scholarly journals Discoloration of new nanohybrid composites into two different solutions  (an invitro study)

2020 ◽  
Author(s):  
mohammad ali wannous ◽  
souad ali abboud
Keyword(s):  
Resin Composite ◽  
Study Time ◽  
The Other ◽  
Time Points ◽  
Color Measurements ◽  
Time Period ◽  
Group A ◽  
Nanohybrid Composite

Abstract Objective: this study aimed to evaluate discoloration of two inorganic nanohybrid composite and an organic modified ceramic resin composite (ormocer) into two solution at different periods of time.Methods: 60 discs of (admira fusion voco, tetric evoceram vivadet ivoclar , tetric N-ceram vivadent ivoclar) were prepared with dimentions of (2mm x 5mm) and devided into three group (A ,B, C) Each group of 20 specimens were randomized into two subgroups, one of them were immersed in coffee and the other in cola for 1, 7, and 28 days of immersion. Color measurements were recorded every time period using Vita Easy shade compact according to the CIE L*a*b* system and results were saved for comparing .The ΔE values between the study time points were calculated. Results: Admira Fusion x-tra showed the lowest ΔE variations (P < 0.01) at all periods of time comparing with Tetric evoceram and Tetric N-ceram at both solution. Coffee caused higher discoloration at all periods of time.Conclusion: Staining beverages caused significant discolorations for all the materials tested. Coffee caused higher discoloration comparing with cola. Nanohybrid ormocer composite reported the lowest color variations.

scholarly journals Cyber-bullying: An exploration of bystander behavior and motivation

2014 ◽  
Vol 8 (4) ◽  
Author(s):  
Emily Shultz ◽  
Rebecca Heilman ◽  
Kathleen J. Hart
Keyword(s):  
Quantitative Research ◽  
Cyber Bullying ◽  
The Other ◽  
Bystander Behavior ◽  
Future Studies ◽  
Time Points ◽  
College Age ◽  
Time Period ◽  
Negative Comments

While previous research has examined mainly self-reported bystander behavior during cyber-bullying, the current study explored if and how bystanders responded when presented with a cyber-bullying simulation. We hypothesized that individuals high in empathy would supportively intervene (defend the victim) most frequently. College age participants (M = 20.34, SD = 1.26, range 18-27; N = 149), viewed a simulated Facebook conversation in which negative comments were directed towards another student and were provided open-ended opportunities to be involved in the Facebook conversation (i.e., “comment” to the other fictitious characters) and explain their reasoning for their behavior (“motivators”) at two time points in the conversation (Time 1 and Time 2). Using a deductive-inductive process, we categorized participants’ comments and motivators, the frequency of these responses, and their reasons for them. While the majority of participants (91%) asserted that cyber-bullying occurred in the conversation, most participants did not comment (Time 1: 69%, Time 2: 52%). Among those who commented, the most frequently cited motivators were either to defend the victim or mediate the situation. Consistent with our hypothesis, individuals who identified with the victim had higher empathy scores than those who identified with the bullies, although this was true only for the second part of the conversation (Time 2). Empathy scores did not differ by type of response at either time period. Future studies could utilize the categories and motivators established in this study as a framework for more extensive quantitative research to more comprehensively understand the underlying reasons for low intervention rates in cyber-bullying.

The Use of Composite Layering Technique to Mask a Discolored Background: Color Analysis of Masking Ability After Aging—Part II

2019 ◽  
Vol 44 (5) ◽  
pp. 488-498
Author(s):  
BG Perez ◽  
LL Miotti ◽  
AH Susin ◽  
LB Durand
Keyword(s):  
Resin Composite ◽  
Water Immersion ◽  
Background Color ◽  
Color Analysis ◽  
Mean Values ◽  
Time Points ◽  
Color Measurements ◽  
Color Background ◽  
One Year ◽  
Post Hoc

