Bio-based polymer nanocomposites based on nylon 11 and WS2 inorganic nanotubes

Tungsten disulphide nanotubes (INT-WS2) have been successfully dispersed in a bio-based polyamide matrix (nylon 11) by conventional melt processing. The effect of INT-WS2 content on the morphology, thermal stability, crystallization behaviour and dynamic mechanical properties is investigated. The results indicate that these inorganic nanotubes can be efficiently incorporated into the bio-based polymer matrix without the need for modifiers or surfactants. Additionally, it is found that the non-isothermal crystallization behaviour of nylon 11/INT-WS2 depends on both the cooling rate and INT-WS2 concentration. In particular, crystallization kinetics results demonstrate that the nucleating activity of INTs plays a dominant role in accelerating the crystallization of nylon 11. This fact leads to the appearance of the more-disordered phase at higher temperature. More significantly, it was shown that these INT-WS2 nanocomposites can facilitate a good processability and cost efficiency, and will be of interest for many eco-friendly and medical applications

Megaloblastic anaemia, diabetes and deafness in a 2-year-old child

Megaloblastic anaemia in childhood usually occurs as a result of dietary folate deficiency or, rarely, congenital disorders of vitamin B12 metabolism. We present a 2-year-old girl with megaloblastic anaemia and insulin-dependent diabetes mellitus, both of which proved responsive to pharmacological doses of thiamine. She was also found to have sensorineural hearing loss. Also known as Rogers\' syndrome, thiamine-responsive megaloblastic anaemia is the result of inactivating mutations in a gene encoding a thiamine transporter. A clinical diagnosis is supported by characteristic bone marrow findings and can be confirmed by demonstrating apoptosis in skin fibroblasts cultured in thiamine-depleted medium. Where available, DNA sequencing is definitive. There is rapid reticulocytosis after thiamine administration. We recommend a trial of therapy for megaloblastic anaemia not responding to folate and vitamin B12, especially in a deaf and/or diabetic child.Journal of Endocrinology, Metabolism and Diabetes of South Africa Vol. 10(2) 2005: 62-6

Hydrothermal base catalysed treatment of Kraft lignin - time dependent analysis and a techno-economic evaluation for carbon fibre applications

The hydrothermal base-catalysed treatment of industrial Kraft lignin (KL) is investigated as a basis for production of a sustainable carbon fibre precursor, with a focus on the time-dependent evolution and impact on precursor properties. Hydrothermal treatment was performed at T = 300 °C and p = 180 bar, with the retention time (tret) varied between 8, 12, 16, 20, and 24 mins. Molecular weight distribution and thermal stability of the processed lignin were close to maximum after 8 min, and 12–16 min respectively. Chemical modification was found to continue (e.g. demethoxylation) over the entire tret range (24 min). Analysis of the recovered oily phase indicated catechol derivatives were stable end-products with, e.g., vanillin and guaiacol as intermediates. A techno-economic analysis indicated a price of ca. 1600 €/t at a production capacity of 10 kt/a is achievable, with main cost-drivers being lignin (60%), fixed costs (20%), and energy (10%)

Megaloblastic anaemia, diabetes and deafness in a two-year old child

Megaloblastic anaemia in childhood usually occurs as a result of dietary folate deficiency or, rarely, congenital disorders of vitamin B12 metabolism. We present a 2-year-old girl with megaloblastic anaemia and insulin-dependent diabetes mellitus, both of which proved responsive to pharmacological doses of thiamine. She was also found to have sensorineural hearing loss. Also known as Rogers’ syndrome, thiamine-responsive megaloblastic anaemia is the result of inactivating mutations in a gene encoding a thiamine transporter. A clinical diagnosis is supported by characteristic bone marrow findings and can be confirmed by demonstrating apoptosis in skin fibroblasts cultured in thiamine-depleted medium. Where available, DNA sequencing is definitive. There is rapid reticulocytosis after thiamine administration. We recommend a trial of therapy for megaloblastic anaemia not responding to folate and vitamin B12, especially in a deaf and/or diabetic child

Megaloblastic anaemia, diabetes and deafness in a 2-year old child

Megaloblastic anaemia in childhood usually occurs as a result of dietary folate deficiency or, rarely, congenital disorders of vitamin B12 metabolism. We present a 2-year-old girl with megaloblastic anaemia and insulin-dependent diabetes mellitus, both of which proved responsive to pharmacological doses of thiamine. She was also found to have sensorineural hearing loss. Also known as Rogers’ syndrome, thiamine-responsive megaloblastic anaemia is the result of inactivating mutations in a gene encoding a thiamine transporter. A clinical diagnosis is supported by characteristic bone marrow findings and can be confirmed by demonstrating apoptosis in skin fibroblasts cultured in thiamine-depleted medium. Where available, DNA sequencing is definitive. There is rapid reticulocytosis after thiamine administration. We recommend a trial of therapy for megaloblastic anaemia not responding to folate and vitamin B12, especially in a deaf and/or diabetic child

Simple Preparation of Novel Metal-Containing Mesoporous Starches

Metal-containing mesoporous starches have been synthesized using a simple and efficient microwave-assisted methodology followed by metal impregnation in the porous gel network. Final materials exhibited surface areas >60 m2 g−1, being essentially mesoporous with pore sizes in the 10–15 nm range with some developed inter-particular mesoporosity. These materials characterized by several techniques including XRD, SEM, TG/DTA and DRIFTs may find promising catalytic applications due to the presence of (hydr)oxides in their composition

Polysaccharide-derived mesoporous materials (Starbon®) for sustainable separation of complex mixtures

The recovery and separation of high value and low volume extractives are a considerable challenge for the commercial realisation of zero-waste biorefineries. Using solid-phase extractions (SPE) based on sustainable sorbents is a promising method to enable efficient, green and selective separation of these complex extractive mixtures. Mesoporous carbonaceous solids derived from renewable polysaccharides are ideal stationary phases due to their tuneable functionality and surface structure. In this study, the structure-separation relationships of thirteen polysaccharide-derived mesoporous materials and two modified types as sorbents for ten naturally-occurring bioactive phenolic compounds were investigated. For the first time, a comprehensive statistical analysis of the key molecular and surface properties influencing the recovery of these species was carried out. The obtained results show the possibility of developing tailored materials for purification, separation or extraction, depending on the molecular composition of the analyte. The wide versatility and application span of these polysaccharide-derived mesoporous materials offer new sustainable and inexpensive alternatives to traditional silica-based stationary phases

Monolithic mesoporous graphitic composites as super capacitors : From Starbons to Starenes®

In this study, we present a new class of monolithic mesoporous carbonaceous materials produced via the carbonisation of a mesoporous starch aerogel highly doped with graphite. Consecutive ball milling, microwave assisted gelation and carbonization treatment produced a high concentration of dispersed graphite. These treatments induce a strong interaction between the graphite particles and the developing carbonaceous matrix, including partial delamination of graphite and the merging of the nanoflakes into the carbonaceous structure. From a combination of SEM and TEM it was found that the graphite particles reduced in size to 24 and 37 nm, matching the pore wall sizes of the produced materials. From XRD, ball milling and heating helped reduce the number of graphene layers by 40%, with presence within the porous starch matrix reducing this a further 13%. The high degree of graphite dispersion/incorporation induces a pronounced increase in conductivity, and excellent capacitance retention, in excess of 10 000 charge-discharge cycles, offering a cost efficient and sustainably produced alternative to activated carbon based EDLCs and importantly, the resultant monolithic structures mitigate the need for additional binders