801 research outputs found
Using Factorial Design Methodology to Assess PLA-g-Ma and Henequen Microfibrillated Cellulose Content on the Mechanical Properties of Poly(lactic acid) Composites
In this work, a 22 factorial design was used to study the effect of microfibrillated henequen cellulose fibers (HENCEL) and PLA-g-MA coupling agent contents on the tensile, flexural, and impact mechanical properties and the heat deflection temperature (HDT) of biodegradable PLA composites. The results show that the principal effects of HENCEL and MA are statistically significant for the tensile, flexural, HDT, and impact strength properties of PLA composites. Regarding the interactions between the principle effects, MA-HENCEL, there are differences with respect to the mechanical property; for example, for tensile and flexural mechanical properties, there is a synergistic effect between MA and HENCEL, whereas for HDT and impact strength there is not any. The micromechanical analysis shows an excellent agreement between the measured and the estimated values for both the composite tensile strength and the elastic modulus and only slight deviations were noticed for high microfibrillated cellulose fibers content. The morphological analysis via SEM indicated that the addition of PLA-g-MA improved the fiber-matrix adhesion because of the HENCEL unbounding and pull-out decreases from the PLA matrix. The use of appropriate values of matrix strength and stiffness and considering the improved fiber-matrix adhesion of the coupling agent yield a good agreement between experimental and estimated values
Stenocarpella maydis and Sporisorium reilianum: Two Pathogenic Fungi of Maize
Stenocarpella maydis and Sporisorium reilianum are phytopathogenic fungi that cause white rot in corn cob and head smut in maize (Zea mays L.) respectively, diseases that are spread worldwide and cause many economic losses. In this chapter the characteristics of the above diseases, such as their life cycle, pathogenicity factors, control methods, as well as the biotechnological potential of the fungi involved in this processes are described, specifically in connection to their extracellular enzymes
Effect of Diacerein on Insulin Secretion and Metabolic Control in Drug-NaĂŻve Patients With Type 2 Diabetes: A randomized clinical trial
OBJECTIVE - To assess the effect of diacerein on insulin secretion and metabolic control in drug-naïve patients with type 2 diabetes. RESEARCH DESIGN AND METHODS - A randomized, double-blind, placebo-controlled clinical trial was carried out in 40 drug-naïve adult patients with type 2 diabetes. A metabolic profile including interleukin (IL)-1β, tumor necrosis factor-a, IL-6, and fasting insulin levelswas carried out before the intervention and 2months afterward. A hyperglycemic-hyperinsulinemic clamp technique was performed to assess the phases of insulin secretion and insulin sensitivity. After randomization, 20 patients received diacerein (50mg once daily) for the first 15 days and twice daily for 45 additional days. The remaining patients received placebo. Intra- and intergroup differences were calculated by Wilcoxon signed rank and Mann-Whitney U tests. RESULTS-Therewere significant increases in first (102 ± 63 vs. 130 ± 75 pmol/L; P<0.01), late (219 ± 111 vs. 280 ± 135 pmol/L; P<0.01), and total insulin (178691 vs. 216699pmol/L; P<0.01) secretionswithout changes in insulin sensitivity after diacerein administration. There were significant decreases in fasting glucose (7.9 ± 1.4 vs. 6.8 ± 1.0mmol/L; P<0.01) and in A1C levels (8.3 ± 1.0 vs. 7.0 ± 0.8%; P < 0.001) after diacerein administration. There were no significant changes after placebo administration in the above-mentioned evaluations. CONCLUSIONS - Insulin secretion increased and metabolic control improved after diacerein administration in drug-naïve patients with type 2 diabetes. © 2011 by the American Diabetes Association
Non-L\'evy mobility patterns of Mexican Me'Phaa peasants searching for fuelwood
We measured mobility patterns that describe walking trajectories of
individual Me'Phaa peasants searching and collecting fuelwood in the forests of
"La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow
a mixed pattern of nearly-constant steps when individuals displace from their
homes towards potential collecting sites and a mixed pattern of steps of
different lengths when actually searching for fallen wood in the forest.
Displacements in the searching phase seem not to be compatible with L\'evy
flights described by power-laws with optimal scaling exponents. These findings
however can be interpreted in the light of deterministic searching on heavily
degraded landscapes where the interaction of the individuals with their scarce
environment produces alternative searching strategies than the expected L\'evy
flights. These results have important implications for future management and
restoration of degraded forests and the improvement of the ecological services
they may provide to their inhabitants.Comment: 15 pages, 4 figures. First version submitted to Human Ecology. The
final publication will be available at http://www.springerlink.co
CD32 is expressed on cells with transcriptionally active HIV but does not enrich for HIV DNA in resting T cells
The persistence of HIV reservoirs, including latently infected, resting CD4+ T cells, is the major obstacle to cure HIV infection. CD32a expression was recently reported to mark CD4+ T cells harboring a replication-competent HIV reservoir during antiretroviral therapy (ART) suppression. We aimed to determine whether CD32 expression marks HIV latently or transcriptionally active infected CD4+ T cells. Using peripheral blood and lymphoid tissue of ART-treated HIV+ or SIV+ subjects, we found that most of the circulating memory CD32+ CD4+ T cells expressed markers of activation, including CD69, HLA-DR, CD25, CD38, and Ki67, and bore a TH2 phenotype as defined by CXCR3, CCR4, and CCR6. CD32 expression did not selectively enrich for HIV- or SIV-infected CD4+ T cells in peripheral blood or lymphoid tissue; isolated CD32+ resting CD4+ T cells accounted for less than 3% of the total HIV DNA in CD4+ T cells. Cell-associated HIV DNA and RNA loads in CD4+ T cells positively correlated with the frequency of CD32+ CD69+ CD4+ T cells but not with CD32 expression on resting CD4+ T cells. Using RNA fluorescence in situ hybridization, CD32 coexpression with HIV RNA or p24 was detected after in vitro HIV infection (peripheral blood mononuclear cell and tissue) and in vivo within lymph node tissue from HIV-infected individuals. Together, these results indicate that CD32 is not a marker of resting CD4+ T cells or of enriched HIV DNA–positive cells after ART; rather, CD32 is predominately expressed on a subset of activated CD4+ T cells enriched for transcriptionally active HIV after long-term ART
Manejo del pastizal y su influencia en la respuesta econĂłmica de rebaños de crĂa.
