304 research outputs found
Multimodal and Multistimuli 4D-Printed Magnetic Composite Liquid Crystal Elastomer Actuators
Liquid crystal elastomer (LCE)-based soft actuators are being studied for their significant shape-changing abilities when they are exposed to heat or light. Nevertheless, their relatively slow response compared with soft magnetic materials limits their application possibilities. Integration of magnetic responsiveness with LCEs has been previously attempted; however, the LCE response is typically jeopardized in high volumes of magnetic microparticles (MMPs). Here, a multistimuli, magnetically active LCE (MLCE), capable of producing programmable and multimodal actuation, is presented. The MLCE, composed of MMPs within an LCE matrix, is generated through extrusion-based 4D printing that enables digital control of mesogen orientation even at a 1:1 (LCE:MMPs) weight ratio, a challenging task to accomplish with other methods. The printed actuators can significantly deform when thermally actuated as well as exhibit fast response to magnetic fields. When combining thermal and magnetic stimuli, modes of actuation inaccessible with only one input are achieved. For instance, the actuator is reconfigured into various states by using the heat-mediated LCE response, followed by subsequent magnetic addressing. The multistimuli capabilities of the MLCE composite expand its applicability where common LCE actuators face limitations in speed and precision. To illustrate, a beam-steering device developed by using these materials is presented
Lorentz spaces of vector measures and real interpolation of operators
[EN] Using the representation of the real interpolation of spaces of p-integrable functions with respect to a vector measure, we show new factorization theorems for p-th power factorable operators acting in interpolation couples of Banach function spaces. The recently introduced Lorentz spaces of the semivariation of vector measures play a central role in the resulting factorization theorems. We apply our results to analyze extension of operators from classical weighted Lebesgue Lp-spaces ¿ in general with di¿erent weights ¿ that can be extended to their q-th powers. This is the case, for example, of the convolution operators defined by Lp-improving measures acting in Lebesgue Lp-spaces or Lorentz spaces. A new representation theorem for Banach lattices with a special lattice geometric property, as a space of vector measure integrable functions, is also proved.The fifth author acknowledges the support of the Ministerio de Economia y Competitividad (Spain) and FEDER under grant MTM2016-77054-C2-1-PDel Campo, R.; Fernández, A.; Mayoral, F.; Naranjo, F.; Sánchez Pérez, EA. (2020). Lorentz spaces of vector measures and real interpolation of operators. Quaestiones Mathematicae. 43(5-6):591-609. https://doi.org/10.2989/16073606.2019.1605413S591609435-
Metal-insulator transition in NdEuNiO compounds
Polycrystalline NdEuNiO () compounds
were synthesized in order to investigate the character of the metal-insulator
(MI) phase transition in this series. Samples were prepared through the sol-gel
route and subjected to heat treatments at 1000 C under oxygen
pressures as high as 80 bar. X-ray Diffraction (XRD) and Neutron Powder
Diffraction (NPD), electrical resistivity , and Magnetization
measurements were performed on these compounds. The results of NPD and XRD
indicated that the samples crystallize in an orthorhombic distorted perovskite
structure, space group . The analysis of the structural parameters
revealed a sudden and small expansion of 0.2% of the unit cell volume
when electronic localization occurs. This expansion was attributed to a small
increase of 0.003 \AA{} of the average Ni-O distance and a simultaneous
decrease of of the Ni-O-Ni superexchange angle. The
measurements revealed a MI transition occurring at temperatures
ranging from to 336 K for samples with and 0.50,
respectively. These measurements also show a large thermal hysteresis in
NdNiO during heating and cooling processes suggesting a first-order
character of the phase transition at . The width of this thermal
