Exploring the interior of 3D endoluminal lesions in the air spaces by a novel electronic biopsy technique: A preliminary study of endoluminal colon lesions.

To explore the interior of a lesion in a 3D endoluminal view, this study investigates the application of an 'electronic biopsy' (EB) technique to computed tomographic colonography (CTC) for further differentiation and 2D image correlation of endoluminal lesions in the air spaces. A retrospective study of sixty-two various endoluminal lesions from thirty patients (13 males, 17 females; age range, 31 to 90 years) was approved by our institutional review board and evaluated. The endoluminal lesions were segmented using gray-level threshold and reconstructed into isosurfaces using a marching cube algorithm. EB allows users to interactively erode and apply grey-level mapping (GM) to the surface of the region of interest (ROI) in 3D CTC. Radiologists conducted the clinical evaluation, and the resulting data were analyzed. EB significantly improves 3D gray-level presentation for evaluating the surface and inside of endoluminal lesions over that of SR, GM or target GM (TGM) (P < 0.01) with preservation of the 3D spatial effect. Moreover, 3D to 2D image correlation were achieved in any layer of the lesion using EB as did GM/TGM on the surface. The specificity and diagnostic accuracy of EB are significantly greater than those of SR (P < 0.01). These performance can be better further with GM/TGM and reach the best with EB (specificity, 89.3-92.9%; accuracy, 95.2-96.8%). EB can be used in CTC to improve the differentiation of endoluminal lesions. EB increases 3D to 2D image correlations of the lesions on or beneath the lesion surface.

Surface energy and surface stability of cesium tin halide perovskites: a theoretical investigation.

Lead halide perovskites have been widely studied in the fields of photovoltaics and optoelectronics for over a decade. The toxicity of lead poses a big challenge to the potential applications of the materials. In recent years, lead-free halide perovskites have received significant attention due to their excellent optoelectronic properties and environment-friendly character. Tin halide perovskites have emerged as one of the most promising candidates for lead-free optoelectronic materials. It is of fundamental importance to understand the surface properties of tin halide perovskites that remain largely unknown. Using the density functional theory (DFT) method, we explore the surface energy and surface stability of low-index surfaces of cubic CsSnX3 (X = Cl, Br, I), i.e., (100), (110), and (111) surfaces. We calculate the stability phase diagrams of these surfaces and find that the (100) surface is more stable than the (110) and (111) surfaces. Interestingly, Br2-terminated (110) and CsBr3-terminated (111) polar surfaces are relatively more stable in CsSnBr3 than those in CsPbBr3 due to a higher level of valence band maximum and thus lesser energy cost in removing electrons to compensate for the polarity of the former. We calculate the surface energies of CsSnX3 surfaces that are difficult to access from experiments. The surface energies are very low in comparison with that of oxide perovskites. The origin of this lies in the relatively low binding strength of halide perovskites because of the soft nature of their structures. Furthermore, the connection between exfoliation energy and the cleavage energy in CsSnX3 is discussed.

Analysis of Heart Rate Variability in Response to Serious Games in Elderly People.

As the proportion of elderly people continues to grow, so does the concern about age-related cognitive decline. Serious games have been developed for cognitive training or treatment, but measuring the activity of the autonomic nervous system (ANS) has not been taken to account. However, cognitive functioning has been known to be heavily influenced by the autonomic nervous system (ANS), and ANS activity can be quantified using heart rate variability (HRV). This paper aims to analyze the physiological response in normal elderly people as they play two types of serious games using HRV features from electrocardiography (ECG). A wearable device designed in-house was used to measure ECG, and the data from this device was pre-processed using digital signal processing techniques. Ten HRV features were extracted, including time-domain, nonlinear, and frequency-domain features. The experiment proceeds as follows: rest for three minutes, play a cognitive aptitude game, rest for another three minutes, followed by two reaction time games. Data from thirty older adults (age: 65.9 ± 7.34; male: 15, female: 15) were analyzed. The statistical results show that there was a significant difference in the HRV between the two types of games. From this, it can be concluded that the type of game has a significant effect on the ANS response. This can be further used in designing games for the elderly, either for training or mood management.

fMRI Investigation of Semantic Lexical Processing in Healthy Control and Alzheimer's Disease Subjects Using Naming Task: A Preliminary Study.

