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OBJECTIVE: Technology is changing the way individuals socially connect. However, not much is known about how online forms of social exchanges might link to outcomes that predict longevity. This preregistered study examined the association between online social support and social negativity with self-rated health (SRH) and potential pathways responsible for such links. METHOD: In this preregistered analysis, a sample of 1,356 U.S. residents was recruited based on the U.S. Census track. Participants were at least 18-year-old social media users and completed the study online. Well-validated measures of online social support, online social negativity, general offline perceived support, internet addiction, social anxiety, and SRH were obtained. RESULTS: Main results indicate that both online social support and social negativity were related to better SRH. However, the association between social negativity and better SRH was due to its statistical overlap with online social support. The association between online social support and SRH was primarily mediated by offline social support. CONCLUSIONS: These results highlight the importance of considering how positive and negative online social interactions are related to health outcomes. It also highlights potential pathways that might be targeted for interventions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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Mídias Sociais , Apoio Social , Humanos , AdolescenteRESUMO
Social-evaluative threat plays a key role in research on stress, health and related psychophysiological mechanisms such as cardiovascular reactivity (CVR). Social-evaluative threats can activate two broad social motives: striving for status, achievement and influence, and/or striving for acceptance, inclusion, and connection. Prior research emphasizes threats related to status (e.g., task performance) or combined threats to status and acceptance, obscuring their independent effects. Further, because prior research has mostly utilized single stressors, it is not clear if effects of social-evaluative threats involving status and acceptance on CVR persist or adapt quickly over repeated exposures. To address these issues, 139 undergraduates (93 females) were randomly assigned to undergo two repetitions of a stressful role-played interaction with a pre-recorded antagonistic partner under one of four conditions in a factorial design: low evaluative threat, high status threat only, high acceptance threat only, or a combined threat. In a single laboratory session, systolic and diastolic blood pressure (SBP, DBP) and heart rate (HR) were recorded during baseline and two stressor exposures. Task-induced CVR demonstrated significant adaptation across exposures. Both forms of social evaluative threat produced additional CVR, and these differences between high and low social-evaluative threat were generally maintained across exposures. Hence, threats to social status and acceptance have independent and sustained effects on CVR across multiple stressor exposures, even in the context of overall adaptation of cardiovascular responses.
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Sistema Cardiovascular , Estresse Psicológico , Feminino , Humanos , Pressão Sanguínea/fisiologia , Adaptação Fisiológica , Hostilidade , Frequência Cardíaca/fisiologiaRESUMO
BACKGROUND: Third year clerkship grades include subjective evaluations. The purpose of this study is to identify if personality traits and self-esteem predispose students to better clerkship performance. METHODS: Third-year medical students completed the OCEAN Five Factor Model Personality Test and Rosenberg Self-Esteem Scale. Clerkship grades were matched to survey results. Chi-squared and linear regression analyses assessed the correlation between students' clerkship grades, personality traits, and self-esteem. RESULTS: There was no association between OCEAN personality domains and any component of clerkship grade. In secondary post hoc analysis, students who are "deep thinking" (OR 2.97, 95% CI 1.26-7.01, p = 0.01), "sophisticated" (OR 2.70, 95% CI 1.12-6.50, p = 0.03), and "outgoing" (OR 2.45, 95% CI 1.02-5.89, p = 0.04) were significantly more likely to get an overall clerkship grade of Honors. "Deep thinking" (OR 3.44, 95% CI 1.47-8.04, p = 0.004) and "efficient" (OR 2.87, 95% CI 1.12-7.36, p = 0.03) students scored better on shelf exams, while "shy" students scored worse (OR 0.30, 95% CI 0.13-0.69, p = 0.004); "aloof" students received worse clinical scores (OR 0.57, 95% CI 0.37-0.89, p = 0.03), and "rude" (OR 5.08, 95% CI 1.03-24.94, p = 0.03) and "sophisticated" (OR 2.47, 95% CI 1.02-6.00, p = 0.04) students received higher preceptor scores. There was no correlation between self-esteem and clerkship grades. CONCLUSION: Students with certain personality traits may be predisposed to success during clerkships. Medical educators should be cognizant of biases favoring certain personalities and help students maximize success by recognizing their strengths and identifying gaps.
