Knowledge and technology transfer to improve the municipal solid waste management system of Durango City, Mexico.

As society evolves its welfare level increases, and as a consequence the amount of municipal solid waste increases, imposing great challenges to municipal authorities. In developed countries, municipalities have established integrated management schemes to handle, treat, and dispose of municipal solid waste in an economical and environmentally sound manner. Municipalities of developing and transition countries are not exempted from the challenges involving municipal solid waste handling, but their task is not easy to accomplish since they face budget deficits, lack of knowledge, and deficiencies in infrastructure and equipment. In the northern territory of Mexico, the municipality of Durango is facing the challenge of increased volumes of waste with a lack of adequate facilities and infrastructure. This article analyses the evolution of the municipal solid waste management of Durango city, which includes actions such as proper facilities construction, equipment acquisition, and the implementation of social programmes. The World Bank, offering courses to municipal managers on landfill operation and waste management, promoted the process of knowledge and technology transfer. Thereafter, municipal authorities attended regional and some international workshops on waste management. In addition they followed suggestions of international contractors and equipment dealers with the intention to improve the situation of the waste management of the city. After a 15-year period, transfer of knowledge and technology resulted in a modern municipal solid waste management system in Durango municipality. The actual system did not reach the standard levels of an integrated waste management system, nevertheless, a functional evaluation shows clear indications that municipality actions have put them on the right pathway.

Unravelling the stereoselectivity in 6-exo-trig radical cyclization of alpha,beta-unsaturated ester-tethered sugars. A tale of two stereocenters.

A computational investigation on the origin of the stereoselectivity of 6-exo-trig radical cyclization of alpha,beta-unsaturated ester-tethered sugars has revealed that a boat-like transition state, which keeps the ester in a planar conformation, holds the chiral information. Following this model, the stereocenter to which the ester functionality is connected reports the chirality to the newly formed stereocenter via a 1,4-transfer mechanism.

Cat-scratch Disease in the Pediatric Population: 6 Years of Evaluation and Follow-up in a Public Hospital in Chile.

BACKGROUND: Bartonella henselae is the etiologic agent of cat-scratch disease, which affects the entire world population. Due to how poorly characterized the child population is, the objective was to describe the clinical behavior of this disease in children younger than 16 years of age. METHODS: This was a descriptive study with prospective follow-up of all children younger than 16 years with clinical and serologic diagnoses between 2013 and 2018. RESULTS: There were 142 patients; of these, 55.6% had localized disease, 34.5% disseminated with hepatosplenic involvement and 9.8% had atypical disease. The cases of atypical disease were prolonged febrile illness, Parinaud syndrome, subacute bacterial endocarditis/glomerulonephritis and aseptic meningitis. Cervical lymphadenopathy was the most frequent, followed by inguinal adenopathy. There were no differences between the type of manifestation and laboratory values except for a higher erythrocyte sedimentation rate tendency in patients with disseminated and/or atypical disease. The serologic titers throughout were distributed as follows: titer of 1/1024, 71.7%; titer of 1/512, 10.4% and titer of 1/256, 17.9%. CONCLUSIONS: This is, to our knowledge, the largest series of cat-scratch disease published. We demonstrate that in our environment, the inguinal location is suggestive of this disease, the disseminated presentation, frequent, and that the titers are probably much higher than in other populations, which perhaps indicates the need to re-examine the cut-off point for positivity.

Synthesis of new heterocyclic derivatives of alpha,alpha-trehalose.

Several novel N-1, N-2, and S-5 tetrazole and 1,3,4-oxadiazole derivatives of alpha,alpha-trehalose disubstituted at C-6,6', with potential synthetic and pharmacological interest were prepared from commercial tetrazoles and 1,3,4-oxadiazoles in reaction with hexa-O-benzyl-6,6'-di-O-triflyl-alpha,alpha-trehalose.