For decades, scientists have been trying to solve the problem of dementia, with no cure currently available. Semantic-lexical impairment is well established as the early critical sign of dementia, although there are still gaps in knowledge that must be investigated. In this study, we used fMRI to observe the neural activity of 31 subjects, including 16 HC (Healthy Control) and 15 AD (Alzheimer's Disease), who participated in the naming task. The neuropsychology profile of HC (Healthy Control) and AD (Alzheimer's Disease) are discussed in this study. The involvement of FG (Fusiform Gyrus) and IFG (Inferior Frontal Gyrus) shows dominant activation in both of the groups. We observed a decrease in neural activity in the AD group, resulting in semantic deficit problems in this preliminary study. Furthermore, ROI analysis was performed and revealed both hyperactivation and hypoactivation in the AD group. The compensatory mechanism demonstrated during the task, due to the effort required to identify an animal's name, represents the character profile of AD.

Energetic and electronic properties of CsPbBr3 surfaces: a first-principles study.

Surface properties of all-inorganic halide perovskites play a crucial role in determining optoelectronic performance of these materials. We investigate the surface energies and electronic structures of cubic CsPbBr3 surfaces systematically using density functional theory (DFT) methods. We calculate the surface phase diagrams of low-index surfaces of CsPbBr3, i.e., (100), (110), (111) surfaces. We found that nonpolar (100) surfaces are more stable than polar (110) and (111) surfaces. The nonpolar CsBr-terminated (100) surface shows the best stability, which is attributed to the effect of surface relaxation and high ionicity of the surface layer. The electronic structures reveal that charge transfer to compensate the polarity raises the energy of polar surfaces, which makes polar surfaces unstable. Furthermore, we found that the modulation of surface chemical composition provides an effective way to compensate polarity and thus make polar surfaces of CsPbBr3 stable. Our results provide physical insights into understanding and further enhancing the surface stability of all-inorganic halide perovskites. This would be helpful in promoting the advancement of all-inorganic halide perovskite-based materials and devices.

Improving Image Correlation and Differentiation of 3D Endoluminal Lesions in the Air Spaces Using a Novel Target Gray Level Mapping Technique: A Preliminary Study of Its Application to Computed Tomographic Colonography and Comparison with Traditional Surface Rendering Method.

Purpose: To improve the three dimensional (3D) and two dimensional (2D) image correlation and differentiation of 3D endoluminal lesions in the traditional surface rendering (SR) computed tomographic endoscopy (CTE), a target gray level mapping (TGM) technique is developed and applied to computed tomographic colonography (CTC) in this study. Methods: A study of sixty-two various endoluminal lesions from thirty patients (13 males, 17 females; age range 31-90 years) was approved by our institutional review board and evaluated retrospectively. The endoluminal lesions were segmented using gray level threshold. The marching cubes algorithm was used to detect isosurfaces in the segmented volumetric data sets. TGM allows users to interactively apply grey level mapping (GM) to region of interest (ROI) in the 3D CTC. Radiologists conducted the clinical evaluation and the resulting data were analyzed. Results: TGM and GM are significantly superior to SR in terms of surface texture, 3D shape, the confidence of 3D to 2D, 2D to 3D image correlation, and clinical classification of endoluminal lesions (P < 0.01). The specificity and diagnostic accuracy of GM and TGM methods are significantly better than those of SR (P < 0.01). Moreover, TGM performs better than GM (specificity: 75.0-85.7% vs. 53.6-64.3%; accuracy: 88.7-93.5% vs. 77.4-83.9%). TGM is a preferable display mode for further localization and differentiation of a lesion in CTC navigation. Conclusions: Compared with only the spatial shape information in traditional SR of CTC images, the 3D shapes and gray level information of endoluminal lesions can be provided by TGM simultaneously. 3D to 2D image correlations are also increased and facilitated at the same time. TGM is less affected by adjacent colon surfaces than GM. TGM serves as a better way to improve the image correlation and differentiation of endoluminal lesions.

Stability of pyridine-like and pyridinium-like nitrogen in graphene.

Identification of N configurations in N-doped graphene is important to improve its functionalities. In most experiments, graphite-like, pyridine-like, and pyrrole-like N was usually chosen to assign the spectral features of N-doped graphene. Based on the first-principles simulations, we find that since one of nitrogen's electrons occupies the LUMO state, stability of pyridinium-like N (pyridine-like N with hydrogen termination) in multi-benzenes systems increases with the HOMO-LUMO gap decreasing. Therefore, unlike benzene with a large HOMO-LUMO gap, pyridinium-like N is a stable configuration in graphene with zero band gap, and the pyridinium-like N should be considered during the assignments of N configurations even under the environments with higher temperatures and lower hydrogen partial pressure than ambient conditions.

