CHARACTERIZATION OF SPONGE-GOURD RESIDUE PRETREATED BY MECHANICAL DISC REFINING

The present works describes the effect produced by mechanical disc refining in the pretreatment of lignocellulose agro-industrial waste, using scraps of sponge gourd. Two batches of sponge gourd scraps were refined in a laboratory disc refiner, at a consistence of 2.9 wt% (fiber/water) and residence time of 2 and 4 min. The two batches were then coded as MRS and HRS, respectively. MRS and HRS samples, as well as non-refined sponge gourd (NRS), were characterized in terms of morphological aspects, structural characteristics and thermal behavior. The analysis of SEM micrographs revealed that internal fibrillation dominated the refining process of sponge gourd, which, consequently, led to an increased surface area of the fibers. It was observed that the use of the disc refiner promoted the extraction of some hemicellulose content, increased the devolatilization index to 70% and 60%, as well as crystallinity – to 22% and 31% for MRS and HRS, respectively.

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Small dams alter thermal regimes of downstream water

Hydrology and Earth System Sciences ◽

10.5194/hess-23-4509-2019 ◽

2019 ◽

Vol 23 (11) ◽

pp. 4509-4525 ◽

Cited By ~ 2

Author(s):

André Chandesris ◽

Kris Van Looy ◽

Jacob S. Diamond ◽

Yves Souchon

Keyword(s):

Water Temperature ◽

Surface Area ◽

Residence Time ◽

Structural Characteristics ◽

Daily Temperature ◽

Aquatic Communities ◽

Maximum Daily Temperature ◽

Small Dams ◽

Thermal Regimes ◽

Minimum Daily Temperature

Abstract. The purpose of this study was to quantify the downstream impacts of different types of small dams on summer water temperature in lowland streams. We examined (1) temperature regimes upstream and downstream of dams with different structural characteristics, (2) relationships between stream temperature anomalies and climatic variables, watershed area, dam height, impoundment length and surface area, and residence time, (3) the most significant variables explaining the different thermal behaviors, and (4) the dam thermal effect considering a biological threshold of 22 ∘C, with a calculation of both the number of days with a temperature above this threshold and the average hourly duration above this threshold. Water temperature loggers were installed upstream and downstream of 11 dams in the Bresse region (France) and monitored at 30 min intervals during summer (June to September) over the 2009–2016 period, resulting in 13 paired water temperature time series (two sites were monitored for two summers, allowing the opportunity to compare cold and hot summers). At 23 % of the dams, we observed increased downstream maximum daily temperatures of more than 1 ∘C; at the remaining dams we observed changes in the maximum daily temperature of −1 to 1 ∘C. Across sites, the mean downstream increase of the minimum daily temperature was 1 ∘C, and for 85 % of the sites this increase was higher than 0.5 ∘C. We hierarchically clustered the sites based on three temperature anomaly variables: upstream–downstream differences in (1) maximum daily temperature (ΔTmax), (2) minimum daily temperature (ΔTmin), and (3) daily temperature amplitude (ΔTamp). The cluster analysis identified two main types of dam effects on thermal regime: (1) a downstream increase in Tmin associated with Tmax either unchanged or slightly reduced for impoundments of low volume (i.e., a residence time shorter than 0.7 d and a surface area less than 35 000 m2), and (2) a downstream increase of both Tmin and Tmax of the same order of magnitude for impoundments of larger volume (i.e., a residence time longer than 0.7 d and a surface area greater than 35 000 m2). These downstream temperature increases reached 2.4 ∘C at certain structures with the potential to impair the structure of aquatic communities and the functioning of the aquatic ecosystem. Overall, we show that small dams can meaningfully alter the thermal regimes of flowing waters, and that these that these effects can be explained with sufficient accuracy (R2=0.7) using two simple measurements of small dam physical attributes. This finding may have importance for modelers and managers who desire to understand and restore the fragmented thermalscapes of river networks.

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Development and Characterization of Amine-Clay Hybrid Adsorbents for CO2 Capture

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.547 ◽

2016 ◽

Vol 1133 ◽

pp. 547-551 ◽

Cited By ~ 2

Author(s):

Ali E.I. Elkhalifah ◽

Mohammad Azmi Bustam ◽

Azmi Mohd Shariff ◽

Sami Ullah ◽

Nadia Riaz ◽

...

