Synthesis of multicyclic β-Lactam derivatives via solid-phase- generated ketenes

An efficient approach for the solid-phase synthesis of multicyclic â-lactam derivatives is described. The key step is the cycloaddition reaction between an immobilized ketene and different cyclic imines to afford the corresponding benzofused carbacepham derivatives in high yield for the overall synthetic sequence.Fil: Mendez, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Mata, Ernesto Gabino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Rigorous diffraction of an electromagnetic beam by wavelength-size slits

A rigorous modal theory for the diffraction of Gaussian beams from N slits in an otherwise perfectly plane conducting screen (line finite-grating) is presented. The case of normal incidence and T.E.-polarization is considered, i.e. the electric field is parallel to the strips. The characteristics of the far-field radiation pattern as a function of the wavelength are analyzed, particularly within the vectorial region where the influence of polarization is more important. Furthermore, the influence of the beam width and beam alignment on the transmission coefficient, on the normally diffracted energy, and on the diffraction is studied

Teoría rigurosa de la dispersión de haces gaussianos por una rejilla con sustrato metálico

Se presenta una teoría rigurosa de la dispersión de haces Gaussianos a incidencia normal y oblicua por una rejilla finita en una pantalla conductora, de espesor cero y con sustrato metálico. El sustrato puede ser el vacío o un conductor. Se considera el caso de polarización T.E., es decir, el campo eléctrico es paralelo a las rendijas. Se analiza en la región vectorial de la difracción a patrones de dispersión en función de la longitud de onda, del hacho del haz y de la posición del haz. De estos resultados se ha encontrado que el ancho de los órdenes de dispersión aumenta con la relación λ/L, donde λ es la longitud de onda y L el ancho del haz incidente. Cuando el sustrato es un conductor la ecuación de dispersión por una rejilla en reflexión predice la posición angular de los órdenes dispersados de una rejilla finita con una buena aproximación. Además, la posición angular de estos órdenes es independiente del sustrato, del ancho y de la posición del haz

La dialéctica de los cambios ambientales El antagonismo del cambio climático

The essay feature the Intergovernmental Panel on Climate Change and the antagonistic group of Skeptical scientists who promote Global Warming. The aim was to analyze both positions that deal with the origin or causes of the environmental changes that exist to date. Literature in different databases was reviewed to argue its characteristics through the epistemic exercise that applies critical dialectics in the comparison of the concepts Climate Change and Global Warming. As a result, the synthesis was elaborated to understand both positions analyzed from their strengths as a result of critical thinking. The essay contributes so that the readers understand and appropriate clear perspectives of the positions, regarding common themes. In addition, the bases were provided to create awareness regarding the temporality of environmental changes, their effects, consequences and their mitigation. It was concluded that even today, although the proven effects of an ecological imbalance are observed or not, there is a reality in the majority of humanity of a lack of collective consciousness that is harmful to living beings and the environment.El ensayo presenta al Panel Intergubernamental del Cambio Climático y al grupo antagónico de científicos Escépticos que promueven el Calentamiento Global. El objetivo fue analizar ambas posturas que tratan del origen o causas de los cambios ambientales que existen a la fecha. Se revisó literatura en diferentes bases de datos para argumentar sus características a través del ejercicio epistémico que aplica la dialéctica crítica en la comparación de los conceptos Cambio Climático y Calentamiento Global. Como resultado se elaboró la síntesis para comprender ambas posturas analizadas desde sus fortalezas como resultado del pensamiento crítico. El ensayo contribuye para que los lectores comprendan y se apropien de perspectivas claras de las posturas, con respecto de temas en común. Además, fueron proporcionadas las bases para crear conciencia con respecto a la temporalidad de los cambios en el medio ambiente, sus efectos, consecuencias y su mitigación. Se concluyó que aún en la actualidad, aunque se observan los efectos comprobados o no de un desequilibrio ecológico, existe una realidad en la mayoría de la humanidad de una falta de conciencia colectiva dañina para los seres vivos y el medio ambiente

Shape resonances in nested diffraction gratings

The diffraction problem of a plane wave impinging on a grating formed by nested cavities is solved by means of the modal method, for $s$ and $p$ polarization modes. The cavities are formed by perfectly conducting sheets that describe rectangular profiles. The electromagnetic response of the grating is analyzed, paying particular attention to the generation of resonances within the structure. The dependence of the resonances on the geometrical parameters of the grating is studied, and results of far and near field are shown. The results are checked and compared with those available in the literature for certain limit cases.Comment: 18 pages, 8 figure

Gingival fibroblasts behavior on bioactive zirconia and titanium dental implant surfaces produced by a functionally graded technique

