Polarization of disintegrating Comet C/2019 Y4 (ATLAS)

2020 ◽  
Vol 497 (2) ◽  
pp. 1536-1542
Author(s):  
Evgenij Zubko ◽  
Maxim Zheltobryukhov ◽  
Ekaterina Chornaya ◽  
Anton Kochergin ◽  
Gorden Videen ◽  
...  
Keyword(s):  
Volume Ratio ◽  
Carbonaceous Material ◽  
Solar Radiation Pressure ◽  
Carbonaceous Particles ◽  
Wide Range ◽  
Before And After ◽  
Nucleus Surface ◽  
Cometary Material ◽  
Absorbing Material ◽  
Phase Angles

ABSTRACT We observe Comet C/2019 Y4 (ATLAS) before and after its disintegration while making polarimetric measurements over a wide range of phase angles. The disintegration event was marked with a dramatic growth of the positive polarization branch that is consistent with a large relative abundance of absorbing material of up to (96.5 ± 3.4) per cent. This polarization spike relaxed as the carbonaceous particles are preferentially swept from the coma due to solar-radiation pressure. The observations suggest that the primordial material stored within comets is extremely rich in carbonaceous material. The pristine cometary material is processed by subsequent solar interactions, forming a refractory crust on the nucleus surface. Polarimetry provides a means of measuring the volume ratio of carbonaceous material, and hence the weathering that has occurred on the comet due to these interactions. The polarimetric response of Comet C/2019 Y4 (ATLAS) appears similar to that of Comet C/1995 O1 (Hale-Bopp), except on few epochs that are similar to that of Comet C/1996 B2 (Hyakutake).

Perioperative Skin Conditioning for Patients With Skin of Color

2021 ◽  
pp. 074880682198989
Author(s):  
Alix Ferdinand ◽  
Suzan Obagi
Keyword(s):  
Treatment Regimen ◽  
Skin Care ◽  
Practical Approach ◽  
Postoperative Phase ◽  
Upward Trend ◽  
Wide Range ◽  
Before And After

The interest in cosmetic procedures for patients with skin of color is on an upward trend. Globally, dyschromia and hyperpigmentation remain the most common disorders for which patients seek treatment. The goals of a perioperative skin conditioning program include allowing a broad range of patients to be treated regardless of skin phototypes, maximizing results, and reducing risk of complications such as post-inflammatory hyperpigmentation and managing post-inflammatory hyperpigmentation if it occurs. The purpose of this article is to highlight common pigmentation concerns among patients with skin of color, the topical agents used to combat these concerns, and a practical approach to creating an effective yet straightforward topical skin care regimen that can be used across a wide range of patient skin phototypes. Before and after photos of patients with a variety of pigmentation concerns are presented along with a description of the treatment regimen used to improve their conditions and to get their skin to a safer state prior to performing any office-based procedures. By understanding the main concerns of patients with skin of color, one can use a simple and effective skincare regimen to allow these patients to be more safely treated. An effective skincare regimen both prepares the skin prior to procedures and postoperatively to help minimize dyschromias in the postoperative phase.

scholarly journals Changes in Cellular Regulatory Factors before and after Decompression of Odontogenic Keratocysts

2020 ◽  
Vol 10 (1) ◽  
pp. 30
Author(s):  
Slmaro Park ◽  
Han-Sung Jung ◽  
Young-Soo Jung ◽  
Woong Nam ◽  
Jung Yul Cha ◽  
...  
Keyword(s):  
Recurrence Rate ◽  
Biological Behavior ◽  
Nuclear Antigen ◽  
Epithelial Cyst ◽  
Ki 67 ◽  
Proliferation Markers ◽  
Odontogenic Keratocysts ◽  
Wide Range ◽  
Before And After ◽  
Cyst Lining

Decompression followed by enucleation, which is one of the treatments used for odontogenic keratocysts (OKCs), is frequently used in OKC lesions of large sizes. This method offers the advantage of minimizing the possibility of sensory impairment without creating a wide-range bone defect; moreover, the recurrence rate can be significantly lower than following simple enucleation. This study aimed to assess the changes in histology and expression of proliferation markers in OKCs before and after decompression treatment. A total of 38 OKC tissue samples from 19 patients who had undergone decompression therapy were examined morphologically and immunohistochemically to observe changes in proliferative activity before and after decompression. The markers used for immunohistochemistry (IHC) staining were Bcl-2, epidermal growth factor receptor (EGFR), Ki-67, P53, PCNA, and SMO. The immunohistochemistry positivity of the 6 markers was scored by using software ImageJ, version 1.49, by quantifying the intensity and internal density of IHC-stained epithelium. The values of Bcl-2, Ki-67, P53, proliferating cell nuclear antigen (PCNA), and SMO in OKCs before and after decompression showed no significant change. No correlation between clinical shrinkage and morphologic changes or expression of proliferation and growth markers could be found. There was no statistical evidence that decompression treatment reduces potentially aggressive behavior of OKC within the epithelial cyst lining itself. This might indicate that decompression does not change the biological behavior of the epithelial cyst lining or the recurrence rate.