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BACKGROUND: Surgical excision is a mainstay of treatment for non-melanoma skin cancer (NMSC); improving margin delineation can reduce the need for further monitoring/treatment. The objective of this pilot study was to determine if near-infrared radiation (NIR) application to skin causes visible changes in normal and NMSC skin, to help delineate margins. MATERIALS/METHODS: Eleven biopsy-proven NMSC lesions were included. The skin was then heated under a 175W NIR heating bulb; margins were traced onto acetate film before and after heating. Lesions were then randomly assigned to excision based on pre- or post-heating margins. Composite images were generated by overlaying the heat and no-heat lesion contours. All specimens were sent for histopathology. RESULTS: The range of closest margins in the control group was 2.0-3.0 mm with a median of 2.0 mm; the range in the intervention group was 4.0-9.0 mm with a median of 5.0 mm. Composite images showed larger heat contours when the initial lesion was larger. There was a statistically significant difference between the two groups. Overall, NIR light caused visible hyperaemia to skin, and more intense erythema to malignant skin lesions. CONCLUSION: Near-infrared light may have use in an outpatient setting for skin cancer delineation, possibly reducing the rate of positive margins.
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Melanoma , Neoplasias Cutâneas , Calefação , Humanos , Margens de Excisão , Projetos Piloto , Neoplasias Cutâneas/diagnóstico por imagemRESUMO
A large percentage of a fish's weight is generally discarded during fish processing. Reducing the waste products of marine origin is a subject of great interest within the scientific community. Pelagic byproducts, such as the structural protein collagen, which can be generated during the processing of fish, have been proposed as an alternative to terrestrial, mammalian sources due to advantages including high availability and low risk of zoonotic disease transmission. Gelatine has multiple possible applications, ranging from nutraceutical applications to cosmetics and has the advantage of being generally regarded as safe. In this multidisciplinary review, the chemistry of gelatine and its parent protein collagen, the chemical reactions to generate their hydrolysates, and studies on their biological activities using animal cell culture are discussed.
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Colágeno , Gelatina , Animais , Técnicas de Cultura de Células , Suplementos Nutricionais , PeixesRESUMO
The degree of resin swelling in a particular solvent system is one of the critical parameters for solid-phase peptide synthesis (SPPS) and for solid-phase synthesis in general. Methods used for measuring the degree of resin swelling include microscopy-based and volumetry-based methods. This study describes and compares the use of both methods for a number of commercially available resins commonly used in SPPS, with a range of solvents, which have been identified in the literature as 'greener' than DCM, DMF and NMP. The results were analysed by statistical methods, and a significant correlation between the two distinct methods has been demonstrated for the first time. The results will likely be used, in conjunction with other literature methods, to help in choosing both the resin and solvent system for greener SPPS, as well as for continuous flow SPPS, which is of growing importance.
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Peptídeos/síntese química , Resinas Sintéticas/química , Técnicas de Síntese em Fase Sólida , Microscopia , Tamanho da Partícula , Peptídeos/química , Solventes/química , Propriedades de SuperfícieRESUMO
According to the U.S. Census Bureau, 18.2 million veterans were living in the United States in 2017, of whom 1.6 million were female. Less than one-half of all veterans receive care at a Veterans Health Administration or military treatment facility, leaving most to receive services from primary care physicians. Injuries and illnesses common among this patient population include musculoskeletal injuries and chronic pain, mental health issues such as posttraumatic stress disorder (PTSD) and moral injury, traumatic brain injury, chemical and noise exposures, and infectious disease concerns. Family physicians should ask about military service and be well informed about the range of veterans' health concerns, particularly PTSD, depression, and suicidality. Physicians should screen veterans for depression using the Patient Health Questionnaire-9 and for PTSD using the PTSD Checklist for DSM-5. Veterans with traumatic brain injury should be screened specifically for comorbid PTSD and chronic pain because the diagnosis informs treatment. Exposures to loud noise, chemicals, and infectious diseases are prevalent and can cause disability. Family physicians can use available resources and clinical practice guidelines such as those from the U.S. Department of Veterans Affairs and Department of Defense to inform care and to assist veterans.
