149 research outputs found
Conservation of James Sowerby’s Fungi Models
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Blue Whale on the Move: Dismantling a 125 Year-Old Specimen
The Natural History Museum (London, UK) intends to suspend a 25 metre-long, blue whale (Balaenoptera musculus) from its central Hintze Hall. Alongside other specimens which are to be put on open display in this space the environment was looked at in terms of sustainable improvements. Works are being undertaken to improve the conditions by utilizing natural ventilation and re-using existing duct work. This specimen, acquired by the Museum in 1891, was suspended from the ceiling of the Mammal Hall, where it has been on display since 1934. Conservators worked with a specialist specimen handling company to carefully dismantle and remove each of the 220 bones from its original mount. The skull required a special frame and a precise calculation of movement to dismantle it and remove it. Many complex decisions were made during this process – as each bone removal did not dictate what the next would bring. During the dismantling phase, the conservation team have had to address the many requirements of curators, researchers, senior management and the media.© 2016 The Authors. The abstracts published in
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Diverse calcium channel types are present in the human placental syncytiotrophoblast basal membrane
The functional expression of calcium channels has been scarcely studied in human placental syncytiotrophoblast. We have presently sought to characterize Ca2+ currents of the healthy syncytiotrophoblast basal membrane using purified basal membranes reconstituted in giant liposomes subjected to patch-clamp recordings.
We detected presence of channels with high permeability to Ca2+ (relative PCa/PK up to 99.5) using K+ solutions in symmetric conditions. Recordings performed in Ba2+ gradients showed Ba2+-conducting channels in 100% of experiments. Ba2+ total patch currents were consistently blocked by addition of NiCl2, Nifedipine (L-type voltage-gated calcium channel blocker) or Ruthenium Red (TRPV5-TRPV6 channel blocker); Nifedipine and Ruthenium Red exerted a synergic blocking effect on Ba2+ total patch currents. lmmunohistochemistry of placental villi sections evidenced presence of alpha(1) subunit of voltage-gated calcium channels and TRPV5-TRPV6 channels in basal and apical syncytiotrophoblast plasma membranes; these three calcium channels were also detected in purified basal and apical fractions using Western blot. These results show the presence of three types of calcium channels in the syncytiotrophoblast basal membrane by both functional and molecular means. These basal membrane calcium channels would not be directly involved in mother-to-fetus Ca2+ transport, but could participate in other relevant trophoblast processes, such as exocytosis and Ca2+ transport regulation
Rheological characterization of asphalt binders used in strain relief asphalt mixtures (SRAM)1
The use of 'interlayers' that tolerate high tensile and shear strain that exists above cracks in deteriorated pavements is becoming aninteresting solution to prevent reflective cracking. Recent advances in polymer technology have led to binders that can be used to produceinterlayer mixtures with good mechanical properties. In this study, two polymer-modified asphalt binders were evaluated, both from theproduction of strain relief asphalt mixtures used as interlayers in the field. The binder characterization was presented in two groups: (i) theempirical tests required in the Brazilian specification, and (ii) the rheological properties (frequency/temperature sweep and MSCR tests).Results showed that the difference in rheological properties of the asphalt binder used for strain relief asphalt mixtures did not follow thesame difference obtained according to the empirical tests of the Brazilian specification. The G*/sinδ and MSCR parameters (Jnr andpercentage of recovery) were able to differentiate the asphalt binders, but the MSCR parameters were more sensitive.El uso de capas intermedias que toleren los altos esfuerzos de tensión y cortantes que existen alrededor de las grietas de pavimentos deteriorados se ha constituido en una solución interesante para prevenir la reflexión de grietas. Avances recientes en la tecnología de polímeros han generado ligantes que pueden ser usados para producir mezclas para capas intermedias con buenas propiedades mecánicas. En este estudio, dos asfaltos modificados con polímeros fueron evaluados, ambos empleados en la producción de mezclas asfálticas de alivio de deformaciones usadas como capas intermedias en campo. La caracterización de los ligantes se presentó en dos grupos: (i) los ensayos empíricos requeridos por la especificación brasilera, y (ii) las propiedades reológicas (barrido de frecuencia/temperatura y ensayos MSCR). Los resultados mostraron que el ligante asfáltico usado para las mezclas asfálticas de alivio de deformaciones presentó propiedades reológicas considerablemente diferentes, a pesar de que su caracterización a través de ensayos empíricos es similar. Los parámetros G*/sinδ y MSCR (Jnr y porcentaje de recuperación) lograron diferenciar los ligantes asfálticos, aunque los parámetros del MSCR mostraron mayor sensibilidad