scholarly journals A Review on Biosensors and Recent Development of Nanostructured Materials-Enabled Biosensors

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1109
Author(s):  
Varnakavi. Naresh ◽  
Nohyun Lee
Keyword(s):  
High Surface ◽  
Three Dimensional ◽  
Biological Response ◽  
Volume Ratio ◽  
Recent Decade ◽  
Disease Diagnosis ◽  
Electrical Signal ◽  
Detection Sensitivity ◽  
Wide Range ◽  
Color Tunability

A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal. The design and development of biosensors have taken a center stage for researchers or scientists in the recent decade owing to the wide range of biosensor applications, such as health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery. The main challenges involved in the biosensor progress are (i) the efficient capturing of biorecognition signals and the transformation of these signals into electrochemical, electrical, optical, gravimetric, or acoustic signals (transduction process), (ii) enhancing transducer performance i.e., increasing sensitivity, shorter response time, reproducibility, and low detection limits even to detect individual molecules, and (iii) miniaturization of the biosensing devices using micro-and nano-fabrication technologies. Those challenges can be met through the integration of sensing technology with nanomaterials, which range from zero- to three-dimensional, possessing a high surface-to-volume ratio, good conductivities, shock-bearing abilities, and color tunability. Nanomaterials (NMs) employed in the fabrication and nanobiosensors include nanoparticles (NPs) (high stability and high carrier capacity), nanowires (NWs) and nanorods (NRs) (capable of high detection sensitivity), carbon nanotubes (CNTs) (large surface area, high electrical and thermal conductivity), and quantum dots (QDs) (color tunability). Furthermore, these nanomaterials can themselves act as transduction elements. This review summarizes the evolution of biosensors, the types of biosensors based on their receptors, transducers, and modern approaches employed in biosensors using nanomaterials such as NPs (e.g., noble metal NPs and metal oxide NPs), NWs, NRs, CNTs, QDs, and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

Space Modeling of Problem Solving Strategies of “Prisoner's Dilemma”

2021 ◽  
pp. 99-116
Author(s):  
D.J. Balanev ◽  
Keyword(s):  
Neural Networks ◽  
Social Identity ◽  
Identity Formation ◽  
Social Factors ◽  
Prisoner's Dilemma ◽  
Prisoner’S Dilemma ◽  
Real People ◽  
Space Modeling ◽  
Wide Range ◽  
Before And After

An iterated version of the game "Prisoner's Dilemma" is used as a model of cooperation largely due to the wide range of strategies that the subjects can use. The problem of the effec-tiveness of strategies for solving the Iterated Prisoner's Dilemma (IPD) is most often considered from the point of view of information models, where strategies do not take into account the relationship that arise when real people play. Some of these strategies are obvious, others depend upon social context. In our paper, we use one of the promising directions in the development of studying IPD strategies – the use of artificial neural networks. We use neural networks as a modeling tool and as a part of game environment. The main goal of our work is to build an information model that predicts the behavior of an individual person as well as group of people in the situation of solving of social dilemma. It takes into account social relationship, including those caused by experimental influence, gender differences, and individual differences in the strategy for solving cognitive tasks. The model demonstrates the transition of individual actions into socially determined behavior. Evaluation of the effect of socialization associated with the procedure of the game provides additional information about the effectiveness and characteristics of the experimental impact.The paper defines the minimum unit of analysis of the IPD player's strategy in a group, the identity with which can be considered as a variable. It discusses the influence of the experi-mentally formed group identity on the change of preferred strategies in social dilemmas. We use the possibilities of neural networks as means of categorizing the results of the prisoner's iterative dilemma in terms of the strategy applied by the player, as well as social factors. We define the patterns of changes in the IPD player's strategy before and after socialization are determined. The paper discusses the questions of real player's inclination to use IPD solution strategies in their pure form or to use the same strategy before and after experimental inter-ventions related to social identity formation. It is shown that experimentally induced socialization can be considered as a mechanism for increasing the degree of certainty in the choice of strategies when solving IPD task. It is found out that the models based on neural networks turn out to be more efficient after experi-mentally evoked social identity in a group of 6 people; and the models based on neural net-works are least effective in the case of predicting a subject's belonging to a gender group. When solving IPD problems by real people, it turns out to be possible to talk about generalized strategies that take into account not only the evolutionary properties of «pure» strategies, but also reflect various social factors.

