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1.
Özgür Keleṣ Nicholas P. Barcenas Daniel H. Sprys Keith J. Bowman 《AAPS PharmSciTech》2015,16(6):1455-1464
Fracture strength of pharmaceutical compacts varies even for nominally identical samples, which directly affects compaction, comminution, and tablet dosage forms. However, the relationships between porosity and mechanical behavior of compacts are not clear. Here, the effects of porosity on fracture strength and fracture statistics of microcrystalline cellulose compacts were investigated through diametral compression tests. Weibull modulus, a key parameter in Weibull statistics, was observed to decrease with increasing porosity from 17 to 56 vol.%, based on eight sets of compacts at different porosity levels, each set containing ∼50 samples, a total of 407 tests. Normal distribution fits better to fracture data for porosity less than 20 vol.%, whereas Weibull distribution is a better fit in the limit of highest porosity. Weibull moduli from 840 unique finite element simulations of isotropic porous materials were compared to experimental Weibull moduli from this research and results on various pharmaceutical materials. Deviations from Weibull statistics are observed. The effect of porosity on fracture strength can be described by a recently proposed micromechanics-based formula.Key words: diametral compression test, finite element simulations, normal distribution, reliability, Weibull modulus 相似文献
2.
Glenda L. Torres W. Rodney Cooper David R. Horton Kylie D. Swisher Stephen F. Garczynski Joseph E. Munyaneza Nina M. Barcenas 《PloS one》2015,10(11)
“Candidatus Liberibacter solanacearum” (Proteobacteria) is an important pathogen of solanaceous crops (Solanales: Solanaceae) in North America and New Zealand, and is the putative causal agent of zebra chip disease of potato. This phloem-limited pathogen is transmitted to potato and other solanaceous plants by the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae). While some plants in the Convolvulaceae (Solanales) are also known hosts for B. cockerelli, previous efforts to detect Liberibacter in Convolvulaceae have been unsuccessful. Moreover, studies to determine whether Liberibacter can be acquired from these plants by B. cockerelli are lacking. The goal of this study was to determine whether horizontal transmission of Liberibacter occurs among potato psyllids on two species of Convolvulaceae, sweet potato (Ipomoea batatas) and field bindweed (Convolvulus arvensis), which grows abundantly in potato growing regions of the United States. Results indicated that uninfected psyllids acquired Liberibacter from both I. batatas and C. arvensis if infected psyllids were present on plants concurrently with the uninfected psyllids. Uninfected psyllids did not acquire Liberibacter from plants if the infected psyllids were removed from the plants before the uninfected psyllids were allowed access. In contrast with previous reports, PCR did detect the presence of Liberibacter DNA in some plants. However, visible amplicons were faint and did not correspond with acquisition of the pathogen by uninfected psyllids. None of the plants exhibited disease symptoms. Results indicate that horizontal transmission of Liberibacter among potato psyllids can occur on Convolvulaceae, and that the association between Liberibacter and Convolvulaceae merits additional attention. 相似文献
3.
M Imboden A Nieters AJ Bircher M Brutsche N Becker M Wjst U Ackermann-Liebrich W Berger NM Probst-Hensch 《Clinical and molecular allergy : CMA》2006,4(1):1-9
Background
Avoidance of allergens is still recommended as the first and best way to prevent allergic illnesses and their comorbid diseases. Despite a variety of attempts there has been very limited success in the area of environmental control of allergic disease. Our objective was to identify a non-invasive, non-pharmacological method to reduce indoor allergen loads in atopic persons' homes and public environments. We employed a novel in vivo approach to examine the possibility of using aluminum sulfate to control environmental allergens.Methods
Fifty skin test reactive patients were simultaneously skin tested with conventional test materials and the actions of the protein/glycoprotein modifier, aluminum sulfate. Common allergens, dog, cat, dust mite, Alternaria, and cockroach were used in the study.Results
Skin test reactivity was significantly reduced by the modifier aluminum sulfate. Our studies demonstrate that the effects of histamine were not affected by the presence of aluminum sulfate. In fact, skin test reactivity was reduced independent of whether aluminum sulfate was present in the allergen test material or removed prior to testing, indicating that the allergens had in some way been inactivated.Conclusion
Aluminum sulfate was found to reduce the in vivo allergic reaction cascade induced by skin testing with common allergens. The exact mechanism is not clear but appears to involve the alteration of IgE-binding epitopes on the allergen. Our results indicate that it may be possible to diminish the allergenicity of an environment by application of the active agent aluminum sulfate, thus producing environmental control without complete removal of the allergen. 相似文献4.
