scholarly journals Preparation and Characterization of Calcium Cross-Linked Starch Monolithic Cryogels and Their Application as Cost-Effective Green Filters

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3975
Author(s):  
Chanita Boonkanon ◽  
Kharittha Phatthanawiwat ◽  
Laemthong Chuenchom ◽  
Nareumon Lamthornkit ◽  
Tarawee Taweekarn ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Cost Effective ◽  
Dry Weight ◽  
Rice Flour ◽  
Monolithic Material ◽  
Surface Areas ◽  
First Time ◽  
Interconnected Pores ◽  
Resultant Material

Monolithic cryogels from starch were successfully synthesized and applied as alternative biodegradable filters for the first time. Rice flour was cross-linked with Ca2+ from limewater during gelatinization before being frozen and then thawed for three cycles. The resultant material was then soaked in ethanol for 3 h before incubation at 80 °C for 1 h, yielding monolithic material with interconnected pores in sizes of 51 ± 18 to 52 ± 15 µm without any need of freeze-drying. The cryogels possessed macroporous structure with specific surface areas from 1.1 to 4.3 m2g−1, they could adsorb water from 599 ± 27 to 635 ± 59% of their dry weight with low swelling ratios of 6.0 ± 0.3 to 6.4 ± 0.6 gwater/gcryogel, and could be applied as biofilters to remove suspended particles and reduce the light absorption of water sample from 25 ± 3 to 96 ± 5%. The prepared biofilters can be re-used up to three times, although they cost only USD 0.0004/piece. Complete weight loss resulted from burial in soil for 30 days, indicating environmentally friendly biodegradation and potential for environmental applications.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

Hydroxyapatite/Biopolymers Composite Scaffolds for Bone Tissue Engineering

2011 ◽  
Vol 493-494 ◽  
pp. 826-831
Author(s):  
A.C.B.M. Fook ◽  
Thiago Bizerra Fideles ◽  
R.C. Barbosa ◽  
G.T.F.S. Furtado ◽  
G.Y.H. Sampaio ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Freeze Drying ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interconnected Pores

The application of a hybrid composite consisting of biopolymer and calcium phosphate, similar morphology and properties of natural bone, may be a way to solve the problem of the fragility of ceramics without reducing its mechanical properties, retaining the properties of biocompatibility and high bioactivity. This work aims at the preparation and characterization of three-dimensional scaffolds composite HA / biopolymers (chitosan and gelatin). The freeze-drying technique was employed in this study to obtain these frameworks and partial results showed the effectiveness of this method. This involved the study of structural, chemical and morphological frameworks, in order to direct the research suggested the application. The X Ray Diffraction (XRD) and infrared spectroscopy and Fourier transform (FTIR) results confirmed the formation of hydroxyapatite (HA) phase and the presence of characteristic bands of HA and biopolymers in all compositions. The microstructure of the scaffolds study conducted by Scanning Electron Microscopy (SEM) revealed the formation of longitudinally oriented microchannels with interconnected pores. In all compositions the porous scaffolds showed varying sizes and mostly larger than 100μm, and is therefore considered materials with potential for application in bone tissue engineering.

Virulence Characterization of Puccinia graminis f. sp. avenae and Resistance of Oat Cultivars in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Tianya Li ◽  
Yiwei Xu ◽  
Xue Zhang ◽  
Xian Xin Wu ◽  
Yazhao Zhang ◽  
...  
Keyword(s):  
Stem Rust ◽  
Rust Resistance ◽  
Cost Effective ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Resistant Cultivars ◽  
Oat Cultivars ◽  
First Time

Oat stem rust, caused by Puccinia graminis f. sp. avenae (Pga), is one of the most devastating diseases of oat. The most cost-effective and eco-friendly strategy to control this disease is the use of resistant cultivars. However, P. graminis f. sp. avenae can overcome the resistance of cultivars by rapidly changing its virulence. Thus, information on the virulence of P. graminis f. sp. avenae populations and resistance of cultivars is critical to control the disease. The current study was conducted to monitor the virulence composition and dynamics in the P. graminis f. sp. avenae population in China and to evaluate resistance of oat cultivars. Oat leaves naturally infected by P. graminis f. sp. avenae were collected during 2018 and 2019 and 159 isolates were derived from single uredinia. The isolates were tested on 12 international differential lines, and eight races, TJJ, TBD, TJB, TJD, TJL, TJN, TGD, and TKN, were identified for the first time in China. The predominant race was TJD, virulent against Pg1, Pg2, Pg3, Pg4, Pg8, Pg9, and Pg15, accounting for 35.8% and 37.8% in 2018 and 2019, respectively. The sub-predominant races were TJN (30.2% in 2018, 28.3% in 2019) and TKN (20.8% in 2018, 12.3% in 2019). All isolates were virulent to Pg1, Pg2, Pg3, and Pg4, and avirulent to Pg6 and Pg16. The three predominant races (TJD, TJN, and TKN) were used to evaluate resistance in 30 Chinese oat cultivars at the seedling and adult-plant stages. Five cultivars, Bayan 1, Baiyan 2, Baiyan 3, Baiyan 5, and Baiyan 9, were highly resistant to the three races at both seedling and adult-plant stages. The results of the virulences and frequencies of P. graminis f. sp. avenae races and the resistant cultivars will be useful in understanding the pathogen migration and evolution and for breeding oat cultivars with stem rust resistance.