Model Child Care Health Policies

2013 ◽  
Author(s):  
Keyword(s):  
Child Care ◽  
Early Education ◽  
Health And Safety ◽  
Large Family ◽  
Health Policies ◽  
After School ◽  
Wide Range ◽  
Before And After ◽  
Care Health ◽  
Child Care Facilities

Significantly revised and updated, the new Model Child Care Health Policies, 5th Edition is a must-have tool to foster adoption and implemenation of best practices for health and safety in group care settings for young children. These settings include early care and education as well as before and after school child care programs. These model policies are intended to ease the burden of writing site-specific health and safety policies from scratch. They cover a wide range of aspects of operation of early education and child care programs. Child care programs of any type can use Model Child Care Health Policies by selecting relevant issues for their operation and modifying the wording to make selected policies appropriate to the specific settings. These settings include early education and child care centers, small and large family child care homes, part day-programs for ill children, facilities that serve children with special needs, school-age child care facilities, and drop-in facilities. The model policies can be adapted for public, private, Head Start, and tuition-funded facilities. All of the most commonly covered health and safety topics the National Association of Child Care Resource and Referral Agencies found in state regulations are included in this guide.

Peak calf blood flow estimates are higher with Dohn than with Whitney plethysmograph

1996 ◽  
Vol 81 (3) ◽  
pp. 1418-1422 ◽  
Author(s):  
D. N. Proctor ◽  
J. R. Halliwill ◽  
P. H. Shen ◽  
N. E. Vlahakis ◽  
M. J. Joyner
Keyword(s):  
Blood Flow ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Calf Blood Flow ◽  
Absolute Flow ◽  
Wide Range ◽  
Before And After ◽  
The Mean ◽  
Highly Correlated

Estimates of calf blood flow with venous occlusion plethysmography vary widely between studies, perhaps due to the use of different plethysmographs. Consequently, we compared calf blood flow estimates at rest and during reactive hyperemia in eight healthy subjects (four men and four women) with two commonly used plethysmographs: the mercury-in-silastic (Whitney) strain gauge and Dohn air-filled cuff. To minimize technical variability, flow estimates were compared with a Whitney gauge and a Dohn cuff on opposite calves before and after 10 min of bilateral femoral arterial occlusion. To account for any differences between limbs, a second trial was conducted in which the plethysmographs were switched. Resting flows did not differ between the plethysmographs (P = 0.096), but a trend toward lower values with the Whitney was apparent. Peak flows averaged 37% lower with the Whitney (27.8 +/- 2.8 ml.dl-1.min-1) than with the Dohn plethysmograph (44.4 +/- 2.8 ml.dl-1.min-1; P < 0.05). Peak flow expressed as a multiple above baseline was also lower with the Whitney (10-fold) than with the Dohn plethysmograph (14.5-fold; P = 0.02). Across all flows at rest and during reactive hyperemia, estimates were highly correlated between the plethysmographs in all subjects (r2 = 0.96-0.99). However, the mean slope for the Whitney-Dohn relationship was only 60 +/- 2%, indicating that over a wide range of flows the Whitney gauge estimate was 40% lower than that for the Dohn cuff. These results demonstrate that the same qualitative results can be obtained with either plethysmograph but that absolute flow values will generally be lower with Whitney gauges.

scholarly journals Efficient Removal of Methyl Orange and Rhodamine-B Dyes with Low Cost Banana Peel Activated Carbon

2020 ◽  
Vol 32 (5) ◽  
pp. 1121-1127
Author(s):  
Mahesh Kumar Gupta ◽  
P.K. Tandon ◽  
Neelam Shukla ◽  
Harendra Singh ◽  
Shalini Srivastava
Keyword(s):  
Activated Carbon ◽  
Methyl Orange ◽  
Rhodamine B ◽  
Low Cost ◽  
Banana Peel ◽  
Duration Of Treatment ◽  
Wide Range ◽  
Before And After ◽  
Efficient Adsorbent ◽  
Solution Changes

