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1.
Nat Commun ; 15(1): 5546, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956055

RESUMO

C-H bond activation enables the facile synthesis of new chemicals. While C-H activation in short-chain alkanes has been widely investigated, it remains largely unexplored for long-chain organic molecules. Here, we report light-driven C-H activation in complex organic materials mediated by 2D transition metal dichalcogenides (TMDCs) and the resultant solid-state synthesis of luminescent carbon dots in a spatially-resolved fashion. We unravel the efficient H adsorption and a lowered energy barrier of C-C coupling mediated by 2D TMDCs to promote C-H activation and carbon dots synthesis. Our results shed light on 2D materials for C-H activation in organic compounds for applications in organic chemistry, environmental remediation, and photonic materials.

2.
Plants (Basel) ; 13(12)2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38931050

RESUMO

Harlequin bug (Murgantia histrionica) poses a significant threat to cruciferous vegetable crops, leading to economic losses and challenges in sustainable agriculture. This 2-year field study evaluated the efficacy of exclusion netting and selected biopesticides in controlling harlequin bug populations in a field-grown broccoli crop. Treatments included an untreated control, industry standards Azera and Entrust, and ProtekNet mesh netting. Additionally, three commercial essential oil treatments including Essentria IC-3, Nature-Cide, and Zero Tolerance were tested along with two bokashi fermented composting products BrewKashi and Oriental Herbal Nutrient (OHN). During both the first and second year of the study, none of the commercially produced essential oil products or bokashi products were effective in controlling harlequin bug or preventing leaf scars. Conversely, ProtekNet consistently provided the highest level of protection against harlequin bugs of all stages as well as leaf damage scars; it also provided the largest broccoli head width and highest yield. Entrust showed similar results compared to ProtekNet, both with the control of harlequin bug life stages and with leaf scars. These findings indicate that both ProtekNet and Entrust are effective organic alternatives for managing harlequin bug on broccoli, while the selected essential oil and bokashi products do not appear to be effective.

3.
ACS Nano ; 18(23): 15270-15283, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38788214

RESUMO

Lithium fluoride (LiF) is a ubiquitous component in the solid electrolyte interphase (SEI) layer in Li-ion batteries. However, its nanoscale structure, morphology, and topology, important factors for understanding LiF and SEI film functionality, including electrode passivity, are often unknown due to limitations in spatial resolution of common characterization techniques. Ultrabroadband near-field synchrotron infrared nanospectroscopy (SINS) enables such detection and mapping of LiF in SEI layers in the far-infrared region down to ca. 322 cm-1 with a nanoscale spatial resolution of ca. 20 nm. The surface sensitivity of SINS and the large infrared absorption cross section of LiF, which can support local surface phonons under certain circumstances, enabled characterization of model LiF samples of varying structure, thickness, surface roughness, and degree of crystallinity, as confirmed by atomic force microscopy, attenuated total reflectance FTIR, SINS, X-ray photoelectron spectroscopy, high-angle annular dark-field, and scanning transmission electron microscopy. Enabled by this approach, LiF within SEI films formed on Cu, Si, and metallic glass Si40Al50Fe10 electrodes was detected and characterized. The nanoscale morphologies and topologies of LiF in these SEI layers were evaluated to gain insights into LiF nucleation, growth, and the resulting nuances in the electrode surface passivity.

4.
Res Sq ; 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38260621

RESUMO

C-H bond activation enables the facile synthesis of new chemicals. While C-H activation in short-chain alkanes has been widely investigated, it remains largely unexplored for long-chain organic molecules. Here, we report light-driven C-H activation in complex organic materials mediated by 2D transition metal dichalcogenides (TMDCs) and the resultant solid-state synthesis of luminescent carbon dots in a spatially-resolved fashion. We unravel the efficient H adsorption and a lowered energy barrier of C-C coupling mediated by 2D TMDCs to promote C-H activation. Our results shed light on 2D materials for C-H activation in organic compounds for applications in organic chemistry, environmental remediation, and photonic materials.