Keyword(s):

Adsorption Capacity ◽

Surface Area ◽

Surface Properties ◽

Molar Mass ◽

Adsorption Ability ◽

Stepwise Increase ◽

Inverse Effect ◽

Bet Method ◽

Sodium Form

The present work aims at a better understanding of the influences of the intercalated mono-, di- and triethanolamines on the characteristics and CO2 adsorption ability of sodium form of bentonite (Na-bentonite). The results revealed that the molar mass of intercalated amines significantly influenced the structural and surface properties as well as the CO2 adsorption capacity of Na-bentonite. In this respect, a stepwise increase in the d-spacing of Na-bentonite with the molar mass of amine was recorded by XRD technique. However, an inverse effect of the molar mass of amine on the surface area was confirmed by BET method. CO2 adsorption experiments on amine-bentonite hybrid adsorbents showed that the CO2 adsorption capacity inversly related to the molar mass of amine at 25 ͦC and 101 kPa. Accordingly, Na-bentonite modified by monoethanolammonium cations adsorbed as high as 0.475 mmol CO2/g compared to 0.148 and 0.087 mmol CO2/g for that one treated with di- and triethanolammonium cations, respectively.

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Design and Characterization of Gypsum Mortars Dosed with Polyurethane Foam Waste PFW

Materials ◽

10.3390/ma13071497 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1497 ◽

Cited By ~ 1

Author(s):

Isabel Santamaría Vicario ◽

Lourdes Alameda Cuenca-Romero ◽

Sara Gutiérrez González ◽

Verónica Calderón Carpintero ◽

Ángel Rodríguez Saiz

Keyword(s):

Natural Resources ◽

Construction Industry ◽

Polyurethane Foam ◽

Industrial Waste ◽

Vapour Permeability ◽

Polyurethane Waste ◽

New Material ◽

Technical Specifications ◽

Mechanical Strengths

The properties and the behaviour of plaster mortars designed with Polyurethane Foam Waste (PFW) are studied in this investigation. A characterization of the mixtures is completed, in accordance with the technical specifications of European Norms. The incorporation of polyurethane waste foam can yield porous and lighter mortars, with better resistance to water-vapour permeability, although with weaker mechanical strength and higher levels of absorbency. Nevertheless, suitable mechanical strengths were achieved, resulting in a new material that is compliant with the requirements of the construction industry. The use of PFW in the the manufacture of gypsum mortars for construction reduces the consumption of natural resources and, at the same time, recovers an industrial waste that is otherwise difficult to recycle.

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Synthesis and characterization of some polyimide-epoxy composites

e-Polymers ◽

10.1515/epoly.2011.11.1.244 ◽

2011 ◽

Vol 11 (1) ◽

Cited By ~ 2

Author(s):

Toheed Akhter ◽

Humaira Masood Siddiqi ◽

Zareen Akhter ◽

M. Saeed Butt

Keyword(s):

Thermal Behavior ◽

Epoxy Resins ◽

Analytical Techniques ◽

Char Yield ◽

Epoxy Composites ◽

Hydroxyl Group ◽

Synthesis And Characterization ◽

Tetracarboxylic Acid ◽

Epoxy Amine

AbstractComposites from some novel polyimide and commercial epoxy were prepared aiming to improve the thermal behavior of epoxy resins. Two diamines namely 4-4'-diamino-4''-hydroxytriphenyl methane (DHTM) and 4-4'- diaminotriphenyl methane (DTM) were synthesized by reacting aniline and aldehydes according to a reported method. The synthesized diamines were blended with commercially available epoxy 1, 4-butanedioldiglycidylether (BDDE) to synthesize model epoxy amine networks which were compared with polyimideepoxy composites. The polyimides were synthesized by reaction of these diamines with aromatic anhydride namely 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA). These synthesized polyimides were dispersed in epoxy diamine networks to prepare composites. All the monomers and composites were characterized by making use of various analytical techniques including FTIR, NMR, TGA, DSC and XRD. Presence of hydroxyl group in the diamine helped in better dispersion of polyimide leading to high Tg and high char yield at 600 °C.