Adding a biological apatite layer to the implant surface enhances bone healing around the implant. Objective: This study aimed to characterize the mechanical properties and test human gingival fibroblasts behavior in contact with Zirconia and Titanium bioactive-modified implant materials. Methodology: 6 groups were considered: Titanium (Ti6Al4V), Ti6Al4V with 5% HA and 5% ßTCP, Zirconia (YTZP), YTZP with 5% HA and 5% ßTCP. For each group, we produced discs using a novel fabrication method for functionally graded materials, under adequate conditions for etching and grit-blasting to achieve equivalent surface microroughness among the samples. Surface roughness (Ra, Rz), water contact angle, shear bond strength, and Vickers hardness were performed. Human gingival fibroblasts immortalized by hTERT gene from the fourth passage, were seeded on discs for 14 days. Cell viability and proliferation were assessed using a resazurin-based method, and cellular adhesion and morphology using field emission gun scanning electron microscopy (FEG-SEM). After 3 days of culture, images of fluorescent nucleic acid stain were collected by confocal laser scanning microscopy (CLSM). Results: Results were presented as mean ± standard deviation (SD). We compared groups using one-way ANOVA with Tukey’s post-hoc test, and significance level was set at p<0.05. After 14 days of culture, cell viability and proliferation were significantly higher in YTZP group than in other groups (p<0.05). Samples of YTZP-ßTCP presented significantly higher wettability (p<0.05); yet, we observed no improvement in cell behavior on this group. Fibroblast spreading and surface density were more evident on YTZP specimens. Adding calcium-phosphate bioactive did not alter the tested mechanical properties; however, Ti6Al4V material shear bond strength was statistically higher than other groups (p<0.05). Conclusion: Adding bioactive materials did not improve soft-tissue cell behavior. When compared to other zirconia and titanium groups, pure zirconia surface improved adhesion, viability and proliferation of fibroblasts. Cell behavior seems to depend on surface chemical composition rather than on surface roughness

Glycemic control and the risk of tuberculosis in patients with diabetes : A cohort study in a Mediterranean city

Altres ajuts: Institut Universitari per a la Recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (Institut Català de la Salut), PREDOC_ECO-19/2; Fundación redGDPS (Beca de apoyo José Luis Torres a la Investigación)Background: Diabetes mellitus (DM) is one of the leading chronic diseases globally and one of the most common causes of death, morbidity, and poor quality of life. According to the WHO, DM is also one of the main risk factors for developing active tuberculosis (TB). Subjects with DM are at a higher risk of infections, in addition to frequent micro and macrovascular complications, and therefore sought to determine whether poor glycemic control is linked to a higher risk of developing TB. Methods: We used a retrospective cohort of diabetic subjects to predict the incidence of TB. All DM patients were recruited from Ciutat Vella (the inner-city of Barcelona) from January 2007 until December 2016, with a follow-up period until December 2018 (≥2 years). Data were extracted from Barcelona's Primary Care medical record database - SIDIAP, and linked to the Barcelona TB Control Program. The incidence of TB and the impact of glycemic control were estimated using time-to-event curves analyzed by Cox proportional hazard regression. Hazard ratios (HRs) and 95% confidence intervals (CIs), unadjusted and adjusted by potential confounding variables, were also assessed, which included age, sex, diabetes duration, macrovascular and microvascular signs, BMI, smoking habit, alcohol consumption and geographical origin. Results: Of 8,004 DM patients considered for the study (equating to 68,605 person-years of follow-up), 84 developed TB [incidence rate = 70 (95% CI: 52-93) per 100,000 person-years]. DM subjects with TB were younger (mean: 52.2 vs. 57.7 years old), had higher values of glycosylated hemoglobin (HbA1c) (7.66 vs. 7.41%) and total triglycerides (122 vs. 105 mg/dl), and had twice the frequency of diabetic nephropathy (2.08 vs. 1.18%). The calculated incidence rate increased with increasing HbA1c: 120.5 (95% CI 77.2-179.3) for HbA1c ≥ 7.5%, 143 (95% CI 88.3-218.1) for HbA1c ≥ 8% and 183.8 (95% CI 105-298) for HbA1c ≥ 9%. An increase in the risk of TB was also observed according to a poorer optimization of glycemic control: adjusted HR 1.80 (95% CI 0.60-5.42), 2.06 (95% CI 0.67-6.32), and 2.82 (95% CI 0.88-9.06), respectively. Conclusion: Diabetic subjects with worse glycemic control show a trend toward a higher risk of developing TB