5.
J Cardiothorac Vasc Anesth ; 38(1): 73-79, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37953174

RESUMO

OBJECTIVES: Anemia and transfusion are common in cardiac surgery patients, and are associated with significant morbidity and mortality. Multiple perioperative interventions have been described to reduce blood transfusion, but are rarely combined altogether. The aim of this study was to compare the incidence of red blood cell (RBC) transfusion in adult patients undergoing cardiac surgery before and after the implementation of a perioperative patient blood management (PBM) program. DESIGN: Before-and-after observational study. SETTING: Single-center French university teaching hospital. PARTICIPANTS: Adult patients scheduled for cardiac surgery. INTERVENTIONS: Perioperative patient blood management program including pre-, intra-, and postoperative interventions aimed at identifying and correcting anemia, minimizing blood loss during surgery, and optimizing coagulation. MEASUREMENTS AND MAIN RESULTS: Four hundred thirty-four patients were included in the study from January 2021 to July 2022. The incidence of perioperative RBC transfusion (intraoperatively and during the first 2 postoperative days) was significantly reduced from 43% (90/213) in the pre-PBM period to 27% (60/221) in the post-PBM period (p < 0.001). The application of a PBM program was associated with a reduction in perioperative RBC transfusion by multivariate analysis (odds ratio 0.55, 95% CI 0.36-0.85, p = 0.007), and was associated with a reduction in the median number of RBC units transfused within transfused patients (p = 0.025). These effects persisted at day 30 after surgery (p = 0.029). CONCLUSION: A perioperative PBM program in adult patients undergoing cardiac surgery was associated with a significant reduction in perioperative RBC transfusion, which persisted at day 30.


Assuntos
Anemia , Procedimentos Cirúrgicos Cardíacos , Adulto , Humanos , Transfusão de Eritrócitos , Transfusão de Sangue , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Hospitais Universitários
6.
Phys Rev E ; 108(2-1): 024308, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37723718

RESUMO

Mechanistic network models specify the mechanisms by which networks grow and change, allowing researchers to investigate complex systems using both simulation and analytical techniques. Unfortunately, it is difficult to write likelihoods for instances of graphs generated with mechanistic models, and thus it is near impossible to estimate the parameters using maximum likelihood estimation. In this paper, we propose treating the node sequence in a growing network model as an additional parameter, or as a missing random variable, and maximizing over the resulting likelihood. We develop this framework in the context of a simple mechanistic network model, used to study gene duplication and divergence, and test a variety of algorithms for maximizing the likelihood in simulated graphs. We also run the best-performing algorithm on one human protein-protein interaction network and four nonhuman protein-protein interaction networks. Although we focus on a specific mechanistic network model, the proposed framework is more generally applicable to reversible models.


Assuntos
Algoritmos , Mapas de Interação de Proteínas , Humanos , Funções Verossimilhança , Simulação por Computador
7.
J Occup Environ Hyg ; 20(9): 414-425, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37267511

RESUMO

The impact of water consumption bolus volume and frequency on hydration biomarkers during work in the heat is unknown. In a randomized, crossover fashion, eight males consumed either 500 mL of water every 40 min or 237 mL of water every 20 min during 2 hr of continuous walking at 6.4 kph, 1.0% grade in a 34 °C/30% relative humidity environment, followed by 2 hr of rest. Hydration biomarkers and variables were assessed pre-work, post-work, and after the 2 hr recovery. There were no differences in body mass between trials at any time point (all p > 0.05). Percent change in plasma volume during work was not different when 237 mL of water was repeatedly consumed (-1.6 ± 8.2%) compared to 500 mL of water (-1.3 ± 3.0%, p = 0.92). Plasma osmolality was maintained over time (p = 0.55) with no difference between treatments (p = 0.21). When consuming 500 mL of water repeatedly, urine osmolality was lower at recovery (205 ± 108 mOsmo/L) compared to pre-work (589 ± 95 mOsmo/L, p < 0.01), different from repeatedly consuming 237 mL of water which maintained urine osmolality from pre-work (548 ± 144 mOsmo/L) through recovery (364 ± 261 mOsmo/L, p = 0.14). Free water clearance at recovery was greater with repeated consumption of 500 mL of water (1.2 ± 1.0 mL/min) compared to 237 mL of water (0.4 ± 0.8 mL/min, p = 0.02). Urine volume was not different between treatments post-work (p = 0.62), but greater after 2 hr of recovery when repeatedly consuming 500 mL of water compared to 237 mL (p = 0.01), leading to greater hydration efficiency upon recovery with repeated consumption of 237 mL of water (68 ± 12%) compared to 500 mL (63 ± 14%, p = 0.01). Thirst and total gastrointestinal symptom scores were not different between treatments at any time point (all p > 0.05). Body temperatures and heart rate were not different between treatments at any time point (all p > 0.05). Drinking larger, less frequent water boluses or drinking smaller, more frequent water boluses are both reasonable strategies to promote adequate hydration and limit changes in body mass in males completing heavy-intensity work in the heat.


