scholarly journals A CONTRIBUTION TO THE HYDROCHEMISTRY AND WATER TYPOLOGY OF THE AMAZON RIVER AND ITS TRIBUTARIES

2019 ◽  
Vol 20 (72) ◽  
pp. 360-374 ◽  
Author(s):  
Maria do Socorro Rocha da Silva ◽  
Eduardo Antonio Ríos-Villamizar ◽  
Hillândia Brandão da Cunha ◽  
Sebastião Átila Fonseca Miranda ◽  
Sávio José Filgueiras Ferreira ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Physicochemical Properties ◽  
Amazon Basin ◽  
The Other ◽  
Amazon River ◽  
Left Bank ◽  
Guiana Shield ◽  
Ionic Charge ◽  
Physical Chemical ◽  
Geological Diversity

The geological diversity of the Amazon Basin, as well as the pluvial regime, influences the characteristics of the waters. To know the water types of the rivers of the Amazon basin, 288 superficial water samples were collected, 94 of them along the Amazon River and 194 in their tributaries, from March 2009 to September 2012. The physical, chemical, and physicochemical properties were analyzed. Rivers with pH between 6.5 and 7.6 and electrical conductivity (40.00 - 80.00 μS cm-1) are water bodies that are influenced by the Andean region (e.g., the Amazon River and some of its right bank tributaries). On the other hand, the rivers with pH in the range of 3.5 to 5.5 and conductivity <30.00 μS cm-1, which are Amazon River’s left bank tributaries, reflect the characteristics of the Guiana Shield. The rivers with pH (6.0 to 7.0), low ionic charge, and conductivity <40.0 μS cm-1, such as the lower Amazon River’s right bank tributaries (Tapajos and Xingu) which are influenced by the Central Brazilian Shield, and also the middle/upper Amazon River’s right bank tributaries (Tefé, Coari and Jutaí).

scholarly journals Rapid assessment of the ichthyofauna of the southern Guiana Shield tributaries of the Amazonas River in Pará, Brazil

2020 ◽  
Vol 50 (1) ◽  
pp. 24-36 ◽  
Author(s):  
Guilherme M. DUTRA ◽  
Tiago M. S. FREITAS ◽  
Bruno S. PRUDENTE ◽  
Gilberto N. SALVADOR ◽  
Manuela D. V. LEÃO ◽  
...  
Keyword(s):  
Protected Areas ◽  
Fish Species ◽  
Amazon Basin ◽  
New Records ◽  
Rapid Assessment ◽  
Drainage System ◽  
Future Research ◽  
Left Bank ◽  
Guiana Shield ◽  
Conservation Programs

ABSTRACT The Northern Pará Drainage System encompasses the left-bank tributaries of the Amazonas River in the southern Guiana Shield region of Pará state, Brazil. Five of the region’s state protected areas are considered strategic for the conservation of its biodiversity. In the present study, we assessed the ichthyofauna of the five state protected areas of the Northern Pará Drainage System. Seven expeditions were conducted between January 2008 and January 2009, which surveyed stretches of the Cuminá, Cuminapanema, Curuá, Jari, Mapuera, Nhamundá, and Paru rivers. These surveys yielded 286 species belonging to 38 families and eight orders, including seven new records of fish species for Brazil, six of which are also new records for the Amazon basin. Our results provide a valuable database for future research and conservation programs in the protected areas of the region.

scholarly journals Effect of Chitosan, Clay, and CMC on Physicochemical Properties of Bioplastic from Banana Corm with Glycerol.

2021 ◽  
Vol 10 (1) ◽  
pp. 31-35
Author(s):  
Agung Sugiharto ◽  
Adilla Syarifa ◽  
Nindita Handayani ◽  
Rizky Mahendra
Keyword(s):  
Tensile Strength ◽  
Physicochemical Properties ◽  
Physical Properties ◽  
Organic Material ◽  
Chemical Properties ◽  
The Other ◽  
Physical Chemical ◽  
Composition Variation ◽  
Elongation Percentage

