Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 71
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 120(18): e2217090120, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37094138

RESUMO

We present the first observations of seismic waves propagating through the core of Mars. These observations, made using seismic data collected by the InSight geophysical mission, have allowed us to construct the first seismically constrained models for the elastic properties of Mars' core. We observe core-transiting seismic phase SKS from two farside seismic events detected on Mars and measure the travel times of SKS relative to mantle traversing body waves. SKS travels through the core as a compressional wave, providing information about bulk modulus and density. We perform probabilistic inversions using the core-sensitive relative travel times together with gross geophysical data and travel times from other, more proximal, seismic events to seek the equation of state parameters that best describe the liquid iron-alloy core. Our inversions provide constraints on the velocities in Mars' core and are used to develop the first seismically based estimates of its composition. We show that models informed by our SKS data favor a somewhat smaller (median core radius = 1,780 to 1,810 km) and denser (core density = 6.2 to 6.3 g/cm3) core compared to previous estimates, with a P-wave velocity of 4.9 to 5.0 km/s at the core-mantle boundary, with the composition and structure of the mantle as a dominant source of uncertainty. We infer from our models that Mars' core contains a median of 20 to 22 wt% light alloying elements when we consider sulfur, oxygen, carbon, and hydrogen. These data can be used to inform models of planetary accretion, composition, and evolution.

2.
Proc Natl Acad Sci U S A ; 119(42): e2204474119, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36215469

RESUMO

Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars' deep mantle is demarcated by a seismic discontinuity arising from the pressure-induced phase transformation of the mineral olivine to its higher-pressure polymorphs, making the depth of this boundary sensitive to both mantle temperature and composition. Here, we report on the seismic detection of a midmantle discontinuity using the data collected by NASA's InSight Mission to Mars that matches the expected depth and sharpness of the postolivine transition. In five teleseismic events, we observed triplicated P and S waves and constrained the depth of this discontinuity to be 1,006 [Formula: see text] 40 km by modeling the triplicated waveforms. From this depth range, we infer a mantle potential temperature of 1,605 [Formula: see text] 100 K, a result consistent with a crust that is 10 to 15 times more enriched in heat-producing elements than the underlying mantle. Our waveform fits to the data indicate a broad gradient across the boundary, implying that the Martian mantle is more enriched in iron compared to Earth. Through modeling of thermochemical evolution of Mars, we observe that only two out of the five proposed composition models are compatible with the observed boundary depth. Our geodynamic simulations suggest that the Martian mantle was relatively cold 4.5 Gyr ago (1,720 to 1,860 K) and are consistent with a present-day surface heat flow of 21 to 24 mW/m2.


Assuntos
Meio Ambiente Extraterreno , Marte , Planeta Terra , Ferro , Minerais
3.
Sensors (Basel) ; 24(7)2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38610300

RESUMO

Variations in Global Positioning Systems (GPSs) have been used for tracking users' locations. However, when location tracking is needed for an indoor space, such as a house or building, then an alternative means of precise position tracking may be required because GPS signals can be severely attenuated or completely blocked. In our approach to indoor positioning, we developed an indoor localization system that minimizes the amount of effort and cost needed by the end user to put the system to use. This indoor localization system detects the user's room-level location within a house or indoor space in which the system has been installed. We combine the use of Bluetooth Low Energy beacons and a smartwatch Bluetooth scanner to determine which room the user is located in. Our system has been developed specifically to create a low-complexity localization system using the Nearest Neighbor algorithm and a moving average filter to improve results. We evaluated our system across a household under two different operating conditions: first, using three rooms in the house, and then using five rooms. The system was able to achieve an overall accuracy of 85.9% when testing in three rooms and 92.106% across five rooms. Accuracy also varied by region, with most of the regions performing above 96% accuracy, and most false-positive incidents occurring within transitory areas between regions. By reducing the amount of processing used by our approach, the end-user is able to use other applications and services on the smartwatch concurrently.