hysteresis was found to decrease appreciably for the sample
NdEuNiO. The results indicate that cation disorder
associated with increasing substitution of Nd by Eu is responsible for changing
the first order character of the transition in NdNiO.Comment: 19 pages, 9 figure
Cavernous sinus metastasis from oropharyngeal squamous cell carcinoma
Metastasis to the cavernous sinus from head and neck cancer is uncommon and has been previously reported by a few authors. It is usually a late manifestation of the primary tumor and may be the first evidence of a widespread dissemination of the disease. Main clinical findings are those related with involvement of cranial nerves III to VI as they pass through the cavernous sinus. Although diagnosis may be difficult, the appearance of clinical and radiological findings of cavernous sinus involvement in a context of head and neck cancer must alert us about an intracranial metastatic infiltration. In most cases treatment is palliative with radiotherapy and/or chemotherapy. The prognosis of this entity is poor, with survival of a few months. We present the case of cavernous sinus metastasis from oropharyngeal squamous cell carcinoma and review the literature about the clinical presentation and management of this rare entity
Solitary cystic lymph neck node metastasis of occult thyroid papillary carcinoma
The appearance of a solitary lateral cervical cystic mass as the only initial presenting symptom of occult thyroid carcinoma is uncommon. Its presence is often misdiagnosed due to the more frequent branchial cyst in young people. Although oronasopharyngeal squamous cell carcinoma has been reported as the main cause of lymph neck node metastasis, thyroid papillary carcinoma may be responsible for solitary cervical cystic masses as the initial manifestation of the disease. This situation has been rarely reported, although solid masses are much more frequent. In most of these cases all such lesions may initially be considered as metastatic foci from a primary thyroid lesion. However, an alternative explanation by means of which ectopic thyroid tissue is associated with a branchial cyst has to be considered, especially if no primary tumour is observed in the histological examination of the thyroid gland. We present a rare case of solitary cystic lymph node metastasis of occult papillary carcinoma of the thyroid. We also discuss possible ethiology for thyroid papillary carcinoma in lateral neck cysts
Effect of exercise on sleep quality and insomnia in middle-aged women: A systematic review and meta-analysis of randomized controlled trials
OBJECTIVE:
We assessed the effects of programmed exercise (PE) on sleep quality and insomnia in middle-aged women (MAW).
METHODS:
Searches were conducted in five databases from inception through December 15, 2016 for randomized controlled trials (RCTs) evaluating the effects of PE versus a non-exercising control condition on sleep quality, sleep disturbance and/or insomnia in MAW. Interventions had to last at least 8 weeks. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and insomnia with the Insomnia Severity Index (ISI). Random effects models were used for meta-analyses. The effects on outcomes were expressed as mean differences (MDs) and their 95% confidence intervals (CI).
RESULTS:
Five publications reported data from four RCTs on PE effects during 12-16 weeks on sleep quality (n=4 studies reporting PSQI results) and/or insomnia (n=3 studies reporting ISI results), including 660 MAW. Low-moderate levels of exercise significantly lowered the PSQI score (MD=-1.34; 95% CI -2.67, 0.00; p=0.05) compared with controls. In a subgroup analysis, moderate PE (aerobic exercise) had a positive effect on sleep quality (PSQI score MD=-1.85; 95% CI -3.62, -0.07; p=0.04), while low levels of physical activity (yoga) did not have a significant effect (MD-0.46, 95% CI -1.79, 0.88, p=0.50). In three studies (two studies of yoga, one study of aerobic exercise), there was a non-significant reduction in the severity of insomnia measured with the ISI score (MD -1.44, 95% CI -3.28, 0. 44, p=0.13) compared with controls. Heterogeneity of effects among studies was moderate to high.
