A novel and chemoselective process of N-alkylation of aromatic nitrogen compounds using quaternary ammonium salts as starting material

Artículo Internacional Open AccesThe process of N-alkylation of several pyrroles, indoles, and derivative heterocycles is herein described, using quaternary ammonium salts as the source of an alkylating agent. These reactions were carried out on several heterocyclic rings with triethylbenzylammonium chloride or tetradecyltrimethyl ammonium bromide and an NaOH solution at 50%, leading to a chemoselective N-alkylated product and an average yield of 73%. This is an alternative process to the traditional benzylation and methylation of N-heterocycles with direct handling of alkyl halides.CONACYT, Secretaría de Investigación y Estudios Avanzados de la UAE

Conditions of work and dermatitis in workers exposed to chemical risks by cement

This research was carried out in order to identify the working conditions in workers exposed to cement in a cement factory in the city of Cartagena. Through different tools it was possible to carry out the diagnosis of the working conditions and to identify the hazards to which the workers of the company are exposed when being in direct contact with the cement; in this way it was possible to know that the dermatitis that were manifesting the workers has its direct relation with this chemical and therefore to be able to establish those measures tending to ensure the complete state of health of the workers. The type of research carried out is descriptive-qualitative, the applied methodology used as a closed questions survey tool, it was obtained as a result that 70% of the respondents did not use personal protection elements when handling cement, so can say that there is a considerable number of people exposed, which increases the likelihood that they may suffer contact dermatitis, through this the different preventive measures for working and health conditions among the employees of the cement company were raised

Evaluación del triflumurón y la mezcla de Bacillus thuringiensis más Bacillus sphaericus para el control de las formas inmaduras de Aedes aegypti y Culex quinquefasciatus en sumideros en Cali, Colombia

Introduction. In Cali, Colombia, catch basins (streetside storm drains) are one of the main larval habitats of Aedes aegypti and Culex quinquefasciatus. Since 1999, these mosquitoes have been controlled by the Secretaría de Salud Municipal (Secretary of Municipal Public Health) using the larvicide triflumuron. Because of high densities of these mosquitoes that remain in the city, treatment failure was suspected -possibly insecticide resistance of the target species.Objectives. The efficacy of triflumuron and VectoMax® (biorational mixture of Bacillus thuringiensis var. israelensis plus Bacillus sphaericus) were evaluated in the control of A. aegypti and C. quinquefasciatus in catch basins. The residual effect of a single application of the biorational formulation was determined in catch basins during periods of high and low rainfall.Materials and methods. The efficacy of the products was measured in 60 catch basins located in a residential neighborhood of Cali for a period of 90 days. The mean number of immature.Control de estadios inmaduros de mosquitos en sumideros instars ( A. aegypti and C. quinquefasciatus larvae and pupae of both species) was determined biweekly from 40 catch basins with insecticide intervention (20 treated with triflumuron, 20 with VectoMax®) and 20 untreated (control group). The residual effect of the biorational larvicide was evaluated biweekly in 10 catch basins during each of the 2 climatic periods.Results. The catch basins treated with VectoMax® presented a significantly lower mean number of immature instars of both species compared with the control ( p<0.01). In contrast, the triflumuron treatment significantly reduced only immature instars of A. aegypti compared with the control ( p<0.001). The residual effect of VectoMax® was higher during low rainfall compared to the control ( p<0.001).Conclusion. The biorational formulation was the more effective treatment for the control of both species during the period of evaluation (15 days).Introducción. En Cali los sumideros son uno de los principales criaderos de Aedes aegypti y Culex quinquefasciatus que son controlados por la Secretaría de Salud Municipal utilizando el insecticida triflumurón desde 1999. Se sospecha falla al tratamiento.Objetivos. Evaluar la eficacia del Starycide® (triflumurón) y VectoMax® (mezcla bacteriana de Bacillus thuringiensis var. israelensis y Bacillus sphaericus) en el control de A. aegypti y C. quinquefasciatus en los sumideros y determinar el efecto residual de una única aplicación de VectoMax®, en épocas de alta y baja pluviosidad.Materiales y métodos. La eficacia de los productos fue medida en 60 sumideros de una zona residencial de Cali por un período de 90 días. La media de individuos inmaduros (larvas y pupas de A. aegypti y C. quinquefasciatus) fueron obtenidas quincenalmente de 40 sumideros intervenidos (20 con triflumurón y 20 con VectoMax®) y 20 sin tratamiento (grupo testigo). El efecto residual de la mezcla bacteriana se evaluó quincenalmente en 10 sumideros en cada temporada climática.Resultados. Los sumideros tratados con VectoMax® presentaron diferencias en el promedio de estadios inmaduros en ambas especies frente al testigo (p<0,01). En contraste, el tratamiento con triflumurón sólo presentó diferencias en los estadios inmaduros de A. aegypti con respecto al testigo (p<0,001). El efecto residual del VectoMax® fue mayor en la época de baja pluviosidad con respecto al testigo (p<0,001).Conclusión. La mezcla bacteriana fue el tratamiento más eficaz en el control de ambas especies durante el período evaluado (15 días)

