Author
Jeffrey J. Richards
Other affiliations: University of Kentucky, National Institute of Standards and Technology, United States Naval Research Laboratory ...read more
Bio: Jeffrey J. Richards is an academic researcher from Northwestern University. The author has contributed to research in topics: Small-angle neutron scattering & Neutron scattering. The author has an hindex of 13, co-authored 25 publications receiving 721 citations. Previous affiliations of Jeffrey J. Richards include University of Kentucky & National Institute of Standards and Technology.
Papers
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TL;DR: A mixed anxiety-depression category be included in the DSM-IV appendix for proposed diagnostic categories that need further study and a criteria set is proposed.
Abstract: Objective This field trial was designed to answer four questions. First, are patients presenting with anxious or depressed symptoms that are associated with significant impairment but do not meet DSM-III-R definitional thresholds for axis I anxiety or mood disorders? Second, is the impairment experienced by these patients simply the consequence of the severity of their medical conditions? Third, what percent of these patients present with depressive symptoms only, anxious symptoms only, and a mixture of both? Fourth, how should the operational criteria for the syndrome(s) presented by these patients be defined? Method A total of 666 patients from five primary care medical sites and two outpatient mental health sites were administered a semistructured psychiatric interview. Results Patients presenting with affective symptoms that did not meet definitional thresholds for DSM-III-R axis I disorders were at least as common as patients with several of the already established anxiety and mood disorders in each of the seven sites, and their disorders were associated with significant distress or impairment. A nonspecific pattern of anxious and depressed symptoms was the modal presentation among these patients with currently subdefinitional threshold disorders, and they could be significantly differentiated in terms of current symptoms from patients presenting with a principal diagnosis of generalized anxiety disorder, major depressive episode, or panic disorder with agoraphobia. Conclusions The authors recommend that a mixed anxiety-depression category be included in the DSM-IV appendix for proposed diagnostic categories that need further study. A criteria set is proposed.
206 citations
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TL;DR: A simple sheath flow microfluidic device is used to fabricate polymer micro/nanofibers that have precisely controlled shapes and sizes.
Abstract: A simple sheath flow microfluidic device is used to fabricate polymer micro/nanofibers that have precisely controlled shapes and sizes. Poly(methylmethacrylate) (PMMA) was used as the model polymer for these experiments. The sheath-flow device uses straight diagonal and chevron-shaped grooves integrated in the top and bottom walls of the flow channel to move sheath fluid completely around the polymer stream. Portions of the sheath stream are deflected in such a way as to define the cross-sectional shape of the polymer core. The flow-rate ratio between the sheath and core solution determines the fiber diameter. Round PMMA fibers with a diameter as small as 300 nm and flattened fibers with a submicron thickness are demonstrated.
83 citations
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TL;DR: In this paper, the morphological effects of the incorporation of C60 into blended thin-films of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) are investigated.
Abstract: The morphological effects of the incorporation of C60 into blended thin-films of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) are investigated. The results show that addition of C60 readily alters the growth-rate and morphology of PCBM crystallites under different environmental conditions. The effect of C60 on the growth of large PCBM crystallites is thoroughly characterized using optical microscopy, electron microscopy and UV-visible absorption spectroscopy. Results show that C60 incorporation modifies fullerene aggregation and crystallization and greatly reduces the average crystallite size at C60 loadings of ≈50 wt% in the fullerene phase. Organic field-effect transistors (OFETs) are prepared to evaluate the electron mobility of PCBM/C60 films and organic solar cells (OSCs) are fabricated from mixed-fullerene active layers to evaluate their performance. It is demonstrated that the use of fullerene mixtures in organic electronic applications is a viable approach to produce more stable devices and to control the growth of micrometer-sized fullerene crystals.
70 citations
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TL;DR: The comparable rates of symptomatic distress, functional impairment, and prior psychiatric illness and treatment suggest that patients with subsyndromal anxiety and depressive symptoms warrant clinical recognition and possibly specific treatment.
Abstract: Objective: To determine in primary care settings the prevalence, clinical characteristics, and functional status of patients who have anxious and depressive symptoms who did not meet diagnostic criteria for major mood and anxiety diagnoses.
69 citations
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TL;DR: From quiescent mechanical and structural studies, it is found that the gelation of these carbon black suspensions is best described by the dynamic arrest of a clustered fluid phase, and the temperature and frequency dependence of the ac conductivity near this transition shows that mesoscale charge transport is determined by hopping between localized states that does not require a stress-bearing network.