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Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽

10.3390/pr9020217 ◽

2021 ◽

Vol 9 (2) ◽

pp. 217

Author(s):

Marin Ugrina ◽

Martin Gaberšek ◽

Aleksandra Daković ◽

Ivona Nuić

Keyword(s):

Chemical Modification ◽

Aqueous Solutions ◽

Specific Surface ◽

Surface Area ◽

Natural Zeolite ◽

Contact Time ◽

Liquid Ratio ◽

X Ray ◽

Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

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Exploiting the Amazing Diversity of Natural Source-Derived Polysaccharides: Modern Procedures of Isolation, Engineering, and Optimization of Antiviral Activities

Polymers ◽

10.3390/polym13010136 ◽

2020 ◽

Vol 13 (1) ◽

pp. 136

Author(s):

Bimalendu Ray ◽

Martin Schütz ◽

Shuvam Mukherjee ◽

Subrata Jana ◽

Sayani Ray ◽

...

Keyword(s):

Structural Characteristics ◽

Antiviral Drug ◽

Natural Source ◽

Target Interaction ◽

Charge Densities ◽

Linkage Pattern ◽

Naturally Occurring ◽

Antiviral Activities ◽

One Step

Naturally occurring polysaccharide sulfates are highly diverse, owning variations in the backbone structure, linkage pattern and stereochemistry, branching diversity, sulfate content and positions of sulfate group(s). These structural characteristics bring about diverse sulfated polymers with dissimilar negative charge densities and structure–activity relationships. Herein, we start with a short discussion of techniques needed for extraction, purification, chemical sulfation, and structural characterization of polysaccharides. Processes of isolation and sulfation of plant-derived polysaccharides are challenging and usually involve two steps. In this context, we describe an integrated extraction-sulfation procedure that produces polysaccharide sulfates from natural products in one step, thereby generating additional pharmacological activities. Finally, we provide examples of the spectrum of natural source-derived polysaccharides possessing specific features of bioactivity, in particular focusing on current aspects of antiviral drug development and drug–target interaction. Thus, the review presents a detailed view on chemically engineered polysaccharides, especially sulfated derivatives, and underlines their promising biomedical perspectives.

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Nanocomposite Materials Based on Electrochemically Synthesized Graphene Polymers: Molecular Architecture Strategies for Sensor Applications

Chemosensors ◽

10.3390/chemosensors9060149 ◽

2021 ◽

Vol 9 (6) ◽

pp. 149

Author(s):

André Olean-Oliveira ◽

Gilberto A. Oliveira Brito ◽

Celso Xavier Cardoso ◽

Marcos F. S. Teixeira

Keyword(s):

Conducting Polymers ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Electrochemical Sensors ◽

Structural Characteristics ◽

Low Cost ◽

Large Specific Surface Area ◽

Molecular Architecture ◽

Sensor Applications

The use of graphene and its derivatives in the development of electrochemical sensors has been growing in recent decades. Part of this success is due to the excellent characteristics of such materials, such as good electrical and mechanical properties and a large specific surface area. The formation of composites and nanocomposites with these two materials leads to better sensing performance compared to pure graphene and conductive polymers. The increased large specific surface area of the nanocomposites and the synergistic effect between graphene and conducting polymers is responsible for this interesting result. The most widely used methodologies for the synthesis of these materials are still based on chemical routes. However, electrochemical routes have emerged and are gaining space, affording advantages such as low cost and the promising possibility of modulation of the structural characteristics of composites. As a result, application in sensor devices can lead to increased sensitivity and decreased analysis cost. Thus, this review presents the main aspects for the construction of nanomaterials based on graphene oxide and conducting polymers, as well as the recent efforts made to apply this methodology in the development of sensors and biosensors.

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Characterization of Recombinant Adeno-Associated Viruses (rAAVs) for Gene Therapy Using Orthogonal Techniques

Pharmaceutics ◽

10.3390/pharmaceutics13040586 ◽

2021 ◽

Vol 13 (4) ◽

pp. 586

Author(s):

Liam Cole ◽

Diogo Fernandes ◽

Maryam T. Hussain ◽

Michael Kaszuba ◽

John Stenson ◽

...

