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1.
Science ; 364(6445)2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-30923171

RESUMO

Saturn's main ring system is associated with a set of small moons that either are embedded within it or interact with the rings to alter their shape and composition. Five close flybys of the moons Pan, Daphnis, Atlas, Pandora, and Epimetheus were performed between December 2016 and April 2017 during the ring-grazing orbits of the Cassini mission. Data on the moons' morphology, structure, particle environment, and composition were returned, along with images in the ultraviolet and thermal infrared. We find that the optical properties of the moons' surfaces are determined by two competing processes: contamination by a red material formed in Saturn's main ring system and accretion of bright icy particles or water vapor from volcanic plumes originating on the moon Enceladus.

2.
Appl Ergon ; 65: 130-138, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28802432

RESUMO

This paper reports the results of an investigation into changes in body shape anthropometry over the past several decades and discusses the impact of those changes on seating in transport, especially airliners. Changes in some body shape dimensions were confirmed in a sample of students at TU Delft; several of the changes, e.g. hip breadth, seated, are relevant to the ongoing design of seating. No change in buttock knee length was observed. The fit between current user anthropometry and current airline seat design, especially regarding seat width, was investigated. A comparison of the average current seat breadth with global anthropometric data suggests that accommodation may be problematic, with less than optimal width for passengers' shoulder and elbow widths.


Assuntos
Aeronaves/instrumentação , Tamanho Corporal , Desenho de Equipamento , Quadril/anatomia & histologia , Decoração de Interiores e Mobiliário , Adolescente , Adulto , Antropometria , Ergonomia , Feminino , Humanos , Masculino , Adulto Jovem
3.
J Mater Chem B ; 5(24): 4690-4696, 2017 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32264311

RESUMO

Self-assembly of a tetrapeptide covalently attached to a thiophene-based monomer produced a gel with a fibrous, porous structure. Conditions were identified in which the thiophene end groups could undergo polymerization while retaining the 3D structure, resulting in the formation of nanofibrous gels with conductivities averaging 10-4 S cm-1.

4.
J Adv Res ; 7(6): 863-71, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27672449

RESUMO

The present work focused on the synthesis of ß-chitosan submicron particles (CSPs) from Todarodes pacificus using mechanochemical techniques. The gladius was submitted to a sequence of mechanical and chemical treatments to synthesize ß-chitin (CT), which was further deacetylated to form spherical chitosan submicron particles with an average diameter of ⩽100 nm. The surface morphology of ß-chitin and CSPs was observed using electron microscopy. The degree of deacetylation (DD%), evaluated from the absorbance peak of a Fourier Transform Infrared (FTIR) spectrum, was 80 ± 2.5%. Physicochemical characterization exhibited good crystallinity, positive zeta potential and low molecular weight, as well as reduced ash content and high water-binding capacity. CSPs exhibit significant antimicrobial properties toward all tested pathogenic bacterial and fungal microorganisms. Antioxidant analysis revealed high reducing power and excellent scavenging and chelating ability. Hence, CSPs synthesized from gladius of Todarodes pacificus using mechanochemical techniques are promising candidates for biomedical applications.

5.
Int J Biomater ; 2016: 5379424, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26977152

RESUMO

We report the synthesis, characterization, and biological properties of chitosan nanoaggregates from gladius of squid, Uroteuthis duvauceli. ß-Chitin extracted from gladius was deacetylated to chitosan and further reduced to nanosize using ionic gelation process. The morphology and occurrence of chitosan nanoaggregates (CSNA) were observed using transmission electron microscopy (TEM). The degree of deacetylation (DD%) calculated from Fourier transform infrared (FTIR) spectrum showed high value (~94 ± 1.25%) for chitosan. The CSNA depicts low molecular weight, stable positive zeta potential, and less ash and moisture content with high water and fat binding capacity. The antimicrobial activity was tested against pathogenic microorganisms, which depicted significant rate of inhibition against Staphylococcus aureus and Escherichia coli due to high cellular uptake. The antioxidant analysis for CSNA demonstrated high reducing power and scavenging activity towards superoxide radicals compared with the commercially available chitosan. Furthermore, nanoaggregates exhibited low cytotoxic behavior in biological in vitro tests performed using cervical cancer cell line. These results indicate that chitosan nanoaggregates synthesized from waste gladius will be highly efficient and safe candidate for biological applications as food packing film, drug carrier, and tissue engineering.

