formation -- polymers, metal alloys, and molten salts, to name a few. Given such diversity, organising principles which systematise data concerning glass formation are invaluable. One such principle is the classification of glass formers according to their fragility\cite{fragility}. Fragility measures the rapidity with which a liquid's properties such as viscosity change as the glassy state is approached. Although the relationship between features of the energy landscape of a glass former, its configurational entropy and fragility have been analysed previously (e. g.,\cite{speedyfr}), an understanding of the origins of fragility in these features is far from being well established. Results for a model liquid, whose fragility depends on its bulk density, are presented in this letter. Analysis of the relationship between fragility and quantitative measures of the energy landscape (the complicated dependence of energy on configuration) reveal that the fragility depends on changes in the vibrational properties of individual energy basins, in addition to the total number of such basins present, and their spread in energy. A thermodynamic expression for fragility is derived, which is in quantitative agreement with {\it kinetic} fragilities obtained from the liquid's diffusivity.Comment: 8 pages, 3 figure

Time-temperature superposition in viscous liquids

Dielectric relaxation measurements on supercooled triphenyl phosphite show that at low temperatures time-temperature superposition (TTS) is accurately obeyed for the primary (alpha) relaxation process. Measurements on 6 other molecular liquids close to the calorimetric glass transition indicate that TTS is linked to an $\omega^{-1/2}$ high-frequency decay of the alpha loss, while the loss peak width is nonuniversal.Comment: 4 page

Anisotropic Local Stress and Particle Hopping in a Deeply Supercooled Liquid

The origin of the microscopic motions that lead to stress relaxation in deeply supercooled liquid remains unclear. We show that in such a liquid the stress relaxation is locally anisotropic which can serve as the driving force for the hopping of the system on its free energy surface. However, not all hopping are equally effective in relaxing the local stress, suggesting that diffusion can decouple from viscosity even at local level. On the other hand, orientational relaxation is found to be always coupled to stress relaxation.Comment: 4 pages, 3 figure