248 research outputs found
Improvement in PWV estimation from GPS due to the absolute calibration of antenna phase center variations
Climatology of column-integrated atmospheric water vapor over Spain has been carried out by means of three techniques: soundings, sun photometers and GPS receivers. Comparing data from stations equipped with more than one of these instruments, we found that a large discontinuity occurred on November 6, 2006, in the differences between the data series from GPS receivers and those from the other two techniques. Prior to that date, the GPS data indicate a wet bias of 2–3 mm for all stations when compared with sounding or photometer data, whereas after that date this bias practically reduces to zero. The root mean square error also decreases about half of its value. On November 6, 2006, the International GNSS Service adopted an absolute calibration model for the antennas of the GPS satellites and receivers instead of the relative one. This change is expected to be an improvement, increasing the accuracy of station position determination and consequently benefiting post-processing products such as zenith total delay from which the atmospheric water vapor content is calculated
Alveolar distraction osteogenesis for dental implant treatments of the vertical bone atrophy : a systematic review
To determine if alveolar vertical distraction osteogenesis obtains better results compared to other bone regeneration treatments (guided bone regeneration with membranes and / or filling material, or autogenous bone graft) in terms of bone gain, complications, and implant survival and success rates. An electronic search was performed in Pubmed (MEDLINE), Cochrane Library and Scopus databases in March 2017. Besides, a manual search was carried out. Inclusion criteria were randomized controlled trials published within the last 10 years with at least 1 year of follow-up after implant placement. No language restriction was applied. Exclusion criteria were studies in patients with bone defects produced by trauma, congenital malformation or oncologic surgical treatment. The methodological quality of the selected studies was evaluated by means of the Cochrane Collaboration?s Tool for assessing risk of bias. The reports were classified into different levels of recommendation according to the ?Strength of Recommendation Taxonomy ?. Out of 221 articles, two randomized controlled trials were finally selected for the inclusion in the systematic review. Bone gain and complications were higher with the alveolar vertical distraction osteogenesis compared to the autologous bone graft. There was higher bone resorption with the autologous bone graft. Implant survival and success rates were similar between studies, despite of the used technique. Both alveolar distraction osteogenesis and autogenous bone graft are effective bone regeneration techniques for the treatment of mandibular vertical bone atrophy. A level B recommendation can be established for the use of alveolar vertical distraction osteogenesis for the treatment of the mandibular vertical bone atrophy
A first comparison between Almucantar and principal plane retrieval products within AERONET network
Resumen de la comunicación oral presentada en: 1st Iberian Meeting on Aerosol Science and Technology – RICTA 2013, celebrado del 1 al 3 de julio de 2013 en Évora, Portugal
Florid cemento-osseous dysplasia : report of 2 cases
Florid cemento-osseous dysplasia is a non-neoplastic fibro-osseous lesion which often has an asymptomatic slow growth. Unfortunately, these lesions are usually diagnosed through routine radiographic examination. The aim of this study was to describe the main clinical, radiological and histological characteristics of two case reports diagnosed with florid cemento-osseous dysplasia. Two cases of florid cemento-osseous dysplasia with different clinical and radiological features were presented. Panoramic radiographs showed multiple radiopacities compatible with fibro-osseous lesions in distinct areas of the maxillary bones. The histological study revealed a sclerotic mass which continued imperceptibly with root cement with scarce fibrous lax tissue. The replacement of healthy bone by metaplastic bone and fibrous tissue is the main histological feature. Therapeutic abstention with active clinical and radiographic control visits is recommended in asymptomatic cases
Doxycycline and Zinc Loaded Silica-Nanofibrous Polymers as Biomaterials for Bone Regeneration
Themain target of bone tissue engineeringis to design biomaterials that support bone regeneration
and vascularization. Nanostructured membranes of (MMA)1-co-(HEMA)1/(MA)3-co-(HEA)2 loaded with
5% wt of SiO2-nanoparticles (HOOC-Si-Membrane) were doped with zinc (Zn-HOOC-Si-Membrane)
or doxycycline (Dox-HOOC-Si-Membrane). Critical bone defects were effectuated on six New
Zealand-bred rabbit skulls and covered with the membranes. After six weeks, the bone architecture
was evaluated with micro computed tomography. Three histological analyses were utilized to
analyse bone regeneration, including von Kossa silver nitrate, toluidine blue and fluorescence.
