Voids in Materials: Adding Functionality during Additive Manufacturing

An often overlooked implication of controlling materials at ever smaller length scales is the control of the inevitable void spaces contained in those materials and components. This miniaturization is widespread and at these small length scales, properties become size dependent, trending toward more ideal material properties. This is corroborated by the extensive selection dispersed phases such as nanotubes and nanometer-scale particles that are available. The technique of additive manufacturing is gaining enormous attention as it offers the ability to make multifunctional components that cannot be made by traditional processing routes. In additive manufacturing, more precise control of material placement presents a unique opportunity to build functionality by the simultaneous control of solid material and voids at multiple length scales. We present an overview of the functionality of voids from the atomic to the millimeter scale, highlighting the current research involving the introduction of voids in additive manufacturing and present future opportunities to incorporate voids by specific additive manufacturing techniques to add functionality

Coated glass microballoons and syntactic foams thereof for environmental cleanup

Titania is of great interest to water purification applications mainly because of its nontoxic nature and its photocatalytic properties. In the presence of ultraviolet (UV) radiation (with energy equal to or greater than its band gap (EG = 3.02 eV) which translates to a wavelength less than or equal to 400 nm) titania exhibits semiconducting properties and creates electron-hole pairs. These electrons and holes give rise to ions, particularly hydroxyl radicals and various superoxides that can be useful in cleaning up a range of organic compounds in their liquid and gaseous phases. We have developed titania coated glass microballoons (GMBs) with high surface area. These hollow GMBs are made of borosilicate glass, have a density of 0.39 g/cm3, and an average diameter of 47µm. The objective is to use syntactic foams made of titania coated GMBs for water purification. This materials system is of great interest because it has the potential of a practical material with broad implications for improving the quality and quantity of drinking water. In this work, we describe the processing by sol-gel of titania-coated glass microballoons (GMBs), followed by making a functional foam for environmental applications by sintering. We will highlight the processing of coated GMBs starting with titanium isopropoxide precursor, the microstructure of the coated GMBs, and some critical materials related issues in environmental cleanup applications

COMPARATIVE MUCOPENETRATION ABILITY OF METRONIDAZOLE LOADED CHITOSAN AND PEGYLATED CHITOSAN NANOPARTICLES

Objective: The objective of this study is to compare the mucopenetration ability of metronidazole loaded chitosan (CS) and pegylated CS nanoparticles.Methods: Nanoparticles were prepared by ionic gelation technique using negatively charged pH sensitive polymer, hydroxyl propyl methyl cellulose phthalate with positively charged CS and methoxy polyethylene glycol-grafted-CS (mPEG-g-CS). mPEG-g-CS was synthesized by formaldehyde linkage method and characterized by Fourier transform infrared spectroscopy. The optimized formulations were compared for morphology, particle size, polydispersity index (PDI), entrapment efficiency, bioadhesion detachment force, in vitro and in vivo mucopenetration for CS-mPEG-g-CS nanoparticles.Results: The morphological assessment revealed smooth spherical particles with uniform dispersions. The optimized formulations particle size was found to be 202.7±27 nm and 294.1±46 nm, zeta potential 26.94±2.4 mV and 6.0±1.3 mV. PDI 0.231 and 0.268, entrapment efficiency 79.8±5.4% and 83.6±9.7%, bio-adhesion detachment force 14.98*103 dyne/cm2 and 10.67*103 dynes/cm2, in vitro mucopenetration 78% and 98% for CS-mPEG-g-CS, respectively. The qualitative in vivo mucopenetration result confirms retention of fluorescein isothiocyanate (FITC) labeled mPEG-g-CS nanoparticles till 24 hrs.Conclusion: Nanoparticles with lesser zeta potential and mucoadhesion showed higher mucosal penetration which is evident from FITC labeled histopathological mucus penetration test. Studies thus provided evidence that planned pharmaceutical strategies open new vistas for effective treatment of mucosal infections

State-Selective Studies of T→R, V Energy Transfer: The H+CO System

Collisional energy transfer from H atoms to CO(v=0, J≈2) has been studied at a collision energy of 1.58±0.07 eV by photolyzing H2S at 222 nm in a nozzle expansion with CO and probing the CO(v , J ) levels using tunable VUV laser-induced fluorescence. The ratio CO(v =1)/CO(v =0) is found to be 0.1±0.008. The rotational distribution of CO(v =0) peaks at J gradually; population is still observed at J \u3e45. The rotational distribution of CO(v =1) is broad and peaks near J =20. The experimental results are compared to quasiclassical trajectory calculations performed both on the H+CO surface of Bowman, Bittman, and Harding (BBH) and on the surface of Murrell and Rodriguez (MR). The experimental rotational distributions, particularly those for CO(v =1), show that the BBH surface is a better model than the MR surface. The most significant difference between the two surfaces appears to be that for energetically accessible regions of configuration space the derivative of the potential with respect to the CO distance is appreciable only in the HCO valley for the BBH surface, but is large for all H atom approaches in the MR potential. Because the H-CO geometry is bent in this valley, vibrational excitation on the BBH surface is accompanied by appreciable rotational excitation, as observed experimentally