Bioplactic from banana corm and glycerol has been studied in this research. In addition, the physical chemical properties of it has been improved by adding chitosan, clay and CMC as filler and glycerol as plasticizer. Plastic that produced form organic material such as starch usually has poor properties in physical and mechanical. Composition variation of chitosan, clay and CMC as filler then combined by variation of glycerol as plasticizer have produced significant improve of the bioplastic physical properties. Properties of the bioplastic that studied in this research was focused to biodegradation, elongation, and tensile strength. The addition of fillers and plasticizers is carried out to produce a better bioplastics. This study used 3 variations of the filler composition : 4, 5, and 6 grams and 2 variations of the plasticizer composition: 1 ml and 2 ml. The bioplastics that produced were tested for tensile strength, elongation, and biodegradation of the soil for 7 days. The best tensile strength results is 8.43 MPa for bioplastic that using CMC fillers. On the other side, the best elongation percentage is 9.87% for bioplastic which using CMC fillers. The bioplastic that added Clay as filler can be degraded up to 100% in 7 days.

scholarly journals First record of Annonaceae wood for the Neogene of South America, Amazon Basin, Brazil

2017 ◽  
Vol 47 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Emilio Alberto Amaral Soares ◽  
Adriana Cabral Kloster ◽  
Silvia Cristina Gnaedinger ◽  
Silvio Roberto Riker ◽  
Felipe José da Cruz Lima ◽  
...  
Keyword(s):  
South America ◽  
Amazon Basin ◽  
River System ◽  
First Record ◽  
Morphological Data ◽  
Amazon River ◽  
Left Bank ◽  
Paleoenvironmental Reconstruction ◽  
Depositional Processes ◽  
Systematic Character

ABSTRACT: The relief of the regions of Manaus and Itacoatiara, Central Amazon, is supported by Neogene siliciclastic rocks, bounded at the base and top by lateritic paleosols and covered by quaternary sedimentary deposits from the Solimões-Amazon river system. This unit is informally assigned to the Novo Remanso Formation, consists of usually reddish and ferruginized sandstones, conglomerates and pelites, with few identified fossil records, a fact that has hindered its stratigraphic position, and the paleoenvironmental reconstruction of the last phase of the Amazon Basin settling. This study describes, for the first time, the occurrence of fossil wood in outcroppings of the left bank of the Amazon River, where anatomical and morphological data has enabled its characterization to the species level. Thus, the data marks the record of the Annonaceae in South America, as well as the depositional processes related to incorporation of organic material in the sandy layer and the fossilization processes that allowed its preservation. In an unprecedented way, this study has described Duguetiaxylon amazonicum nov. gen and sp. and provided information on the anatomical and systematic character, as well as data on plant-insect interaction, and a better understanding of the family.

Polymer-Graphene Nanoassemblies and their Applications in Cancer Theranostics

2020 ◽  
Vol 20 (11) ◽  
pp. 1340-1351 ◽  
Author(s):  
Ponnurengam M. Sivakumar ◽  
Matin Islami ◽  
Ali Zarrabi ◽  
Arezoo Khosravi ◽  
Shohreh Peimanfard
Keyword(s):  
Mechanical Stability ◽  
Chemical Properties ◽  
The Other ◽  
Hydrophilic Polymer ◽  
Two Dimensional ◽  
Normal Tissues ◽  
Physical Chemical ◽  
Anti Cancer ◽  
Good Biocompatibility ◽  
Cancer Theranostics

Background and objective: Graphene-based nanomaterials have received increasing attention due to their unique physical-chemical properties including two-dimensional planar structure, large surface area, chemical and mechanical stability, superconductivity and good biocompatibility. On the other hand, graphene-based nanomaterials have been explored as theranostics agents, the combination of therapeutics and diagnostics. In recent years, grafting hydrophilic polymer moieties have been introduced as an efficient approach to improve the properties of graphene-based nanomaterials and obtain new nanoassemblies for cancer therapy. Methods and results: This review would illustrate biodistribution, cellular uptake and toxicity of polymergraphene nanoassemblies and summarize part of successes achieved in cancer treatment using such nanoassemblies. Conclusion: The observations showed successful targeting functionality of the polymer-GO conjugations and demonstrated a reduction of the side effects of anti-cancer drugs for normal tissues.

