897 research outputs found
Comentarios a la reflexión «Osteoporosis y ecografía ósea de calcáneo. Empresas farmacéuticas y atención primaria. ¿Qué estamos haciendo?»
Tumor desmoide extraabdominal en rodilla: a propósito de un caso
Los tumores desmoides o fibromatosis agresiva son neoplasias de partes blandas muy poco frecuentes.
Son localmente agresivos y recurrentes, aunque carecen de potencial metastásico. La forma extraabdominal
es la más infrecuente y asienta habitualmente sobre la cintura pélvica o escapular. Presentamos el caso de
una paciente a la que se le diagnosticó un tumor desmoide extraabdominal en la rodilla izquierda que se manifestó
inicialmente como una tumoración dolorosa.Desmoid tumours or aggressive fibromatosis are rare neoplasm of soft tissues. They are locally
aggressive and recurrent, although they have no metastatic potential. The extra-abdominal appearance is the less
common and tumors are frequently located around pelvic or scapular vicinity. We report a case of a patient who
suffered an extra-abdominal desmoid tumor in her left knee that arose as a painful bump
Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
The synthesis and characterisation of the nonsymmetric liquid crystal dimer, 1-(4-cyanobiphenyl-40-yloxy)-6- (4-cyanobiphenyl-40-yl)hexane (CB6OCB) is reported. An enantiotropic nematic (N)–twist-bend nematic (NTB) phase transition is observed at 109 1C and a nematic–isotropic phase transition at 153 1C. The NTB phase assignment has been confirmed using polarised light microscopy, freeze fracture transmission electron microscopy (FFTEM), 2H-NMR spectroscopy, and X-ray diffraction. The effective molecular length in both the NTB and N phases indicates a locally intercalated arrangement of the molecules, and the helicoidal pitch length in the NTB phase is estimated to be 8.9 nm. The surface anchoring properties of CB6OCB on a number of aligning layers is reported. A Landau model is applied to describe high-resolution heat capacity measurements in the vicinity of the NTB–N phase transition. Both the theory and heat capacity measurements agree with a very weak first-order phase transition. A complementary extended molecular field theory was found to be in suggestive accord with the 2H-NMR studies of CB6OCB-d2, and those already known for CB7CB-d4. These include the reduced transition temperature, TNTBN/TNI, the order parameter of the mesogenic arms in the N phase close to the NTB–N transition, and the order parameter with respect to the helix axis which is related to the conical angle for the NTB phase.Postprint (published version
Analysis of the power balance In the cells of a multilevel cascaded H-Bridge converter
Multilevel cascaded H-Bridge converters (CHB)
have been presented as a good solution for high power applications.
In this way, several control and modulation techniques
have been proposed for this power converter topology. In this
paper the steady state power balance in the cells of the single
phase two cell CHB is studied. The capability to be supplied with
active power from the grid or to deliver active power to the grid
in each cell is analyzed according to the dc-link voltages and
the desired ac output voltage value. Limits of the maximum and
minimum input active power for stable operation of the CHB are
addressed. Simulation results are shown to validate the presented
analysis
Brønsted acid−catalyzed synthesis of tetrasubstituted allenes and polysubstituted 2H-chromenes from tertiary propargylic alcohols
A practical and environmentally benign Brønsted acid−catalyzed protocol for the preparation of all-carbon tetrasubstituted allenes, consisting in the direct SNˈ addition of tri- or dimethoxy arenes or allyltrimethylsilane to tertiary propargylic alcohols, has been developed. In addition, a straightforward synthesis of densely substituted 2H-chromenes by metal-free tandem allenylation/heterocyclization reaction of methoxyphenols and tertiary alkynols is presented.Junta de Castilla y León and FEDER (BU291P18) and Ministerio de Economía y Competitividad (MINECO) and FEDER (CTQ2016-75023-C2-1-P
Host Range of Meloidogyne Arenaria (NEAL, 1889) Chitwood, 1949 (Nematoda: Meloidogynidae) in Spain
11 páginas, ilustraciones y tablas estadísticas.The distribution of Meloidogyne arenaria in Spain was revised and new samples collected from representative
areas. Species and races of the populations were determined by morphometrics, differential host tests and SCAR-PCR.
Meloidogyne arenaria was found most often in warm areas, but it can occur in Northern Spain in greenhouses. A total of
125 citations were found, corresponding to 45 different host plants, of which 41 new reports (32.8%) are from this study.