Fabrication and Characterisation of Polymer and Composite Scaffolds Based on Polyhydroxybutyrate and Polyhydroxybutyrate-Co-Hydroxyvalerate

2007 ◽  
Vol 334-335 ◽  
pp. 1229-1232 ◽  
Author(s):  
Naznin Sultana ◽  
Min Wang
Keyword(s):  
Freeze Drying ◽  
Polymer Concentration ◽  
Three Dimensional ◽  
Polymer Scaffolds ◽  
Composite Scaffolds ◽  
Fabrication And Characterization ◽  
Fabrication Parameters ◽  
Highly Porous ◽  
Interconnected Pores

This paper reports the fabrication and characterization of three-dimensional, highly porous polyhydroxybutyrate (PHB), polyhydroxybutyrate-co-valerate (PHBV) and composite scaffolds made by the emulsion freezing / freezing-drying technique. Freeze-drying of the polymer/solvent/ water phase emulsions produced hard and tough scaffolds with interconnected pores. The effects of the fabrication parameters such as polymer concentration in emulsions and emulsion stabilizer were examined and optimized. The density of polymer scaffolds was found to increase with an increasing polymer concentration. Structural analyses of selected samples using scanning electron microscopy indicated that the scaffolds had pore sizes ranging from several microns to a few hundred microns. The porosity of scaffolds of up to 85% was achieved and it increased with a decreasing polymer concentration. It was found that mechanical properties of composite scaffolds increased with the increasing amount of hydroxyapatite (HA) incorporated in the scaffolds.

scholarly journals Poly(Urethane-Acrylate) Aerogels via Radical Polymerization of Dendritic Urethane-Acrylate Monomers

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2249 ◽  
Author(s):  
Maria Papastergiou ◽  
Aspasia Kanellou ◽  
Despoina Chriti ◽  
Grigorios Raptopoulos ◽  
Patrina Paraskevopoulou
Keyword(s):  
Thermal Stability ◽  
Material Properties ◽  
Urethane Acrylate ◽  
Porous Network ◽  
Surface Areas ◽  
Similar Materials ◽  
Free Radical Chemistry ◽  
Acrylate Monomers ◽  
First Time

The purpose of this work was to investigate the effect of multifunctionality on material properties of synthetic polymer aerogels. For this purpose, we present the synthesis and characterization of monolithic dendritic-type urethane-acrylate monomers based on an aliphatic/flexible (Desmodur N3300), or an aromatic/rigid (Desmodur RE) triisocyanate core. The terminal acrylate groups (three at the tip of each of the three branches, nine in total) were polymerized with 2,2′-azobis(isobutyronitrile) (AIBN) via free radical chemistry. The resulting wet-gels were dried with supercritical fluid (SCF) CO2. Aerogels were characterized with ATR-FTIR and solid-state 13C NMR. The porous network was probed with N2-sorption and scanning electron microscopy (SEM). The thermal stability of aerogels was studied with thermogravimetric analysis (TGA). Most aerogels were macroporous materials (porosity > 80%), with high thermal stability (up to 300 °C). Aerogels were softer at low monomer concentrations and more rigid at higher concentrations. The material properties were compared with those of analogous aerogels bearing only one acrylate moiety at the tip of each branch and the same cores, and with those of analogous aerogels bearing norbornene instead of acrylate moieties. The nine-terminal acrylate-based monomers of this study caused rapid decrease of the solubility of the growing polymer and made possible aerogels with much smaller particles and much higher surface areas. For the first time, aliphatic/flexible triisocyanate-based materials could be made with similar properties in terms of particle size and surface areas to their aromatic/rigid analogues. Finally, it was found that with monomers with a high number of crosslinkable groups, material properties are determined by multifunctionality and thus aerogels based on 9-acrylate- and 9-norbornene-terminated monomers were similar. Materials with aromatic cores are carbonizable with satisfactory yields (20–30% w/w) to mostly microporous materials (BET surface areas: 640–740 m2 g−1; micropore surface areas: 360–430 m2 g−1).