SUMMARY The aim of this study was to evaluate the effectiveness of the layering technique to mask a discolored background (C4) after one year of water aging. The technique was used with three resin composite restorative systems (IPS Empress Direct, Charisma Diamond, and Filtek Z350XT). Ninety 1.5-mm-thick specimens were divided into groups and subgroups according to the restorative system and resin composite shade combination used in the layering technique (enamel, body, and dentin). The color measurements were made by reflection spectrophotometer (SP60, EX-Rite) over the C4 substrate at two time points: after 24-hour water immersion (T0) and after one-year water aging (T1). The masking ability was evaluated by calculating the ΔE between an inherent color background and a C4 background at T0 and T1. CIELAB and CIEDE2000 formulas were used for comparative analysis between T0 and T1 color measurements. Analysis of variance and Turkey's post hoc test (a=0.05) were performed to analyze ΔEab and ΔE00 mean values. The Z350XT restorative system presented adequate masking ability in the combinations of 0.5 mm body + 1.0 mm dentin, 0.5 mm enamel + 1.0 mm dentin, and 1.5 mm dentin after 24-hour water immersion. The masking ability was affected negatively by water aging in most of the combinations. The IPS Empress Direct was the only system that remained stable after aging in the combinations of 0.5 mm enamel + 1.0 mm dentin and + 1.5 mm dentin (p=0.05 and p=0.47 for CIELAB; p=0.15 and p=0.51 for CIEDE2000), although it did not present adequate masking ability in both time points. None of the combinations of any system presented adequate masking ability after prolonged water aging.

scholarly journals Effects of staining and bleaching on a nanohybrid composite with or without surface sealant

2016 ◽  
Vol 10 (03) ◽  
pp. 361-365 ◽  
Author(s):  
Derya Merve Halacoglu ◽  
Kıvanc Yamanel ◽  
Saffet Basaran ◽  
Duygu Tuncer ◽  
Cigdem Celik
Keyword(s):  
Surface Roughness ◽  
Red Wine ◽  
Resin Composite ◽  
Color Stability ◽  
Analysis Data ◽  
Repeated Measurements ◽  
The Other ◽  
Bleaching Procedure ◽  
Composite Resin Restoration ◽  
Nanohybrid Composite

ABSTRACT Objective: The effect of different staining solutions and a bleaching procedure on color stability and surface roughness of a nanohybrid resin composite were evaluated with or without liquid resin polishing (RP). Materials and Methods: Ninety-six disc-shaped resin composite specimens (A1 Shade, Z550 Filtek 3M ESPE, St. Paul, MN, USA) were prepared and divided randomly into two groups (n = 48). Liquid RP (BisCover LV, Bisco Inc., Schaumburg, IL, USA) was applied in one group (RP) and not in the other (P). Specimen color and surface roughness were determined using a colorimeter and profilometer, respectively. After baseline measurements, each group was divided into four subgroups (n = 12) for immersion in a control (distilled water) or three different staining solutions (ice tea, red wine, and cola) for 1 week. Color and surface roughness were then reevaluated. After measurements, all specimens were bleached using a 35% hydrogen peroxide gel. The color and surface roughness of the specimens were reevaluated. Statistical Analysis: Data were subjected to an analysis of variance for repeated measurements among the groups (P < 0.05). Results: Staining and bleaching did not change the surface roughness of the RP and P groups (P > 0.05). Discoloration in the red wine group was higher than for the other staining solutions for the RP (P < 0.001) and P groups (P = 0.018). Conclusion: Application of liquid RP did not enhance the color stability and surface roughness of the composite resin restoration.

Tonsillar Inflammation, a Rare Cause of Bradycardia and Hypotension

2018 ◽  
Vol 3 (3) ◽  
Keyword(s):  
Streptococcus Pyogenes ◽  
Fusobacterium Necrophorum ◽  
Outpatient Setting ◽  
Peritonsillar Abscess ◽  
The Other ◽  
Streptococcus Group ◽  
Other Hand ◽  
Group A

Tonsillitis is a frequently encountered pathology in the outpatient setting, usually caused by viruses [1]. When bacterial, the most common causatory microbe is streptococcus group A [1]. Tonsillar and peritonsillar abscess (PTA) on the other hand are never viral, and are usually caused by streptococcus pyogenes, Streptococcus melleri, fusobacterium necrophorum and staphylococci [1,2]. The overall incidence of PTA is suggested to be 37/100,000 patients, with the highest incidence between ages 14-21 at 124/100,000 [3].

