A theoretical scheme of annulenes aromaticity

1984 ◽  
Vol 49 (4) ◽  
pp. 920-935 ◽  
Author(s):  
Jaroslav Leška ◽  
Dušan Loos
Keyword(s):  
Ring Size ◽  
Aromaticity Index ◽  
Theoretical Scheme ◽  
Quantitative Results

An aromaticity scheme for annulenes is developed and applied on set of [6] to [18]annulenes. The dependence of annulenes aromaticity on the ring size, noncoplanarity and strain is considered which factors are in the aromaticity indices HOMAW and HOMAM implicitely included. The decrease in aromaticity index with increasing ring size was modelled for [4n+2] and [4n] annulenes by the functions Δ4n+2(N) and Δ4n(N). Two quantities, κd and νs, as the average measures of noncoplanarity and strain have been defined. Significant correlations of the differences Δx(N) - HOMAW and Δx(N) - HOMAM, which represent the decrease in aromaticity index by noncoplanarity and strain, with a function of the parameters κd and νs, have been obtained. The quantitative results show that not only the [4n]annulenes, but also the large part of the [4n+2]annulenes are antiaromatic, even for the presence of noncoplanarity and strain in the molecules.

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

An Improved Quantitative Image Analyser

1977 ◽  
Vol 35 ◽  
pp. 226-227
Author(s):  
J.P. Fallon ◽  
P.J. Gregory ◽  
C.J. Taylor
Keyword(s):  
Feature Extraction ◽  
Quantitative Analysis ◽  
Frequency Content ◽  
General Sense ◽  
Physical Measurements ◽  
Quantitative Image ◽  
Image Analyser ◽  
Automatic Methods ◽  
Quantitative Results

Quantitative image analysis systems have been used for several years in research and quality control applications in various fields including metallurgy and medicine. The technique has been applied as an extension of subjective microscopy to problems requiring quantitative results and which are amenable to automatic methods of interpretation.Feature extraction. In the most general sense, a feature can be defined as a portion of the image which differs in some consistent way from the background. A feature may be characterized by the density difference between itself and the background, by an edge gradient, or by the spatial frequency content (texture) within its boundaries. The task of feature extraction includes recognition of features and encoding of the associated information for quantitative analysis.Quantitative Analysis. Quantitative analysis is the determination of one or more physical measurements of each feature. These measurements may be straightforward ones such as area, length, or perimeter, or more complex stereological measurements such as convex perimeter or Feret's diameter.

Determining Emotional Tone and Verbal Behavior in Patients With Tinnitus and Hyperacusis: An Exploratory Mixed-Methods Study

2019 ◽  
Vol 28 (3) ◽  
pp. 660-672
Author(s):  
Suzanne H. Kimball ◽  
Toby Hamilton ◽  
Erin Benear ◽  
Jonathan Baldwin
Keyword(s):  
Mixed Methods ◽  
Verbal Behavior ◽  
Coping Strategies ◽  
Mixed Methods Study ◽  
Self Report ◽  
Anxiety And Depression ◽  
Negative Consequences ◽  
Emotional Tone ◽  
Explanatory Mixed Methods ◽  
Quantitative Results