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Dor Crônica/terapia , Doenças Transmissíveis/terapia , Transtornos Mentais/terapia , Medicina Militar/normas , Guias de Prática Clínica como Assunto , Veteranos/psicologia , Ferimentos e Lesões/terapia , Adulto , Dor Crônica/epidemiologia , Doenças Transmissíveis/epidemiologia , Comorbidade , Currículo , Educação Médica Continuada , Feminino , Humanos , Masculino , Transtornos Mentais/epidemiologia , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Ferimentos e Lesões/epidemiologiaAssuntos
Apêndice Atrial , Fibrilação Atrial , Acidente Vascular Cerebral , Átrios do Coração , HumanosAssuntos
Apêndice Atrial , Fibrilação Atrial , Acidente Vascular Cerebral , Átrios do Coração , HumanosRESUMO
Background and Purpose- Left atrial enlargement has been shown to be associated with ischemic stroke, but the association with embolic stroke mechanisms remains unknown. We aim to study the associations between left atrial volume index (LAVI) and embolic stroke subtypes and atrial fibrillation (AF) detection on cardiac event monitoring in patients with embolic stroke of unknown source. Methods- Data were collected from a prospective cohort of consecutive patients with ischemic stroke admitted to a comprehensive stroke center over 18 months. Stroke subtype was classified into cardioembolic stroke, noncardioembolic stroke of determined mechanism (NCE), or embolic stroke of undetermined source (ESUS). Univariate and prespecified multivariable analyses were performed to assess associations between LAVI and stroke subtype and AF detection in patients with ESUS. Results- Of 1224 consecutive patients identified during the study period, 1020 (82.6%) underwent transthoracic echocardiography and had LAVI measurements. LAVI was greater in patients with cardioembolic stroke than NCE (41.4 mL/m2±18.0 versus 28.6 mL/m2±12.2; P<0.001) but not in ESUS versus NCE (28.9 mL/m2±12.6 versus 28.6 mL/m2±12.2; P=0.61). In multivariable logistic regression models, LAVI was greater in cardioembolic stroke versus NCE (adjusted odds ratio per mL/m2, 1.07; 95% CI, 1.05-1.09; P<0.001) but not in ESUS versus NCE (adjusted odds ratio per mL/m2, 1.00; 95% CI, 0.99-1.02; P=0.720). Among 99 patients with ESUS who underwent cardiac monitoring, 18.2% had AF detected; LAVI was independently associated with AF detection in ESUS (adjusted odds ratio per mL/m2, 1.09; 95% CI, 1.02-1.15; P=0.007). Conclusions- LAVI is associated with cardioembolic stroke as well as AF detection in patients with ESUS, 2 subsets of ischemic stroke that benefit from anticoagulation therapy. Patients with increased LAVI may be a subgroup where anticoagulation may be tested for stroke prevention.
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Fibrilação Atrial/etiologia , Cardiomiopatias/complicações , Átrios do Coração/patologia , Embolia Intracraniana/etiologia , Acidente Vascular Cerebral/etiologia , Fibrilação Atrial/diagnóstico , Feminino , Humanos , MasculinoRESUMO
Dimethylformamide (DMF), which is still the most commonly used solvent for Fmoc-SPPS, has the potential for degradation over time on exposure to air (and water vapour) and storage, to give dimethylamine and formic acid impurities. In particular, dimethylamine can lead to unwanted deprotection of the fluorenylmethyloxycarbonyl (Fmoc) group during, for example, the initial loading of Fmoc amino acids in SPPS, which leads reduced calculated loading values. We have found that treatment of such aged DMF by simple sparging with an inert gas (N2 ), or vacuum sonication, can regenerate the DMF in order to restore loading levels back to those found for newer, fresh, DMF samples.