Omar JM Hamza Mecky IN Matee Mainen J Moshi Elison NM Simon Ferdinand Mugusi Frans HM Mikx Wim H van Palenstein Helderman Antonius JMM Rijs André JAM van der Ven Paul E Verweij 《BMC microbiology》2008,8(1):135
Background
In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis. 相似文献5.
Steve Horvath Abu NM Nazmul-Hossain Rodney PE Pollard Frans GM Kroese Arjan Vissink Cees GM Kallenberg Fred KL Spijkervet Hendrika Bootsma Sara A Michie Sven U Gorr Ammon B Peck Chaochao Cai Hui Zhou David TW Wong 《Arthritis research & therapy》2012,14(6):1-13
Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications. 相似文献
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7.
NM Kouyoumdzian NL Rukavina Mikusic G Cao MR Choi SL Della Penna BE Fernández 《Biotechnic & histochemistry》2016,91(8):510-521
We studied the effects of tempol, an oxygen radical scavenger, on hydrosaline balance in rats with acute sodium overload. Male rats with free access to water were injected with isotonic (control group) or hypertonic saline solution (0.80 mol/l NaCl) either alone (Na group) or with tempol (Na-T group). Hydrosaline balance was determined during a 90 min experimental period. Protein expressions of aquaporin 1 (AQP1), aquaporin 2 (AQP2), angiotensin II (Ang II) and endothelial nitric oxide synthase (eNOS) were measured in renal tissue. Water intake, creatinine clearance, diuresis and natriuresis increased in the Na group. Under conditions of sodium overload, tempol increased plasma sodium and protein levels and increased diuresis, natriuresis and sodium excretion. Tempol also decreased water intake without affecting creatinine clearance. AQP1 and eNOS were increased and Ang II decreased in the renal cortex of the Na group, whereas AQP2 was increased in the renal medulla. Nonglycosylated AQP1 and eNOS were increased further in the renal cortex of the Na-T group, whereas AQP2 was decreased in the renal medulla and was localized mainly in the cell membrane. Moreover, p47-phox immunostaining was increased in the hypothalamus of Na group, and this increase was prevented by tempol. Our findings suggest that tempol causes hypernatremia after acute sodium overload by inhibiting the thirst mechanism and facilitating diuresis, despite increasing renal eNOS expression and natriuresis. 相似文献
8.
Background
Various software tools are available for the display of pairwise linkage disequilibrium across multiple single nucleotide polymorphisms. The HapMap project also presents these graphics within their website. However, these approaches are limited in their use of data from multiallelic markers and provide limited information in a graphical form. 相似文献9.
There are gaps in existing understanding of fungal pellet growth dynamics. We used scanning electron microscopy (SEM) for morphological characterization of the biomass organization of Termitomyces pellets for seven species: T. microcarpus (TMI1), T. albuminosus (TAL1, TAL2), T. striatus (TSTR), T. aurantiacus (TAUR), T. heimii (THE1, THE2), T. globulus (TGLO) and T. clypeatus (TCL1, TCL2, TCL3, TCL4, TCL5). We assessed the utility of SEM for morphological and structural characterization of Termitomyces spp. in three dimensional (3D) pellet form to identify ideal pellet morphology for industrial use. Typological classification of Termitomyces species was based on furrows, isotropy, total motifs and fractal dimensions. The pellets formed were entangled and exhibited highly compacted mycelial mass with microheterogeneity and microporosity. The mean density of furrows of Termitomyces species was between 10,000 and 11,300 cm/cm2, percentage isotropy was 30?80 and total motifs varied from 300 to 2500. TGLO exhibited the highest furrow mean density, 11243 cm/cm2, which indicated a compact, cerebroid structure with complex ridges and furrows, whereas TAL2 exhibited the lowest furrow density. TMI1a exhibited a high percentage isotropic value, 74.6, TSTR exhibited the lowest, 30.9. Total motif number also was used as a typological classification parameter. Fractal values were 2.64?2.78 for various submerged conditions of Termitomyces species. TAL1 exhibited the highest fractal dimension and TAL2 the lowest, which indicates the complexity of branching patterns. Three-dimensional SEM image analysis can provide insight into pellet micromorphology and is a powerful tool for exploring topographical details of pellets. 相似文献
10.
Cristina Firanescu Paul NM Lohle Jolanda de Vries Caroline A Klazen Job R Juttmann William Clark Willem Jan van Rooij 《Trials》2011,12(1):1-5