Noble gas bond and the behaviour of XeO3 under pressure.

Over the past few decades, the concept of hydrogen bonds, in which hydrogen is electrophilic, has been extended to halogen bonds, chalcogen bonds and pnicogen bonds. Herein, we show that such a non-covalent bonding also exists in noble gas compounds. Using first principles calculations, we illustrate the OXe-O bond in molecular crystal XeO3 and its effect on the behavior of this compound under pressure. Our calculations show that the covalent Xe-O bond lengths were elongated with increasing pressure and correspondingly the Xe-O stretching vibration frequencies were red shifted, which is similar to the change of H-bonds under pressure. The OXe-O bond and related hopping of O between neighboring Xe sites also correspond to the structural changes in the XeO3 compounds at about 2 GPa. Our study extends the concept of hydrogen bonding to include all p-block elements and show a new bonding type for Noble gas elements in which it acts as an electrophilic species.

Application of gray level mapping in computed tomographic colonography: a pilot study to compare with traditional surface rendering method for identification and differentiation of endoluminal lesions.

OBJECTIVE: In traditional surface rendering (SR) computed tomographic endoscopy, only the shape of endoluminal lesion is depicted without gray-level information unless the volume rendering technique is used. However, volume rendering technique is relatively slow and complex in terms of computation time and parameter setting. We use computed tomographic colonography (CTC) images as examples and report a new visualization technique by three-dimensional gray level mapping (GM) to better identify and differentiate endoluminal lesions. METHODS: There are 33 various endoluminal cases from 30 patients evaluated in this clinical study. These cases were segmented using gray-level threshold. The marching cube algorithm was used to detect isosurfaces in volumetric data sets. GM is applied using the surface gray level of CTC. Radiologists conducted the clinical evaluation of the SR and GM images. The Wilcoxon signed-rank test was used for data analysis. RESULTS: Clinical evaluation confirms GM is significantly superior to SR in terms of gray-level pattern and spatial shape presentation of endoluminal cases (p < 0.01) and improves the confidence of identification and clinical classification of endoluminal lesions significantly (p < 0.01). The specificity and diagnostic accuracy of GM is significantly better than those of SR in diagnostic performance evaluation (p < 0.01). CONCLUSION: GM can reduce confusion in three-dimensional CTC and well correlate CTC with sectional images by the location as well as gray-level value. Hence, GM increases identification and differentiation of endoluminal lesions, and facilitates diagnostic process. Advances in knowledge: GM significantly improves the traditional SR method by providing reliable gray-level information for the surface points and is helpful in identification and differentiation of endoluminal lesions according to their shape and density.

Iodine Anions beyond -1: Formation of LinI (n = 2-5) and Its Interaction with Quasiatoms.

Novel phases of LinI (n = 2, 3, 4, 5) compounds are predicted to form under high pressure using first-principles density functional theory and an unbiased crystal structure search algorithm. All of the phases identified are thermodynamically stable with respect to decomposition into elemental Li and the binary LiI at a relatively low pressure (≈20 GPa). Increasing the pressure to 100 GPa yields the formation of a high pressure electride where electrons occupy interstitial quasiatom (ISQ) orbitals. Under these extreme pressures, the calculated charge on iodine suggests the oxidation state goes beyond the conventional and expected -1 charge for the halogens. This strange oxidative behavior stems from an electron transfer going from the ISQ to I(-) and Li(+) ions as high pressure collapses the void space. The resulting interplay between chemical bonding and the quantum chemical nature of enclosed interstitial space allows this first report of a halogen anion beyond a -1 oxidation state.

Pressure-induced structural and valence transition in AgO.

The pressure-induced evolution of AgO crystal structures and the oxygen environment of Ag atoms were investigated by means of density functional theory with a hybrid functional and a structure prediction method. Under ambient conditions, AgO has two nonequivalent Ag1 and Ag2 sites that adopt linear and square planar oxygen environment configuration, respectively, corresponding to Ag mixed-valence states. The results show that both the coordination environment and the valence state of the Ag1 site are sensitive to pressure and will gradually approach those of the Ag2 site as it increases. The band gap also decreases significantly and at 75 GPa AgO experiences a pressure-induced semiconductor-to-metal transition. At ∼77 GPa, there is a structural transition from monoclinic (P21/c) to trigonal (R3[combining macron]m), accompanied by a valence state transition from the mixed-valence state to a single-valence state.

Mercury under Pressure acts as a Transition Metal: Calculated from First Principles.