Assuntos
Desidratação , Ingestão de Líquidos , Humanos , Masculino , Desidratação/prevenção & controle , Ingestão de Líquidos/fisiologia , Exercício Físico/fisiologia , National Institute for Occupational Safety and Health, U.S. , Concentração Osmolar , Estados Unidos , Água , Equilíbrio Hidroeletrolítico/fisiologia
8.
J Am Coll Health ; : 1-5, 2023 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-37093701

RESUMO

Objective: To examine providers' perceptions of integrated care prior to the merger of a university's student health center and counseling services. Participants: Seventeen providers across student health services (n = 9) and counseling (n = 8) agreed to participate in the qualitative study. Method: Semi-structured individual interviews that focused on the perceived benefits and challenges of the merger were conducted in December 2019. Following the interviews, a thematic analysis was completed. Results: The perceived benefits noted by providers centered on the ability of an interdisciplinary team to improve the coordination of, access to, and quality of care delivered to students. However, more anticipated challenges were reported by providers (e.g., differences in training and care protocols, losing one's autonomy as a provider). Conclusions: This qualitative study provides a more in-depth analysis of providers' perceptions of integrated care prior to implementation in a university setting and may have implications for model adoption.

9.
ACS Nano ; 17(7): 6943-6954, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-36972420

RESUMO

The solid electrolyte interphase (SEI) on a Si negative electrode in carbonate-based organic electrolytes shows intrinsically poor passivating behavior, giving rise to unsatisfactory calendar life of Li-ion batteries. Moreover, mechanical strains induced in the SEI due to large volume changes of Si during charge-discharge cycling could contribute to its mechanical instability and poor passivating behavior. This study elucidates the influence that static mechanical deformation of the SEI has on the rate of unwanted parasitic reactions at the Si/electrolyte interface as a function of electrode potential. The experimental approach involves the utilization of Si thin-film electrodes on substrates with disparate elastic moduli, which either permit or suppress the SEI deformation in response to Si volume changes upon charging-discharging. We find that static mechanical stretching and deformation of the SEI results in an increased parasitic electrolyte reduction current on Si. Furthermore, attenuated total reflection and near-field Fourier-transform infrared nanospectroscopy reveal that the static mechanical stretching and deformation of the SEI fosters a selective transport of linear carbonate solvent through, and nanoconfinement within, the SEI. These, in turn, promote selective solvent reduction and continuous electrolyte decomposition on Si electrodes, reducing the calendar life of Si anode-based Li-ion batteries. Finally, possible correlations between the structure and chemical composition of the SEI layer and its mechanical and chemical resilience under prolonged mechanical deformation are discussed in detail.

10.
ACS Appl Mater Interfaces ; 15(5): 6755-6767, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36696964

RESUMO

Si anodes for Li-ion batteries are notorious for their large volume expansion during lithiation and the corresponding detrimental effects on cycle life. However, calendar life is the primary roadblock for widespread adoption. During calendar life aging, the main origin of impedance increase and capacity fade is attributed to the instability of the solid electrolyte interphase (SEI). In this work, we use ex situ nano-Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy to characterize the structure and composition of the SEI layer on amorphous Si thin films after an accelerated calendar aging protocol. The characterization of the SEI on non-washed and washed electrodes shows that brief washing in dimethyl carbonate results in large changes to the film chemistry and topography. Detailed examination of the non-washed electrodes during the first lithiation and after an accelerated calendar aging protocol reveals that PF6- and its decomposition products tend to accumulate in the SEI due to the preferential transport of PF6- ions through polyethylene oxide-like species in the organic part of the SEI layer. This work demonstrates the importance of evaluating the SEI layer in its intrinsic, undisturbed form and new strategies to improve the passivation of the SEI layer are proposed.