From data to practice: brain meningioma treatment in elderly patients – a survey of the Italian Society of Neurosurgery (SINch®) and systematic review and meta-analysis
The management of meningioma in elderly patients (MEP) presents a complex and evolving challenge. Data available offer conflicting information on treatment options and complications. This survey aimed to examine the current approach to MEP, comparing the national profile to data in the current literature. A survey addressing the treatments options and management of meningioma in elderly was designed on behalf of SINch (R) (Societa Italiana di Neurochirurgia) and sent via email to all Chiefs of Neurosurgical Departments. The survey remained open for responses from May 5th, 2022, until November 21st, 2022. A search of the literature published between January 2000 and March 2023, in accordance to PRISMA guidelines, was included. A total of 51 Neurosurgical centers participated in the survey. The caseload profile of each center influences the choice of treatment selection (Stereotactic Radiosurgery versus open surgery) (p = 0.01) and the consolidated practice of discussing cases within a multidisciplinary group (p = 0.02). The pooled meta-analysis demonstrated a significant increased risk in the elderly group for permanent deficits (p < 0.00001), postoperative infections (p = 0.0004) and hemorrhage (p = 0.0001), perioperative mortality (p < 0.00001), and medical complications (p < 0.00001) as compared to the young population. This study presents the initial comprehensive analysis of the existing trends in the surgical management of MEP in Italy. The significant variation in practices primarily stems from the absence of standardized guidelines. While most centers have adopted an integrated approach, there is a need to promote a multidisciplinary care model. Prospective studies are needed to gather robust evidence in this clinical setting
DOSAGEM DE MISTURA BETUMINOSA A FRIO E SEU ESTUDO SOB EFEITOS DE CARGAS ESTÁTICAS E REPETIDAS1
RESUMO Este trabalho apresenta os resultados de uma pesquisa experimental que objetivou estudar o comportamento mecânico de uma mistura betuminosa a frio sob efeitos de cargas estáticas e repetidas. Após a caracterização dos agregados e do ligante empregados na pesquisa, efetuou-se a mistura, a partir da dosagem Marshall, obtendo o teor de projeto equivalente a 8,5% de emulsão. Nesse teor de emulsão, moldaram-se várias amostras, que foram submetidas aos ensaios de módulo de resiliência, resistência à tração por compressão diametral e fadiga. A caracterização dos agregados e do ligante mostrou-se concordante com vários estudos, exceto o resíduo da peneiração, que não atendeu à exigência do IBP (1999). Para os ensaios com as misturas asfálticas, empregaram-se três corpos de prova, pesando cada um deles cerca de 1.200 g, compactados com 75 golpes em cada uma de suas faces. Observou-se que a estabilidade e a fluência Marshall de 620 kgf e de 4,20 mm, respectivamente, superaram o limite mínimo recomendado na especificação de serviço do DNIT (2010a). Com relação aos ensaios de módulo de resiliência e de resistência à tração por compressão diametral, obtiveram-se os valores de 1.616 MPa e 0,44 MPa, respectivamente, quando se verificou que os resultados foram bem inferiores aos encontrados em misturas a quente. Esse mesmo comportamento foi observado no ensaio de fadiga que, na maioria dos níveis de tensão aplicados, foi inferior a 1.000 aplicações do carregamento
Comportamento resiliente de um solo argiloso da região de Viçosa-MG no estado natural e estabilizado com cimento e alcatrão fracionado
Molecular and Electrophysiological Characterization of a Novel Cation Channel of Trypanosoma cruzi
We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of a novel cation channel (TcCat) from Trypanosoma cruzi, the etiologic agent of Chagas disease. This channel is potassium permeable and shows inward rectification in the presence of magnesium. Western blot analyses with specific antibodies indicated that the protein is expressed in the three main life cycle stages of the parasite. Surprisingly, the parasites have the unprecedented ability to rapidly change the localization of the channel when they are exposed to different environmental stresses. TcCat rapidly translocates to the tip of the flagellum when trypomastigotes are submitted to acidic pH, to the plasma membrane when epimastigotes are submitted to hyperosmotic stress, and to the cell surface when amastigotes are released to the extracellular medium. Pharmacological block of TcCat activity also resulted in alterations in the trypomastigotes ability to respond to hyperosmotic stress. We also demonstrate the feasibility of purifying and reconstituting a functional ion channel from T. cruzi after recombinant expression in bacteria. The peculiar characteristics of TcCat could be important for the development of specific inhibitors with therapeutic potential against trypanosomes
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