4.
Alcohol Alcohol ; 57(6): 755-761, 2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36047807

RESUMO

AIMS: Alcohol expectancies are directly linked to alcohol misuse and indirectly linked to negative consequences via use. Likewise, willingness to experience negative consequences imparts direct risk for negative consequences and may represent an important individual difference when predicting risky alcohol use. To date, no studies have examined how willingness to experience consequences may moderate relations between expectancies and alcohol use in the prediction of negative consequences. It is possible that those who expect appetitive effects and are high in willingness may discount the severity of negative consequences and drink more to realize positive expectations. Alternatively, those who expect aversive alcohol-related effects and are high in willingness may drink more to overcome negative experiences. METHODS: The current study tested these hypotheses in a sample of undergraduate students (N = 657) from a larger study focused on alcohol and cannabis co-use. RESULTS: Findings suggested that high-arousal positive expectancies (e.g. sociable, lively, talkative) function as a risk factor for negative consequences indirectly through heavier drinking, whereas low-arousal positive (e.g. mellow, relaxed) expectancies served as an indirect protective factor against negative consequences through lighter drinking. Willingness to experience negative consequences had direct and indirect effects on negative consequences through drinking but did not interact with alcohol expectancies. CONCLUSIONS: The present study demonstrates the utility of assessing the full range of alcohol expectancies and behavioral willingness in continued research into the dynamic nature of antecedents to alcohol misuse and negative consequences.


Assuntos
Consumo de Bebidas Alcoólicas , Alcoolismo , Humanos , Consumo de Bebidas Alcoólicas/efeitos adversos , Estudantes , Fatores de Risco
5.
Age Ageing ; 50(5): 1792-1801, 2021 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-33837769

RESUMO

BACKGROUND: The global population is ageing, and rates of multimorbidity and chronic illness are rapidly rising. Given specialist palliative care has been shown to improve overall care and reduce health care costs, how best to provide this care to older people is internationally significant. AIM: To examine the knowledge, attitudes and practices of geriatricians in providing palliative care and working with specialist palliative care services. We also aimed to capture self-reported barriers, confidence and satisfaction in providing palliative care. DESIGN: A prospective cross-sectional study surveying Australasian geriatricians was conducted. SETTING/PARTICIPANTS: This was a voluntary anonymous online survey, distributed to all full members of the Australian and New Zealand Society of Geriatric Medicine. RESULTS: A total of 168 completed responses were received; 58.3% were female and 36.6% had over 20 years of clinical experience. Most geriatricians (85%) reported caring for patients in their last 12 months of life represented a substantial aspect or most of their practice. Geriatricians overwhelmingly believed they should coordinate care (84%) and derived satisfaction from providing palliative care (95%). The majority (69%) believed all patients with advanced illness should receive concurrent specialist palliative care. Regarding knowledge, participants scored an average of 13.5 correct answers out of 18 in a Modified Palliative Care Knowledge Test. CONCLUSIONS: Geriatricians find reward in providing generalist palliative care to their patients; however, potential exists for improved collaborations with specialist palliative care services. An evidence base for geriatric patients who benefit most from specialist palliative care services is needed to improve resourcing, collaborative practice and ultimately palliative care delivery.


Assuntos
Geriatras , Cuidados Paliativos , Idoso , Atitude do Pessoal de Saúde , Austrália , Estudos Transversais , Feminino , Humanos , Estudos Prospectivos
6.
Pain Med ; 21(7): 1331-1346, 2020 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-32259247

RESUMO

BACKGROUND: It is nearly impossible to overestimate the burden of chronic pain, which is associated with enormous personal and socioeconomic costs. Chronic pain is the leading cause of disability in the world, is associated with multiple psychiatric comorbidities, and has been causally linked to the opioid crisis. Access to pain treatment has been called a fundamental human right by numerous organizations. The current COVID-19 pandemic has strained medical resources, creating a dilemma for physicians charged with the responsibility to limit spread of the contagion and to treat the patients they are entrusted to care for. METHODS: To address these issues, an expert panel was convened that included pain management experts from the military, Veterans Health Administration, and academia. Endorsement from stakeholder societies was sought upon completion of the document within a one-week period. RESULTS: In these guidelines, we provide a framework for pain practitioners and institutions to balance the often-conflicting goals of risk mitigation for health care providers, risk mitigation for patients, conservation of resources, and access to pain management services. Specific issues discussed include general and intervention-specific risk mitigation, patient flow issues and staffing plans, telemedicine options, triaging recommendations, strategies to reduce psychological sequelae in health care providers, and resource utilization. CONCLUSIONS: The COVID-19 public health crisis has strained health care systems, creating a conundrum for patients, pain medicine practitioners, hospital leaders, and regulatory officials. Although this document provides a framework for pain management services, systems-wide and individual decisions must take into account clinical considerations, regional health conditions, government and hospital directives, resource availability, and the welfare of health care providers.