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Dimetilaminas/química , Dimetilformamida/química , Reutilização de Equipamento , Fluorenos/química , Formiatos/química , Técnicas de Síntese em Fase Sólida/normas , Estabilidade de Medicamentos , Cinética , Nitrogênio/química , Oxirredução , Resinas Sintéticas/química , Técnicas de Síntese em Fase Sólida/instrumentação , Técnicas de Síntese em Fase Sólida/métodos , Solventes , SonicaçãoRESUMO
Optical cone beam computed tomography (CT), using a digital camera to acquire 2D projection images, provides a fast, mechanically simple method for 3D radiation dosimetry. However, original cone beam designs had poor accuracy as a result of considerable scatter/stray light reaching the camera. Previously, our group presented a redesigned convergent light source for optical cone beam CT that considerably reduced stray light contribution and improved accuracy (Dekker et al 2016 Phys. Med. Biol. 61 2910). Here, we performed an evaluation of a newly updated commercial optical cone beam CT scanner (VistaTM, ModusQA, London, Canada) based on that design. Two different light source configurations were examined: the manufacturer's default configuration which uses a 10 cm wide, 5 cm high diffuser light source, and a smaller, 1.5 cm diameter diffuser light source that more closely aligns with our previously described design. We imaged large volume (15 cm diameter cylinders) absorbing and scattering solution phantoms as well as a 1.25 cm diameter absorber placed within 15 cm diameter gel-like scattering phantom. Optical CT reconstructions were compared against narrow-beam measurements of attenuation made by placing an aperture in the optical CT system. Our results show that considerable stray light is present when using the manufacturer's default configuration, as cupping artifacts and large (⩾10%) discrepancies between optical CT and narrow-beam attenuation measurements occur when imaging scattering phantoms. However, when imaging is performed using the 1.5 cm diameter source, optical CT measurements agree with narrow-beam measurements within â¼3% for both absorbing and scattering objects, as well as the small absorber in a scattering medium. Using this light source will require higher optical quality vessels than are currently provided by the manufacturer.
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Tomografia Computadorizada de Feixe Cônico/instrumentação , Tomografia Computadorizada de Feixe Cônico/métodos , Luz , Imagens de Fantasmas , Radiometria/instrumentação , Humanos , Radiometria/métodos , Espalhamento de RadiaçãoRESUMO
In the Mindfulness-Based Eating Awareness Training program (MB-EAT) (Kristeller and Wolever, 2014; Kristeller and Wolever, in press), mindfulness practice is taught, mindful eating is cultivated, and self-acceptance and spiritual well-being are enhanced. An integrative concept is the value of cultivating 'wisdom' in regard to creating a new and sustainable relationship to eating and food. 'Wisdom' refers to drawing on personal experience and understanding in a flexible, insightful manner, rather than strictly following external rules and guidelines. Several clinical trials involving variations of MB-EAT have documented substantive improvement in how people relate to their eating, including individuals with both binge eating disorder (BED) and subclinical eating issues. Based on the traditional value of contemplative practices for cultivating spiritual engagement, and on evidence from related research showing that spiritual well-being increases in the Mindfulness-Based Stress Reduction (MBSR) program and is related to other effects, we hypothesized that the MB-EAT program would also engage this aspect of experience, as assessed by the Functional Assessment of Chronic Illness Therapy - Spiritual Well-Being subscale (FACIT-Sp), and that increases in spiritual well-being would relate to other measures of adjustment such as emotional balance and improvement in disordered eating. Participants (N = 117) with moderate to morbid obesity, including 25.6% with BED, were randomly assigned to MB-EAT or a wait-list control, and assessed on the FACIT-Sp and other measures at baseline, immediate post (IP), and 2-month followup (F/Up). Both FACIT-Sp factors [Meaning/Peace (M/P) and Faith] increased significantly in the MB-EAT group and were stable/decreased in the control group. Increases in these factors related to improvement in emotional adjustment and eating regulation at IP and at F/Up, and to increases in aspects of mindfulness measured by the Five Facet Mindfulness Questionnaire (FFMQ). Increases in M/P during treatment mediated effects of the FFMQ Observe factor on eating regulation and depression at IP. Results are discussed in terms of the role that mindfulness practice plays in cultivating 'wise mind' and the related value of spirituality. It is argued that the core elements of the MB-EAT program lead to meaningful spiritual engagement, which plays a role in people's ability to improve and maintain overall self-regulation.
