Potential use of cellulose soybean hulls as a source of carboxymethyl cellulose for coating bean seeds.

Implementing sustainable practices for using agricultural waste is urgent in the face of the challenges of climate change. This study aimed to investigate the application of carboxymethyl cellulose (CMC) derived from soybean hulls as a bioinput in the seed coat of beans. CMC was obtained after bleaching the pulp, alkalizing and etherifying it varying the chloroacetic acid concentration and the reaction time. The properties of CMC were compared to those of soybean hulls and bleached pulp. The CMC with the highest degree of substitution (DS) was chosen as bioinput. In addition to the control treatment, concentrations of 1%, 2%, and 3% CMC were used for coating, and the impact on the physiological quality of seeds was evaluated. CMC proved suitable as a coating agent for seeds, with a DS of 1.56 obtained with 1.2 g chloroacetic acid per gram of bleached pulp during 192 min at 63 °C. The 2% CMC solution proved to be effective, resulting in 93%, 94%, and 43.5% of germinated seeds at 5 days, 8 days, and after accelerated aging, respectively. Seedlings reached 34.2 cm in length and a dry mass of 0.05 g. Our results indicate that soybean hulls can be successfully used in the production of CMC as a coating material, improving the physiological quality of bean seeds and contributing to more sustainable agricultural practices

Fabrication of endothelial cell-laden carrageenan microfibers for microvascularized bone tissue engineering applications

ecent achievements in the area of tissue engineering (TE) have enabled the development of three-dimensional (3D) cell-laden hydrogels as in vitro platforms that closely mimic the 3D scenario found in native tissues. These platforms are extensively used to evaluate cellular behavior, cell-cell interactions, and tissue-like formation in highly defined settings. In this study, we propose a scalable and flexible 3D system based on microsized hydrogel fibers that might be used as building blocks for the establishment of 3D hydrogel constructs for vascularized bone TE applications. For this purpose, chitosan (CHT) coated κ-carrageenan (κ-CA) microfibers were developed using a two-step procedure involving ionotropic gelation (for the fiber formation) of κ-CA and its polyelectrolyte complexation with CHT (for the enhancement of fiber stability). The performance of the obtained fibers was assessed regarding their swelling and stability profiles, as well as their ability to carry and, subsequently, promote the outward release of microvascular-like endothelial cells (ECs), without compromising their viability and phenotype. Finally, the possibility of assembling and integrating these cell-laden fibers within a 3D hydrogel matrix containing osteoblast-like cells was evaluated. Overall, the obtained results demonstrate the suitability of the microsized κ-CA fibers to carry and deliver phenotypically apt microvascular-like ECs. Furthermore, it is shown that it is possible to assemble these cell-laden microsized fibers into 3D heterotypic hydrogels constructs. This in vitro 3D platform provides a versatile approach to investigate the interactions between multiple cell types in controlled settings, which may open up novel 3D in vitro culture techniques to better mimic the complexity of tissues.Authors thank the Portuguese Foundation for Science and Technology (FCT) for the personal grants SFRH/BD/42968/2008 through the MIT-Portugal Program (SMM) and SFRH/BD/64070/2009 (EGP). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS and MIT/ECE/0047/2009 project

Efeito de Aditivos na Desacetilação de Quitina Effects from Additives on Deacetylation of Chitin

Reações de desacetilação de quitina comercial em suspensão aquosa de hidróxido de sódio foram realizadas em etapa única de 6 horas a 115°C. Os efeitos de aditivos (boro hidreto de sódio ou antraquinona) e de borbulhamento de gases inertes (nitrogênio ou argônio) sobre as características das amostras desacetiladas foram avaliados. A espectroscopia de ressonância magnética nuclear de hidrogênio e viscosimetria capilar foram empregadas para determinações de graus médios de acetilação e de viscosidades intrínsecas de quitosanas, respectivamente. A difração de raiosX foi empregada para comparar as amostras quanto à cristalinidade e os espectros no infravermelho foram comparados para avaliar modificações estruturais decorrentes da reação de desacetilação. As quitosanas mais cristalinas foram obtidas quando um dos gases inertes foi borbulhado no meio durante a reação de desacetilação. Amostras ligeiramente mais desacetiladas foram obtidas na ausência de qualquer aditivo, mas severa despolimerização ocorreu nesses casos. A adição de boro hidreto de sódio ao meio reacional reduziu significativamente a despolimerização, mas a presença de antraquinona e o borbulhamento de nitrogênio, ou de argônio, não surtiu qualquer efeito, sugerindo que a presença de oxigênio não é um pré-requisito para a ocorrência de despolimerização.<br>Deacetylation reactions of commercial chitin were carried out in aqueous sodium hydroxide solution at 115°C for 6 hours. The effect from additives (sodium borohydride or anthraquinone) and of bubbling inert gas (nitrogen or argon) on the characteristics of deacetylated samples were evaluated. Average degrees of acetylation and intrinsic viscosity were determined by ¹H NMR spectroscopy and capillary viscometry, respectively. X-ray diffraction was employed to evaluate changes in crystallinity and infrared spectroscopy was used to monitor structural changes due to deacetylation. The bubbling of inert gas during the deacetylation reaction resulted in more crystalline samples of chitosan. Deacetylations carried out without any additive produced slightly more deacetylated chitosans but they were severely depolymerized. The depolymerization process was much less important when sodium borohydride was added to the reaction medium but the addition of anthraquinone and the bubbling of nitrogen, or argon, did not have any effect, this suggests that oxygen is not required for depolymerization

A 5mA CMOS FM Front-End with 39 dB IRR and 52 dB Channel Selectivity

A complete analog front-end, with the exclusion of the frequency synthesizer, for FM broadcasting occupies 2.8 mm2 active area in a standard 0.35 mum CMOS technology. The use of current driven passive mixer and switch capacitor polyphase filter gives +100 dBmuV IIP3, 52 dB adjacent channel selectivity and +39 dB image rejection without trimming or tuning. The output noise is 390 nVparradic(Hz), with a conversion gain of about 39 dB. This front-end consumes only 5 mA from a 2.4 V suppl