Assuntos
Analgésicos Opioides/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Dor Crônica/terapia , Infecções por Coronavirus/epidemiologia , Glucocorticoides/uso terapêutico , Manejo da Dor/métodos , Pneumonia Viral/epidemiologia , Guias de Prática Clínica como Assunto , Telemedicina , Agendamento de Consultas , Betacoronavirus , COVID-19 , Desinfecção , Acessibilidade aos Serviços de Saúde , Humanos , Injeções , Injeções Intra-Articulares , Programas de Rastreamento , Medicina Militar , Pandemias , Equipamento de Proteção Individual , Admissão e Escalonamento de Pessoal , Saúde Pública , SARS-CoV-2 , Sociedades Médicas , Síndrome de Abstinência a Substâncias/diagnóstico , Triagem , Pontos-Gatilho , Estados Unidos , United States Department of Veterans Affairs
7.
NMR Biomed ; 32(5): e4065, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30735273

RESUMO

Primary sclerosing cholangitis (PSC) has been considered to be either an "autoimmune disease" or a "bile acid-induced injury." In vitro MRS studies on PSC patients have limitations due to the contamination of bile with contrast agent (commonly administered during endoscopic retrograde cholangiopancreatography) and/or the use of patient cohorts with other diseases as controls. The objective of this study was to quantify biliary metabolites using in vivo 1 H MRS and gain insight into the pathogenesis of PSC. Biliary metabolites in 10 PSC patients and 14 healthy controls were quantified in vivo using 1 H MRS on a 3 T MR scanner. The concentrations of total bile acids plus cholesterol, glycine-conjugated bile acids, taurine-conjugated bile acids, and choline-containing phospholipids (chol-PLs) were compared between the two groups. There were statistically significant decreases in the levels of the above mentioned biliary metabolites in the PSC patients compared with controls. The reduction in bile acid secretion in bile of PSC patients indicates accumulation of bile acids in hepatocytes. Moreover, reduction in the levels of chol-PLs in bile may increase the toxic effects of bile acids. Our findings suggest that the bile duct injury in PSC patients is most likely due to "bile acid-induced injury."


Assuntos
Ácidos e Sais Biliares/metabolismo , Colangite Esclerosante/imunologia , Colangite Esclerosante/fisiopatologia , Vesícula Biliar/diagnóstico por imagem , Vesícula Biliar/lesões , Espectroscopia de Prótons por Ressonância Magnética , Adulto , Feminino , Humanos , Masculino , Metaboloma , Pessoa de Meia-Idade , Adulto Jovem
8.
BMC Urol ; 18(1): 66, 2018 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-30055610

RESUMO

BACKGROUND: New biologic therapies directly injected into the prostate are in clinical trials for prostatic diseases. There is a need to understand distribution of injected therapies as a function of prostatic anatomy, physiology, and device design. METHODS: A needle with a porous length of customizable-length was tested and its performance compared with a standard needle. Injections of magnetic resonance contrast reagent were placed into ex-vivo human prostates after surgical excision in standard of care therapy for invasive bladder cancer patients. Magnetic resonance images were acquired using sequences to quantify volume delivered, distributed, and backflow. RESULTS: Magnetic resonance images analysis revealed heterogeneity distribution with injection into the specimens. There was low resistance to flow along ductal pathways and high resistance to flow into glandular nodules and smooth muscle/fibrous parenchyma. Data confirm previous studies showing injection loss via urethra backflow, urethra, and prostatic ducts. Tissue fraction of dose was significantly higher with porous needle compared with standard needle (p = .03). We found that a greater volume of distribution divided by the amount infused (Vd/Vi) increased by 80% with the porous needle, though no statistically significant association due to small sample size. CONCLUSIONS: This study demonstrated that prostatic tissue is anatomically heterogenic and limits distribution of needle injection. There is greater distribution in the ex-vivo prostate using a porous needle. The complexity of intra prostatic flow pathways suggests preoperative imaging and pre-treatment planning will enhance therapy.


