5,512 research outputs found

    Doubly resonant second-harmonic generation of a vortex beam from a bound state in the continuum

    Full text link
    Second harmonic generation in nonlinear materials can be greatly enhanced by realizing doubly-resonant cavities with high quality factors. However, fulfilling such doubly resonant condition in photonic crystal (PhC) cavities is a long-standing challenge, because of the difficulty in engineering photonic bandgaps around both frequencies. Here, by implementing a second-harmonic bound state in the continuum (BIC) and confining it with a heterostructure design, we show the first doubly-resonant PhC slab cavity with 2.4×1022.4\times10^{-2} W1^{-1} conversion efficiency under continuous wave excitation. We also report the confirmation of highly normal-direction concentrated far-field emission pattern with radial polarization at the second harmonic frequency. These results represent a solid verification of previous theoretical predictions and a cornerstone achievement, not only for nonlinear frequency conversion but also for vortex beam generation and prospective nonclassical sources of radiation.Comment: revtex4-2, 7 pages, 5 figures, conference CLE

    Extend Your Experience: The Northwest\u27s Natural and Cultural Landscape

    Get PDF
    The article provides information on the natural and cultural landscape of the Pacific Northwest, the venue for the Association of the College and Research Libraries (ACRL) 14th National Conference in Seattle, Washington on March 12-15, 2009. It discusses various tourist attractions found within the area, as well as its climate. A recount of various historical events that happened in the place, as well as the culture of the living inhabitants is also presented. Computer information resources of several sceneries found within the area of Washington state is presented

    Perinatal exposure of rats to a maternal diet with varying protein quantity and quality affects the risk of overweight in female adult offspring

    Get PDF
    The maternal protein diet during the perinatal period can program the health of adult offspring. This study in rats evaluated the effects of protein quantity and quality in the maternal diet during gestation and lactation on weight and adiposity in female offspring. Six groups of dams were fed a high-protein (HP; 47% protein) or normal-protein (NP; 19% protein) isocaloric diet during gestation (G) using either cow's milk (M), pea (P) or turkey (T) proteins. During lactation, all dams received the NP diet (protein source unchanged). From postnatal day (PND) 28 until PND70, female pups (n=8) from the dam milk groups were exposed to either an NP milk diet (NPMW) or to dietary self-selection (DSS). All other pups were only exposed to DSS. The DSS design was a choice between five food cups containing HPM, HPP, HPT, carbohydrates or lipids. The weights and food intakes of the animals were recorded throughout the study, and samples from offspring were collected on PND70. During the lactation and postweaning periods, body weight was lower in the pea and turkey groups (NPG and HPG) versus the milk group (P<.0001). DSS groups increased their total energy and fat intakes compared to the NPMW group (P<.0001). In all HPG groups, total adipose tissue was increased (P=.03) associated with higher fasting plasma leptin (P<.05). These results suggest that the maternal protein source impacted offspring body weight and that protein excess during gestation, irrespective of its source, increased the risk of adiposity development in female adult offspring

    Classic Kaposi’s sarcoma with multifocal gastrointestinal involvement. A case report

    Get PDF
    Although intestinal involvement occurs in more than half of the cases with KS that are HIV positive, it is uncommon in the classical form, as it occurs in approximately 10% of the patients. We present the case of a 60-year-old male patient with a one-year disease time characterized by having violaceous lesions on the feet and the hands, slightly pruritic and 2 months of epigastralgia and constipation with weight loss of approximately 12 percent of his total body weight. In the physical examination multiple violaceous papule-like lesions are shown on the hands and the feet, some coalescing to form plaques. Laboratory tests revealed a mild normocytic normocytic anemia, the serology for viral hepatitis B and C was negative, HIV negative and ELISA test too. An upper endoscopy was performed and multiple maculopapular and erythematous-violaceous lesions were observed in the esoph-agus, the stomach and the duodenum. In the colonoscopy, multiple lesions with similar characteristics in the ileum, throughout the colon and in the rectum were recognized. The biopsy result was compatible with the KS in all lesions and it was confirmed with the positive HVV-8 immunohis-tochemistry. This case highlights the likelihood of presenting GI SK in elderly patients with gastrointestinal compromise and cutaneous findings, HIV negatives as well as the need to realize an adequate discarding by performing endoscopic studies with the biopsies to optimize treatment.Revisión por pare

    Studies on the Detection, Expression, Glycosylation, Dimerization, and Ligand Binding Properties of Mouse Siglec-E