CONCLUSION:
In middle-aged women, programmed exercise improved sleep quality but had no significant effect on the severity of insomnia.Actividad Física y Deport
Recommended from our members
Quick abnormal-bid-detection method for construction contract auctions
Noncompetitive bids have recently become a major concern in both public and private sector construction contract auctions. Consequently, several models have been developed to help identify bidders potentially involved in collusive practices. However, most of these models require complex calculations and extensive information that is difficult to obtain. The aim of this paper is to utilize recent developments for detecting abnormal bids in capped auctions (auctions with an upper bid limit set by the auctioner) and extend them to the more conventional uncapped auctions (where no such limits are set). To accomplish this, a new method is developed for estimating the values of bid distribution supports by using the solution to what has become known as the German Tank problem. The model is then demonstrated and tested on a sample of real construction bid data, and shown to detect cover bids with high accuracy. This paper contributes to an improved understanding of abnormal bid behavior as an aid to detecting and monitoring potential collusive bid practices
Mandibular odontogenic myxoma : reconstructive considerations by means of the vascularized fibular free flap
The odontogenic myxoma is a rare entity located in mandible and upper maxilla. Due to its local aggressiveness, wide surgical excision is mandatory. Several surgical techniques have been described for the reconstruction of segmental mandibular defects. In comparison with other free flaps, the vascularized free fibular flap (VFFF) supports the longest amount of bone and, due to the nature of the vascular supply a complete freedom in location of the osteotomy is present. A precise mandibular arc can be performed following bone resection. We suggest the performance of the ?in situ? VFFF technique in order to recreate mandibular contour by means of several osteotomies, while the pedicle is still attached to the leg. Substantial decrease in surgical time is obtained. With the ?double-barrel? technique and subsequent osseointegrated implants, good results are obtained in the reconstruction of dentate patients without maxillary atrophy. We present two new cases of large odontogenic mandibular myxoma. Wide surgical excision by means of hemimandibulectomies and subsequent reconstruction with VFFF were performed
Endoscopically-assisted transoral approach for the treatment of subcondylar fractures of the mandible
Introduction: Treatment of subcondylar fractures of the mandible is one of the most controversial aspects in the field of maxillofacial traumatology. This controversy centers on the positive and negative aspects of open and closed approaches for the treatment of this kind of fractures. Open techniques lead to good reduction and osteosynthesis, but have a high risk of injury to the facial nerve and produce facial scars. Closed techniques (intermaxillary fixation) reduce all the above-mentioned risks but rarely produce correct anatomic reduction, and complications such as ankylosis, condylar necrosis and inhibition of mandibular growth, causing abnormal occlusion, may occur. Despite all the associated risks, closed techniques are currently the most popular treatment. Objectives: To introduce the endoscopically-assisted transoral approach for the treatment of subcondylar fractures, presenting three cases treated in our department. A description of the technique has been included as well as the clinical and radiographic results obtained. Material and Methods: The study is based in three patients with subcondylar fractures of the mandible who were treated by an endoscopically-assisted transoral approach. A description of the surgical technique is included. The results were assessed by postsurgical radiographic control (orthopantomography), maximum mouth opening, occlusion and pain. Results: Three reductions of subcondylar fractures with transoral endoscopically-assisted approach were undertaken. The follow-up period was 6 months. Postsurgical radiographic control showed good reduction of the fracture in all three cases. None of the patients showed any sign of temporomandibular dysfunction after 6 months. Conclusion: Endoscopic treatment by transoral approach combines the positive aspects of both conventional techniques: closed and open reduction; allowing anatomic reduction and a stable fixation leaving no visible facial scars and with a minimum risk of injury to the facial nerve
Tumores óseos de la pelvis
Se presenta la experiencia del Servicio de Ortopedia del Adulto del Hospital
«Ramón y Cajal», en neoplasias de la pelvis, desde su creación hasta la actualidad, siendo 61
los pacientes recogidos y no se hace un trabajo estadístico, sino más bien se muestran las peculiaridades
recogidas con la experiencia, que abarca desde la abstención en algunos casos de tumores
secundarios, y el simple curetage hasta las grandes sustituciones con homoinjertos de
banco, relacionándolo a su vez con publicaciones de aparición más o menos moderna sobre este
tema, para concluir que se trata de una cirugía no exenta de complicaciones y problemas,
pero necesaria a la hora de proporcionar a los enfermos curaciones, que le ofrezcan una salida
a este difícil problema.The experience of Adult Orthopaedics Unit at the Hospital «Ramón y Cajal»,
Madrid, treating patients with malignant tumors of the pelvic bons is presented. In this paper,
the results after surgery are not reported in terms of statistical analysis. The aún of this work is
to comment the surgical experience covering from simple curettage to great bone replacement
using bank allografts. The message is that surgical treatment of pelvic tumors is not exent of
complications, but it seems to be worth in order to offer a better quality of Ufe for patients
- …