Assuntos
Fatores Biológicos/administração & dosagem , Imageamento por Ressonância Magnética/métodos , Agulhas , Próstata/diagnóstico por imagem , Doenças Prostáticas/tratamento farmacológico , Idoso , Desenho de Equipamento , Humanos , Injeções Intralesionais , Masculino , Projetos Piloto , Doenças Prostáticas/diagnóstico por imagem
9.
AJR Am J Roentgenol ; 208(4): 785-793, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28328258

RESUMO

OBJECTIVE: The purpose of this article is to assess the value of a large panel of clinical and MDCT variables in patients with suspected small-bowel obstruction (SBO) for predicting urgent surgical intervention (< 72 hours), bowel ischemia, and bowel resection. MATERIALS AND METHODS: MDCT studies performed at admission for 179 nonconsecutive adults (mean age, 55.8 years; 86 men and 93 women) with suspected SBO were retrospectively reviewed by three board-certified radiologists. In addition to assessing individual CT features, each radiologist scored the overall likelihood of each main outcome measure using a 5-point scale. All relevant clinical and laboratory data were abstracted from electronic medical record review. Univariate and multivariate analyses were performed. RESULTS: Among all 179 patients with suspected SBO, 56 (31.3%) underwent surgical intervention within 72 hours, 10 (5.6%) had ischemia at surgery, and nine (5.0%) required small-bowel resection. On univariate analysis, multiple CT findings were highly significant (p < 0.01) for predicting the main surgical outcomes, including degree of obstruction, 5-point radiology likelihood scores, and the presence of a transition point, closed loop, and mesenteric congestion. None of the objective clinical or laboratory variables (including serum lactate level) reached this level of significance. At multivariate analysis, forward stepwise logistic regression with 0.05 significance level cutoff included both degree of obstruction (p < 0.001) and closed loop (p < 0.01), with the presence of a transition point showing a trend toward significance (p = 0.081). CONCLUSION: A number of findings at abdominal MDCT are associated with the need for surgery and other important surgical outcomes in patients with suspected SBO. Overall radiologist impression of need for surgical intervention was a better predictor than any clinical or laboratory parameter.


Assuntos
Técnicas de Laboratório Clínico/estatística & dados numéricos , Procedimentos Cirúrgicos do Sistema Digestório/estatística & dados numéricos , Obstrução Intestinal/diagnóstico , Obstrução Intestinal/cirurgia , Intestino Delgado/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/estatística & dados numéricos , Feminino , Humanos , Obstrução Intestinal/epidemiologia , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Cuidados Pré-Operatórios/estatística & dados numéricos , Prevalência , Prognóstico , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco/métodos , Sensibilidade e Especificidade , Wisconsin/epidemiologia
10.
J Comput Assist Tomogr ; 41(3): 388-393, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27759602

RESUMO

OBJECTIVE: To compare performance of junior (JR)/senior (SR) abdominal radiologists using multidetector computed tomography (MDCT) to predict surgical intervention, bowel resection, and presence of bowel ischemia in patients with suspected small-bowel obstruction (SBO). METHODS: Retrospective, institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, blinded, independent review of MDCT studies for suspected SBO in 179 adults (mean age, 55.8 years; 86 men/93 women) was performed by 12 board-certified radiologists (6 JR, 6 SR). Readers rated likelihood of need for surgery, bowel ischemia, and resection. Correlation with clinical outcomes/pathology was performed. RESULTS: Pooled receiver operating characteristic area under the curve for surgery, ischemia, and resection were 0.802, 0.736, and 0.824 and 0.773, 0.851, and 0.751 JR/SR, respectively. Sensitivity/specificity for predicting surgery was 86.7%/65.4% and 79.6%/64.4%. No differences existed between JR/SR performance overall (P = 0.451); highest/lowest performing readers between groups (P < 0.001) and within groups (P = 0.008) varied. CONCLUSIONS: Junior radiologists performed as well as SR in predicting surgical outcomes on MDCT in patients with suspected SBO.


