759 research outputs found

    Spanish Poplar Biomass as a Precursor for Nanocellulose Extraction

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    The effect of acidic hydrolysis duration on nanocellulose size, morphology, and proper ties was investigated, which opens up a whole new horizon of versatility in poplar applications. This study aimed to examine Spanish poplar wastes as raw material to extract crystalline nanocellulose (CNC), which substantiates the importance of poplar wastes. Wastes were pulped using 1 L of 10% NaOH (wt./wt.) solution, and bleached several times by NaClO2 ; afterwards, white wastes were subjected to acidic hydrolysis by 60% H2SO4 for either 5, 10, or 15 min. Microcrystalline cellulose (MCC) underwent a similar hydrolysis protocol as poplar as control. TEM, IR, and XRD characterization techniques were performed. Poplar based nanocellulose sized 219 nm length and 69 nm width after 15 min acidic hydrolysis. MCC yielded 122 nm length and 12 nm width crystals after 10 min acidic hydrolysis. Hydrolysis resulted in a drastic change and intense peaks at 3500 and 2900 cm−1 for nanocellulose. Although pre-hydrolysis fiber treatment was not influencial on the crystallinity of poplar, acidic hydrolysis remarkably raised the crystallinity index (CI) by 7–8%. The more hydrolysis duration was prolonged, the size of the resulting crystal (whisker) decreased, and the aspect ratio increased. Hydrolysis was more impactful on MCC than poplar. However, for future work, it seems that longer duration of pulping and bleaching could have significantly removed unwanted components (hemicellulose and lignin), showcased in IR and XRD, and hence smoothened the following hydrolysis.European Union under umbrella of Erasmus+ KA107 PhD Mobility schem

    La influencia del acoso laboral en el entorno de trabajo

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    Objetivo. Analizar las investigaciones sobre la influencia que tiene el acoso laboral dentro del entorno de trabajo, mediante artículos científicos hispanoamericanos realizados en los últimos 16 años. Material y métodos. Para alcanzar el objetivo del presente artículo, efectuamos ciertos principios de búsqueda, con el fin de seleccionar las investigaciones más adecuadas para la realización de la revisión. Resultados. El acoso laboral es el comportamiento que se caracteriza por la agresión y hostigamiento, el cual va a ser ejercido de un empleador hacia otro en un centro laboral. El afectado va a ser sometido a ataques de manera continua durante un tiempo, y bien puede ser directo o indirecto. El hostigamiento laboral trae consecuencias negativas hacia la víctima, las cuales afectan el ambiente laboral de la empresa y su productividad. Por otro lado, existen conductas que presentan dificultades en el desempeño laboral, en consecuencia, existe la disminución de la productividad ligado con la motivación de la víctima, lo cual influye en las actividades desarrolladas en la empresa, como también en el clima laboral. Conclusiones. Existe una gran problemática dentro de las organizaciones que presentan esta situación conflictiva laboral y para poder solucionar este conflicto se debe dar la atención necesaria a las necesidades de los trabajadores y que estos sean escuchados. También, se debe promover un clima laboral adecuado que incremente la productividad, la motivación y el desempeño del trabajador

    Analysis of Healthy Lifestyle Habits and Oral Health in a Patient Sample at the Dental Hospital of the University of Barcelona

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    The association between general health and oral health has been studied over recent years. In order to evaluate the lifestyle and the presence of healthy habits, a descriptive observational study was conducted from December 2018 to April 2019 with 230 patients, aged from 18 to 65 years old, that attended the Dental Hospital of the University of Barcelona for the first time. A total of 230 participants were considered, 98 (43%) were men and 132 (57%) were women, with a mean age of 37 years old. Our hypothesis was that patients with healthy habits had a better oral status in comparison with patients with bad lifestyle habits. No statistically significant results were found regarding oral hygiene between gender, smokers and patients with systemic pathology. Regarding a healthy lifestyle (High adherence to dietary intake), no statistically significant results were found. No significant differences were found regarding physical activity between male and female patients. Our hypothesis wasn't confirmed; therefore, we cannot conclude that patients with healthy habits have better oral status in comparison with patients with bad lifestyle habits. Consequently, more prospective longitudinal studies should be carried out