All membrane-treated defects exhibited higher number of osteocytes and bone perimeter than
the control group without the membrane. Zn-HOOC-Si-Membranes induced higher new bone
and osteoid area than those treated with HOOC-Si-Membranes, and control group, respectively.
Zn-HOOC-Si-Membranes and Dox-HOOC-Si-Membranes attained the lowest ratio M1 macrophages/M2
macrophages. Dox-HOOC-Si-Membranes caused the lowest number of osteoclasts, and bone density.
At the trabecular new bone, Zn-HOOC-Si-Membranes produced the highest angiogenesis, bone thickness,
connectivity, junctions and branches. Zn-HOOC-Si-Membranes enhanced biological activity, attained a
balanced remodeling, and achieved the greatest regenerative efficiency after osteogenesis and angiogenesis
assessments. The bone-integrated Zn-HOOC-Si-Membranes can be considered as bioactive modulators
provoking a M2 macrophages (pro-healing cells) increase, being a potential biomaterial for promoting
bone repair.Ministerio de Economía y Competitividad y Fondo Europeo de Desarrollo Regional MINECO/FEDER MAT2017-85999
Recurrence rate of oral squamous cell papilloma after excision with surgical scalpel or laser therapy : a retrospective cohort study
The aim was to describe the recurrence rates of Oral Squamous Cell Papilloma (OSCP) following surgical treatment with surgical scalpel and two different lasers (CO2 or Er,Cr;YSGG) and to determine the clinical and histopathologic features of these lesions. A retrospective cohort study covering a period of 12 years (1997-2009) that included patients diagnosed of OSCP treated with surgical excision was performed. Data was processed using SPSS 22.0 (SPPS Inc. Chicago, USA) and a descriptive and bivariate analysis were conducted. A total of 37 histopathologically confirmed OSCP in 36 patients, 19 women (52.7%) and 17 men (47.2%) with an average age of 33.4 years (14-86 years) were included. Twenty-two cases were treated by excision with surgical scalpel excision, 11 with CO2 laser and 3 with Er,Cr:YSGG laser. The mean age was 35.4 years (14-86 years) and the distribution by gender was 19 women (52.7%) and 17 men (47.2%). The most common locations were the palate in 14 cases (37.8%), followed by the tongue in 11 cases (29.7%) and gingiva with 5 cases (13.5%). The average size of the lesions was 4.25 mm in diameter, with a mean evolution time of 5.9 months. The recurrence rate was slightly higher with the CO2 laser (14.3 %) in comparison with the conventional scalpel (10%). No recurrences for Er,Cr:YSGG were found. No differences for recurrence rates for OSCP between groups were found. The recurrence rate is low, happening usually before 15 months of follow-up. OSCPs are lesions usually appearing in patients between 30 and 50 years of both genders and located predominantly on the palate, tongue and gingiva
Osteoradionecrosis of the jaws triggered by dental implants placement : a case report
The decision-making process about how to rehabilitate edentulous osseous defects in patients with head and neck cancer history can be complex. Even though, endosseous dental implants could be considered to be the first choice for treating these patients, it is highly important to be aware of the complications that might occur. The aim of this report was to describe the clinical features of mandibular fracture after dental implants placement on a cancer irradiated patient and update the available information about this event. The case describes a 70-year-old man, with medical background of radiotherapy in jaw bones to treat a carcinoma in the floor of the mouth and later on in the soft palate and cheek. One week after dental implant surgery, the patient presented a mandibular osteoradionecrosis that healed in 8 months. A fracture on the right side of the body mandible was diagnosed one year after implant placement. Although several options were suggested in order to repair the fracture, the patient did not accept any further treatment despite the callus formation not being radiographically evident. The implant-supported prosthesis is functionally useful for more than 8 years of follow-up without significant problems. The implant treatment and management of oncologic irradiated patients require special considerations due to the risk of osteoradionecrosis and its possible complications, such as pathologic fracture. It is necessary to provide full information to the patient about risk factors and complications