The populations studied belong to race 2, which reproduces on tomato plants carrying the Mi gene, or race 3, which
reproduces on both resistant pepper and tomato. The most frequent hosts were vegetables, fruit trees, tobacco, grapevine,
and weeds.INIA OT-
03-006C7-4 and RTA2007-00099-C00-00; Castilla
La Mancha PAI09-0010-4701, INCRECYT CICyT CTM2006-07309.Peer reviewe
Estrategia medioambiental de la empresa exportadora gallega: ventajas e inconvenientes percibidos
La importancia que gran parte de la población mundial concede a la conservación del medio ambiente
supone un nuevo reto para la empresa. Por otra parte, en un mundo globalizado como el actual resulta
evidente la importancia que poseen las empresas exportadoras como motor de crecimiento de las
economías de los diferentes países del mundo. Con este punto de partida, el objetivo que se persigue
en el presente trabajo consiste en evaluar las percepciones de las empresas exportadoras de Galicia en
torno a las ventajas e inconvenientes derivados de la implantación de una estrategia medioambiental.Nowadays, most of the population gives a lot of importance to environment conservation, which is a
new challenge for the firms. On the other hand, in a world with increasing globalization, the export
firms are important to the economic growth of the countries. With this starting point, the objective of
this work is to evaluate the perceptions of the Galician export firm about the advantages and
disadvantages of the implantation of an environmental strategy
Distinctive dielectric properties of nematic liquid crystal dimers
We provide an overview of the effect of the molecular structure on the dielectric properties of dimers exhibiting nematic and twist-bend nematic phases with special focus on how the conformational distribution changes are reflected by the dielectric behaviour. Nematic dimers show distinctive dielectric properties which differ from those of archetypical nematic liquid crystals, as for example, unusual temperature dependence of the static permittivity or dielectric spectra characterised by two low-frequency relaxation processes with correlated strengths. The interpretation of such characteristic behaviour requires that account is taken of the effect of molecular flexibility on the energetically favoured molecular shapes. The anisotropic nematic interactions greatly influence the conformational distribution. Dielectric behaviour can be used to track those conformational changes due to dependence of the averaged molecular dipole moment on the averaged molecular shape. Results for a number of dimers are compared and analysed on the basis of the influence of details of the molecular structure, using a recently developed theory for the dielectric properties of dimers.Postprint (author's final draft
Associations between Bone Material Strength Index, Calcaneal Quantitative Ultrasound, and Bone Mineral Density in Men
Impact micro-indentation (IMI) measures bone material strength index (BMSi) in vivo. This study investigated how IMI is associated with calcaneal quantitative ultrasound and bone densitometry parameters in men. BMSi was measured on the tibial plateau using the OsteoProbe in 377 men (age 33-96 years) from the Geelong Osteoporosis Study. Broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) were assessed at the calcaneus using an ultrasonometer. Areal BMD was measured at several skeletal sites using dual-energy x-ray absorptiometry. Linear associations between parameters were tested using Pearson's correlation. Multivariable regression techniques were used to determine associations between BMSi and other measures of bone, independent of confounders. BMSi was negatively correlated with age (r = -0.171, P =.001), weight (r = -0.100, P =.052), and body mass index (r = -0.187, P =.001), and positively with height (r = +0.109, P =.034). There was some evidence to support a positive association between BMSi and BUA (β = 0.052, P =.037), SOS (β = 0.013, P =.144), and SI (β = 0.036, P =.051). After age adjustment, this association was attenuated. No correlations were observed between BMSi and BMD at any skeletal site (r values ranged from -0.006 to +0.079, all P ≥.13). There was a small positive association between BMSi and quantitative ultrasound (QUS) parameters, which were not independent of age. No associations were detected between BMSi and BMD. This suggests that BMSi and QUS are capturing common age-dependent properties of bone. Further research on the utility of IMI alone and complementary to conventional bone testing methods for predicting fracture risk is warranted
General synthesis of alkenyl sulfides by palladium-catalyzed thioetherification of alkenyl halides and tosylates
The cross-coupling reaction of alkenyl bromides with thiols catalyzed by palladium complexes derived from inexpensive dppf ligand is reported. These reactions occur under low catalyst loading and in high yields and display wide scope, including the coupling of bulky thiols and trisubstituted bromoolefins, and functional group tolerance. In addition, the thioetherification of less reactive chloroalkenes and, for the first time, alkenyl tosylates was accomplished using a catalyst generated from CyPFtBu alkylbisphosphine ligand.Junta de Castilla y León and FEDER
(BU076U16) and Ministerio de Economía
y Competitividad
(MINECO) and FEDER (CTQ2016-75023-C2-1-P
- …