    Periodontal treatment on patients with cardiovascular disease : systematic review and meta-analysis

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    Atherosclerotic cardiovascular disease is the main cause of mortality in developed countries. It is a chronic and systemic inflammatory disease with a multifactorial etiology. Periodontal disease is one of the many factors that contribute to its development. To analyze the effects of periodontal treatment on cardiovascular risk parameters in patients with atherosclerotic cardiovascular disease. A systematic research was conducted in the Pubmed/Medline databases for clinical trials published up to and including the year 2017. Ten articles were included for analysis. Periodontal treatment reduced C-reactive protein levels (77.8% of clinical trials), tumor necrosis factor-alpha (66.7%), interleukin-6 (100%) and leukocytes (50%). Fibrinogen levels also improved considerably (66.7%). Effects on lipid parameters were more limited, whereby only oxidized low density lipoprotein and very low density lipoprotein cholesterol decreased significantly. Meta-analysis showed a statistically significant decreased in C-reactive protein and leukocytes values when patients were submitted to non-surgical periodontal treatment in contrast to receiving no treatment at all (mean difference 1.199 mg/L, 95% confidence interval: 1.100-1.299, p<0.001; and mean difference 0,79 g/L, 95% confidence interval: 0.717-0.879, p<0.001, respectively). Periodontal treatment has a beneficial effect on some of the biochemical parameters considered to represent cardiovascular risk. Further randomized clinical trials are necessary, with longer follow-up periods including regular periodic monitoring, in order to determine the extent of the impact of periodontal treatment

    Family history of breast and ovarian cancer and triple negative subtype in hispanic/latina women.

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    Familial breast and ovarian cancer prevalence was assessed among 1150 women of Mexican descent enrolled in a case-only, binational breast cancer study. Logistic regression was conducted to compare odds of triple negative breast cancer (TNBC) to non-TNBC according to family history of breast and breast or ovarian cancer among 914 of these women. Prevalence of breast cancer family history in a first- and first- or second-degree relative was 13.1% and 24.1%, respectively; that for breast or ovarian cancer in a first-degree relative was 14.9%. After adjustment for age and country of residence, women with a first-degree relative with breast cancer were more likely to be diagnosed with TNBC than non-TNBC (OR=1.98; 95% CI, 1.26-3.11). The odds of TNBC compared to non-TNBC were 1.93 (95% CI, 1.26-2.97) for women with a first-degree relative with breast or ovarian cancer. There were non-significant stronger associations between family history and TNBC among women diagnosed at age &lt;50 compared to ≥50 years for breast cancer in a first-degree relative (P-interaction = 0.14) and a first- or second-degree relative (P-interaction = 0.07). Findings suggest that familial breast cancers are associated with triple negative subtype, possibly related to BRCA mutations in Hispanic/Latina women, which are strongly associated with TNBC. Family history is an important tool to identify Hispanic/Latina women who may be at increased risk of TNBC, and could benefit from prevention and early detection strategies

    Titanium Meshes in Guided Bone Regeneration: A Systematic Review

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    The presence of satisfactory bone volume is fundamental for the achievement of osseointegration. This systematic review aims to analyse the use of titanium meshes in guided bone regeneration in terms of bone gain, survival and success rates of implants, and percentages of exposure. An electronic search was conducted Articles were selected from databases in MEDLINE (PubMed), SCOPUS, Scielo, and Cochrane Library databases to identify studies in which bone regeneration was performed through particulate bone and the use of titanium meshes. Twenty-one studies were included in the review. In total, 382 patients, 416 titanium meshes, and 709 implants were evaluated. The average bone gain was 4.3 mm in horizontal width and 4.11 mm in vertical height. The mesh exposure was highly prevalent (28%). The survival rate of 145 simultaneous implants was 99.5%; the survival rate of 507 delayed implants was 99%. The success rate of 105 simultaneous implants was 97%; the success rate of 285 delayed implants was 95.1%. The clinical studies currently available in the literature have shown the predictability of this technique. It has a high risk of soft tissue dehiscence and membrane exposure although the optimal management of membrane exposition permits obtaining a sufficient bone regeneration volume and prevents compromising the final treatment outcome