    Get PDF
    © 2017 by The American Society for Biochemistry and Molecular Biology, Inc. Published in the U.S.A. This is an Open Access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/)CD33-related Siglecs are a family of proteins widely expressed on innate immune cells. Binding of sialylated glycans or other ligands triggers signals that inhibit or activate inflammation. Immunomodulation by Siglecs has been extensively studied, but relationships between structure and functions are poorly explored. Here we present new data relating to the structure and function of Siglec-E, the major CD33-related Siglec expressed on mouse neutrophils, monocytes, macrophages, and dendritic cells. We generated nine new rat monoclonal antibodies specific to mouse Siglec-E, with no cross-reactivity to Siglec-F. Although all antibodies detected Siglec-E on transfected human HEK-293T cells, only two reacted with mouse bone marrow neutrophils by flow cytometry and on spleen sections by immunohistochemistry. Moreover, whereas all antibodies recognized Siglec-E-Fc on immunoblots, binding was dependent on intact disulfide bonds and N-glycans, and only two antibodies recognized native Siglec-E within spleen lysates. Thus, we further investigated the impact of Siglec-E homodimerization. Homology-based structural modeling predicted a cysteine residue (Cys-298) in position to form a disulfide bridge between two Siglec-E polypeptides. Mutagenesis of Cys-298 confirmed its role in dimerization. In keeping with the high level of 9-O-acetylation found in mice, sialoglycan array studies indicate that this modification has complex effects on recognition by Siglec-E, in relationship to the underlying structures. However, we found no differences in phosphorylation or SHP-1 recruitment between dimeric and monomeric Siglec-E expressed on HEK293A cells. Phylogenomic analyses predicted that only some human and mouse Siglecs form disulfide-linked dimers. Notably, Siglec-9, the functionally equivalent human paralog of Siglec-E, occurs as a monomer.Peer reviewedFinal Published versio

    Distribución de estadios de OLGA y OLGIM según edad y estado del Helicobacter pylori en un hospital público nivel III en Lima, Perú

    Get PDF
    Introducción. El sistema operativo de evaluación de gastritis (OLGA) y el enlace operativo sobre la evaluación de metaplasia intestinal gástrica (OLGIM) proporcionan una evaluación del riesgo de desarrollar cáncer gástrico. Objetivo. Evaluar la distribución de estadios del OLGA y OLGIM por edad y presencia del Helicobacter pylori. Material y métodos. Se estudiaron 197 sujetos sometidos a una endoscopía digestiva alta electiva. La presencia del H. pylori y los cambios histológicos se evaluaron utilizando el sistema actualizado de Sídney. Los estadios III y IV del OLGA/OLGIM se consideraron estadios de alto riesgo. Resultados. La tasa del H. pylori fue del 56,85% (112/197). Los casos de OLGA/OLGIM de alto riesgo fueron poco frecuentes: 7/112 (6,5%) casos del OLGA en el grupo del H. pylori positivo y 6/85 (7%) en el del H. pylori negativo; 5 (4,4%) casos del OLGIM en el H. pylori positivo y 6 (7%) en el H. pylori negativo. La proporción de estadios avanzados del OLGA y OLGIM aumentó con la edad (p < 0,001). No se encontró el OLGA de alto riesgo antes de los 40 años independientemente de la presencia del H. pylori, pero aumentó a 16,2%, 10,3%, 17,3% y 40,8% en sujetos en la cuarta, quinta, sexta y séptima década de vida respectivamente. El OLGIM de alto riesgo mostró una tendencia similar: 0% antes de los 40 años y hasta 22,6% en personas de 70 años. Conclusiones. Los casos del OLGA/OLGIM de alto riesgo son infrecuentes antes de los 40 años y aumentan significativamente con la edad. No se evidenció relación con la presencia del H. pylori. Según estos protocolos solamente la quinta parte de los pacientes requeriría estrictamente un control endoscópico.Campus Lima Centr

    A life course examination of the physical environmental determinants of physical activity behaviour: A “Determinants of Diet and Physical Activity” (DEDIPAC) umbrella systematic literature review

    Get PDF
    Background: Participation in regular physical activity is associated with a multitude of health benefits across the life course. However, many people fail to meet PA recommendations. Despite a plethora of studies, the evidence regarding the environmental (physical) determinants of physical activity remains inconclusive. Objective: To identify the physical environmental determinants that influence PA across the life course. Methods: An online systematic literature search was conducted using MEDLINE, ISI Web of Science, Scopus and SPORTDiscus. The search was limited to studies published in English (January 2004 to April 2016). Only systematic literature reviews (SLRs) and meta-analyses (MAs) of observational studies, that investigated the association between physical determinants and physical activity outcomes, were eligible for inclusion. The extracted data were assessed on the importance of determinants, strength of evidence and methodological quality. Results: The literature search identified 28 SLRs and 3 MAs on 67 physical environmental characteristics potentially related to physical activity that were eligible for inclusion. Among preschool children, a positive association was reported between availability of backyard space and outdoor toys/equipment in the home and overall physical activity. The availability of physical activity programs and equipment within schools, and neighbourhood features such as pedestrian and cyclist safety structure were positively associated with physical activity in children and adolescents. Negative street characteristics, for example, lack of sidewalks and streetlights, were negatively associated with physical activity in adults. Inconsistent associations were reported for the majority of reviewed determinants in adults. Conclusion: This umbrella SLR provided a comprehensive overview of the physical environment determinants of physical activity across the life course and has highlighted, particularly amongst youth, a number of key determinants that may be associated with overall physical activity. Given the limited evidence drawn mostly from cross-sectional studies, longitudinal studies are needed to further explore these associations. Registration: PROSPERO CRD42015010616

