1,157 research outputs found
Toward predicting tensile strength of pharmaceutical tablets by ultrasound measurement in continuous manufacturing
No full textAn ultrasound measurement system was employed as a non-destructive method to evaluate its reliability in predicting the tensile strength of tablets and investigate the benefits of incorporating it in a continuous line, manufacturing solid dosage forms. Tablets containing lactose, acetaminophen, and magnesium stearate were manufactured continuously and in batches. The effect of two processing parameters, compaction force and level of shear strain were examined. Young's modulus and tensile strength of tablets were obtained by ultrasound and diametrical mechanical testing, respectively. It was found that as the blend was exposed to increasing levels of shear strain, the speed of sound in the tablets decreased and the tablets became both softer and mechanically weaker. Moreover, the results indicate that two separate tablet material properties (e.g., relative density and Young's modulus) are necessary in order to predict tensile strength. A strategy for hardness prediction is proposed that uses the existing models for Young's modulus and tensile strength of porous materials. Ultrasound testing was found to be very sensitive in differentiating tablets with similar formulation but produced under different processing conditions (e.g., different level of shear strain), thus, providing a fast, and non-destructive method for hardness prediction that could be incorporated to a continuous manufacturing process.Peer reviewe
The effect of mechanical strain on properties of lubricated tablets compacted at different pressures
No full textA full factorial design of experiments was used to study the effect of blend shear strain on the compaction process, relative density and strength of pharmaceutical tablets. The powder blends were subjected to different shear strain levels (integral of shear rate with respect to time) using an ad hoc Couette shear cell. Tablets were compressed at different compaction forces using an instrumented compactor simulator, and compaction curves showing the force-displacement profiles during compaction were obtained. Although the die-fill blend porosity (initial porosity) and the minimum in-die tablet porosity (at maximum compaction) decreased significantly with shear strain, the final tablet porosity was surprisingly independent of shear strain. The increase in the in-die maximum compaction with shear strain was, in fact, compensated during post-compaction relaxation of the tables, which also increased significantly with shear strain. Therefore, tablet porosity alone was not sufficient to predict tablet tensile strength. A decrease in the ‘work of compaction’ as a function of shear strain, and an increase in the recovered elastic work was observed, which suggested weaker particle-particle bonding as the shear strain in- creased. For each shear strain level, the Ryskewitch Duckworth equation was a good fit to the tensile strength as a function of tablet porosity, and the obtained asymptotic tensile strength at zero porosity exhibited a 60% reduction as a function of shear strain. This was consistent with a reduced bonding efficiency as the shear strain increased.Peer reviewed
Multifractals and El Naschie E-Infinity Cantorian Spacetime
No full textThe aim of this work is the analysis of multifractals in the context of Mohamed El Naschie's epsilon((infinity)) Cantorian spacetime applied to cosmology. As starting point we consider the results of the first author of the present paper describing scaling rules in nature, R(N) = (h/m(n)c)N-phi. Then, we use multifractal analysis to show that the result, already developed by the authors as Brownian motion, is a Multifractal process. Indeed, Brownian paths play a crucial role if considered to be a multifractal. Moreover, we summarize some recent results concerning fractal structure and the Brownian paths in order to calculate fractal dimension and characteristic parameters for large scale structures and for the atomic elements that live in an El Naschie's epsilon((infinity)) Cantorian space-time
Bourdieu and the Social History of Scientific Reason
No full textThe themes of the historical roots, the social function, and the validity of the sciences (both human and social sciences and natural sciences) represent one of the nerve centers of Bourdieusian reflections. In the thought of this author, the theme of science has been both an object of socio-historical investigation and a cardinal problem of epistemological reflection – a way to justify the validity of sociological research in itself (the problem of reflexivity). The main objective of this chapter is to show the originality of Bourdieu’s approach to the analysis of science by showing its link and theoretical positioning with respect to the main contemporary historiographical debates (such as historical epistemology and science and technology studies)