    Narrow Diameter Dental Implants as an Alternative Treatment for Atrophic Alveolar Ridges. Systematic Review and Meta-Analysis

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    To determine the marginal bone loss and the survival, success and failure rates of narrow dental implants, a systematic literature search was carried out in the MEDLINE (Pubmed), Cochrane, Scopus, and Scielo databases for articles published between 2010 and 2021. The exclusion criteria were: systematic reviews, case reports, expert opinions; animal studies; samples of less than 10 subjects; follow-up periods of less than 36 months; smokers of minimum 10 cigarettes/day; and articles about mini-implants for orthodontic anchorage. Meta-analyses were performed to assess marginal bone loss and implant survival, success, and failure rates. Fifteen studies were included: 7 clinical trials, 3 randomized clinical trials, 3 cohort studies, and 2 case series. The total number of subjects was 773, in whom 1245 implants were placed. The survival rate for the narrow diameter implants was 97%, the success rate 96.8%, and the failure rate 3%. Marginal bone loss was 0.821 mm. All these data were evaluated at 36 months. Based on the literature, it can be considered that there is sufficient evidence to consider small diameter implants a predictable treatment option. These show favorable survival and success rates and marginal bone loss. All of them are comparable to those of standard diameter dental implants

    Aqueous Processes and Microbial Habitability of Gale Crater Sediments from the Blunts Point to the Glenn Torridon Clay Unit

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    A driving factor for sending the Mars Science Laboratory, Curiosity rover to Gale Crater was the orbital detection of clay minerals in the Glen Torridon (GT) clay unit. Clay mineral detections in GT suggested a past aqueous environment that was habitable, and could contain organic evidence of past microbiology. The mission of the Sample Analysis at Mars (SAM) instrument onboard Curiosity was to detect organic evidence of past microbiology and to detect volatile bearing mineralogy that can inform on whether past geochemical conditions would have supported microbiological activity. The objective of this work was to 1) evaluate the depositional/alteration conditions of Blunts Point (BP) to GT sediments 2) search for evidence of organics, and 3) evaluate microbial habitability in the BP, Vera Rubin Ridge (VRR), and GT sedimentary rock

    The Application of Statins in the Regeneration of Bone Defects. Systematic Review and Meta-Analysis

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    This systematic review aims to analyze the effect of the local application of statins in the regeneration of non-periodontal bone defects. A systematic study was conducted with the Pubmed/Medline, Embase, Cochrane Library and Scielo databases for in vivo animal studies published up to and including February 2019. Fifteen articles were included in the analysis. The local application of the drug increased the percentage of new bone formation, bone density, bone healing, bone morphogenetic protein 2, vascular endothelial growth factor, progenitor endothelial cells and osteocalcin. Meta-analyses showed a statistically significant increase in the percentage of new bone formation when animals were treated with local statins, in contrast to the no introduction of filling material or the introduction of polylactic acid, both in an early (4–6 weeks) and in a late period (12 weeks) (mean difference 39.5%, 95% confidence interval: 22.2–56.9, p <0.001; and mean difference 43.3%, 95% confidence interval: 33.6–52.9, p < 0.001, respectively). Basing on the animal model, the local application of statins promotes the healing of critical bone size defects due to its apparent osteogenic and angiogenic effects. However, given the few studies and their heterogenicity, the results should be taken cautiously, and further pilot studies are necessary, with radiological and histological evaluations to translate these results to humans and establish statins’ effec
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