    DE-PASS best evidence statement (BESt): determinants of adolescents’ device-based physical activity and sedentary behaviour in settings: a systematic review and meta-analysis

    Get PDF
    Background: Although physical activity (PA) is associated with significant health benefits, only a small percentage of adolescents meet recommended PA levels. This systematic review with meta-analysis explored the modifiable determinants of adolescents’ device-based PA and/or sedentary behaviour (SB), evaluated in previous interventions and examined the associations between PA/SB and these determinants in settings. Methods: A search was conducted on five electronic databases, including papers published from January 2010 to July 2023. Randomized Controlled Trials (RCTs) or Controlled Trials (CTs) measuring adolescents’ device-based PA/SB and their modifiable determinants at least at two time points: pre- and post-intervention were considered eligible. PA/SB and determinants were the main outcomes. Modifiable determinants were classified after data extraction adopting the social-ecological perspective. Robust Bayesian meta-analyses (RoBMA) were performed per each study setting. Outcomes identified in only one study were presented narratively. The risk of bias for each study and the certainty of the evidence for each meta-analysis were evaluated. The publication bias was also checked. PROSPERO ID: CRD42021282874. Results: Fourteen RCTs (eight in school, three in school and family, and one in the family setting) and one CT (in the school setting) were included. Fifty-four modifiable determinants were identified and were combined into 33 broader determinants (21 individual–psychological, four individual–behavioural, seven interpersonal, and one institutional). RoBMAs revealed none or negligible pooled intervention effects on PA/SB or determinants in all settings. The certainty of the evidence of the impact of interventions on outcomes ranged from very low to low. Narratively, intervention effects in favour of the experimental group were detected in school setting for the determinants: knowledge of the environment for practicing PA, d = 1.84, 95%CI (1.48, 2.20), behaviour change techniques, d = 0.90, 95%CI (0.09, 1.70), choice provided, d = 0.70, 95%CI (0.36, 1.03), but no corresponding effects on PA or SB were found. Conclusions: Weak to minimal evidence regarding the associations between the identified modifiable determinants and adolescents’ device-based PA/SB in settings were found, probably due to intervention ineffectiveness. Well-designed and well-implemented multicomponent interventions should further explore the variety of modifiable determinants of adolescents’ PA/SB, including policy and environmental variables

    Socio-cultural determinants of physical activity across the life course: A \u27Determinants of Diet and Physical Activity\u27 (DEDIPAC) umbrella systematic literature review

    Get PDF
    Objective: Regular physical activity (PA) reduces the risk of disease and premature death. Knowing factors associated with PA might help reducing the disease and economic burden caused by low activity. Studies suggest that socio-cultural factors may affect PA, but systematic overviews of findings across the life course are scarce. This umbrella systematic literature review (SLR) summarizes and evaluates available evidence on socio-cultural determinants of PA in children, adolescents, and adults. Methods: This manuscript was drafted following the recommendations of the \u27Preferred Reporting Items for Systematic reviews and Meta-Analyses\u27 (PRISMA) checklist. The MEDLINE, Web of Science, Scopus, and SPORTDiscus databases were searched for SLRs and meta-analyses (MAs) on observational studies published in English that assessed PA determinants between January 2004 and April 2016. The methodological quality was assessed and relevant information on socio-cultural determinants and any associations with PA was extracted. The available evidence was evaluated based on the importance of potential determinants and the strength of the evidence. Results: Twenty SLRs and three MAs encompassing 657 eligible primary studies investigated potential socio-cultural PA determinants, with predominantly moderate methodological quality. Twenty-nine potential PA determinants were identified that were primarily assessed in children and adolescents and investigated the micro-environmental home/household level. We found probable evidence that receiving encouragement from significant others and having a companion for PA were associated with higher PA in children and adolescents, and that parental marital status (living with partner) and experiencing parental modeling were not associated with PA in children. Evidence for the other potential determinants was limited, suggestive, or non-conclusive. In adults, quantitative and conclusive data were scarce. Conclusions: A substantial number of SLRs and MAs investigating potential socio-cultural determinants of PA were identified. Our data suggest that receiving social support from significant others may increase PA levels in children and adolescents, whereas parental marital status is not a determinant in children. Evidence for other potential determinants was limited. This was mainly due to inconsistencies in results on potential socio-cultural determinants of PA across reviews and studies. Trial registrations: This umbrella SLR was recorded on PROSPERO (Record ID: CRD42015010616)
    corecore