Renyong Zhang¹, Caisheng Wei^{2, *}, Zeyang Yin^{3, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.1, pp. 89-107, 2020, DOI:10.32604/cmes.2020.07985

Abstract This paper investigates a novel quasi fixed-time orbit tracking control method for spacecraft around an asteroid in the presence of uncertain dynamics and unknown uncertainties. To quantitatively characterize the transient and steady-state responses of orbit tracking error system, a continuous performance function is devised via using a quartic polynomial. Then, integrating backstepping control technique and barrier Lyapunov function leads to a quasi fixed-time convergent orbit tracking controller without using any fractional state information and symbolic functions. Finally, two groups of illustrative examples are employed to test the effectiveness of the proposed orbit control method. More >

Xin Wang^{1, 2, *}, Xiaokui Yue^{1, 2}, Haowei Wen^{1, 2}, Jianping Yuan^{1, 2}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.1, pp. 61-87, 2020, DOI:10.32604/cmes.2020.06871

Abstract In this paper, a hybrid passive/active vibration (HPAV) controller of a loosely connected spacecraft consisting of a servicing satellite, a target and an X-shape structure isolator is first proposed to suppress vibrations of the system when subjected to the impulsive external excitations during the on-orbit missions. The passive dynamic response of the combined system can be adjusted appropriately to achieve the desired vibration isolation performance by tuning the structural parameters of the bio-inspired X-shape structure. Moreover, the adaptive control design through dynamic scaling technique is selected as the active component to maintain high vibration isolation performance in the presence of… More >

M. G. RÍOS-DURÁN*, A. R. HERNÁNDEZ-TÉLLEZ**, C. A. MARTÍNEZ-PALACIOS**, L. G. ROSS***

BIOCELL, Vol.30, Suppl.S, pp. 149-155, 2006

Abstract This article has no abstract. More >

JACQUELINE NELISIS ZANONI, RENATA VIRGINIA FERNANDES PEREIRA

BIOCELL, Vol.32, No.2, pp. 163-168, 2008, DOI:10.32604/biocell.2008.32.163

Abstract The objective of this work was to evaluate the effect of the ascorbic acid supplementation on the cellular proliferation on the ileum mucosa of diabetic rats. Fifteen 90-days rats were divided in the groups: control, diabetic and diabetic supplemented with ascorbic acid (DA). Two hours prior the sacrifice, they were injected with Vincristin. Semi-seriate histological cuts stained with HE were accomplished. About 2500 crypt cells from the intestinal mucosa were counted in order to obtain the metaphasic indexes. The height and depth of 30 villi and 30 crypts were measured for each animal, respectively. The metaphasic indexes showed no significant… More >

SONIA ROSENFELDT, BEATRIZ GLORIA GALATI

BIOCELL, Vol.32, No.1, pp. 41-47, 2008, DOI:10.32604/biocell.2008.32.041

Abstract Eleven Oxalis L. species from the province of Buenos Aires (Argentina) were investigated with scanning and transmission electron microscopes. We identified four different types and two subtypes of orbicules. We conclude that the close morphological similarity between these species is also reflected in their orbicules, and we suggest that the orbicules morphology may be a useful character in systematic studies. More >

MARLI APARECIDA DOS SANTOS PEREIRA, MARIA CLAÚDIA BAGATIN, JACQUELINE NELISIS ZANONI

BIOCELL, Vol.30, No.2, pp. 295-300, 2006, DOI:10.32604/biocell.2006.30.295

Abstract We assessed the ascorbic acid (AA) supplementation on the myenteric neurons in the duodenum of rats. Fifteen rats with 90 days of age were divided into three groups: control (C), diabetics (D) and ascorbic acid treated diabetics (DA). After 120 days of daily treatment with AA, the duodenum was submitted to the NADH-diaphorase (NADH-d) histochemical technique, which allowed us to evaluate the neuronal density in an area of 8.96 mm² for each duodenum, and also to measure the cellular profile area of 500 neurons per group. The supplementation promoted an increase on AA levels. The neuronal density (p <0.05) was… More >

Hassan AMA, EM Mostafa

Phyton-International Journal of Experimental Botany, Vol.85, pp. 262-269, 2016, DOI:10.32604/phyton.2016.85.262

Abstract Plants of Azolla caroliniana were treated with different selenium concentrations (0, 1, 2, 5, 7, 10 ppm) for seven days. Selenium (Se) content in Azolla plants increased significantly with increasing Se concentrations in the culture media up to 5 ppm. This indicated that Azolla plants were a good accumulator for Se. Selenium accumulation determined changes in Azolla biomass, doubling time and relative growth rates. Treatment of Azolla plants with low concentrations of Se (1 ppm) resulted in a significant increase in biomass. This was accompanied by a reduction in hydrogen peroxide and malondialdehyde (MDA) contents; the decrease percentages were 78%… More >

Alvarado-Vázquez MA, R Foroughbakhch, MA Guzmán- Lucio, A Rocha-Estrada, JL Hernández-Piñero, ML Cárdenas-Ávila, BM Soto-García

Phyton-International Journal of Experimental Botany, Vol.84, No.1, pp. 70-79, 2015, DOI:10.32604/phyton.2015.84.070

Abstract Candelilla (Euphorbia antisiphylitica Zucc.) is a very important plant resource in the arid lands of Northern Mexico. This is because the wax content coating the stem has unique properties which have been useful for multiple applications in the food industry, electronics, cosmetics, etc. However, the intensive exploitation of this resource has caused a great decrease in the populations of this species making necessary to consider strategies for their conservation and sustainable use. One of the primary needs with regeneration purposes is to know their reproductive processes, particularly the biotic and/or abiotic factors that determine the viability and germination of seeds.… More >

Ocampo Ocampo T¹, DL Ochoa Martínez¹, S Ramírez Rojas², G Valdovinos Ponce¹, C Nava Díaz¹

Phyton-International Journal of Experimental Botany, Vol.82, pp. 235-241, 2013, DOI:10.32604/phyton.2013.82.235

Abstract The Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), in Zacatepec Morelos, started a genetic improvement program of wild and semi-cultivated poinsettia plants ("nochebuena de sol"). It is important to generate a phytosanitary database that allows the release of new varieties and hybrids that provide tolerance to the major pathogens reported in cultivated poinsettia plants. The phytosanitary status of the “nochebuena de sol” plants is not available in Mexico, so the objective of this research was to generate preliminary data about viruses associated to these materials. Based on DAS-ELISA and RT-PCR results, we reported the presence of the Tobacco… More >

Flores-del Angel ML, R Foroughbakhch, A Rocha-Estrada, ML Cárdenas-Ávila, MA GuzmánLucio, YL Hernández-Aguilar, MA Alvarado-Vázquez

Phyton-International Journal of Experimental Botany, Vol.82, pp. 161-167, 2013, DOI:10.32604/phyton.2013.82.161

Abstract Candelilla (Euphorbia antisyphilitica Zucc.) is a native plant in the desert regions of northern Mexico and the southern United States. The primary commercial use of this plant is for wax production. This study assessed the morphology, viability, and the effects of temperature in combination with chemical and mechanical scarification on the germination of candelilla seeds. Seeds were collected in four localities in northeastern Mexico. The seeds were predominantly pyriform with foveolate surfaces and brown in color; on average, the seeds measured 2.92 ± 0.26, 1.91 ± 0.22, and 1.50 ± 0.41 mm in length, width, and thickness, respectively. The average… More >