11.
J Occup Environ Hyg ; 19(10-11): 596-602, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36083153

RESUMO

The National Institute for Occupational Safety and Health recommendations for work in the heat suggest workers consume 237 mL of water every 15-20 min and allow for continuous work at heavy intensities in hot environments up to 34 °C and 30% relative humidity. The goal was to determine whether the National Institute for Occupational Safety and Health recommendations prevented core temperature from exceeding 38.0 °C and greater than 2% body mass loss during heavy-intensity work in the heat. Eight males consumed 237 mL of water every 20 min during 2 hr of continuous heavy-intensity walking (6.4 kph, 1% grade) in a 34 °C/30% relative humidity environment, in accordance with the National Institute for Occupational Safety and Health recommendations. Projected core temperature and percent body mass loss were calculated for 4 and 8 hr of continuous work. Core temperature rose from baseline (36.8 ± 0.3 °C) to completion of 2 hr of work (38.1 ± 0.6 °C, p < 0.01), with two participants reaching the 38.0 °C threshold. Projected core temperatures remained elevated from baseline (p < 0.01), did not change from 2 to 4 hr (38.1 ± 0.7 °C, p > 0.99) and 4 to 8 hr (38.1 ± 0.8 °C, p > 0.99), respectively, and one participant exceeded 38.0 °C at 4 to 8 hr. There was no change in body mass loss over time (p > 0.99). During 2 hr of continuous heavy-intensity work in the heat, 75% of participants did not reach 38 °C core temperature and 88% did not reach 2% body mass loss when working to National Institute for Occupational Safety and Health recommendations.


Assuntos
Transtornos de Estresse por Calor , Hipertermia Induzida , Masculino , Estados Unidos , Humanos , Temperatura Alta , Transtornos de Estresse por Calor/prevenção & controle , National Institute for Occupational Safety and Health, U.S. , Água , Temperatura Corporal , Regulação da Temperatura Corporal
12.
Nat Commun ; 13(1): 1398, 2022 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-35301308

RESUMO

Solid-state batteries possess the potential to significantly impact energy storage industries by enabling diverse benefits, such as increased safety and energy density. However, challenges persist with physicochemical properties and processes at electrode/electrolyte interfaces. Thus, there is great need to characterize such interfaces in situ, and unveil scientific understanding that catalyzes engineering solutions. To address this, we conduct multiscale in situ microscopies (optical, atomic force, and infrared near-field) and Fourier transform infrared spectroscopies (near-field nanospectroscopy and attenuated total reflection) of intact and electrochemically operational graphene/solid polymer electrolyte interfaces. We find nanoscale structural and chemical heterogeneities intrinsic to the solid polymer electrolyte initiate a cascade of additional interfacial nanoscale heterogeneities during Li plating and stripping; including Li-ion conductivity, electrolyte decomposition, and interphase formation. Moreover, our methodology to nondestructively characterize buried interfaces and interphases in their native environment with nanoscale resolution is readily adaptable to a number of other electrochemical systems and battery chemistries.

13.
J Neuroradiol ; 49(2): 198-204, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34800563

RESUMO

BACKGROUND & PURPOSE: Perfusion collateral index (PCI) has been recently defined as a promising measure of collateral status. We sought to compare collateral status assessed via CT-PCI in comparison to single-phase CTA and their relationship to outcome measures including final infarction volume, final recanalization status and functional outcome in ELVO patients. METHODS: ELVO patients with anterior circulation large vessel occlusion who had baseline CTA and CT perfusion and underwent endovascular treatment were included. Collateral status was assessed on CTA. PCI from CT perfusion was calculated in each patient and an optimal threshold to separate good vs insufficient collaterals was identified using DSA as reference. The collateral status determined by CTA and PCI were assessed against 3 measured outcomes: 1) final infarction volume; 2) final recanalization status defined by TICI scores; 3) functional outcome measured by 90-day mRS. RESULTS: A total of 53 patients met inclusion criteria. Excellent recanalization defined by TICI ≥2C was achieved in 36 (68%) patients and 23 patients (43%) had good functional outcome (mRS ≤2). While having good collaterals on both CTA and CTP-PCI was associated with significantly (p<0.05) smaller final infarction volume, only good collaterals status determined by CTP-PCI was associated with achieving excellent recanalization (p = 0.001) and good functional outcome (p = 0.003). CONCLUSION: CTP-based PCI outperforms CTA collateral scores in determination of excellent recanalization and good functional outcome and may be a promising imaging marker of collateral status in patients with delayed presentation of AIS.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/terapia , Angiografia Cerebral/métodos , Circulação Colateral , Angiografia por Tomografia Computadorizada , Humanos , Perfusão , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
14.
Nano Lett ; 19(8): 5388-5393, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31306028

