The neuro-enhancement Modafinil promises to dramatically increase users' waking hours without much sacrifice to clarity of thought and without serious side effects (inducing addiction). For Modafinil to be advantageous, its usage must enable access to goods that themselves improve the quality of one’s life. I draw attention to a variety of conditions that must be met for an experience, activity or object to improve the quality of one’s life, such as positional, relational, and saturation conditions, as well as it’s being good for its own sake. I discuss and describe the contexts in which widespread usage (legal or not) of Modafinil would undermine these conditions being met, and thus users would fail to significantly improve the quality of their lives and would in fact potentially make both themselves and nonusers worse off in important respects thus far overlooked by critics. In the right contexts, where free time is protected and prolonged, Modafinil does have a variety of potential benefits including, most interestingly, a distinctive form of agency possible only in free time. The potential disadvantages and advantages highlighted in this article are relevant not only to public institutions deciding whether to legalize Modafinil’s use as an enhancement but also to individuals deciding whether to use it illegally, as well as to the questions of how and whether to alter key features of one’s context (e.g. regulating work hours or extending social services) rather than, or in addition, to regulating the use of enhancement drugs such as Modafinil.
An approximate expression for Henry’s function, describing the electrophoretic mobility of a spherical colloidal particle in the limit of low surface potentials, is developed through a physical analogy to a colloidal particle with a linearly slipping surface (i.e. satisfies the Navier slip condition). The resulting expression reproduces Henry’s function with a relative error of no more than 0.1%. This approach is generalized for the electrophoretic mobility of a particle regardless of surface potential though necessary data for rigorous testing is lacking.
Comparison of Segmentation-Based Attenuation Correction Methods for PET/MRI: Evaluation of Bone and Liver Standardized Uptake Value with Oncologic PET/CT Data.
- Journal of nuclear medicine : official publication, Society of Nuclear Medicine
- Published about 5 years ago
For attenuation correction (AC) in PET/MRI systems, segmentation-based methods are most often used. However, the standardized uptake value (SUV) of lesions in the bone and liver, which have higher attenuation coefficients than other organs, can be underestimated, potentially leading to misinterpretation of clinical cases. Errors in SUV estimation are also dependent on the segmentation schemes used in the segmentation-based AC. In this study, this potential bias in SUV estimation using 4 different segmentation-based AC methods was evaluated for the PET/CT data of cancer patients with bone and liver lesions.
A series of ruthenium-polypyridyl complexes were studied using UV/vis absorption and luminescence spectroscopy as well as luminescence lifetime determination by time-correlated single photon counting (TCSPC). The complexes were characterized with regard to the variation in the electronic band gap as a result of the sequential variation of the auxiliary ligand 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), and 2,2'-biquinoline (biq) ligands while the main ligand remained constant for three different main ligand types. Luminescence yields were calculated and correlated with structural and electronic variation. It was found that both the absorption and emission characteristics could be tailored through the systematic variation of the reduction potential of the individual auxiliary ligand. This was shown to be the case regardless of the functional group at the end of the main ligand. Stokes shift and Raman spectroscopy were employed as a means to gauge the effect of ligand change on the conjugation and vibrational characteristics of the complexes. Luminescence yield and lifetimes were also shown to be well-defined with regards to systematic structure variations. The well-defined trends established elucidate the effect which variation of auxiliary ligands has on the electronic and excited state characteristics of the ruthenium-polypyridyl systems. These well-defined relationships can potentially be extended to optimize luminescence yield and lifetimes and therefore suitability of such compounds for the application in for example photodynamic therapy.
Adults of three age groups (18-27, 39-45, and 59-66 years) performed an auditory duration discrimination task with short (200ms) or long (400ms) sinusoidal tones. Performance was highly accurate and reaction times were on the same level in all groups, indicating no differences in auditory duration processing. Task irrelevant rare changes of the frequency of the stimuli were introduced to check whether the subjects, firstly, were distracted by changes in the environment while focusing on the task relevant information (indicated by prolonged responses), and, secondly, could re-focus on the relevant task after distraction. The results show that a distraction effect is present in all groups. Importantly, the 59-66 years group showed a behavioral distraction effect nearly twice as high as the other groups. The event-related brain potentials (ERPs) show mismatch negativity (MMN), P3a, and reorienting negativity (RON) elicited by deviants which are present in all groups. Aging effects on these ERP components were observable in all three components but a revealed a weak significant effect for the MMN only. Taken together, the behavioral and ERP results suggest that the function of balancing the processing of task irrelevant changes in the stimulation while focusing on task relevant information is effective during adulthood until the 7(th) decade of life.
Spontaneous EEG fluctuations determine the readiness potential: is preconscious brain activation a preparation process to move?