Purpose The purpose of this study was to evaluate the emotional tone and verbal behavior of social media users who self-identified as having tinnitus and/or hyperacusis that caused self-described negative consequences on daily life or health. Research Design and Method An explanatory mixed-methods design was utilized. Two hundred “initial” and 200 “reply” Facebook posts were collected from members of a tinnitus group and a hyperacusis group. Data were analyzed via the LIWC 2015 software program and compared to typical bloggers. As this was an explanatory mixed-methods study, we used qualitative thematic analyses to explain, interpret, and illustrate the quantitative results. Results Overall, quantitative results indicated lower overall emotional tone for all categories (tinnitus and hyperacusis, initial and reply), which was mostly influenced by higher negative emotion. Higher levels of authenticity or truth were found in the hyperacusis sample but not in the tinnitus sample. Lower levels of clout (social standing) were indicated in all groups, and a lower level of analytical thinking style (concepts and complex categories rather than narratives) was found in the hyperacusis sample. Additional analysis of the language indicated higher levels of sadness and anxiety in all groups and lower levels of anger, particularly for initial replies. These data support prior findings indicating higher levels of anxiety and depression in this patient population based on the actual words in blog posts and not from self-report questionnaires. Qualitative results identified 3 major themes from both the tinnitus and hyperacusis texts: suffering, negative emotional tone, and coping strategies. Conclusions Results from this study suggest support for the predominant clinical view that patients with tinnitus and hyperacusis have higher levels of anxiety and depression than the general population. The extent of the suffering described and patterns of coping strategies suggest clinical practice patterns and the need for research in implementing improved practice plans.

Physico-Chemical Explanation of Blood Cell Adhesion in Thrombus Formation

1976 ◽  
Vol 36 (02) ◽  
pp. 430-440 ◽  
Author(s):  
A Marmur ◽  
E Ruckenstein ◽  
S. R Rakower
Keyword(s):  
Blood Cells ◽  
Thrombus Formation ◽  
Experimental Information ◽  
Deposition Surface ◽  
Physico Chemical ◽  
Quantitative Results ◽  
Energy Of Interaction ◽  
Induced Aggregation ◽  
Adhesion Of Platelets ◽  
Hydrodynamic Factors

SummaryA model is suggested which assumes that the rate of deposition of cells is determined both by hydrodynamic factors and by Brownian motion over the potential barrier caused by London and double-layer forces in the immediate vicinity of the deposition surface. The height of the barrier in the potential energy of interaction between blood cells and various surfaces is analyzed in relation to the physical properties of the cells, surfaces, and solutions. Based on this analysis, the adhesion of platelets to injured blood vessel walls and to non-biologic materials, the lack of adhesion of red blood cells under the same conditions, the mechanism of ADP induced aggregation and the interaction with blood flow are explained. The qualitative predictions of the model are substantiated by available experimental information. Quantitative results are presented in terms of a time constant, which typifies a period of contact with a surface, during which appreciable deposition occurs.

Lack of Agreement of Chromogenic and Glotting Assays for Factor X and Protein C in Warfarinised Plasma

1991 ◽  
Vol 65 (04) ◽  
pp. 360-363 ◽  
Author(s):  
P Han ◽  
K P Fung ◽  
U Rahdakrishnan
Keyword(s):  
Serine Proteases ◽  
Protein C ◽  
Warfarin Therapy ◽  
Intraclass Correlation ◽  
Chromogenic Substrate ◽  
Factor X ◽  
Laboratory Automation ◽  
Quantitative Results ◽  
Assay Methods

SummaryCoagulation serine proteases can be measured with either a chromogenic substrate assay or a clotting assay using deficient plasmas. It is a concern whether both assays give similar quantitative results, in particular in plasma obtained fiom patients on long term warfarin therapy. If these two assay methods were interchangeable, then the chromogenic substrate assay has the advantages of precision as well as laboratory automation. We used the intraclass correlation coefficient (r1) to assess the agreement between the two methods in measuring factor X and protein C levels in warfarinised plasma. The results indicate that the extent and pattern of agreement of the two methods for the measurement of the two variables in warfarinised plasma are poor, despite high Pearson product moment coefficients of correlation.