RESUMO

We present a new methodology that enables studies of the molecular structure of graphene-liquid interfaces with nanoscale spatial resolution. It is based on Fourier transform infrared nanospectroscopy (nano-FTIR), where the infrared (IR) field is plasmonically enhanced near the tip apex of an atomic force microscope (AFM). The graphene seals a liquid electrolyte reservoir while acting also as a working electrode. The photon transparency of graphene enables IR spectroscopy studies of its interface with liquids, including water, propylene carbonate, and aqueous ammonium sulfate electrolyte solutions. We illustrate the method by comparing IR spectra obtained by nano-FTIR and attenuated total reflection (which has a detection depth of a few microns) demonstrating that the nano-FTIR method makes it possible to determine changes in speciation and ion concentration in the electric double and diffuse layers as a function of bias.

15.
Sci Adv ; 4(6): eaas8927, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29888327

RESUMO

Energy storage science calls for techniques to elucidate ion transport over a range of conditions and scales. We introduce a new technique, pascalammetry, in which stress is applied to a solid-state electrochemical device and induced faradaic current transients are measured and analyzed. Stress-step pascalammetry measurements are performed on operando microbattery probes (Li2O/Li/W) and Si cathodes, revealing stress-assisted Li+ diffusion. We show how non-Cottrellian lithium diffusional kinetics indicates stress, a prelude to battery degradation. An analytical solution to a diffusion/activation equation describes this stress signature, with spatiotemporal characteristics distinct from Cottrell's classic solution for unstressed systems. These findings create an unprecedented opportunity for quantitative detection of stress in solid-state batteries through the current signature. Generally, pascalammetry offers a powerful new approach to study stress-related phenomena in any solid-state electrochemical system.

16.
IEEE Trans Vis Comput Graph ; 24(1): 267-277, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28866577

RESUMO

As Visual Analytics (VA) research grows and diversifies to encompass new systems, techniques, and use contexts, gaining a holistic view of analytic practices is becoming ever more challenging. However, such a view is essential for researchers and practitioners seeking to develop systems for broad audiences that span multiple domains. In this paper, we interpret VA research through the lens of Activity Theory (AT)-a framework for modelling human activities that has been influential in the field of Human-Computer Interaction. We first provide an overview of Activity Theory, showing its potential for thinking beyond tasks, representations, and interactions to the broader systems of activity in which interactive tools are embedded and used. Next, we describe how Activity Theory can be used as an organizing framework in the construction of activity typologies, building and expanding upon the tradition of abstract task taxonomies in the field of Information Visualization. We then apply the resulting process to create an activity typology for Visual Analytics, synthesizing a wide range of systems and activity concepts from the literature. Finally, we use this typology as the foundation of an activity-centered design process, highlighting both tensions and opportunities in the design space of VA systems.

17.
J Undergrad Neurosci Educ ; 17(1): A72-A80, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30618503

RESUMO

Presented is a lab exercise designed to augment an upper-level undergraduate class covering the topics of psychopharmacology, biopsychology, physiological psychology, or introductory neuroscience. The exercise was developed as a tool to allow students to investigate behavioral correlates of oral psychomotor stimulant ingestion and observe firsthand the benefits and challenges of using animal models to study behavior. The purpose of the exercise was to observe the unconditioned, natural behaviors of laboratory rats prior to, and following, the oral administration of commonly used, over-the-counter psychomotor stimulants, and for students to experience the process of neuroscience research. Of specific interest was the comparison of behaviors demonstrated by the animals following ingestion of the nonprescription stimulants caffeine and pseudoephedrine. Students went through the steps of a research project by actively participating in all aspects of experimental design, including construction of testing apparatus, animal care, drug measurement and dosage, data collection, and analyzing behavioral data to determine animal response to psychomotor stimulant exposure. Through repetition of treatment conditions separated by a clearance phase, students observed experiment replication and learned about a research design commonly applied in animal research. Successful replication of treatment effects also served to exemplify the concepts of reliability and validity in behavioral research, while observable responses in animal models provided students with the opportunity to extrapolate important considerations for differential behavioral effects of psychostimulant consumption in humans.