The incumbent, challenger, and population during revolution and civil war

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Kjell Hausken ◽  
Mthuli Ncube
Keyword(s):  
Civil War ◽  
Public Goods ◽  
Arab Spring ◽  
The Other ◽  
Time Period ◽  
Geographic Regions

We consider revolutions and civil war involving an incumbent, a challenger, and the population. Revolutions are classified into eight outcomes. In four outcomes incumbent repression occurs (viewed as providing sub-threshold benefits such as public goods to the population). Accommodation occurs in the other four outcomes (benefits provision above a threshold). The incumbent and challenger fight each other. The incumbent may win and retain power or else lose, thereby causing standoff or coalition. In a standoff, which is costly, no one backs down and uncertainty exists about who is in power. In a coalition, which is less costly, the incumbent and challenger cooperate, compromise, and negotiate their differences. If the population successfully revolts against the incumbent, the challenger replaces the incumbent. Eighty-seven revolutions during 1961–2011, including the recent Arab spring revolutions, are classified into the eight outcomes. When repressive, the incumbent loses 46 revolutions, remains in power through 21 revolutions, and builds a coalition after 12 revolutions. When accommodative, the incumbent loses seven revolutions and builds a coalition after one revolution. The 87 revolutions are classified across geographic regions and by time-period.

Effect of short-term use of oral contraceptive pills on intraocular pressure

2020 ◽  
Vol 35 (3) ◽  
Author(s):  
Tayyaba Gul Malik ◽  
Hina Nadeem ◽  
Eiman Ayesha ◽  
Rabail Alam
Keyword(s):  
Oral Contraceptive ◽  
Childbearing Age ◽  
Short Term ◽  
Oral Contraceptive Pills ◽  
Contraceptive Pills ◽  
Time Period ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Short Time

Objective: To study the effect of short-term use of oral contraceptive pills on intra-ocular pressures of women of childbearing age.   Methods: It was a comparative observational study, conducted at Arif memorial teaching hospital and Allied hospital Faisalabad for a period of six months. Hundred female subjects were divided into two groups of 50 each. Group A, included females, who had been taking oral contraceptive pills (OCP) for more than 6 months and less than 36 months. Group B, included 50 age-matched controls, who had never used OCP. Ophthalmic and systemic history was taken. Careful Slit lamp examination was performed and intraocular pressures (IOP) were measured using Goldman Applanation tonometer. Fundus examination was done to rule out any posterior segment disease. After collection of data, we analyzed and compared the intra ocular pressures between the two groups by using ANOVA in SPSS version 21.   Results: Average duration of using OCP was 14.9 months. There was no significant difference of Cup to Disc ratios between the two groups (p= 0.109). However, significant difference was noted between the IOP of OCP group and controls. (p=0.000). Conclusion: OCP significantly increase IOP even when used for short time period.

Utilization of remote sensing for estimation of scale of cutting and growing of forest zones

2017 ◽  
Vol 920 (2) ◽  
pp. 57-60
Author(s):  
F.E. Guliyeva
Keyword(s):  
Remote Sensing ◽  
Fixed Time ◽  
Time Interval ◽  
Time Points ◽  
Average Value ◽  
Time Period ◽  
Remote Estimation ◽  
The Given ◽  
Forest Cutting

The study of results of relevant works on remote sensing of forests has shown that the known methods of remote estimation of forest cuts and growth don’t allow to calculate the objective average value of forests cut volume during the fixed time period. The existing mathematical estimates are not monotonous and make it possible to estimate primitively the scale of cutting by computing the ratio of data in two fixed time points. In the article the extreme properties of the considered estimates for deforestation and reforestation models are researched. The extreme features of integrated averaged values of given estimates upon limitations applied on variables, characterizing the deforestation and reforestation processes are studied. The integrated parameter, making it possible to calculate the averaged value of estimates of forest cutting, computed for all fixed time period with a fixed step is suggested. It is shown mathematically that the given estimate has a monotonous feature in regard of value of given time interval and make it possible to evaluate objectively the scales of forest cutting.

