30 research outputs found
A Review of Tertiary Palynomorph Assemblage in Cuu Long Basin: Case Study of Palynomorphs in Miocene
Tertiary deposits in Cuu Long Basin are very important because they contain fossil fuels such as oil and gas. More than 50% of oil and gas has been produced in Vietnam from Cuu Long Basin. Palynology is used as a valuable tool to support for depositional and age interpretation as well as well correlation
Investigation of Energy Transfer in a Blend of electroluminescent Conducting Polymers
With the aim of improving the photonic efficiency of an organic light emitting diode a blend of electroluminescent polymers, poly[9-vinylcarbarzole] (PVK) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) was prepared. The energy transfer in the blend was investigated through the comparison of absorption, photoluminescence (PL) and current-voltage (I-V) characteristics of the blend and standard polymers. The obtained results showed that energy transfer from PVK to MEH-PPV enable to form localized excited-state complexes (e.g. exciplexes) in MEH-PPV. The PL intensity of the blended polymers was enhanced as the relative content of MEH-PPV was increased, and particularly, the highest improved PL was observed for an weight fraction of 15 wt{\%} of MEH-PPV in PVK. Organic light emitting diodes made from these blends would exhibit a large photonic efficiency
Preparation and Inverstigation of MEH-PPV Films Used for White Light Emitting Diodes
With the aim to prepare white Light Emitting Diode (WLED), the conjugate polymer films like (Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were investigated. Spectroscopic (absorption and emission) spectra of the MEH-PPV films showed that this polymer is suitable for casting onto the chips of the blue InGaN LED to make WLED. The luminous flux measured on the WLEDs in the integrating sphere proved that the white light emission can be obtained from the combination of inorganic LED and conjugate (MEH-PPV) polymers with an optimal thickness and a high quality. The aging process of MEH-PPV films was found to be strongly dependent post-treatment conditions. Reasonable heat treatment condition for the MEH-PPV polymers was suggested as in vacuum of 5×10-2 Pa at a temperature of 120°C in, for 2 hous
Late Holocene riparian vegetation dynamics, environmental changes, and human impact in the Harapan forest of Sumatra, Indonesia
Riparian wetland ecosystems provide important ecological services but are also vulnerable to climate change and human activities. To understand the influence of natural factors (e.g. climate change, flooding, drought) and human activities (e.g. agriculture) as well as to support management strategies, reconstructions of past vegetation and environmental changes are needed. To achieve this, we conducted a multi-proxy paleoecological analysis, including pollen and spores, macro-charcoal and radiocarbon dating, on a sediment core taken from a riparian area in the Harapan forest of Sumatra. Three distinct periods were identified: i) AD 1100 – 1400: Upland and swamp forest with riparian and herbaceous vegetation, possibly part of a riparian buffer zone (e.g. riverbank), was present in the study area under a stronger dry season regime; ii) AD 1400 – 1870: freshwater swamps expanded to the study site; iii) later, from AD 1870 to present, upland forests dominated in the study area with a strong dry season. The presence of cereal cultivation from AD 1300 – 1450, and oil palm (Elaeis guineensis) since the mid-19th century AD indicates the presence of small-scale agriculture in the study area. This study of riparian vegetation dynamics and environmental changes in the Harapan forest of Sumatra shows the development from a riparian forest to a freshwater swamp and upland forest under the impact of climate change and human activities
Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial
Background
Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population.
Methods
AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921.
Findings
Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months.