The inclusion of Hg among the transition metals is readily debated. Recently, molecular HgF4 was synthesized in a low-temperature noble gas but the potential of Hg to form compounds beyond a +2 oxidation state in a stable solid remains unresolved. We propose high-pressure techniques to prepare unusual oxidation states of Hg-based compounds. Using an advanced structure search algorithm and first-principles electronic structure calculations, we find that under high pressure Hg in Hg-F compounds transfers charge from the d orbitals to the F, thus behaving as a transition metal. Oxidizing Hg to +4 and +3 yielded the thermodynamically stable compounds HgF4 and HgF3. The former consists of HgF4 planar molecules, a typical geometry for d(8) metal centers. HgF3 is metallic and ferromagnetic owing to the d(9) configuration of Hg, with a large gap between its partially occupied and unoccupied bands under high pressure.

Right and left amygdalae activation in patients with major depression receiving antidepressant treatment, as revealed by fMRI.

BACKGROUND: A differential contribution of the right and left amygdalae to affective information processing has been proposed. However, the direction of this lateralization has not been confirmed. In this study, we used a pre- and post-treatment (escitalopram) design to analyze the relative differences between neural activity in the right and left amygdalae during exposure to emotional stimuli in currently depressed patients. To the best of our knowledge, this study is to compare neural activity between the left and right amygdalae in people with depression. Our findings could lead to the development of parameters or biomarkers for depressive symptoms and treatment response. METHODS: We used a pre-post-test design without a control group. Twenty currently depressed participants underwent an emotion processing task during fMRI. These participants were then treated with an antidepressant for 6 weeks. We used amygdala region-of-interest analysis to evaluate the hemodynamic response during exposure to colored emotional pictures. RESULTS: In total, thirteen of the 20 participants were placed into a separate group based on degree of response to antidepressants. The partial response group had an averaged HDRS score of 10.75 ± 2.25 and an averaged DBOLDLR signal of 189.18 ± 140.23 (m1 = 8), and the remitted group had an averaged HDRS score of 4.80 ± 1.64 and an averaged DBOLDLR signal of 421.26 ± 109.19 (m2 = 5). Each individual had lateralized amygdala activity, and the direction of asymmetry persisted following treatment. Amygdala responses to four types of emotional stimuli did not significantly change (p > 0.05) with treatment in either the right or the left amygdala. However, the difference in neural activity between the right and left amygdalae was greater after treatment, and the variation in neural activity was larger in the left amygdala. CONCLUSIONS: We found that the response between the right and left amygdala did not differ in terms of time series, although activity increased after pharmaceutical treatment for each emotion tested. In the future, changes in BOLD signals as revealed by fMRI might be useful in evaluating the clinical manifestation of major depression.

The image feature analysis for microscopic thyroid tissue classification.

Thyroid diseases are prevalent among endocrine diseases. Observation and examination of histological tissue images can help in understanding the cause and pathogenesis of the tumor. The aim of this study was to quantify the histological image features of microscopic thyroid images in order to classify varying tissue types. Five typical histological thyroid tissues were characterized using seven image features including hue, brightness, standard deviation of brightness, entropy, energy, regularity, and fractal analysis. Statistical stepwise selection and multiple discriminant analysis were then used to classify the features. The results show all of the features are significant and our algorithm has the capability of differentiating histological tissue types. The algorithm is applied utilizing quad-tree based region splitting methods to segment the tissue regions from the heterogeneous microscopic image. The preliminary results show the system has good performance for tissue segmentation.

Computer-aided auscultation learning system for nursing technique instruction.

Pulmonary auscultation is a physical assessment skill learned by nursing students for examining the respiratory system. Generally, a sound simulator equipped mannequin is used to group teach auscultation techniques via classroom demonstration. However, nursing students cannot readily duplicate this learning environment for self-study. The advancement of electronic and digital signal processing technologies facilitates simulating this learning environment. This study aims to develop a computer-aided auscultation learning system for assisting teachers and nursing students in auscultation teaching and learning. This system provides teachers with signal recording and processing of lung sounds and immediate playback of lung sounds for students. A graphical user interface allows teachers to control the measuring device, draw lung sound waveforms, highlight lung sound segments of interest, and include descriptive text. Effects on learning lung sound auscultation were evaluated for verifying the feasibility of the system. Fifteen nursing students voluntarily participated in the repeated experiment. The results of a paired t test showed that auscultative abilities of the students were significantly improved by using the computer-aided auscultation learning system.