Etiology of chronic urticaria: the Ecuadorian experience

Background: The purpose of this study was to identify chronic urticaria (CU) etiologies and treatment modalities in Ecuador. We propose that the sample distribution fits the expected one, and that there is an association between the etiology and its treatment. Methods: We performed a retrospective study involving 112 patients diagnosed with CU using a Checklist for a complete chronic urticaria medical history. Demographic and clinical variables were collected. The etiology of CU was classified using the EAACI/GA2LEN/EDF/WAO guideline. Descriptive analyses were performed for demographical and clinical variables. Chi square tests were applied to analyze the fit of distribution and the independence of variables. P values less than 0.05 were considered significant. Results: Among all the patients, 76.8% were diagnosed with chronic spontaneous urticaria (CSU), of which 22.3% had a known etiology or possible exacerbating condition. Food allergy was identified as the most common accompanying condition in patients with CSU (10.7%) (p < 0.01).. On the other hand, 23.2% inducible urticarias (CIndU) were indentified; dermographism was the most common (10.7%) (p < 0.01). Regarding treatment regimens, sg-H1-antihistamines alone represented the highest proportion (44.6%). The combination of any H1-antihistamine plus other drug was a close second (42.0%) (p < 0.01). Almost 48% of CSUs of unknown etiology were treated with any antihistamine plus another drug. In patients with known etiology, sg-antihistamines alone (44.0%) was the most common management. In addition, 53.8% of CIndUs were treated with sg-antihistamines alone. Though, these associations were not statistically significant. Conclusion: CSU is the most frequent subtype of CU. Modern non-sedating antihistamines in licensed doses are the drug of choice. Nevertheless, a great proportion of patients require the addition of another type of medication

High-K dielectric sulfur-selenium alloys.

Upcoming advancements in flexible technology require mechanically compliant dielectric materials. Current dielectrics have either high dielectric constant, K (e.g., metal oxides) or good flexibility (e.g., polymers). Here, we achieve a golden mean of these properties and obtain a lightweight, viscoelastic, high-K dielectric material by combining two nonpolar, brittle constituents, namely, sulfur (S) and selenium (Se). This S-Se alloy retains polymer-like mechanical flexibility along with a dielectric strength (40 kV/mm) and a high dielectric constant (K = 74 at 1 MHz) similar to those of established metal oxides. Our theoretical model suggests that the principal reason is the strong dipole moment generated due to the unique structural orientation between S and Se atoms. The S-Se alloys can bridge the chasm between mechanically soft and high-K dielectric materials toward several flexible device applications

Characterization and analysis of metropolitan freight patterns in Medellin, Colombia

This paper seeks to pilot test a novel way to collect freight and service activity data and analyze the collected data in the metropolitan area of Medellin, Colombia. This research collects data using a multi-layer and multi-actor approach that includes surveys to receivers, suppliers, carriers, and truck drivers. The data are used by the authors to describe the overall freight patterns in the area of study and to show lessons learned. The data collection resulted in 2947 establishments (4.4% of the total establishments in the city), a cordon survey of 2950 commercial vehicles (17% of the total vehicle volume) accessing the urban area, and carrier interviews to ten companies and 130 truck drivers. The results indicate that a total of 33,274 metric tons/day enter the study area, 35,240 tons/day leave the area; while 7000 tons/day are distributed in the study area. In terms of freight trips, 6600 trips/day enter the study zone and 6600 trips/day leave it. The data collection effort enabled the analyses of freight generation patterns. The freight surveys used in the study complement each other, and provided a good depiction of the freight movements in urban areas. It was found that in the Medellin Metropolitan Area, freight-intensive sector establishments generates, on average, significantly more cargo (freight attraction plus production) than the service-intensive sectors. The analyses of the surveys allow the decision makers to understand the nature of the cargo and the generation patterns in different type of establishments. This characterization of the freight patterns is vital for the forecasting of the behavior of the cargo and it is the main input to perform freight demand modeling for city planning, especially for developing countries, where there are too many budget constraints