Interpretation
Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke
Molecular imprinting science and technology: a survey of the literature for the years 2004-2011
The Influence of the Activation Temperature on the Structural Properties of the Activated Carbon Xerogels and Their Electrochemical Performance
The effect of activation temperature on the structural properties and the electrochemical performance of KOH-activated carbon xerogel was investigated in range of 700 to 1000°C. At a high temperature (1000°C), the chemical activation regenerated a more crystalline network structure of activated carbon xerogels, which was observed by Raman, XRD, and TEM images. Additionally, SEM images, BET, BJH, and t-plot were used to study the structural properties of carbon xerogels. The carbon xerogel sample activated at 900°C was found with the most appropriate structure, which has the high micropore area and a more-balanced porosity between the micropores and mesopores, for using as an electrode material. The highest obtained specific capacitance value was 270 Fg−1 in 6 M KOH electrolyte at scan rate of 5 mVs−1 from the cyclic voltammetry
Forest Dynamics and Agroforestry History since AD 200 in the Highland of Sumatra, Indonesia
Understanding past forest dynamics and human influence is essential for future forest management and ecosystem conservation. This study aims to provide insights into the forest dynamics and agroforestry history in the highlands of Sumatra for the last 1800 years. We carried out palaeoecological multi-proxy analyses of pollen, spores, non-pollen palynomorphs, macro-charcoal, and X-ray fluorescence on a limnic sediment core taken from Danau Kecil in the submontane area of Kerinci Seblat National Park in Sumatra, Indonesia. Our results provide an 1800-year record of forest dynamics under climate change and human influence including the transition from forest opening to shifting cultivation and eventually permanent agroforestry. Indicators for forest openings and secondary forest formation have been present since the beginning of records (AD 200). This is followed by the possible initiation of sugar palm (Arenga) cultivation (AD 400). Since AD 500, potential agroforestry and forest gardening practices have promoted major timber trees such as Lithocarpus/Castanopsis, Bischofia, and Dipterocarpaceae combined with sugar palm (Arenga). Permanent agroforestry systems were possibly established since AD 1760, evinced by an increase in commodity trees such as Dipterocarpaceae for resin production. With the Dutch invasion ca. AD 1900, agroforestry intensified and expanded to the Kerinci Valley. This was followed by land use intensification and potential rice cultivation around Danau Kecil since the 1940s. This study provides the first details on past forest dynamics around Danau Kecil since AD 200, showing among others how appropriate forest management and a closed canopy could reduce fire vulnerability in submontane rainforest
Assembled Porphyrin Nanofiber on the Surface of g-C<sub>3</sub>N<sub>4</sub> Nanomaterials for Enhanced Photocatalytic Degradation of Organic Dyes
In this work, a g-C3N4/porphyrin nanocomposite was fabricated through the self-assembling of monomeric Tetrakis (4-carboxyphenyl) porphyrin (TCPP) molecules with g-C3N4 nanomaterials. The characterizing results showed a good distribution of TCPP nanofibers with a diameter of 3N4 nanoflakes’ surfaces. The prepared g-C3N4/porphyrin nanocomposite had two bandgap energies of 2.38 and 2.7 eV, which could harvest a wide range of photon energy in the light spectrum, particularly in visible light. The obtained C3N4/TCPP nanocomposite revealed a remarkable photodegradation efficiency toward rhodamine B dyes, with a RhB removing rate of 3.3 × 10−2 min−1. The plausible mechanism for the photocatalytic performance of the g-C3N4/porphyrin photocatalyst for the RhB dye’s degradation was also studied and discussed
Assembled Porphyrin Nanofiber on the Surface of g-C3N4 Nanomaterials for Enhanced Photocatalytic Degradation of Organic Dyes
In this work, a g-C3N4/porphyrin nanocomposite was fabricated through the self-assembling of monomeric Tetrakis (4-carboxyphenyl) porphyrin (TCPP) molecules with g-C3N4 nanomaterials. The characterizing results showed a good distribution of TCPP nanofibers with a diameter of < 100 nm and several micrometers in length on the g-C3N4 nanoflakes’ surfaces. The prepared g-C3N4/porphyrin nanocomposite had two bandgap energies of 2.38 and 2.7 eV, which could harvest a wide range of photon energy in the light spectrum, particularly in visible light. The obtained C3N4/TCPP nanocomposite revealed a remarkable photodegradation efficiency toward rhodamine B dyes, with a RhB removing rate of 3.3 × 10−2 min−1. The plausible mechanism for the photocatalytic performance of the g-C3N4/porphyrin photocatalyst for the RhB dye’s degradation was also studied and discussed