Acid activated carbon obtained from cheap, non-toxic and locally available banana peel was used as a low cost and efficient adsorbent for the removal of dyes methyl orange and rhodamine-B from the aqueous solution. Changes in the resulting material before and after activation and after treatment were studied by different techniques, such as SEM-EDX, XRD, FTIR measurements. Effects of duration of treatment, amount of banana peel activated carbon, pH, and initial methyl orange and rhodamine-B concentration, on the removal of dye were studied to get optimum conditions for maximum dye removal. Removal efficiency of the activated ash remains almost constant in a wide range of pH from 2.5 to 5.6. In 75 min at room temperature removal of 98.5 % methyl orange (anionic) and 99.0 % rhodamine-B (cationic) dyes with 0.1 g and 0.125 g, respectively was obtained from the contaminated water having 10 ppm dye concentration.

scholarly journals Using snowflake surface-area-to-volume ratio to model and interpret snowfall triple-frequency radar signatures

2017 ◽  
Vol 17 (19) ◽  
pp. 12011-12030 ◽  
Author(s):  
Mathias Gergely ◽  
Steven J. Cooper ◽  
Timothy J. Garrett
Keyword(s):  
Surface Area ◽  
Cross Sections ◽  
Volume Ratio ◽  
High Sensitivity ◽  
Maximum Size ◽  
Strong Impact ◽  
Triple Frequency ◽  
Bounding Volume ◽  
Wide Range ◽  
Radar Signatures

Abstract. The snowflake microstructure determines the microwave scattering properties of individual snowflakes and has a strong impact on snowfall radar signatures. In this study, individual snowflakes are represented by collections of randomly distributed ice spheres where the size and number of the constituent ice spheres are specified by the snowflake mass and surface-area-to-volume ratio (SAV) and the bounding volume of each ice sphere collection is given by the snowflake maximum dimension. Radar backscatter cross sections for the ice sphere collections are calculated at X-, Ku-, Ka-, and W-band frequencies and then used to model triple-frequency radar signatures for exponential snowflake size distributions (SSDs). Additionally, snowflake complexity values obtained from high-resolution multi-view snowflake images are used as an indicator of snowflake SAV to derive snowfall triple-frequency radar signatures. The modeled snowfall triple-frequency radar signatures cover a wide range of triple-frequency signatures that were previously determined from radar reflectivity measurements and illustrate characteristic differences related to snow type, quantified through snowflake SAV, and snowflake size. The results show high sensitivity to snowflake SAV and SSD maximum size but are generally less affected by uncertainties in the parameterization of snowflake mass, indicating the importance of snowflake SAV for the interpretation of snowfall triple-frequency radar signatures.

scholarly journals Different characteristics of char and soot in the atmosphere and their ratio as an indicator for source identification in Xi'an, China

2010 ◽  
Vol 10 (2) ◽  
pp. 595-607 ◽  
Author(s):  
Y. M. Han ◽  
J.J. Cao ◽  
S. C. Lee ◽  
K. F. Ho ◽  
Z. S. An
Keyword(s):  
Seasonal Variations ◽  
Source Identification ◽  
Carbonaceous Material ◽  
Total Carbon ◽  
Carbonaceous Aerosol ◽  
Poor Correlation ◽  
Minimum Concentration ◽  
Carbonaceous Particles ◽  
Carbon Fractions ◽  
Different Characteristics