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Optical cone beam computed tomography (CT) scanning of radiochromic gel dosimeters, using a CCD camera and a low stray light convergent source, provides fast, truly 3D radiation dosimetry with high accuracy. However, a key limiting factor in radiochromic gel dosimetry at large (⩾10 cm diameter) volumes is the initial attenuation of the dosimeters. It is not unusual to observe a 5-10× difference in signal intensity through the dosimeter center versus through the surrounding medium in pre-irradiation images. Thus, all dosimetric information in a typical experiment is measured within the lower 10%-20% of the camera sensor's range, and re-use of gels is often not possible due to a lack of transmission. To counteract this, in this note we describe a simple method to create source compensators by printing on transparent films. This technique, which is easily implemented and inexpensive, is an optical analogue to the bowtie filter in x-ray CT. We present transmission images and solution phantom reconstructions to demonstrate that (1) placing compensators beyond the focal zone of the imaging lens prevents high spatial frequency features of the printed films from generating reconstruction artifacts, and (2) object-specific compensation considerably reduces the range of intensities measured in projection images. This will improve the measurable dose range in optical CT dosimetry, and will enable imaging of larger gel volumes (â¼15 cm diameter). Additionally, it should enable re-use of dosimeters by printing a new compensator for a second experiment.
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Tomografia Computadorizada de Feixe Cônico/métodos , Imagens de Fantasmas , Radiometria/instrumentação , Radiometria/métodos , HumanosRESUMO
Boron nitride nanotubes (BNNTs) are an emerging engineered nanomaterial attracting significant attention due to superior electrical, chemical and thermal properties. Currently, the toxicity profile of this material is largely unknown. Commercial grade BNNTs are composed of a mixture (BNNT-M) of â¼50-60% BNNTs, and â¼40-50% impurities of boron and hexagonal boron nitride. We performed acute in vitro and in vivo studies with commercial grade BNNT-M, dispersed by sonication in vehicle, in comparison to the extensively studied multiwalled carbon nanotube-7 (MWCNT-7). THP-1 wild-type and NLRP3-deficient human monocytic cells were exposed to 0-100 µg/ml and C57BL/6 J male mice were treated with 40 µg of BNNT-M for in vitro and in vivo studies, respectively. In vitro, BNNT-M induced a dose-dependent increase in cytotoxicity and oxidative stress. This was confirmed in vivo following acute exposure increase in bronchoalveolar lavage levels of lactate dehydrogenase, pulmonary polymorphonuclear cell influx, loss in mitochondrial membrane potential and augmented levels of 4-hydroxynonenal. Uptake of this material caused lysosomal destabilization, pyroptosis and inflammasome activation, corroborated by an increase in cathepsin B, caspase 1, increased protein levels of IL-1ß and IL-18 both in vitro and in vivo. Attenuation of these effects in NLRP3-deficient THP-1 cells confirmed NLRP3-dependent inflammasome activation by BNNT-M. BNNT-M induced a similar profile of inflammatory pulmonary protein production when compared to MWCNT-7. Functionally, pretreatment with BNNT-M caused suppression in bacterial uptake by THP-1 cells, an effect that was mirrored in challenged alveolar macrophages collected from exposed mice and attenuated with NLRP3 deficiency. Analysis of cytokines secreted by LPS-challenged alveolar macrophages collected after in vivo exposure to dispersions of BNNT-M showed a differential macrophage response. The observed results demonstrated acute inflammation and toxicity in vitro and in vivo following exposure to sonicated BNNT-M was in part due to NLRP3 inflammasome activation.
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Compostos de Boro/toxicidade , Pulmão/efeitos dos fármacos , Nanotubos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Animais , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Inflamação , Pulmão/metabolismo , Pulmão/patologia , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/imunologia , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Tamanho da Partícula , Piroptose/efeitos dos fármacosRESUMO
PURPOSE: Iterative CT reconstruction algorithms are gaining popularity as GPU-based computation becomes more accessible. These algorithms are desirable in x-ray CT for their ability to achieve similar image quality at a fraction of the dose required for standard filtered backprojection reconstructions. In optical CT dosimetry, the noise reduction capability of such algorithms is similarly desirable because noise has a detrimental effect on the precision of dosimetric analysis, and can create misleading test results. In this study, we evaluate an iterative CT reconstruction algorithm for gel dosimetry, with special attention to the challenging dosimetry of small fields. METHODS: An existing ordered subsets convex algorithm using total variation minimization regularization (OSC-TV) was implemented. Three datasets, which represent the extreme cases of gel dosimetry, were examined: a large, 15 cm diameter uniform phantom, a 1.35 cm diameter finger phantom, and a 15 cm gel dosimeter irradiated with 3 × 3, 2 × 2, 1 × 1, and 0.6 × 0.6 cm fields. These were scanned on an in-house scanning laser system, and reconstructed with both filtered backprojection and OSC-TV with a range of regularization constants. The contrast to artifact + noise ratio (CANR) and penumbra width measurements (80% to 20% and 95% to 5% distances) were used to compare reconstructions. RESULTS: Our results showed that OSC-TV can achieve 3-5× improvement in contrast to artifact + noise ratio compared to filtered backprojection, while preserving the shape of steep dose gradients. For very small objects (≤ 0.6 × 0.6 cm fields in a 16 × 16 cm field of view), the mean value in the center of the object can be suppressed if the regularization constant is improperly set, which must be avoided. CONCLUSIONS: Overall, the results indicate that OSC-TV is a suitable reconstruction algorithm for gel dosimetry, provided care is taken in setting the regularization parameter when reconstructing objects that are small compared to the scanner field of view.