Ring size effect in McMurry cyclization of 1,ω-di((azulen-1-yl)-carbonyl) alkanes

2020 ◽  
Vol 65 (1) ◽  
pp. 83-88
Author(s):  
Eugenia Andreea DRAGU ◽  
◽  
Alexandru C. RAZUS ◽  
Keyword(s):  
Size Effect ◽  
Ring Size

Support and Goal Outcomes during COVID-19

2020 ◽  
Author(s):  
Laura Marika Vowels ◽  
Katherine Carnelley
Keyword(s):  
Catalyst Support ◽  
Daily Diary ◽  
Goal Pursuit ◽  
Structured Interview ◽  
Partner Support ◽  
Mixed Methods Study ◽  
Instrumental Support ◽  
The Face ◽  
Quantitative Results ◽  
Sources Of Support

During the COVID-19 pandemic, people have been stuck indoors with their partners for months. Having a supportive partner is likely to be especially important during this time where access to outside sources of support is limited. Individuals have to continue to work on goals and tasks while dealing with demands caused by the pandemic. The present mixed-methods study aimed to investigate how partner support is associated with goal outcomes during COVID-19. The quantitative participants (n = 200) completed a daily diary for a week and weekly longitudinal reports for a month and 48 participants attended a semi-structured interview. The quantitative results showed that higher relational catalyst support was associated with better goal outcomes; qualitative analyses revealed partners use direct and indirect forms of emotional and instrumental support toward goal pursuit. Across both forms of data, participants’ resilience in the face of the pandemic was evident.

‘No-one knows where you are’: Veterinary perceptions regarding safety and risk when alone and on-call

2019 ◽  
Author(s):  
Amy Irwin ◽  
Janika Vikman ◽  
Hannah Ellis
Keyword(s):  
Quantitative Data ◽  
Qualitative Data ◽  
Safety Climate ◽  
Potential Hazard ◽  
Personal Safety ◽  
Out Of Hours ◽  
Remote Locations ◽  
High Workload ◽  
Quantitative Results ◽  
Large Animals

Background: Veterinary work is considered high risk and involves working with a range of hazards including large animals, high workload and long hours. A key potential hazard is making home visits and providing out of hours emergency care where vets often work alone, without support, and must travel long distances. The current study aimed to examine UK veterinary perceptions of safety climate, lone working and on-call tasks to gain a deeper understanding of the risk and hazards involved. Method: An online mixed-methods survey was used to gather quantitative data relevant to practice safety climate, and qualitative data regarding veterinary perception of lone working and on-call work. A sample of 76 UK veterinarians were recruited.Results: The quantitative results suggest that there may be practice safety climate issues around a lack of communication and discussion pertaining to safety, particularly in terms of maintaining personal safety. Key themes within the qualitative data included feeling pressure to treat patients, dealing with difficult clients, travel concerns and feeling unsafe when meeting clients alone and in remote locations. Conclusion: These findings indicate that personal safety requires more attention and discussion within veterinary practices, and that safety protocols and requirements should be shared with clients.

Quantitative Structure-Property Relationship (QSPR) Study of the Hydrophobicity of Phenols and 2-(Aryloxy-a-acetyl)-phenoxathiin Derivatives

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Adrian Beteringhe ◽  
Ana Cristina Radutiu ◽  
Titus Constantinescu ◽  
Luminita Patron ◽  
Alexandru T. Balaban
Keyword(s):  
Water Solubility ◽  
Molecular Descriptors ◽  
Log P ◽  
Structure Property ◽  
Substituted Phenols ◽  
Reverse Phase ◽  
Aromaticity Index ◽  
Structure Property Relationship ◽  
Layer Chromatography ◽  
Energy Of Formation

In a preceding study, the molecular hydrophobicity (RM0) was determined experimentally from reverse-phase thin-layer chromatography data for several substituted phenols and 2-(aryloxy-a-acetyl)-phenoxathiin derivatives, obtained from the corresponding phenoxides and 2-(a-bromoacetyl)-phenoxathiin. QSPR correlations for RM0 were explored using four calculated molecular descriptors: the water solubility parameter (log Sw), log P, the Gibbs energy of formation (DGf), and the aromaticity index (HOMA). Triparametric correlations do not improve substantially the biparametric correlation of RM0 in terms of log Sw and HOMA.

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