Ancient Host–Pathogen Associations Maintained by Specificity of Chemotaxis and Antibiosis
No full textNicole M Gerardo is with UT Austin and the Smithsonian Tropical Research Institute, Sarah R Jacobs is with UT Austin and Duke University, Cameron R Currie is with the Smithsonian Tropical Research Institute and University of Wisconsin at Madison, Ulrich G Mueller is with UT Austin and the Smithsonian Tropical Research Institute.Switching by parasites to novel hosts has profound effects on ecological and evolutionary disease dynamics. Switching requires that parasites are able to establish contact with novel hosts and to overcome host defenses. For most host–parasite associations, it is unclear as to what specific mechanisms prevent infection of novel hosts. Here, we show that parasitic fungal species in the genus Escovopsis, which attack and consume the fungi cultivated by fungus-growing ants, are attracted to their hosts via chemotaxis. This response is host-specific: Escovopsis spp. grow towards their natural host cultivars more rapidly than towards other closely related fungi. Moreover, the cultivated fungi secrete compounds that can suppress Escovopsis growth. These antibiotic defenses are likewise specific: in most interactions, cultivars can inhibit growth of Escovopsis spp. not known to infect them in nature but cannot inhibit isolates of their naturally infecting pathogens . Cases in which cultivars are susceptible to novel Escovopsis are limited to a narrow set of host–parasite strain combinations. Targeted chemotactic and antibiotic responses therefore explain why Escovopsis pathogens do not readily switch to novel hosts, consequently constraining long-term dynamics of host–parasite coevolution within this ancient association.This work was supported by NSF Doctoral Dissertation Improvement Grant DEB-0308757 to NMG; NSF IRCEB Grant DEB-0110073 to CRC and UGM, and fellowships to NMG from the University of Texas at Austin Graduate School and the U.T. Department of Integrative Biology.Biological Sciences, School o
Blood Gas Analyses in Hyperbaric and Underwater Environments: A Systematic Review
No full textPulmonary gas exchange during diving or in a dry hyperbaric environment is affected by increased breathing gas density and possibly water immersion. During free diving, there is also the effect of apnea. Few studies have published blood gas data in underwater or hyperbaric environments: this review summarizes the available literature and was used to test the hypothesis that arterial PO2 under hyperbaric conditions can be predicted from blood gas measurement at 1 atmosphere assuming a constant arterial/alveolar PO2 ratio (a:A). A systematic search was performed on traditional sources including arterial blood gases obtained on humans in hyperbaric or underwater environments. The a:A was calculated at 1 atmosphere absolute (ATA). For each condition, predicted arterial partial pressure of oxygen (PaO2) at pressure was calculated using the 1 ATA a:A, and the measured PaO2 was plotted against the predicted value with Spearman correlation coefficients. Of 3,640 records reviewed, 30 studies were included: 25 were reports describing values obtained in hyperbaric chambers, and the remaining were collected while underwater. Increased inspired O2 at pressure resulted in increased PaO2, although underlying lung disease in patients treated with hyperbaric oxygen attenuated the rise. PaCO2 generally increased only slightly. In breath-hold divers, hyperoxemia generally occurred at maximum depth, with hypoxemia after surfacing. The a:A adequately predicted the PaO2 under various conditions: dry (r = 0.993, P < 0.0001), rest versus exercise (r = 0.999, P < 0.0001), and breathing mixtures (r = 0.995, P < 0.0001). In conclusion, pulmonary oxygenation under hyperbaric conditions can be reliably and accurately predicted from 1 ATA a:A measurements
SISNIEGA Y HNO., Gerardo
No full textCorrespondence of Mr. Gerardo Sisniega and Mr. Leopoldo Sisniega of the Renaissance Bookstore, and Gen. Alvaro Obregón, in which they tell Gen. Obregón that they have sent bound copies of his work EIGHT THOUSAND KILOMETERS IN BATTLE that were requested of them by Gen. Jesús M. Garza. Gen. Alvaro Obregón sends one hundred copies of the book ALVARO OBREGON written by Mrs. Laura Méndez de Cuenca so that they can sell them. Reply informing that they have received the copies; also, they tell him that they are preparing a book whose author is Mr. Luis L. Leon and the cover art by the cartoonist Ernesto García Cabral and ask him to send a list of the political groups that support him in order to make an announcement to them. Gen. Alvaro Obregón informs them that he will send the list requested and thanks them for their attention to the book by Mrs. Méndez de Cuenca. Gen. Alvaro Obregón asks