scholarly journals Influence of Physicochemical Properties and Parent Material on Chromium Fractionation in Soils

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1073
Author(s):  
Claudia Campillo-Cora ◽  
Laura Rodríguez-González ◽  
Manuel Arias-Estévez ◽  
David Fernández-Calviño ◽  
Diego Soto-Gómez
Keyword(s):  
Physicochemical Properties ◽  
Contaminated Soils ◽  
Research Work ◽  
Parent Material ◽  
The Other ◽  
Oxidation States ◽  
Diethylenetriaminepentaacetic Acid ◽  
Remediation Strategies ◽  
Exchangeable Aluminum ◽  
Efficient Extraction

Chromium is an element that possess several oxidation states and can easily pass from one to another, so its behavior in soils is very complex. For this reason, determining its fate in the environment can be difficult. In this research work we tried to determine which factors affect the chromium fractionation in natural soils, conditioning chromium mobility. We paid special attention to the parent material. For this purpose, extraction experiments were carried out on spiked soils incubated for 50–60 days, using H2O, CaCl2 and diethylenetriaminepentaacetic acid (DTPA). The most efficient extraction rate in all soils was achieved using water, followed by CaCl2 and DTPA. We obtained models with an adjusted R2 of 0.8097, 0.8471 and 0.7509 for the H2O Cr, CaCl2 Cr and DTPA Cr respectively. All models were influenced by the amount of chromium added and the parent material: amphibolite and granite influenced the amount of H2O Cr extracted, and schist affected the other two fractions (CaCl2 and DTPA). Soil texture also played an important role in the chromium extraction, as well as the amounts of exchangeable aluminum and magnesium, and the bioavailable phosphorus. We concluded that it is possible to make relatively accurate predictions of the behavior of the different Cr fractions studied, so that optimized remediation strategies for chromium-contaminated soils can be designed on the basis of a physicochemical soil characterization.

Nanobiotechnology: Nature-inspired silver nanoparticles towards green synthesis

2021 ◽  
pp. 0958305X2198988
Author(s):  
Nur Syakirah Rabiha Rosman ◽  
Noor Aniza Harun ◽  
Izwandy Idris ◽  
Wan Iryani Wan Ismail
Keyword(s):  
Electrical Conductivity ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Metal Nanoparticles ◽  
Current Trend ◽  
Biological Properties ◽  
Noble Metal Nanoparticles ◽  
Current Application ◽  
Physical Chemical ◽  
Physical And Chemical

The emergence of technology to produce nanoparticles (1 nm – 100 nm in size) has drawn significant researchers’ interests. Nanoparticles can boost the antimicrobial, catalytic, optical, and electrical conductivity properties, which cannot be achieved by their corresponding bulk. Among other noble metal nanoparticles, silver nanoparticles (AgNPs) have attained a special emphasis in the industry due to their superior physical, chemical, and biological properties, closely linked to their shapes, sizes, and morphologies. Proper knowledge of these NPs is essential to maximise the potential of biosynthesised AgNPs in various applications while mitigating risks to humans and the environment. This paper aims to critically review the global consumption of AgNPs and compare the AgNPs synthesis between conventional methods (physical and chemical) and current trend method (biological). Related work, advantages, and drawbacks are also highlighted. Pertinently, this review extensively discusses the current application of AgNPs in various fields. Lastly, the challenges and prospects of biosynthesised AgNPs, including application safety, oxidation, and stability, commercialisation, and sustainability of resources towards a green environment, were discussed.

Preparation of Glass-Ceramics Using Molybdenum Tailings

2011 ◽  
Vol 284-286 ◽  
pp. 1431-1434 ◽  
Author(s):  
Jin Rui Zhang ◽  
Ru Wang
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Crystalline Phase ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
The Other ◽  
Raw Material ◽  
Physical Chemical ◽  
Nucleation Agents

In order to utilization the molybdenum tailings which be deposited in large quantities. Test used it to prepare glass-ceramics as main raw material, TiO2 as nucleation agents and CaO-Al2O3-SiO2 system and wollastonite as the principal crystalline phase. Heat treatment system of glass-ceramics was based on the differential thermal analysis. The crystalline phase, microstructure and characteristics of glass-ceramics were analysis by XRD, SEM and physical, chemical properties test. The result shows that the performance of glass-ceramics was superior to the other types of building decoration stone.