A matter of words: NLP for quality evaluation of Wikipedia medical articles

Automatic quality evaluation of Web information is a task with many fields of applications and of great relevance, especially in critical domains like the medical one. We move from the intuition that the quality of content of medical Web documents is affected by features related with the specific domain. First, the usage of a specific vocabulary (Domain Informativeness); then, the adoption of specific codes (like those used in the infoboxes of Wikipedia articles) and the type of document (e.g., historical and technical ones). In this paper, we propose to leverage specific domain features to improve the results of the evaluation of Wikipedia medical articles. In particular, we evaluate the articles adopting an "actionable" model, whose features are related to the content of the articles, so that the model can also directly suggest strategies for improving a given article quality. We rely on Natural Language Processing (NLP) and dictionaries-based techniques in order to extract the bio-medical concepts in a text. We prove the effectiveness of our approach by classifying the medical articles of the Wikipedia Medicine Portal, which have been previously manually labeled by the Wiki Project team. The results of our experiments confirm that, by considering domain-oriented features, it is possible to obtain sensible improvements with respect to existing solutions, mainly for those articles that other approaches have less correctly classified. Other than being interesting by their own, the results call for further research in the area of domain specific features suitable for Web data quality assessment

The physiological basis of attentional modulation in extrastriate visual areas,

Substantial experimental evidence from humans and non-human primates implicates the extrastriate visual area V5 (located in the posterior region of the inferior temporal gyrus and sulcus) in motion processing and area V4 (located in the fusiform gyrus) in color processing The above studies show attentional modulation of stimulusevoked responses. Fewer studies have explicitly investigated attentional modulation of baseline activity. Macaque studies explored baseline shifts in neuronal responses in the context of working memory 8 . They found that both baseline activity and activity evoked by a moving stimulus appear to change with expectation. Even when subjects view a blank screen, baseline activity in 32% of V5 cells doubles. Using direction of motion as the matching criterion, this study employed a delayed match to sample task. Modulation of delay period or baseline activity was not related to specific information in the cue (direction), suggesting that this effect may be modulated, in part, by attention. When interpreting our results in relation to these findings, we assume that baseline attentional modulation is mediated by the same sort of tonic discharge associated with delay period activity evoked by working memory tasks. Monkey electrophysiology also shows that attention can modulate both baseline and stimulus evoked activity in V4, depending on the relative locations of visual stimuli within the cell's receptive field Enhanced baseline activity is taken to reflect attentional 'set' or expectation, whereas changes in stimulus-evoked activity reflect changes in sensory processing 10 . However the functional significance of and relationship between changes in 'set' and changes in evoked activity is unknown. Because of the long periods of time over which hemodynamic signals are integrated, it has been difficult to unambiguously dissociate activity due to attentional set from stimulus-evoked responses in human functional neuroimaging studies 15 . Here, by using a novel event-related protocol and fMRI, we show such a dissociation in V5 and V4, relating attentional set and evoked activity in accord with C. ([email protected]) Selective attention to color or motion enhances activity in specialized areas of extrastriate cortex, but mechanisms of attentional modulation remain unclear. By dissociating modulation of visually evoked transient activity from the baseline for a particular attentional set, human functional neuroimaging was used to investigate the physiological basis of such effects. Baseline activity in motion-and color-sensitive areas of extrastriate cortex was enhanced by selective attention to these attributes, even without moving or colored stimuli. Further, visually evoked responses increased along with baseline activity. These results are consistent with the hypothesis that attention modulates sensitivity of neuronal populations to inputs by changing background activity. 'Correct' denotes events that the subject responded to correctly. 'Incorrect' denotes false-positive responses

Arranged marriages in people with epilepsy: A pilot knowledge, attitudes and practices survey from India

Introduction: Marriage is a socially challenging barrier in the personal lives of people with epilepsy worldwide. However, it is during arranges marriages, which are common in South Asian communities, that epilepsy is most profoundly stigmatizing. We hypothesized that the felt stigma associated with epilepsy during arranged marriages affects women more frequently and intensely. // Materials and methods: A pilot study in married (n = 38) and unmarried PWE (n = 58) and general public (n = 150) to explore gender-based differences in the stigma associated with epilepsy during arranged marriages. // Results: Majority unmarried PWE (87%) considered arranged marriage as the best way to realize their matrimonial plans. More unmarried women (72%) apprehended problems in adhering to their epilepsy medications regime after marriage (p 0.009) and 50% apprehended victimization in marriage on account of epilepsy (p 0.001). Moreover, 41% of the married women with epilepsy felt that the disclosure had a negative impact on their married life (p 0.047). // Conclusions: South Asian WWE experienced more felt stigma than men before and after arranged marriages and this might impact a number of health related psychosocial outcomes. The lack of past experience with epilepsy was associated with a number of misplaced beliefs about and attitudes towards epilepsy

Horizon effects with surface waves on moving water

Surface waves on a stationary flow of water are considered, in a linear model that includes the surface tension of the fluid. The resulting gravity-capillary waves experience a rich array of horizon effects when propagating against the flow. In some cases three horizons (points where the group velocity of the wave reverses) exist for waves with a single laboratory frequency. Some of these effects are familiar in fluid mechanics under the name of wave blocking, but other aspects, in particular waves with negative co-moving frequency and the Hawking effect, were overlooked until surface waves were investigated as examples of analogue gravity [Sch\"utzhold R and Unruh W G 2002 Phys. Rev. D 66 044019]. A comprehensive presentation of the various horizon effects for gravity-capillary waves is given, with emphasis on the deep water/short wavelength case kh>>1 where many analytical results can be derived. A similarity of the state space of the waves to that of a thermodynamic system is pointed out.Comment: 30 pages, 15 figures. Minor change

The prediction of fatigue using speech as a biosignal

Automatic systems for estimating operator fatigue have application in safety-critical environments. We develop and evaluate a system to detect fatigue from speech recordings collected from speakers kept awake over a 60-hour period. A binary classification system (fatigued/not-fatigued) based on time spent awake showed good discrimination, with 80 % unweighted accuracy using raw features, and 90 % with speaker-normalized features. We describe the data collection, feature analysis, machine learning and cross-validation used in the study. Results are promising for real-world applications in domains such as aerospace, transportation and mining where operators are in regular verbal communication as part of their normal working activities