Studies on Structure of Calcium Oxalate Monohydrate Renal Papillary Calculi. Mechanism of Formation

A scanning electron microscopy study of the ultrastructure of 18 calcium oxalate monohydrate papillary calculi was performed with the purpose of establishing the main steps in calculus formation. It is concluded that these calculi originate in a core located near the central part of the calculus. Significant quantities of organic matter as well as calcium phosphates can be found in the core and at the surface of adhesion to the papilla and, in some cases, fibers and calcified tubules can also be found in the contact zone. In no case did this material affect the crystalline structure of the calculi, indicating that its formation follows the calculus genesis. The study of the compact columnar zone revealed that its formation starts in a practically continuous surface formed by organic matter and crystals that surround the core. This layer favors the growth of oriented calcium oxalate monohydrate crystals upon it. Based on these observations, a feasible mechanism of papillary calcium oxalate monohydrate calculus formation is proposed

CACAO PRODUCTION ON WELL-DRAINED SOILS ALONG THE BANKS OF THE MAMORE RIVER ON NORTHEASTERN BOLIVIA

CACAO PRODUCTION ON WELL-DRAINED SOILS ALONG THE BANKS OF THE MAMORE RIVER ON NORTHEASTERN BOLIVI

Alejandro de Humboldt y Felipe Bauzá: una colaboración científica internacional en el primer tercio del siglo XIX

The correspondence maintained between Alexander von Humboldt and Felipe de Bauzá, between 1804 and 1827, serves as a source for the analysis of the methodological and technological state of geographical science, throwing light on the debates and contradictions that existed in European geographical knowledge at the beginning of the nineteenth century.El estudio de la correspondencia mantenida entre Alejandro de Humboldt y Felipe de Bauzá, 1804-1827, permite ahondar en el análisis de la geografía, en el estado metodológico y tecnológico de esta ciencia y, por último, en los debates y contradicciones de los conocimientos geográficos en Europa a comienzos del siglo XIX

An automatic system for crystal growth studies at constant supersaturation

An automatic system for growing crystals from seeded supersaturated solutions at constant supersaturation is described. Control of burettes and data acquisition are controlled by computer. The system was tested with a study of the calcium oxalate kinetics of crystal growth

Analyzing the potential impact of BREXIT on the European research collaboration network

In this work, we study the impact that the withdrawal of institutions from the United Kingdom caused by BREXIT has on the European research collaboration networks. To this aim, we consider BREXIT as a targeted attack to those graphs composed by the European institutions that have collaborated in research projects belonging to the three main H2020 programs (Excellent Science, Industrial Leadership, and Societal Challenges). The consequences of this attack are analyzed at the global, mesoscopic, and local scales and compared with the changes suffered by the same collaboration networks when a similar quantity of nodes is randomly removed from the network. Our results suggest that changes depend on the specific program, with Excellent Science being the most affected by BREXIT perturbation. However, the structure of the integrated collaboration network is not significantly affected by BREXIT compared to the variations observed after the random removal of institutions

Cutaneous polyarteritis nodosa

SUMMARY Classic polyarteritis nodosa (PAN) is a segmentary leucocytoclastic vasculitis that affects small-and medium-sized arteries. In 1931, Lindberg described the existence of a cutaneous variant of PAN, without visceral involvement and with a more favourable prognosis. We present four patients diagnosed with cutaneous PAN in our hospital between 1987 and 1998. The study group was composed of three women and one child, whose ages ranged from 11 to 70 years old. The follow-up period was between 2 and 13 years. Each patient was submitted for an initial clinical, histological and laboratory evaluation and subsequent follow-up. The presence of nodules was the most frequent cutaneous lesion, preferentially located in the lower limbs. The erythrocyte sedimentation rate was the only parameter that was altered in all patients. Cutaneous biopsies from all patients showed a segmentary leucocytoclastic vasculitis in the arteries of the deep dermis and⁄or hypodermis. Direct immunofluorescence was positive in just one patient. No visceral involvement was found in any patient. There is confusion about the correct definition of cutaneous PAN. Some clinical findings, such as nodules or livedo reticularis, typical of cutaneous PAN suggest a good prognosis; however, we consider that it is necessary to evaluate these patients for systemic involvement for the possibility of arteritis in other organs as the term polyarteritis suggests

Estudio paleopatológico de la necrópolis mudéjar de la calle Colón, 3 (Novelda, Alicante)

X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200

Dos embarazadas de la maqbara de la Calle Herrerías (Tudela, Navarra) (s. IX-XI)

X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200