Sensitivity of aerosol retrieval to geometrical configuration of ground-based sun/sky radiometer observations
A sensitivity study of aerosol retrievals to the geometrical configuration of the ground-based sky radiometer observations is carried out through inversion tests. Specifically, this study is focused on principal plane and almucantar observations, since these geometries are employed in AERONET (AErosol RObotic NETwork). The following effects have been analyzed with simulated data for both geometries: sensitivity of the retrieval to variability of the observed scattering angle range, uncertainties in the assumptions of the aerosol vertical distribution, surface reflectance, possible instrument pointing errors, and the effects of the finite field of view.Financial support was provided by the Spanish CICYT (CGL2009-09740 and CGL2011-23413, CGL2011-13085-E). The research leading to these results was supported by funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 262254 [ACTRIS]. We also thank the Environmental Council of the CyL Regional Government (Consejería de Medio Ambiente, Junta de Castilla y León) for supporting this research
Nine years of aerosol optical depth measurements over north-central Spain from ground (AERONET-RIMA) and their comparison with satellite (MODIS) observations
Comunicación presentada en: 2012 European Aerosol Conference (EAC-2012), B-WG01S2P30, celebrada del 2 al 7 de septiembre de 2012 en Granada.Financial supports from the Spanish MICIIN (projects
of ref. CGL2008-05939-CO3-01/CLI, CGL 2009-09740,
and "Acción Complementaria" CGL2010-09480-E and
CGL2011-13085-E), and from the Environmental Council
of the CyL Regional Government (Consejería de Medio
Ambiente, Junta de Castilla y León) are gratefully acknowledged
Novel non-resorbable polymeric-nanostructured scaffolds for guided bone regeneration
Objective The aim of this study was to evaluate the bone-regeneration efficiency of novel polymeric nanostructured membranes and the effect of zinc, calcium, titanium and bone morpho-protein loading on membranes, through an in vivo rabbit model.
Material and Methods Nanostructured membranes of methylmethacrylate were loaded with zinc, calcium, TiO2 nanoparticles and bone-morphogenetic protein (BMP). These membranes covered the bone defects prepared on the skulls of six rabbits. Animals were sacrificed six weeks after surgery. Micro computed tomography was used to evaluate bone architecture through BoneJ pluging and ImageJ script. Three histological processing of samples, including von Kossa silver nitrate, toluidine blue and fluorescence by the deposition of calcein were utilized.
Results Zn-Membranes (Zn-Ms) promoted the highest amount of new bone and higher bone perimeter than both unloaded and Ti-Membranes (Ti-Ms). Ca-Membranes (Ca-Ms) attained higher osteoid perimeter and bone perimeter than Zn-Ms. The skeleton analysis showed that Zn-Ms produced more branches and junctions at the trabecular bone than BMP-loaded membranes (BMP-Ms). Samples treated with Ti-Ms showed less bone formation and bony bridging processes. Both Zn-Ms and Ca-Ms achieved higher number of osteoblasts than the control group. BMP-Ms and Ca-Ms originated higher number of blood vessels than Ti-Ms and control group.
Conclusions Zn incorporation in novel nanostructured membranes provided the highest regenerative efficiency for bone healing at the rabbit calvarial defects.
Clinical relevance Zn-Ms promoted osteogenesis and enhanced biological activity, as mineralized and osteoid new bone with multiple interconnected ossified trabeculae appeared in close contact with the membrane.Project MAT2017-85999-P MINECO/AEI/FEDER/UE supported by the Ministry of Economy and Competitiveness and European Regional Development Fund
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