18.
J Psychiatr Res ; 83: 54-60, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27566139

RESUMO

Our objective was to examine symptom-level changes in the course in posttraumatic stress disorder (PTSD) across the deployment cycle among combat-exposed Marines, and to determine the degree to which combat exposure and post-deployment stressor exposure predicted PTSD symptom profile transitions. We examined PTSD symptoms in a cohort of U.S. Marines (N = 892) recruited for the Marine Resiliency Study (MRS). Marines deployed as one battalion infantry unit to Afghanistan in 2010 and were assessed pre-deployment and one, five, and eight months post-deployment. We employed latent transition analysis (LTA) to examine Marines' movement across PTSD symptom profiles, determined by latent class analysis (LCA). LCAs revealed a 3-class solution one month pre-deployment, a 4-class solution at five months post-deployment, and a 3-class solution at eight months post-deployment. LTA revealed notable movement between classes over time, which depended chiefly on pre-deployment symptom presentation. Marines who reported few pre-deployment symptoms either maintained these low levels or returned to low levels by eight months. Marines who reported a moderate number of symptoms at pre-deployment had variable outcomes; 50% had reductions by eight months, and those who reported numbing symptoms at five months post-deployment tended to report more symptoms at eight months. Marines who reported more PTSD symptoms prior to deployment retained more symptoms eight months post-deployment. Combat exposure and post-deployment stressor exposure predicted profile transitions. Examining transitions between latent class membership over time revealed prognostic information about Marines' eight-month PTSD outcomes. The extent of pre-deployment PTSD symptoms was particularly informative of likely PTSD outcomes.


Assuntos
Militares/psicologia , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/psicologia , Avaliação de Sintomas , Adolescente , Adulto , Campanha Afegã de 2001- , Estudos de Coortes , Humanos , Guerra do Iraque 2003-2011 , Masculino , Fatores de Risco , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Fatores de Tempo , Adulto Jovem
19.
Psychol Trauma ; 8(2): 127-34, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26914679

RESUMO

OBJECTIVE: There has been significant debate about the optimal factor structure of posttraumatic stress disorder (PTSD). In military and veteran samples, most available studies have employed self-report measures, assessed PTSD cross-sectionally, used treatment-seeking samples, and assessed symptoms years after deployment. We extend previous studies by comparing the factor structure of clinician-assessed and self-report Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) PTSD in a nontreatment seeking sample at 4 time points spanning the deployment cycle. METHOD: The data source for this study was the Marine Resiliency Study (MRS), a longitudinal study of 4 battalion cohorts of active-duty male Marines deployed to Iraq and Afghanistan between 2008 and 2012. We examined the fourth cohort (N = 892), which was evaluated 1 month predeployment, and 1, 5, and 8 months postdeployment. RESULTS: Confirmatory factor analyses (CFA) revealed that the 5-factor solution best fit the data across all time points, and across both interview and self-report assessments. CONCLUSION: The temporal consistency and convergence demonstrated by our analyses underscores the validity of the 5-factor model among service members exposed to warzone stressors. In particular, the findings suggest that diagnostic criteria for PTSD may benefit from disaggregating hyperarousal symptoms in military samples.


Assuntos
Militares/psicologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Exposição à Guerra/efeitos adversos , Adolescente , Adulto , Campanha Afegã de 2001- , Análise Fatorial , Humanos , Entrevista Psicológica , Guerra do Iraque 2003-2011 , Estudos Longitudinais , Masculino , Modelos Psicológicos , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/etiologia , Fatores de Tempo , Adulto Jovem
20.
Small ; 11(37): 4946-58, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-26182911

RESUMO

A carbon-nanotube-enabling scanning probe technique/nanotechnology for manipulating and measuring lithium at the nano/mesoscale is introduced. Scanning Li-nanopipette and probe microscopy (SLi-NPM) is based on a conductive atomic force microscope (AFM) cantilever with an open-ended multi-walled carbon nanotube (MWCNT) affixed to its apex. SLi-NPM operation is demonstrated with a model system consisting of a Li thin film on a Si(111) substrate. By control of bias, separation distance, and contact time, attograms of Li can be controllably pipetted to or from the MWCNT tip. Patterned surface Li features are then directly probed via noncontact AFM measurements with the MWCNT tip. The subsequent decay of Li features is simulated with a mesoscale continuum model, developed here. The Li surface diffusion coefficient for a four (two) Li layer thick film is measured as D=8(±1.2)×10(-15) cm(2) s(-1) (D=1.75(±0.15)×10(-15) cm(2) s(-1)). Dual-Li pipetting/measuring with SLi-NPM enables a broad range of time-dependent Li and nanoelectrode characterization studies of fundamental importance to energy-storage research.

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