L-lactic Acid (l-lactic + acid)

Distribution by Scientific Domains


Selected Abstracts


Differentiation Pattern of Vero Cells Cultured on Poly(L-Lactic Acid)/Poly(Hydroxybutyrate-co-Hydroxyvalerate) Blends

ARTIFICIAL ORGANS, Issue 4 2004
Arnaldo R. Santos Jr
Abstract:, This study evaluates the effect of poly(L-lactic acid) (PLLA) and poly(hydroxybutyrate-cohydroxyvalerate) (PHBV) bioabsorbable polymers and their blends on the induction of alteration of cell growth pattern in vitro. Vero cells were cultured on PLLA, PHBV, and different blends (100/0, 60/40, 50/50, 40/60, and 0/100). The cell adhesion assay showed that the best results were obtained with the (60/40, 50/50) blends. Scanning electron microscopy showed that the cells on (100/0) and (60/40) samples grew with a round morphology preferentially in the porous areas. The (50/50) blends had cells in the porous and smooth areas in a similar way. The (40/60) blends showed spreading cells on the smooth areas. The (0/100) sample, which had no pores, had spreading cells interconnected by filaments. Histological sections showed a confluent cell monolayer and the immunocytochemistry showed that the cells produced collagen IV and fibronectin on all substrates. Thus, we conclude that PLLA/PHBV blends were efficient in maintaining cell growth and producing an extracellular ,matrix on them. [source]


Composite coating of bonelike apatite particles and collagen fibers on poly L-lactic acid formed through an accelerated biomimetic coprecipitation process

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006
Yun Chen
Abstract Collagen and apatite were coprecipitated as a composite coating on poly L-lactic acid (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1 g/L) and simulated body fluid with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after a 24-h incubation was characterized by using energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). It was shown that the coating contained carbonated bonelike apatite and collagen, which was similar in composition to natural bone. SEM showed a complex composite coating of submicron bonelike apatite particulates combined with collagen fibrils. It is expected that such biocomposite coating may better facilitate cell interaction and osteoconductivity. This work provided an efficient process to obtain bonelike apatite/collagen composite coating, which is potentially useful in bone tissue engineering. 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]


Sorption and Swelling of Poly(D,L-lactic acid) and Poly(lactic-co-glycolic acid) in Supercritical CO2

MACROMOLECULAR SYMPOSIA, Issue 1 2007
Ronny Pini
Abstract Summary: The equilibrium sorption and swelling behavior in supercritical CO2 of poly(D,L-lactic acid) and poly(lactic-co-glycolic acid) has been studied at a temperature of 35,C and at pressures up to 200 bar. Sorption was measured through a gravimetric technique and swelling by visualization. From these data, the behavior of the different polymers can be compared. In terms of partial molar volume of CO2 in the polymer matrix, all the polymers exhibit a behavior typical of rubbery systems. The experimental results have been modeled using the Sanchez-Lacombe equation of state, which is able to represent the actual behavior of the polymer-CO2 systems with reasonable accuracy. [source]


A carbon dioxide, heat and chemical lure trap for the bedbug, Cimex lectularius

MEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2009
J. F. ANDERSON
Abstract A trap for the collection of bedbugs, Cimex lectularius Linnaeus (Hemiptera: Cimicidae), is described. The trap was baited with CO2 (50,400 mL/min), heat (37.2,42.2 C) and a chemical lure comprised of 33.0 ,g proprionic acid, 0.33 ,g butyric acid, 0.33 ,g valeric acid, 100 ,g octenol and 100 ,g L-lactic acid, impregnated into a gel. Laboratory studies, conducted in a square arena measuring 183 cm on each side, showed that traps with and without baits captured adult bedbugs, but traps with CO2 emissions of 50,400 mL/min caught significantly (P < 0.05) more bedbugs than traps without CO2. In an infested unoccupied apartment, traps with heat and with or without the chemical lure were tested without CO2 on 29 trap-days and with CO2 on 9 trap-days. The numbers of bedbugs captured were 656 and 5898 in traps without and with CO2, respectively. The numbers of bedbugs of all development stages captured were significantly greater in traps with CO2 (,2 = 15 942, d.f. = 1, P < 10,9). A non-parametric two-way analysis of variance evaluation of six different traps with or without CO2, heat or a chemical lure monitored over 19 trap-days in an infested apartment showed that trap type was highly significant (n = 2833 bedbugs collected) (P < 10,7). The trap with CO2, heat and a chemical lure captured more bedbugs than the other traps, but only caught significantly more fourth and fifth instar nymphs than all other traps. Otherwise, the catches in this trap did not differ significantly from those caught by traps that contained CO2 and heat only. The total numbers of bedbugs collected for each trapping date (pooling all six traps) followed an exponential decline over the trapping period. This type of trap, which caught bedbugs in unoccupied apartments with and without furniture, and in an occupied apartment, may have utility in studying the ecology of bedbugs, in detecting bedbug infestations and in reducing numbers of bites by trapping host-seeking bedbugs. [source]


Differentiation Pattern of Vero Cells Cultured on Poly(L-Lactic Acid)/Poly(Hydroxybutyrate-co-Hydroxyvalerate) Blends

ARTIFICIAL ORGANS, Issue 4 2004
Arnaldo R. Santos Jr
Abstract:, This study evaluates the effect of poly(L-lactic acid) (PLLA) and poly(hydroxybutyrate-cohydroxyvalerate) (PHBV) bioabsorbable polymers and their blends on the induction of alteration of cell growth pattern in vitro. Vero cells were cultured on PLLA, PHBV, and different blends (100/0, 60/40, 50/50, 40/60, and 0/100). The cell adhesion assay showed that the best results were obtained with the (60/40, 50/50) blends. Scanning electron microscopy showed that the cells on (100/0) and (60/40) samples grew with a round morphology preferentially in the porous areas. The (50/50) blends had cells in the porous and smooth areas in a similar way. The (40/60) blends showed spreading cells on the smooth areas. The (0/100) sample, which had no pores, had spreading cells interconnected by filaments. Histological sections showed a confluent cell monolayer and the immunocytochemistry showed that the cells produced collagen IV and fibronectin on all substrates. Thus, we conclude that PLLA/PHBV blends were efficient in maintaining cell growth and producing an extracellular ,matrix on them. [source]