- Experimental brain research. Experimentelle Hirnforschung. Experimentation cerebrale
- Published about 4 years ago
It has been repeatedly shown that specific brain activity related to planning movement develops before the conscious intention to act. This empirical finding strongly challenges the notion of free will. Here, we demonstrate that in the Libet experiment, spontaneous fluctuations of the slow electro-cortical potentials (SCPs) account for a significant fraction of the readiness potential (RP). The individual potential shifts preceding self-initiated movements were classified as showing a negative or positive shift. The negative and positive potential shifts were analyzed in a self-initiated movement condition and in a no-movement condition. Comparing the potential shifts between both conditions, we observed no differences in the early part of the potential. This reveals that the apparently negative RP emerges through an unequal ratio of negative and positive potential shifts. These results suggest that ongoing negative shifts of the SCPs facilitate self-initiated movement but are not related to processes underlying preparation or decision to act.
Older adults have demonstrated an avoidance of negative information, presumably with a goal of greater emotional satisfaction. Understanding whether avoidance of negative information is a voluntary, motivated choice or an involuntary, automatic response will be important to differentiate, as decision making often involves emotional factors. With the use of an emotional framing event-related potential (ERP) paradigm, the present study investigated whether older adults could alter neural responses to negative stimuli through verbal reframing of evaluative response options. The late positive potential (LPP) response of 50 older adults and 50 younger adults was recorded while participants categorized emotional images in one of two framing conditions: positive (“more or less positive”) or negative (“more or less negative”). It was hypothesized that older adults would be able to overcome a presumed tendency to down-regulate neural responding to negative stimuli in the negative framing condition, thus leading to larger LPP wave amplitudes to negative images. A similar effect was predicted for younger adults, but for positively valenced images, such that LPP responses would be increased in the positive framing condition compared with the negative framing condition. Overall, younger adults' LPP wave amplitudes were modulated by framing condition, including a reduction in the negativity bias in the positive frame. Older adults' neural responses were not significantly modulated, even though task-related behavior supported the notion that older adults were able to successfully adopt the negative framing condition. (PsycINFO Database Record © 2013 APA, all rights reserved).
The identification of a patterned skin or scalp mark at autopsy can provide key forensic evidence in identifying an injury that may have been left by an assailant’s footwear. It is also important to consider whether such a mark could alternatively have been left by the deceased coming into forceful contact with a hard surface at the scene of an incident, for example by falling. This study was designed to demonstrate how variable surfaces are within paved urban areas, including those which might leave marks resembling footwear patterns, and to evaluate whether dental putty impression lifting is a practical and effective adjunct to photography in assessing patterned surfaces. Eighteen ‘scenes’ of approximately 50 m(2) were assessed for different hard surfaces by photography and by the production of dental putty impression lifts. The number of hard surfaces varied between 4 and 12 per scene, with 90% (122/135) of all hard surfaces deemed likely to leave distinct marking on skin with forceful contact and 46% (62/135) a defined/regular mark potentially similar to a footwear injury (mean = 3.4 per scene). Dental putty proved to be an excellent tool in characterising hard surfaces, producing firm but slightly flexible lifts that can be used in combination with a commercially available inkless footwear impression kit to generate transparencies that help facilitate detailed comparison work. Whenever a potential footwear mark is identified at autopsy, a systematic examination of all hard surfaces at the scene is mandatory, and this process will be significantly strengthened by the use of dental putty.
Pneumonectomy (PNX) in experimental animals leads to a species- and age-dependent compensatory growth of the remaining lung lobes. PNX mimics the loss of functional gas exchange units observed in a number of chronic destructive lung diseases. However, unlike in disease models, this tissue loss is well defined, reproducible and lacks accompanying inflammation. Furthermore, compensatory responses to the tissue loss can be easily quantified. This makes PNX a potentially useful model for the study of the cellular and molecular events which occur during realveolarisation. It may therefore help to get a better understanding of how manipulate these pathways, in order to promote the generation of new alveolar tissue as therapies for destructive lung diseases. This review will explore the insights that experimental PNX has provided into the physiological factors which promote compensatory lung growth as well as the importance of age and species in the rate and extent of compensation. In addition, more recent studies which are beginning to uncover the key cellular and molecular pathways involved in realveolarisation will be discussed. The potential relevance of experimental pneumonectomy to novel therapeutic strategies which aim to promote lung regeneration will also be highlighted.
Treatment for tobacco use is efficacious and beneficial to health. Although guidelines recommend that all patients who use tobacco are offered treatment as a part of their clinical care, implementing treatment has proven challenging. In the case of surgical patients, this lack of treatment is particularly unfortunate, as the benefits of abstinence from tobacco are immediate in terms of reducing the risk of surgical complications, including cardiovascular, respiratory, and wound related complications. Surgery also presents an opportunity for patients to quit for good and reduce the long term health risk. This review examines the principles of tobacco use treatment, the rationale for tobacco use treatment in the perioperative period, and how treatment can be incorporated into the routine care of surgical patients. The discipline of implementation science helps to frame these efforts by seeking to better understand how changes in clinical practice occur, and it has the potential to guide an evidence based approach to embedding tobacco treatment into the routine clinical care of surgical patients. This review uses the consolidated framework for implementation research, which includes five major domains, as a representative conceptual framework. A basic understanding of factors potentially important to successful implementation can help to guide clinicians who accept the challenge of implementing tobacco use treatment in surgical care.