Keyword(s):

Gene Therapy ◽

Light Scattering ◽

Dynamic Light Scattering ◽

Viral Vector ◽

Structural Characteristics ◽

Genetic Material ◽

Label Free ◽

Gene Therapies ◽

Multiple Challenges

Viruses are increasingly used as vectors for delivery of genetic material for gene therapy and vaccine applications. Recombinant adeno-associated viruses (rAAVs) are a class of viral vector that is being investigated intensively in the development of gene therapies. To develop efficient rAAV therapies produced through controlled and economical manufacturing processes, multiple challenges need to be addressed starting from viral capsid design through identification of optimal process and formulation conditions to comprehensive quality control. Addressing these challenges requires fit-for-purpose analytics for extensive characterization of rAAV samples including measurements of capsid or particle titer, percentage of full rAAV particles, particle size, aggregate formation, thermal stability, genome release, and capsid charge, all of which may impact critical quality attributes of the final product. Importantly, there is a need for rapid analytical solutions not relying on the use of dedicated reagents and costly reference standards. In this study, we evaluate the capabilities of dynamic light scattering, multiangle dynamic light scattering, and SEC–MALS for analyses of rAAV5 samples in a broad range of viral concentrations (titers) at different levels of genome loading, sample heterogeneity, and sample conditions. The study shows that DLS and MADLS® can be used to determine the size of full and empty rAAV5 (27 ± 0.3 and 33 ± 0.4 nm, respectively). A linear range for rAAV5 size and titer determination with MADLS was established to be 4.4 × 1011–8.7 × 1013 cp/mL for the nominally full rAAV5 samples and 3.4 × 1011–7 × 1013 cp/mL for the nominally empty rAAV5 samples with 3–8% and 10–37% CV for the full and empty rAAV5 samples, respectively. The structural stability and viral load release were also inferred from a combination of DLS, SEC–MALS, and DSC. The structural characteristics of the rAAV5 start to change from 40 °C onward, with increasing aggregation observed. With this study, we explored and demonstrated the applicability and value of orthogonal and complementary label-free technologies for enhanced serotype-independent characterization of key properties and stability profiles of rAAV5 samples.

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A Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology inChlamydomonas reinhardtii

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1904587116 ◽

2019 ◽

Vol 116 (37) ◽

pp. 18445-18454 ◽

Cited By ~ 14

Author(s):

Alan K. Itakura ◽

Kher Xing Chan ◽

Nicky Atkinson ◽

Leif Pallesen ◽

Lianyong Wang ◽

...

Keyword(s):

Surface Area ◽

Structure And Function ◽

Binding Motif ◽

Starch Granules ◽

Wild Type ◽

Bisphosphate Carboxylase ◽

Biophysical Mechanism ◽

Mechanism Function ◽

And Function

A phase-separated, liquid-like organelle called the pyrenoid mediates CO2fixation in the chloroplasts of nearly all eukaryotic algae. While most algae have 1 pyrenoid per chloroplast, here we describe a mutant in the model algaChlamydomonasthat has on average 10 pyrenoids per chloroplast. Characterization of the mutant leads us to propose a model where multiple pyrenoids are favored by an increase in the surface area of the starch sheath that surrounds and binds to the liquid-like pyrenoid matrix. We find that the mutant’s phenotypes are due to disruption of a gene, which we call StArch Granules Abnormal 1 (SAGA1) because starch sheath granules, or plates, in mutants lacking SAGA1 are more elongated and thinner than those of wild type. SAGA1 contains a starch binding motif, suggesting that it may directly regulate starch sheath morphology. SAGA1 localizes to multiple puncta and streaks in the pyrenoid and physically interacts with the small and large subunits of the carbon-fixing enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), a major component of the liquid-like pyrenoid matrix. Our findings suggest a biophysical mechanism by which starch sheath morphology affects pyrenoid number and CO2-concentrating mechanism function, advancing our understanding of the structure and function of this biogeochemically important organelle. More broadly, we propose that the number of phase-separated organelles can be regulated by imposing constraints on their surface area.

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