Composition-Dependent Electrical Conductivity of Ionic-Electronic Composite

1997 ◽  
Vol 500 ◽  
Author(s):  
M. Park ◽  
G. M. Choi
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Electromotive Force ◽  
Composition Dependence ◽  
Force Measurement ◽  
Ionic Transport ◽  
Charge Carriers ◽  
Stabilized Zirconia ◽  
Ionic Charge ◽  
Polarization Technique

ABSTRACTComposition. dependence of electrical conductivity of ionic-electronic composite was camined using yttria(8mol%) stabilized zirconia-NiO composites. The contributions of ectronic and ionic charge carriers to the electrical conductivity were determined by Hebb-Vagner polarization technique and electromotive force measurement of galvanic cell. Up to 6 sol% NiO addition, the conductivity decreased since the electronic NiO acted as an insulator in onic matrix. However the ionic transport was dominant until NiO content reaches 26 vol%. Mixed conduction was observed between 26 and 68 vol% of NiO. The effects of composition on he electrical properties were explained by the microstructure and thus by the distribution of two hases.

scholarly journals Emergence and biomass accumulation in seedlings of rice cultivars irrigated with saline water

2018 ◽  
Vol 22 (7) ◽  
pp. 471-475
Author(s):  
Márcio H. da C. Freire ◽  
Geocleber G. de Sousa ◽  
Maria V. P. de Souza ◽  
Emanuel D. R. de Ceita ◽  
Jamili N. Fiusa ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dry Matter ◽  
Saline Water ◽  
Biomass Accumulation ◽  
The Other ◽  
Saline Stress ◽  
Rice Cultivars ◽  
Saline Water Irrigation ◽  
Emergence Percentage ◽  
Mean Time

ABSTRACT The objective of this study was to evaluate the performance of three rice cultivars under saline water irrigation. The experiment was carried out in full sun at the Experimental Farm of the Unilab, in Redenção, Ceará, Brazil, in January 2016. The experimental design was completely randomized (CRD), in a 5 x 3 factorial scheme [irrigation water electrical conductivity (ECw: 0.5, 1.0, 2.0, 3.0 and 4.0 dS m-1) versus three rice cultivars (C1 - Ligeirinho, C2 - Casado and C3 - Meruinho)], totaling 15 treatments, with 4 replicates of 30 seeds per cultivar. After 21 days, the following variables were evaluated: emergence percentage (EP), emergence speed index (ESI), mean time of emergence (MTE), mean speed of emergence (MSE), shoot dry matter (SDM), root dry matter (RDM) and total dry matter (TDM). The cultivar Ligeirinho showed higher tolerance to saline stress with respect to the emergence percentage, emergence speed index and mean speed of emergence. The cultivar Casado showed higher tolerance to saline stress for shoot dry matter, root dry matter and total dry matter in comparison to the other cultivars.

scholarly journals Three new records of Remijia (Cinchoneae, Rubiaceae) for the Brazilian Amazon and a new altitudinal record for Venezuela

Rodriguésia ◽  
2019 ◽  
Vol 70 ◽  
Author(s):  
Alessandra Marques de Paiva ◽  
Tamara de Andrade Ferreira Vieira ◽  
Ruy José Válka Alves ◽  
Nílber Gonçalves da Silva
Keyword(s):  
Amazon Basin ◽  
New Records ◽  
Brazilian Amazon ◽  
The State ◽  
Guiana Shield

Abstract We present three new records of Remijia (Rubiaceae) for Brazil. Remijia globosa and R. reducta were known only from Venezuela and R. hispida from Venezuela and Colombia. During a revisional study of the genus, we found these three species had also been collected in the state of Amazonas, Brazil. Additionally, we found a collection of R. hispida from Venezuela, near La Esmeralda, at an altitude over 2,000 m higher than previously known for this species. This contributes to the knowledge of Remijia distribution, especially in the Amazon basin and in the Brazilian part of the Guiana Shield.

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