Assuntos
Obstrução Intestinal/diagnóstico por imagem , Obstrução Intestinal/cirurgia , Intestino Delgado/diagnóstico por imagem , Intestino Delgado/cirurgia , Tomografia Computadorizada Multidetectores/métodos , Radiografia Abdominal/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Resultado do Tratamento
11.
J Propuls Power ; 33(3): 539-555, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-33510551

RESUMO

Accurate, direct measurement of thrust or impulse is one of the most critical elements of electric thruster characterization, and one of the most difficult measurements to make. This paper summarizes recommended practices for the design, calibration, and operation of pendulum thrust stands, which are widely recognized as the best approach for measuring µN- to mN-level thrust and µNs-level impulse bits. The fundamentals of pendulum thrust stand operation are reviewed, along with the implementation of hanging pendulum, inverted pendulum, and torsional balance configurations. Methods of calibration and recommendations for calibration processes are presented. Sources of error are identified and methods for data processing and uncertainty analysis are discussed. This review is intended to be the first step toward a recommended practices document to help the community produce high quality thrust measurements.

12.
Br J Community Nurs ; 22(11): 536-541, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-29091501

RESUMO

This article attempts to examine and explore the change management process that was undertaken by the community palliative care service at Calvary Health Care Bethlehem, Australia, to challenge the historical practice of prescribing 'emergency subcutaneous medications' for all patients admitted to the service. It discusses how, using a team approach, change management was effectively facilitated to ultimately enhance service provision and consumer satisfaction. Literature (both national and international) was examined to identify the use of emergency medications in the community palliative care setting. The historical practice of all community palliative care patients being prescribed this medication within the Victoria region of Australia was tested, and concerns and misconceptions of staff and referrers were challenged in regards to this practice. Through working parties, descriptive surveys and staff evaluations, the use of the term 'emergency medication' was changed to 'anticipatory medication' with clear criteria for usage. Change was undertaken slowly and with continued collaboration of staff to ensure effectiveness. Staff survey results identified that the majority were satisfied with the change, and they considered there to be no impact on the quality of care that their patients were receiving. The natural progression of the project, which resulted in positive quantitative and qualitative results, was the facilitation of an education package for carers to educate them on giving subcutaneous medications to the patient. By undertaking change that was slow and methodical with clear communication to all, the community palliative care service was able to embed the changes into everyday practice, and the use of anticipatory medications within the Calvary Health Care Bethlehem community palliative care service is now understood, acknowledged, and adhered to by all staff.


Assuntos
Gestão de Mudança , Serviços de Saúde Comunitária/organização & administração , Cuidados Paliativos/tendências , Austrália , Humanos
13.
J Environ Manage ; 166: 450-6, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26555101

RESUMO

Due to stringent water quality regulations on stormwater discharges, there is increasing interest in chemically-assisted settling of suspended sediments at construction sites. This study investigated settling characteristics of flocculated sediment by polyacrylamide (PAM) in a top-loading settling tube. Studied sediment materials were obtained from construction sites in North Carolina, USA: Coastal Plain loamy sand (CPLS), Piedmont sandy clay loam (PSCL), Piedmont silt loam (PSL), and Mountain clay loam (MCL). The four different sediment suspensions mixed with and without dissolved PAM were introduced to the top of the column individually. During a 1-h settling period, samples were taken at 1-m depth from surface at various times and analyzed for total suspended solids (TSS). Flocculated sediment by PAM greatly increased its settled TSS fraction up to 95-97% only in 1-min settling period compared to those of unflocculated sediment (16-72%). The settling improvement by PAM was profound in the finer-textured soils (PSL and MCL) by increasing their median particle settling velocity (>2 cm s(-1)) compared to unflocculated counterparts (<1.1 cm s(-1)). Estimated surface area requirement of sediment basin suggested that the basins receiving flocculated sediment could be reduced in size (surface area) by 2- to 4-times compared to those receiving unflocculated sediment. Our results suggests that current sediment basin design could be modified when chemically-assisted settling is implemented, taking up less space and cost in construction sites.