Psychophysically Based Physical Capability Limits For Right Angle Power Tool Operation

2020 ◽  
Vol 64 (1) ◽  
pp. 910-914
Author(s):  
Jonathan Valencia ◽  
Joel Cort
Keyword(s):  
Analysis Of Variance ◽  
The Other ◽  
Mixed Design ◽  
Joint Orientation ◽  
Physical Capability ◽  
Subject Variables ◽  
Group A ◽  
Repeated Analysis ◽  
Post Hoc

A psychophysical methodology was utilized to examine 40 non-skilled female participants performing right-angle power tool (RAPT) fastening tasks. A combination of two between subject variables were examined for a total of four between-subject groups: joint orientation (horizontal and vertical planes) and joint hardness (hard and soft joints). Participants were evenly distributed into one of four joint orientation- hardness groups. Within each group, a combination of three fastening strategies and three fastening frequencies were performed by each participant. The chosen target torque determined the physical capability limits (PCL). A mixed-design repeated analysis of variance with Tukey’ significance post hoc test were used to determine any significance with the measured variables ( p<0.05). Fastening strategy and frequency influenced the chosen torque magnitude. Participants chose significantly higher target torques with the Turbo Tight strategy in comparison to the other two strategies. Furthermore, participants chose to accept lower target torques and forces as fastening frequency increased.

scholarly journals Effect of supplemental dexmedetomidine in interventional embolism on cerebral oxygen metabolism in patients with intracranial aneurysms

2021 ◽  
Vol 49 (4) ◽  
pp. 030006052110029
Author(s):  
Zhang Guo ◽  
Weiwei Wang ◽  
Dahua Xie ◽  
Ruisheng Lin
Keyword(s):  
Intracranial Aneurysms ◽  
Jugular Vein ◽  
Oxygen Metabolism ◽  
Cerebral Oxygen ◽  
Cerebral Oxygen Metabolism ◽  
Time Points ◽  
Venous Oxygen Saturation ◽  
Group A ◽  
Group B ◽  
Oxygen Difference

Objective To investigate the effect of supplemental dexmedetomidine in interventional embolism on cerebral oxygen metabolism in patients with intracranial aneurysms. Methods Ninety patients who underwent interventional embolism of intracranial aneurysms were equally divided into Group A and Group B. In Group A, dexmedetomidine was injected intravenously 10 minutes before inducing anesthesia, with a loading dose of 0.6 µg/kg followed by 0.4 µg/kg/hour. Group B received the same amount of normal saline by the same injection method. Heart rate (HR), mean arterial pressure (MAP), arterial–jugular venous oxygen difference [D(a-jv) (O2)], cerebral oxygen extraction [CE (O2)], and intraoperative propofol use were recorded before inducing anesthesia (T0) and at five time points thereafter. Results The amount of propofol in Group A was lower vs Group B. At all five time points after T0, HR, MAP, D(a-jv) (O2), and CE (O2) in Group A were significantly lower vs Group B, with significant differences for jugular venous oxygen saturation (SjvO2) and the oxygen content of the internal jugular vein (CjvO2) between the groups. Conclusion Dexmedetomidine resulted in less intraoperative propofol, lower D(a-jv) (O2) and CE (O2), and improved cerebral oxygen metabolism.

scholarly journals Effect of Photofunctionalization with 6 W or 85 W UVC on the Degree of Wettability of RBM Titanium in Relation to the Irradiation Time

2021 ◽  
Vol 11 (12) ◽  
pp. 5427
Author(s):  
Arturo Sanchez-Perez ◽  
Nuria Cano-Millá ◽  
María José Moya Villaescusa ◽  
José María Montoya Carralero ◽  
Carlos Navarro Cuellar
Keyword(s):  
Light Source ◽  
Ultraviolet Light ◽  
Irradiation Time ◽  
Contact Angles ◽  
The Other ◽  
Control Group ◽  
Hydrophilic Surface ◽  
Biological Ageing ◽  
Ultraviolet C ◽  
Group A

Photoactivation with ultraviolet C light can reverse the effects derived from biological ageing by restoring a hydrophilic surface. Ten titanium discs were randomly divided into three groups: a control group, a 6 W group, and an 85 W group. A drop of double-distilled, deionized, and sterile 10 µL water was applied to each of the discs. Each disc was immediately photographed in a standardized and perpendicular manner. Measurements were taken based on the irradiation time (15, 30, 60, and 120 min). UVC irradiation improved the control values in both groups. There was no difference in its effect between the 6 W group and the other groups during the first 30 min. However, after 60 min and up to 120 min, 85 W had a significantly stronger effect. The contact angles with the 85 W ultraviolet light source at 60 and 120 min were 19.43° and 31.41°, respectively, whereas the contact angles for the 6 W UVC source were 73.8° and 61.45°. Power proved to be the most important factor, and the best hydrophilicity result was obtained with a power of 85 W for 60 min at a wavelength of 254 nm.

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