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

Monitoring of Petroleum-Related Environmental Contamination Using Fluorescence Fingerprinting

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
P. Literathy ◽  
M. Quinn
Keyword(s):  
Environmental Contamination ◽  
Statistical Evaluation ◽  
Oil Pollution ◽  
Emission Spectra ◽  
Cost Effective ◽  
Petroleum Products ◽  
Danube River ◽  
Aromatic Components ◽  
Analytical Approaches

Petroleum and its refined products are considered the most complex contaminants frequently impacting the environment in significant quantities. They have heterogeneous chemical composition and alterations occur during environmental weathering. No single analytical method exists to characterize the petroleum-related environmental contamination. For monitoring, the analytical approaches include gravimetric, spectrometric and chromatographic methods having significant differences in their selectivity, sensitivity and cost-effectiveness. Recording fluorescence fingerprints of the cyclohexane extracts of the water, suspended solids, sediment or soil samples and applying appropriate statistical evaluation (e.g. by correlating the concatenated emission spectra of the fingerprints of the samples with arbitrary standards (e.g. petroleum products)), provides a powerful, cost-effective analytical tool for characterization of the type of oil pollution and detecting the most harmful aromatic components of the petroleum contaminated matrix. For monitoring purposes, the level of the contamination can be expressed as the equivalent concentration of an appropriate characteristic standard, based on the fluorescence intensities at the relevant characteristic wavelengths. These procedures are demonstrated in the monitoring of petroleum-related pollution in the water and suspended sediment in the Danube river basin

Chemical Constituents and Antibacterial Activity of Cissus Aralioides.

2020 ◽  
Vol 17 ◽  
Author(s):  
Balogun Olaoye Solomon ◽  
Ajayi Olukayode Solomon ◽  
Owolabi Temitayo Abidemi ◽  
Oladimeji Abdulkarbir Oladele ◽  
Liu Zhiqiang
Keyword(s):  
Plant Extract ◽  
Chemical Constituents ◽  
Ethyl Acetate Fraction ◽  
Antibacterial Activities ◽  
Sub Saharan Africa ◽  
Chromatographic Purification ◽  
Whole Plant ◽  
Sub Saharan ◽  
First Time

: Cissus aralioides is a medicinal plant used in sub-Saharan Africa for treatment of infectious diseases; however the chemical constituents of the plant have not been investigated. Thus, in this study, attempt was made at identifying predominant phytochemical constituents of the plant through chromatographic purification and silylation of the plant extract, and subsequent characterization using spectroscopic and GC-MS techniques. The minimum inhibitory concentration (MICs) for the antibacterial activities of the plant extract, chromatographic fractions and isolated compounds were also examined. Chromatographic purification of the ethyl acetate fraction from the whole plant afforded three compounds: β-sitosterol (1), stigmasterol (2) and friedelin (3). The phytosterols (1 and 2) were obtained together as a mixture. The GC-MS analysis of silylated extract indicated alcohols, fatty acids and sugars as predominant classes, with composition of 24.62, 36.90 and 26.52% respectively. Results of MICs indicated that friedelin and other chromatographic fractions had values (0.0626-1.0 mg/mL) comparable with the standard antibiotics used. Characterization of natural products from C. aralioides is being reported for the first time in this study.

scholarly journals Valorization of sugarcane bagasse by chemical pretreatment and enzyme mediated deconstruction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vihang S. Thite ◽  
Anuradha S. Nerurkar
Keyword(s):  
Cell Wall ◽  
Sugarcane Bagasse ◽  
Structural Changes ◽  
Enzymatic Saccharification ◽  
Dry Weight ◽  
Gravimetric Analysis ◽  
Chemical Pretreatment ◽  
Cell Wall Degrading Enzymes ◽  
First Time ◽  
Soluble Components

Abstract After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane bagasse (SCB). Filtrate analysis after NaOH, NH4OH and H2SO4 pretreatments yielded release of soluble reducing sugars (SRS) in range of ~0.17–0.44%, ~0.38–0.75% and ~2.9–8.4% respectively. Gravimetric analysis of pretreated SCB (PSCB) biomass also revealed dry weight loss in range of ~25.8–44.8%, ~11.1–16.0% and ~28.3–38.0% by the three pretreatments in the same order. Release of soluble components other than SRS, majorly reported to be soluble lignins, were observed highest for NaOH followed by H2SO4 and NH4OH pretreatments. Decrease or absence of peaks attributed to lignin and loosened fibrous appearance of biomass during FTIR and SEM studies respectively further corroborated with our observations of lignin removal. Application of commercial cellulase increased raw SCB saccharification from 1.93% to 38.84%, 25.56% and 9.61% after NaOH, H2SO4 and NH4OH pretreatments. Structural changes brought by cell wall degrading enzymes were first time shown visually confirming the cell wall disintegration under brightfield, darkfield and fluorescence microscopy. The microscopic evidence and saccharification results proved that the chemical treatment valorized the SCB by making it amenable for enzymatic saccharification.

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