Assuntos
Indústria da Construção , Sedimentos Geológicos , Resinas Acrílicas , Floculação , Sedimentos Geológicos/química , North Carolina , Solo , Suspensões , Qualidade da Água
14.
NMR Biomed ; 27(10): 1192-202, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25132620

RESUMO

In vitro (1)H MRS of human bile has shown potential in the diagnosis of various hepatopancreatobiliary (HPB) diseases. Previously, in vivo (1)H MRS of human bile in gallbladder using a 1.5 T scanner demonstrated the possibility of quantification of choline-containing phospholipids (chol-PLs). However, other lipid components such as bile acids play an important role in the pathophysiology of the HPB system. We have employed a higher magnetic field strength (3 T), and a custom-built receive array coil, to improve the quality of in vivo (1)H MRS of human bile in the gallbladder. We obtained significant improvement in the quality of 1D spectra (17 healthy volunteers) using a respiratory-gated PRESS sequence with well distinguished signals for total bile acids (TBAs) plus cholesterol resonating at 0.66 ppm, taurine-conjugated bile acids (TCBAs) at 3.08 ppm, chol-PLs at 3.22 ppm, glycine-conjugated bile acids (GCBAs) at 3.74 ppm, and the amide proton (-NH) arising from GCBAs and TCBAs in the region 7.76-8.05 ppm. The peak areas of these signals were measured by deconvolution, and subsequently the molar concentrations of metabolites were estimated with good accuracy, except for that of TBAs plus cholesterol. The concentration of TBAs plus cholesterol was overestimated in some cases, which could be due to lipid contamination. In addition, we report the first 2D L-COSY spectra of human gallbladder bile in vivo (obtained in 15 healthy volunteers). 2D L-COSY spectra will be helpful in differentiating various biliary chol-PLs in pathological conditions of the HPB system.


Assuntos
Bile/química , Vesícula Biliar , Lipídeos/análise , Ressonância Magnética Nuclear Biomolecular/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Adulto , Ácidos e Sais Biliares/análise , Colesterol/análise , Colina/análise , Feminino , Humanos , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Fosfolipídeos/análise , Espectroscopia de Prótons por Ressonância Magnética/instrumentação , Taurina/análise
15.
Addict Behav ; 154: 108019, 2024 07.
Artigo em Inglês | MEDLINE | ID: mdl-38502991

RESUMO

BACKGROUND: Impulsive personality traits are strong, consistent risk factors for heavy drinking, and modern theories suggest that impulsive traits may also confer risk for internalizing symptoms. However, it remains unclear which specific impulsive traits are linked with heavy drinking versus internalizing symptoms, and whether heavy drinking and internalizing symptoms are mechanisms of risk for negative alcohol consequences in impulsive individuals. METHOD: Data are from a longitudinal study of young adults (N = 448, Mage = 22.27, 43.5 % female) assessed at baseline (T1), 6 months (T2), and one year later (T3). Longitudinal path models tested whether T1 impulsive traits (i.e., lack of premeditation, lack of perseverance, sensation seeking, positive urgency, negative urgency) were indirectly associated with T3 negative alcohol consequences through heavy T2 drinking and T2 internalizing symptoms (i.e., depression, anxiety, stress). Separate models were tested for positive and negative urgency given strong correlations between these measures. RESULTS: Across models, T1 lack of premeditation indirectly predicted more T3 negative alcohol consequences through heavy T2 drinking. When tested separately, T1 negative urgency indirectly predicted more T3 negative consequences through higher T2 stress and depressive (but not anxiety) symptoms, and T1 positive urgency predicted higher T2 anxiety symptoms, but T2 anxiety was unrelated to T3 negative consequences. Across models, T1 sensation seeking indirectly predicted less T3 negative consequences through decreased T2 depression. CONCLUSIONS: Distinct impulsive traits prospectively predicted heavy drinking and internalizing symptoms, both of which conferred risk for negative alcohol consequences. Findings underscore the importance of targeted interventions based on personality and suggest that decreases in drinking may be more effective prevention for those who lack premeditation, whereas decreases in internalizing, particularly depression/stress, may be critical for those high in negative urgency.