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Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Radiometria/instrumentação , Tomografia Computadorizada por Raios X , Imagens de FantasmasRESUMO
Non-Hodgkin's lymphoma is a complex heterogeneous group of disease entities that involves nodal and extranodal tissues. Cutaneous involvement can occur either as a primary or secondary in course of disease. Radiation therapy with either total body or localized treatments is often used for local control and symptom relief, depending on the target volume. We describe a 60-year-old male with a remote history of stage IA left neck follicular lymphoma treated with radiation 20 years ago and previous relapses aggressively treated by chemotherapy. Treatment to a large volume of back and posterior shoulders on a helical tomotherapy radiotherapy system is reported. The skin lesions responded completely with no toxicity. Palliative radiotherapy to a fairly large and complex volume of skin with modest dose avoiding underlying critical tissues on tomotherapy is feasible, well tolerated with an excellent durable response, without compromising future chemotherapy and stem cell transplant for systemic relapse.
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The effectiveness of different instrument approach charts to deliver minimum visibility and altitude information during airport equipment outages was investigated. Eighteen pilots flew simulated instrument approaches in three conditions: (a) normal operations using a standard approach chart (standard-normal), (b) equipment outage conditions using a standard approach chart (standard-outage), and (c) equipment outage conditions using a prototype decluttered approach chart (prototype-outage). Errors and retrieval times in identifying minimum altitudes and visibilities were measured. The standard-outage condition produced significantly more errors and longer retrieval times versus the standard-normal condition. The prototype-outage condition had significantly fewer errors and shorter retrieval times than did the standard-outage condition. The prototype-outage condition produced significantly fewer errors but similar retrieval times when compared with the standard-normal condition. Thus, changing the presentation of minima may reduce risk and increase safety in instrument approaches, specifically with airport equipment outages.
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Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.
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Lasers , Imagens de Fantasmas , Tomografia Óptica/métodos , Tomografia Computadorizada por Raios X/instrumentação , Artefatos , Humanos , Radiometria/métodos , Radioterapia de Intensidade Modulada , Tomografia Computadorizada por Raios X/métodosRESUMO
Borderline personality disorder (BPD) confers risk for cardiovascular disease (CVD). The present study used the interpersonal perspective to investigate potential mechanisms underlying this association. In two undergraduate samples (N = 293; N = 188) in Study 1, we replicated and extended research by demonstrating that BPD features were associated with hostile and somewhat submissive interpersonal behavior. Further, BPD features were associated with low social support and high levels of interpersonal conflict, two well-established risk factors for CVD. Also, hostile-submissive behavior contributed to the association of BPD features with low social support. In Study 2, we examined associations of BPD features with blood pressure (BP) responses to two interpersonal stressors implicated in models of the effects of stress on CVD, specifically by using laboratory tasks involving interpersonal conflict and evaluative threat in a third undergraduate sample (N = 143). BPD features predicted elevated BP reactivity to conflict but not evaluative threat, and such heightened reactivity previously has been found to predict the development of CVD. The interpersonal perspective may be useful for investigating mechanisms linking BPD to CVD risk, and processes that undermine otherwise protective social support or heighten exposure and reactivity to interpersonal conflict may be relevant in this regard.