Abstract: High-structured carbon fillers are ubiquitous as the conductive additive comprising suspension-based electrochemical energy storage technologies. Carbon black networks provide the necessary electrical conductivity as well as mechanical percolation in the form of a yield stress. Despite their critical role in determining system performance, a full mechanistic understanding of the relationship between the electrical transport characteristics of the percolated, conductive networks of carbon black, and the rheological properties is lacking, which hinders the rational design and optimization of flowable electrodes and the processing of electrolytes for batteries. Here, we report on the microstructural origin of the rheological and electrical properties of two commonly used conductive additives in neat propylene carbonate. From quiescent mechanical and structural studies, we find that the gelation of these carbon black suspensions is best described by the dynamic arrest of a clustered fluid phase. In contrast, the temperature and frequency dependence of the ac conductivity near this transition shows that mesoscale charge transport is determined by hopping between localized states that does not require a stress-bearing network. This unique combination of microstructural characterization with rheological and electrical measurements enables testing prevailing theories of the connection between electrical and mechanical percolation as well as improving conductive additives to enhance electrochemical performance.
58 citations
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TL;DR: The psychometric properties of the Depression Anxiety Stress Scales were evaluated in two studies using large clinical samples and indicated that the DASS distinguished various anxiety and mood disorder groups in the predicted direction.
1,629 citations
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1,446 citations
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TL;DR: The existing structural evidence establishes that the mood and anxiety disorders should be collapsed together into an overarching class of emotional disorders, which can be decomposed into 3 subclasses.
Abstract: The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994) groups disorders into diagnostic classes on the basis of the subjective criterion of "shared phenomenological features." There are now sufficient data to eliminate this rational system and replace it with an empirically based structure that reflects the actual similarities among disorders. The existing structural evidence establishes that the mood and anxiety disorders should be collapsed together into an overarching class of emotional disorders, which can be decomposed into 3 subclasses: the bipolar disorders (bipolar I, bipolar II, cyclothymia), the distress disorders (major depression, dysthymic disorder, generalized anxiety disorder, posttraumatic stress disorder), and the fear disorders (panic disorder, agoraphobia, social phobia, specific phobia). The optimal placement of other syndromes (e.g., obsessive-compulsive disorder) needs to be clarified in future research.
1,288 citations
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TL;DR: The international prevalence of anxiety disorders varies greatly between published epidemiologic reports, and several factors were found to be associated with heterogeneity among rates, including diagnostic criteria, diagnostic instrument, sample size, country studied, and response rate.
Abstract: Objective To present the results of a systematic review of literature published between 1980 and 2004 reporting findings of the prevalence and incidence of anxiety disorders in the general population. Method A literature search of epidemiologic studies of anxiety disorders was conducted, using Medline and HealthSTAR databases, canvassing English-language publications. Eligible publications were restricted to studies that examined age ranges covering the adult population. A set of predetermined inclusion and exclusion criteria were used to identify relevant studies. Prevalence and incidence data were extracted and analyzed for heterogeneity. Results A total of 41 prevalence and 5 incidence studies met eligibility criteria. We found heterogeneity across 1-year and lifetime prevalence rates of all anxiety disorder categories. Pooled 1-year and lifetime prevalence rates for total anxiety disorders were 10.6% and 16.6%. Pooled rates for individual disorders varied widely. Women had generally higher prevalence rates across all anxiety disorder categories, compared with men, but the magnitude of this difference varied. Conclusion The international prevalence of anxiety disorders varies greatly between published epidemiologic reports. The variability associated with all anxiety disorders is considerably smaller than the variability associated with individual disorders. Women report higher rates of anxiety disorders than men. Several factors were found to be associated with heterogeneity among rates, including diagnostic criteria, diagnostic instrument, sample size, country studied, and response rate.
1,060 citations
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TL;DR: The article reviews the current understanding of the physical mechanisms that determine the (opto)electronic properties of high-performance organic materials and highlights the capabilities of various experimental techniques for characterization, summarizes top-of-the-line device performance, and outlines recent trends in the further development of the field.
Abstract: Organic (opto)electronic materials have received considerable attention due to their applications in thin-film-transistors, light-emitting diodes, solar cells, sensors, photorefractive devices, and many others. The technological promises include low cost of these materials and the possibility of their room-temperature deposition from solution on large-area and/or flexible substrates. The article reviews the current understanding of the physical mechanisms that determine the (opto)electronic properties of high-performance organic materials. The focus of the review is on photoinduced processes and on electronic properties important for optoelectronic applications relying on charge carrier photogeneration. Additionally, it highlights the capabilities of various experimental techniques for characterization of these materials, summarizes top-of-the-line device performance, and outlines recent trends in the further development of the field. The properties of materials based both on small molecules and on conjug...
995 citations