Diagnosis of solid waste management in the petrochemical-plastic sector of Cartagena de indias, Northern Colombia

In the production of most petrochemical products there is a generation of associated solid waste. The objective is to diagnose solid waste management in a company in the petrochemical-plastic sector. The methodology initially consisted in the identification of the different operational areas and type of waste under the NTC GTC 24, in the second instance the solid waste classification was carried out taking into account the simple method of analysis of CEPIS and finally the quantification of The waste taking as a reference what Ruiz (2012)[1] did. It is evident that there is an increase (10.2%) in the generation of solid waste generated, from 545,750 kg in 2013 to 601,492 kg in 2014. The activities with the largest generation of solid waste (cardboard, plastic, wood) Are those of the reception and storage processes and the packaging process in each of the plants

Direct impacts of off-hour deliveries on urban freight emissions

The most significant negative environmental impacts of urban trucking result largely from travel in congested traffic. To illustrate the potential of innovative solutions to this problem, this paper presents new research on the emission reductions associated with off-hour freight deliveries (OHD). The paper uses fine-level GPS data of delivery operations during regular-hours (6 AM to 7 PM), and off-hours (7 PM to 6 AM), to quantify emissions in three major cities in the Americas. Using second-by-second emissions modeling, the paper compares emissions under both delivery schedules for: reactive organic gases, total organic gases, carbon monoxide, carbon dioxide, oxides of nitrogen, and particulate matter. The results show that the magnitude of the emission reductions depends on the extent of the change of delivery time. In the case of the “Full” OHD programs of New York City and São Paulo—where the deliveries were made during the late night and early morning periods (7 PM to 6 AM)—the emission reductions are in the range of 45–67%. In the case of the “Partial” OHD used in Bogotá (where OHD took place between 6 PM and 10 PM), the reductions were about 13%. The emission reductions per kilometer are used to estimate the total reductions for the cities studied, and for all metropolitan areas in the world with more than two million residents. The results indicate the considerable potential of OHD as an effective—business friendly—sustainability tool to improve the environmental performance of urban deliveries. The chief implication is that public policy should foster off-hour deliveries, and all forms of Freight Demand Management, where practicable

Outbreak of persistent cutaneous abscesses due to Mycobacterium chelonae after mesotherapy sessions, Lima, Peru

Surtos de micobactérias de crescimento rápido têm sido relatados ocasionalmente. O estudo relata um surto de abscessos cutâneos por Mycobacterium chelonae após sessões de mesoterapia em Lima, Peru. De dezembro de 2004 a janeiro de 2005, 35 pessoas que haviam passado por sessões de mesoterapia apresentaram esses abscessos cutâneos. Treze (37%) desses casos suspeitos concordaram em realizar exames clínicos. Foram realizadas biópsias de punção de pele de lesões suspeitas e examinadas substâncias injetadas durante a mesoterapia. Os casos suspeitos eram predominantemente mulheres jovens e as lesões incluíram nódulos subcutâneos, abscessos e úlceras. Mycobacterium chelonae foi isolada de quatro pacientes e de um frasco de procaína. Em conclusão, é importante considerar a mesoterapia como fonte potencial de infecções de micobactérias de crescimento rápido.Outbreaks of rapidly growing mycobacteria have been occasionally described. The article reports an outbreak of cutaneous abscesses due to Mycobacterium chelonae following mesotherapy in Lima, Peru. From December 2004 through January 2005, 35 subjects who had participated in mesotherapy training sessions presented with persistent cutaneous abscesses. Thirteen (37%) of these suspected cases consented to underwent clinical examination. Skin punch-biopsies were collected from suspicious lesions and substances injected during mesotherapy were analyzed. Suspected cases were mainly young women and lesions included subcutaneous nodules, abscesses and ulcers. Mycobacterium chelonae was isolated from four patients and from a procaine vial. In conclusion, it is important to consider mesotherapy as a potential source of rapidly growing mycobacteria infections