Abstract. Numerous definitions and analytical techniques for elemental (or black) carbon (EC) have been published in the scientific literature, but still no generally accepted interdisciplinary definition exists. EC is not a single chemical compound, but is mainly composed of two parts of carbon contents: combustion residues from pyrolysis and combustion emissions formed via gas-to-particle conversion. Accordingly EC is subdivided into two classes: char and soot. Char is defined as carbonaceous materials obtained by heating organic substances and formed directly from pyrolysis, or as an impure form of graphitic carbon obtained as a residue when carbonaceous material is partially burned or heated with limited access of air. Soot is defined as only those carbon particles that form at high temperature via gas-phase processes. Since the different classes of EC have different chemical and physical properties, their optical light-absorbing properties differ, so that it is essential to differentiate them in the environment. The thermal optical reflectance (TOR) method was used to differentiate between char-EC and soot-EC according to its stepwise thermal evolutional oxidation of different carbon fractions under different temperatures and atmosphere. Char-EC and soot-EC are operationally defined as EC1-OP and EC2+EC3 (EC1, EC2 and EC3 corresponding to carbon fractions evolved at 550, 700 and 800 °C in a 98% He/2% O2 atmosphere, respectively), respectively. One year of observations of the daily and seasonal variations of carbonaceous particles were conducted in Xi'an, China in 2004 to demonstrate the different characteristics of char and soot in the atmosphere. Total carbon (TC), organic carbon (OC), EC and char-EC showed similar seasonal trends, with high concentrations in winter and low concentrations in summer, while soot-EC revealed relatively small seasonal variations, with maximum concentration (1.85±0.72 μg m−3) in spring and minimum concentration (1.15±0.47 μg m−3) in summer. The strong correlation between EC and char-EC (R2 = 0.99) and poor correlation between EC and soot-EC (R2 = 0.31) indicate that previously reported total EC in the literature reflected the distribution characteristics of char only, while overlooking that of soot. However, soot exhibits stronger light-absorbing characteristics than char, and merits greater focus in climate research. The small seasonal variation of soot-EC indicates that soot may be the background fraction in total EC, and is likely to have an even longer lifetime in the atmosphere than previously estimated for total EC, which suggests that soot may has a greater contribution to global warming. While both char-EC/soot-EC and primary OC/EC ratios vary with emission sources, only OC/EC ratio is affected by SOA. Thus char-EC/soot-EC may be a more effective indicator than OC/EC in source identification of carbonaceous aerosol. Comparison of seasonal variations of OC/EC and char-EC/soot-EC ratios in Xi'an confirms this point. However, wet scavenging by snow and rain was more effective for char than for soot and influenced the char-EC/soot-EC ratio, and this factor should be considered in source identification as well.

scholarly journals Comparative methodological studies of L-asparaginase encapsulation into erythrocytes

2018 ◽  
Vol 13 (3) ◽  
pp. 91-101
Author(s):  
D. V. Borsakova ◽  
M. E. Plakhotnik ◽  
L. D. Koleva ◽  
E. A. Bovt ◽  
Yu. G. Alexandrovich ◽  
...  
Keyword(s):  
Lymphoblastic Leukemia ◽  
Comparative Investigation ◽  
Hypertonic Solution ◽  
Clinical Use ◽  
Hematological Indices ◽  
Healthy Donors ◽  
Wide Range ◽  
Before And After ◽  
Hypotonic Buffer ◽  
Flow Dialysis

Background. L-asparaginase is an enzyme, widely used in the therapy of acute lymphoblastic leukemia in children and adults, but its use is limited due to a wide range of side effects and anaphylactic reactions. L-asparaginase loaded into erythrocytes can solve these problems. This enzyme is protected from the immune system and plasma proteases due to erythrocyte membrane, but continues to work inside the cell because its membrane is permeable to L-asparagine. Thus, the half-life of the drug increases and anaphylactic reactions reduce. The encapsulation of L-asparaginase into erythrocytes can be performed by various osmotic methods. Each of them is characterized by the amount of encapsulated enzyme, the cell yield, as well as by the quality indices of the survived erythrocytes. An important parameter of each method is the possibility to provide sterility of this dosage form for the clinical use.The aim of the study was the comparing of three osmotic methods of L-asparaginase encapsulation into erythrocytes (hypo-osmotic lysis, dialysis and flow dialysis) to select the most promising method for clinical use.Materials and methods. A suspension of erythrocytes of healthy donors (hematocrit 60–70%) was mixed with L-asparaginase from E. сoli. The procedures of hypotonic reversible lysis, dialysis in dialysis bags, or flow dialysis using pediatric dialyzers were performed. The physiological osmolality was restored in suspensions after the procedure by the addition of a hypertonic solution, and they were incubated for 30 min at 37 °C. Then the cells were washed in isotonic phosphate-buffered saline with pH 7.4. Activity of L-asparaginase, volume, hematocrit, hematological indices and osmotic cell fragility of erythrocytes were measured in the suspensions of erythrocytes before and after the enzyme encapsulation procedure.Results. An optimal osmolality of the hypotonic buffer for each method was selected and was equal to 90–110 mOsm/kg. The yields of encapsulation were 4.2 ± 2.0, 6.0 ± 2.3 and 16.2 ± 2.2 % for hypotonic lysis, dialysis and flow dialysis, respectively. The hematological indices of the obtained erythrocyte-carriers differed from the corresponding parameters of the initial erythrocytes, but did not differ significantly for different methods.Conclusion. Comparative investigation of mentioned above parameters allowed choosing the method of flow dialysis as the most promising for clinical use.

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