6.
Bioelectrochemistry ; 104: 44-50, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25727854

RESUMO

An effective enzymatic glucose biosensor was developed by immobilizing glucose oxidase on chitosan submicron particles synthesized from the gladius of Todarodes pacificus (GCSP). The chemically synthesized chitosan from gladius was pulverized to submicron particles by ball milling technique, which was further characterized and compared with the standard chitosan (SCS). The degree of deacetylation of GCSP was determined using FTIR spectroscopy which was comparable to the value of standard chitosan. The glucose oxidase (GOx) was immobilized over GCSP on porous zinc oxide/platinum nanoparticle (ZnO/Pt) based electrode. The morphological and structural properties of the electrodes were analyzed using scanning electron microscopy and X-ray diffraction analysis. The glucose sensing behavior of electrode was estimated using electrochemical analysis and showed an excellent analytical performance. The electrode ZnO/Pt/GCSP conjugated with GOx displayed high sensitivity (88.76 µA mM(-1) cm(-2)) with low detection limit in short response time. In addition, the very low value of Michaelis-Menten constant for GCSP based electrode contributes a better affinity of the electrode surface towards glucose oxidase.


Assuntos
Técnicas Biossensoriais/métodos , Quitosana/química , Decapodiformes/química , Enzimas Imobilizadas/química , Glucose Oxidase/química , Glucose/análise , Tamanho da Partícula , Animais , Técnicas Biossensoriais/instrumentação , Eletroquímica , Eletrodos , Enzimas Imobilizadas/metabolismo , Glucose Oxidase/metabolismo , Platina/química , Óxido de Zinco/química
7.
J Med Toxicol ; 8(4): 436-40, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23104127

RESUMO

BACKGROUND: A 4-year-old, 37 kg, male German shepherd developed hyperthermia, tachycardia, and agitation following consumption of ground meat found in the backyard of its owner. When presented to a veterinary clinic, plasma ethylene glycol (EG) testing was positive, and the dog was given ethanol and lactated Ringer's solution intravenously. Approximately 11 h postexposure the dog died. DISCUSSION: Among tissues submitted for toxicological analysis, urine was negative for EG, ground meat was negative for certain drugs of abuse, and gastric contents were negative for zinc/aluminum phosphide and metaldehyde. Analysis of gastric contents by gas chromatography-mass spectrometry confirmed the presence of caffeine. Caffeine concentration in the ground meat was estimated at 1 %. Caffeine is a methylxanthine alkaloid with a reported canine oral median lethal dose (MLD(50)) of 140 mg/kg (range 120-200 mg/kg). A commercially available 200-mg tablet formulation of caffeine was considered to be a possible source but this was not confirmed. By conservative estimates, the dog would need to ingest approximately 500-550 g of the meat to reach the MLD(50). Acute intoxication affects the cardiovascular, pulmonary, neurologic, gastrointestinal, and metabolic systems. Although no tablet remnants were observed in the bait, tablets could have been crushed and/or dissolved. Other potential caffeine sources include guarana, brewed and concentrated coffee, and caffeine-containing beverages. Based on the history, clinical signs, and the detection of caffeine in the gastric contents and meat, a presumptive diagnosis of malicious caffeine poisoning was made. A suggested treatment regimen for caffeine intoxication in dogs is described. While few cases of accidental ingestion of caffeine by dogs have been described, the intentional use of a concentrated caffeine source to cause mortality in a dog has not been previously reported.


Assuntos
Cafeína/intoxicação , Carne/análise , Administração Oral , Compostos de Alumínio/análise , Animais , Bovinos , Cães , Etilenoglicol/sangue , Evolução Fatal , Cromatografia Gasosa-Espectrometria de Massas , Conteúdo Gastrointestinal/química , Dose Letal Mediana , Masculino , Fosfinas/análise , Xantinas/química , Compostos de Zinco/análise
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