Subjects With Diabetes Mellitus Are at Increased Risk for Developing Tuberculosis : A Cohort Study in an Inner-City District of Barcelona (Spain)

Altres ajuts: Spanish Ministry of Economy and the Institut Universitari per a la Recerca a l'Atenció Primària de Salut Jordi Gol i Gurina (Catalan Health Institute, PREDOC_ECO-19/2).Background: Tuberculosis is the leading cause of mortality from lung infectious disease worldwide in recent years, and its incidence has re-emerged in large cities in low-incidence countries due to migration and socioeconomic deprivation causes. Diabetes mellitus and tuberculosis are syndemic diseases, with diabetes being considered a risk factor for developing tuberculosis. Objective: To investigate whether diabetic patients were at increased risk of tuberculosis living in an inner-district of a large city of northeastern Spain. Methods: Observational matched retrospective cohort study based on clinical records from the population of the lowest socioeconomic status in Barcelona (Ciutat Vella district). A cohort including patients with type 1 and type 2 diabetes mellitus in 2007 and new cases until 2016 (8004 subjects), matched 1:1 by sex and age with a non-diabetic cohort. Follow-up period was until December 31st 2018. We evaluated the risk of developing tuberculosis in diabetic patients compared to non-diabetic patients during the follow up period. We used time-to-event analysis to estimate the incidence of tuberculosis, and competing risks regression by clusters and conditional Cox regression models to calculate the hazard ratio (HR) and its 95% confidence intervals (CI). Results: Among the 16,008 included subjects, the median follow-up was 8.7 years. The mean age was 57.7 years; 61.2% men and 38.8% women in both groups. The incidence of tuberculosis was 69.9 per 100,000 person-years in diabetic patients, and 40.9 per 100,000 person-years in non-diabetic patients (HR = 1.90; CI: 1.18-3.07). After adjustment for the country of origin, chronic kidney disease, number of medical appointments, BMI, alcoholism and smoking, the risk remained higher in diabetic patients (1.66: CI 0.99-2.77). Additionally, subjects from Hindustan or with a history of alcohol abuse also showed a higher risk of developing tuberculosis (HR = 3.51; CI:1.87-6.57, and HR = 2.73; CI:1.22-6.12 respectively). Conclusion: People with diabetes mellitus were at higher risk of developing tuberculosis in a large cohort recruited in an inner-city district with a high incidence for this outcome, and low socioeconomic conditions and high proportion of migrants. This risk was higher among Hindustan born and alcohol abusers

Hormone-Dependent Expression of a Steroidogenic Acute Regulatory Protein Natural Antisense Transcript in MA-10 Mouse Tumor Leydig Cells

Cholesterol transport is essential for many physiological processes, including steroidogenesis. In steroidogenic cells hormone-induced cholesterol transport is controlled by a protein complex that includes steroidogenic acute regulatory protein (StAR). Star is expressed as 3.5-, 2.8-, and 1.6-kb transcripts that differ only in their 3′-untranslated regions. Because these transcripts share the same promoter, mRNA stability may be involved in their differential regulation and expression. Recently, the identification of natural antisense transcripts (NATs) has added another level of regulation to eukaryotic gene expression. Here we identified a new NAT that is complementary to the spliced Star mRNA sequence. Using 5′ and 3′ RACE, strand-specific RT-PCR, and ribonuclease protection assays, we demonstrated that Star NAT is expressed in MA-10 Leydig cells and steroidogenic murine tissues. Furthermore, we established that human chorionic gonadotropin stimulates Star NAT expression via cAMP. Our results show that sense-antisense Star RNAs may be coordinately regulated since they are co-expressed in MA-10 cells. Overexpression of Star NAT had a differential effect on the expression of the different Star sense transcripts following cAMP stimulation. Meanwhile, the levels of StAR protein and progesterone production were downregulated in the presence of Star NAT. Our data identify antisense transcription as an additional mechanism involved in the regulation of steroid biosynthesis

Chaos, decoherence and quantum cosmology

In this topical review we discuss the connections between chaos, decoherence and quantum cosmology. We understand chaos as classical chaos in systems with a finite number of degrees of freedom, decoherence as environment induced decoherence and quantum cosmology as the theory of the Wheeler - DeWitt equation or else the consistent history formulation thereof, first in mini super spaces and later through its extension to midi super spaces. The overall conclusion is that consideration of decoherence is necessary (and probably sufficient) to sustain an interpretation of quantum cosmology based on the Wave function of the Universe adopting a Wentzel - Kramers - Brillouin form for large Universes, but a definitive account of the semiclassical transition in classically chaotic cosmological models is not available in the literature yet.Comment: 40 page