them to send more bound copies of the book EIGHT THOUSAND KILOMETERS IN BATTLE. Reply sending the requested material. Flyer of G. Sisniega and Bro. promoting the newspaper EL MONITOR REPUBLICANO. Flyer of G. Sisniega and Bro. recommending some books for the 1919 school year. / Correspondencia entre los Srs. Gerardo Sisniega y Leopoldo Sisniega de la Librería Renacimiento y el Gral. Alvaro Obregón, en la cual comunican al Gral. Obregón que le han enviado los ejemplares empastados de su obra OCHO MIL KILOMETROS EN CAMPAÑA que les solicitó a través del Gral. Jesús M. Garza. El Gral. Alvaro Obregón envía cien ejemplares del libro ALVARO OBREGON escrito por la Sra. Laura Méndez de Cuenca a fin de que sean vendidos. Respuesta indicando haber recibido su envío; asimismo, le comunican que están elaborando una obra cuyo autor es el Ing. Luis L. León y la carátula del dibujante Ernesto García Cabral y le piden envíe una lista de las agrupaciones políticas que lo apoyan a fin de anunciárselas. El Gral. Alvaro Obregón informa que les enviará la lista que le solicitan y agradece la atención al libro de la Sra. Méndez de Cuenca. El Gral. Alvaro Obregón solicita le envíen más ejemplares empastados del libro OCHO MIL KILOMETROS EN CAMPAÑA. Respuesta enviando el paquete solicitado. Volante de G. Sisniega y Hno. haciendo propaganda al periódico EL MONITOR REPUBLICANO. Volante de G. Sisniega y Hno. recomendando algunas obras de texto para el año escolar de 191
SISNIEGA Y HNO., Gerardo
No full textCorrespondence of Mr. Gerardo Sisniega and Mr. Leopoldo Sisniega of the Renaissance Bookstore, and Gen. Alvaro Obregón, in which they tell Gen. Obregón that they have sent bound copies of his work EIGHT THOUSAND KILOMETERS IN BATTLE that were requested of them by Gen. Jesús M. Garza. Gen. Alvaro Obregón sends one hundred copies of the book ALVARO OBREGON written by Mrs. Laura Méndez de Cuenca so that they can sell them. Reply informing that they have received the copies; also, they tell him that they are preparing a book whose author is Mr. Luis L. Leon and the cover art by the cartoonist Ernesto García Cabral and ask him to send a list of the political groups that support him in order to make an announcement to them. Gen. Alvaro Obregón informs them that he will send the list requested and thanks them for their attention to the book by Mrs. Méndez de Cuenca. Gen. Alvaro Obregón asks them to send more bound copies of the book EIGHT THOUSAND KILOMETERS IN BATTLE. Reply sending the requested material. Flyer of G. Sisniega and Bro. promoting the newspaper EL MONITOR REPUBLICANO. Flyer of G. Sisniega and Bro. recommending some books for the 1919 school year. / Correspondencia entre los Srs. Gerardo Sisniega y Leopoldo Sisniega de la Librería Renacimiento y el Gral. Alvaro Obregón, en la cual comunican al Gral. Obregón que le han enviado los ejemplares empastados de su obra OCHO MIL KILOMETROS EN CAMPAÑA que les solicitó a través del Gral. Jesús M. Garza. El Gral. Alvaro Obregón envía cien ejemplares del libro ALVARO OBREGON escrito por la Sra. Laura Méndez de Cuenca a fin de que sean vendidos. Respuesta indicando haber recibido su envío; asimismo, le comunican que están elaborando una obra cuyo autor es el Ing. Luis L. León y la carátula del dibujante Ernesto García Cabral y le piden envíe una lista de las agrupaciones políticas que lo apoyan a fin de anunciárselas. El Gral. Alvaro Obregón informa que les enviará la lista que le solicitan y agradece la atención al libro de la Sra. Méndez de Cuenca. El Gral. Alvaro Obregón solicita le envíen más ejemplares empastados del libro OCHO MIL KILOMETROS EN CAMPAÑA. Respuesta enviando el paquete solicitado. Volante de G. Sisniega y Hno. haciendo propaganda al periódico EL MONITOR REPUBLICANO. Volante de G. Sisniega y Hno. recomendando algunas obras de texto para el año escolar de 191
The Bean Beetle Microbiome Project: A Course-Based Undergraduate Research Experience in Microbiology
No full textCourse-based undergraduate research experiences (CUREs) are an effective means of transforming the learning and teaching of science by involving students in the scientific process. The potential importance of the microbiome in shaping both environmental health and disease makes investigations of microbiomes an excellent teaching tool for undergraduate microbiology. Here, we present a CURE based on the microbiome of the bean beetle (Callosobruchus maculatus), a model system for undergraduate laboratory education.
Correction to: Long-term efficacy and safety of golimumab in the treatment of multirefractory Behçet’s disease (Clinical Rheumatology, (2017), 36, 9, (2063-2069), 10.1007/s10067-017-3627-4)
No full textIn the original version of this article the author name Gerardo Di Scala was originally presented incorrectly as ‘Di Scala Gerardo’; this has been corrected in this article
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