Assuntos
Consumo de Bebidas Alcoólicas , Comportamento Impulsivo , Adulto Jovem , Humanos , Feminino , Masculino , Consumo de Bebidas Alcoólicas/epidemiologia , Estudos Longitudinais , Fatores de Risco , Personalidade
16.
Psychol Addict Behav ; 38(5): 563-577, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38629939

RESUMO

OBJECTIVE: Decades of research has found support for the motivational model of alcohol use at the between-person level, yet research on event-level drinking motives is in its nascent stage. Similarly, drinking context has been largely ignored in studies of day-level motives. Therefore, the present study sought to test whether drinking context mediates the relation between affect and motivation on drinking outcomes at both day and person levels. METHOD: Emerging adults who drank in solitary and social settings (N = 107; 61.2% female) completed 21 days ecological momentary assessments. Affect was assessed during morning/afternoon reports; drinking motives were assessed during afternoon reports; and past-night drinking context, drinking quantity, and negative consequences were assessed during next morning reports. Two-level multilevel structural equation models tested whether within-person and between-person levels of predrinking affect were indirectly associated with negative consequences through predrinking motives, drinking context (social vs. solitary), and drinking quantity. RESULTS: At the day and person levels, positive affect was associated with higher social and enhancement motives. At the day level, positive affect indirectly predicted consequences through social motives, social (vs. solitary) drinking, and drinking quantity, whereas positive affect indirectly predicted consequences through enhancement motives and drinking quantity above and beyond context. At the day and person levels, negative affect was associated with coping motives, but coping was not associated with context, drinking quantity, nor consequences. CONCLUSIONS: Findings suggest that positive affect was linked to drinking outcomes through motives (enhancement and social) and contexts (social), whereas negative affect was not. Findings suggest that positively valenced drinking motives may be an important just-in-time intervention target. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Assuntos
Afeto , Consumo de Bebidas Alcoólicas , Motivação , Humanos , Feminino , Masculino , Adulto Jovem , Consumo de Bebidas Alcoólicas/psicologia , Afeto/fisiologia , Adulto , Avaliação Momentânea Ecológica , Adolescente , Meio Social
17.
Anal Chem ; 85(16): 7769-76, 2013 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-23855831

RESUMO

We combine in situ Bragg diffraction, laser diffraction, high speed fluorescence scanning, and large-scale data processing to arrive at statistically significant conclusions about the role of order during the microchip electrophoresis separation of short DNA molecules (86 base pairs and 709 base pairs) in colloidal crystals. This experimental approach directly connects the presence of long-range order (obtained by laser diffraction) to the DNA transport (obtained by fluorescence detection) in hundreds of "mini-columns" composed of 500 µm-long regions of the devices. To within statistical significance, the electrophoretic mobility is the same in regions of the chip with long-range order and those with short-range order, independent of the electric field and molecular weight. Moreover, the relative mobilities of the DNA agree well with a recent estimate for the Ogston sieving mobility in a colloidal crystal. Similar to previous work, the band broadening during the transit through the colloidal crystal is negligible. These features imply that colloidal crystals for DNA separation in the Ogston sieving regime do not require exquisite control over the microstructure to maximize the separation resolution, simplifying their assembly for routine use.


Assuntos
Coloides , DNA/isolamento & purificação , Cristalização , Eletroforese em Microchip , Espectrometria de Fluorescência
18.
NMR Biomed ; 26(11): 1602-7, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24019215

RESUMO

Although MRI offers highly diagnostic medical imagery, patient access to this modality worldwide is very limited when compared with X-ray or ultrasound. One reason for this is the expense and complexity of the equipment used to generate the switched magnetic fields necessary for MRI encoding. These field gradients are also responsible for intense acoustic noise and have the potential to induce nerve stimulation. We present results with a new MRI encoding principle which operates entirely without the use of conventional B0 field gradients. This new approach--'Transmit Array Spatial Encoding' (TRASE)--uses only the resonant radiofrequency (RF) field to produce Fourier spatial encoding equivalent to conventional MRI. k-space traversal (image encoding) is achieved by spin refocusing with phase gradient transmit fields in spin echo trains. A transmit coil array, driven by just a single transmitter channel, was constructed to produce four phase gradient fields, which allows the encoding of two orthogonal spatial axes. High-resolution two-dimensional-encoded in vivo MR images of hand and wrist were obtained at 0.2 T. TRASE exploits RF field phase gradients, and offers the possibility of very low-cost diagnostics and novel experiments exploiting unique capabilities, such as imaging without disturbance of the main B0 magnetic field. Lower field imaging (<1 T) and micro-imaging are favorable application domains as, in both cases, it is technically easier to achieve the short RF pulses desirable for long echo trains, and also to limit RF power deposition. As TRASE is simply an alternative mechanism (and technology) of moving through k space, there are many close analogies between it and conventional B0 -encoded techniques. TRASE is compatible with both B0 gradient encoding and parallel imaging, and so hybrid sequences containing all three spatial encoding approaches are possible.