Se estudiĂł la influencia de los principales componentes del manejo del pastizal en la respuesta econĂłmica de rebaños de crĂa de la Empresa GenĂ©tica Rescate de Sanguily, desde enero de 2012 a diciembre de 2014. Se seleccionaron seis unidades de crĂa de la granja Ricardo Flores, perteneciente a esta empresa, ubicada en el Municipio de Jima-guayĂş, provincia CamagĂĽey, Cuba. Se tomaron variables sobre la situaciĂłn de los pastizales y los recursos forrajeros en general y para determinar los componentes fundamentales que determinan la variabilidad de las unidades de crĂa. Se utilizĂł el análisis de componentes principales, seleccionando aquellos componentes que presentaban un autovalor superior a la unidad y dentro de cada componente principal aquellas variables con cargas superiores a 0,60; se pudo definir que entre los elementos del manejo de los pastizales en unidades de crĂa, destacan el área de forraje, de pastos cultivados y pastos naturales, que explican más del 40% de la varianza entre las unidades del estudio. El balance forrajero en las entidades es negativo, como resultado de la pobre atenciĂłn agrotĂ©cnica a los pastiza les; aĂşn asĂ, la relaciĂłn gastos-ingresos es positiva, con ganancias brutas que oscilan entre 2 500 y 17 600 CUP, lo que obedece a los bajos costos por concepto de alimentaciĂłn. Se requiere priorizar las actividades y recursos relacionados con la agrotĂ©cnia de los pastos y forrajes, asĂ como el completamiento de áreas de forrajes.Pastureland Management and Influence on the Economic Response of Breeding Herds.ABSTRACTThe influence of the main pastureland components on the economic response of breeding herds at the Rescate de Sanguily Enterprise was studied, from January 2012 to December 2014. Six breeding units from Ricardo Flores unit were chosen, in the municipality of JimaguayĂş, province of CamagĂĽey, Cuba. Variables of pastureland, and forage resources in general were used. To determine the main components that led to variability of breeding units, a Prin-cipal Component Analysis was performed; components with values above the unit were selected. Stocking rates va-riables, over 0.60, were chosen too. The elements related with pastureland management in breeding units were de-fined (forage area with native and cultivated grass), which explain the more than 40 % variance in all the units under the study. Forage balance is negative in the units, as a result of poor agrotechnical management of grasslands; however, the expenses-income ratio is positive (between CUP 17 600), caused by the low feeding costs. Activities and resources linked to pasture and forage agrotechniques must be prioritized, along with the completion of forage areas
In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent
Introduction: One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. Purpose: In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. Materials and methods: The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet–visible, and Fourier transform infrared. Results: We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Conclusion: Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains. Keywords: silver nanoparticles, green synthesis, in vitro antibacterial activity, in vivo antibacterial activity, skin infection, toxicological stud
Impact of the COVID-19 Pandemic on a Cancer Fast-Track Programme
Introduction: The COVID-19 pandemic has disrupted many aspects of clinical practice in oncology, particularly regarding early cancer diagnosis, sparking public health concerns that possible delays could increase the proportion of patients diagnosed at advanced stages. In 2009, a cancer fast-track program (CFP) was implemented at the Clinico-Malvarrosa Health Department in Valencia, Spain with the aim of shortening waiting times between suspected cancer symptoms, diagnosis and therapy initiation. Objectives: The study aimed to explore the effects of the COVID-19 pandemic on our cancer diagnosis fast-track program. Methods: The program workflow (patients included and time periods) was analysed from the beginning of the state of alarm on March 16th, 2020 until March 15th, 2021. Data was compared with data from the same period of time from the year before (2019). Results: During the pandemic year, 975 suspected cancer cases were submitted to the CFP. The number of submissions only decreased during times of highest COVID-19 incidence and stricter lockdown, and overall, referrals were slightly higher than in the previous 2 years. Cancer diagnosis was confirmed in 197 (24.1%) cases, among which 33% were urological, 23% breast, 16% gastrointestinal and 9% lung cancer. The median time from referral to specialist appointment was 13 days and diagnosis was reached at a median of 18 days. In confirmed cancer cases, treatment was started at around 30 days from time of diagnosis. In total, 61% of cancer disease was detected at early stage, 20% at locally advanced stage, and 19% at advanced stage, displaying time frames and case proportions similar to pre-pandemic years. Conclusions: Our program has been able to maintain normal flow and efficacy despite the challenges of the current pandemic, and has proven a reliable tool to help primary care physicians referring suspected cancer patients.S
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