Assuntos
Imageamento por Ressonância Magnética , Ondas de Rádio , Humanos , Imageamento Tridimensional , Pulso Arterial , Fatores de Tempo
19.
Artigo em Inglês | MEDLINE | ID: mdl-38032611

RESUMO

Pregaming represents a uniquely high-risk drinking event for young adults, and subfacets of impulsivity are robust predictors of alcohol use and related negative outcomes. Further, it is likely that pregame events contain social and physical stimuli that are particularly appealing for impulsive individuals, thus exacerbating risk for negative outcomes. However, no prior studies have investigated the extent to which impulsive personality traits interact with pregame events to confer alcohol-related risk. Thus, the present study examined the extent to which UPPS-P (urgency-perseverance-premeditation-sensation seeking-positive urgency) subfacets of impulsivity interact with the occurrence of pregaming to predict relations between pregaming, drinking quantity, and negative alcohol-related outcomes. College students (N = 737) completed a modified, online version of the 30-day Timeline Followback in which they reported drinking quantity, negative consequences, and whether they engaged in pregaming on a given day. Results indicated that sensation seeking and a lack of premeditation moderated relations between pregaming and drinking quantity such that those who are higher in sensation seeking and lower in their ability to plan ahead drank more on pregaming days. Sensation seeking and positive urgency moderated relations between pregaming and negative consequences such that those who are higher in positive urgency experience more consequences on pregaming days whereas those who are higher in sensation seeking experience less consequences. Future studies may benefit from more granular assessments of pregame-related risk as subfacets of impulsivity may confer momentary risk. Prevention efforts targeting the reduction of pregaming frequency, particularly among impulsive individuals, may lower overall risk for heavy drinking. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

20.
Exp Clin Psychopharmacol ; 31(5): 888-894, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36757961

RESUMO

Alcohol misuse represents a universal public health concern that spans multiple demographics. As such, understanding shared, biological indicators of alcohol-related risk is vital to implementing targeted prevention and intervention efforts. Self-report measures of subjective response to alcohol (SR) capture both psychological and pharmacological effects of alcohol and robustly predict patterns of alcohol use, negative consequences, and the development of alcohol use disorders. Importantly, several biological markers of alcohol's sedating effects, including cortisol, have been identified and complement subjective response assessments. However, biological markers of alcohol's stimulating effects are less understood. Studies have implicated alcohol-induced changes in heart rate as a viable marker, but heart rate measurements are susceptible to measurement error. Salivary α-amylase, a reliable indicator of sympathetic nervous system activation, represents a promising alternative biomarker of alcohol-induced stimulation. Using data from a large, placebo-controlled alcohol administration study (N = 448), the present study examined the extent to which α-amylase is a viable marker of alcohol-induced stimulation. To test this, a measurement model was estimated in which baseline and ascending limb subjective stimulation latent variables were created using two validated measures of subjective response. Ascending self-reports of stimulation and levels of α-amylase were then regressed onto beverage conditions and allowed to correlate with each other. Findings indicated that α-amylase is sensitive to acute alcohol consumption and is positively, but not statistically reliably, related to the ascending limb stimulant SR. Future studies should consider including salivary α-amylase as a noninvasive physiological indicator of alcohol's stimulating effects. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Alcoolismo , alfa-Amilases Salivares , Humanos , Consumo de Bebidas Alcoólicas/psicologia , Biomarcadores , Etanol/efeitos adversos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA