scholarly journals Mathematical analysis of circadian disruption and metabolic re-entrainment of hepatic gluconeogenesis: the intertwining entraining roles of light and feeding

2018 ◽  
Vol 314 (6) ◽  
pp. E531-E542 ◽  
Author(s):  
Seul-A Bae ◽  
Ioannis P. Androulakis
Keyword(s):  
Circadian Rhythms ◽  
Metabolic Activity ◽  
Driving Forces ◽  
Gene Knockout ◽  
Experimental Studies ◽  
Circadian Disruption ◽  
Hepatic Gluconeogenesis ◽  
Uncertainty Analyses ◽  
The Impact ◽  
The Relationship

The circadian rhythms influence the metabolic activity from molecular level to tissue, organ, and host level. Disruption of the circadian rhythms manifests to the host’s health as metabolic syndromes, including obesity, diabetes, and elevated plasma glucose, eventually leading to cardiovascular diseases. Therefore, it is imperative to understand the mechanism behind the relationship between circadian rhythms and metabolism. To start answering this question, we propose a semimechanistic mathematical model to study the effect of circadian disruption on hepatic gluconeogenesis in humans. Our model takes the light-dark cycle and feeding-fasting cycle as two environmental inputs that entrain the metabolic activity in the liver. The model was validated by comparison with data from mice and rat experimental studies. Formal sensitivity and uncertainty analyses were conducted to elaborate on the driving forces for hepatic gluconeogenesis. Furthermore, simulating the impact of Clock gene knockout suggests that modification to the local pathways tied most closely to the feeding-fasting rhythms may be the most efficient way to restore the disrupted glucose metabolism in liver.

The Growth of Vortices in the Vicinity of a Wall of Elastic Moving Airfoils

2013 ◽  
Author(s):  
Masaki Fuchiwaki ◽  
Tomoki Kurinami ◽  
Kazuhiro Tanaka
Keyword(s):  
Flow Field ◽  
Elastic Body ◽  
Elastic Deformation ◽  
Growth Process ◽  
Experimental Studies ◽  
Strain Component ◽  
Pitching Airfoil ◽  
The Impact ◽  
The Relationship ◽  
Significant Attention

There have been a number of studies on the flow field around a pitching airfoil and a heaving airfoil. Especially, the relationship between the wake structure and the characteristics of dynamic thrust has been clarified. Recently, the flow field around an elastic body has been attracted significant attention and the flow field is treated as a coupled problem between the fluid and structure. The flow field around an elastic body has been investigated primarily by numerical means, and there have been experimental studies. However, the details of the impact of elastic deformation effects on the growth process of vortices generated in the vicinity of the wall have not been clarified. In this study, we investigate the growth process of vortices generated in the vicinity of the wall of elastic moving airfoils experimentally. The elastic NACA0010 generates vortices in a large region of a wall and rolls up vortices, with the vortices growing gradually toward the trailing edge as a result of elastic deformation. The elastic NACA0010 has a characteristic whereby vortices having a rotational component that is stronger than the shear-strain component due to the vorticities in the vicinity of a wall of the elastic NACA0010 change not only spatial change of x- and y-components.

scholarly journals Re-Setting the Circadian Clock Using Exercise against Sarcopenia

2020 ◽  
Vol 21 (9) ◽  
pp. 3106 ◽  
Author(s):  
Youngju Choi ◽  
Jinkyung Cho ◽  
Mi-Hyun No ◽  
Jun-Won Heo ◽  
Eun-Jeong Cho ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Intervention Strategy ◽  
Muscle Metabolism ◽  
Circadian Disruption ◽  
Adverse Health Outcomes ◽  
Exercise Timing ◽  
Underlying Mechanisms ◽  
The Impact

Sarcopenia is defined as the involuntary loss of skeletal muscle mass and function with aging and is associated with several adverse health outcomes. Recently, the disruption of regular circadian rhythms, due to shift work or nocturnal lifestyle, is emerging as a novel deleterious factor for the development of sarcopenia. The underlying mechanisms responsible for circadian disruption-induced sarcopenia include molecular circadian clock and mitochondrial function associated with the regulation of circadian rhythms. Exercise is a potent modulator of skeletal muscle metabolism and is considered to be a crucial preventative and therapeutic intervention strategy for sarcopenia. Moreover, emerging evidence shows that exercise, acting as a zeitgeber (time cue) of the skeletal muscle clock, can be an efficacious tool for re-setting the clock in sarcopenia. In this review, we provide the evidence of the impact of circadian disruption on skeletal muscle loss resulting in sarcopenia. Furthermore, we highlight the importance of exercise timing (i.e., scheduled physical activity) as a novel therapeutic strategy to target circadian disruption in skeletal muscle.

scholarly journals Features of technological processing of seeds with an electromagnetic field of microwave before sowing

2021 ◽  
Vol 845 (1) ◽  
pp. 012142
Author(s):  
S V Vendin
Keyword(s):  
Microwave Heating ◽  
Crop Production ◽  
Heating Temperature ◽  
Experimental Studies ◽  
Microwave Treatment ◽  
Microwave Exposure ◽  
Soil Preparation ◽  
Technological Processing ◽  
The Impact ◽  
The Relationship

Abstract To increase the efficiency of crop production in the arsenal of the agronomic service there is a number of techniques, methods and technologies that reveal the potential of agricultural plants for all stages of production, starting with soil preparation, selection and preparation of seeds for sowing, agrotechnological measures during the growing season, harvesting technologies, storage and processing of products. The article presents the results of experimental studies on the use of the energy of ultra-high frequency electromagnetic fields for pre-sowing treatment of lupine seeds in order to increase their germination. Revealed the relationship between the parameters of microwave exposure and seed germination. The areas of modes where microwave treatment allows to increase germination, as well as areas of modes in which the impact does not reach the planned effect, or has a negative (depressing) effect, have been determined. Recommendations are given for ensuring the optimal modes of microwave processing and ensuring control of the parameters of the technological process. Based on the results obtained, it can be reliably asserted that the region of microwave treatment of lupine seeds, with a result exceeding the control values, is observed at exposure in the range from 50 to 60 s and at a specific microwave power of exposure from 1.0 to 1.17 kW/kg. The best result of an increase in germination by 1.5% was obtained at 60 s and 1.17 kW/kg. When treating seeds, it is recommended to maintain an average microwave heating rate of 0.50 °C/s until an average microwave heating temperature of 51.5 °C is reached.

scholarly journals Characterizing the modern light environment and its influence on circadian rhythms

2021 ◽  
Vol 288 (1955) ◽  
pp. 20210721
Author(s):  
Dennis Khodasevich ◽  
Susan Tsui ◽  
Darwin Keung ◽  
Debra J. Skene ◽  
Victoria Revell ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Light Exposure ◽  
Circadian Disruption ◽  
Light Sources ◽  
Night Time ◽  
Circadian Phase ◽  
Temperature Rhythm ◽  
Four Seasons ◽  
Significant Difference ◽  
The Impact

Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, we measured light exposure and wrist temperature among residents of an urban area during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, across all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference occurring between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modelled the impact of morning and night-time light exposure on the timing of the maximum wrist temperature. We found that morning and night-time light exposure had significant but opposing impacts on maximum wrist temperature timing. Our results demonstrate that, within the range of exposure seen in everyday life, night-time light can delay the onset of the maximum wrist temperature, while morning light can lead to earlier onset. Our results demonstrate that humans are minimizing natural seasonal differences in light exposure, and that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized.

scholarly journals Characterizing the Modern Light Environment and its Influence on Circadian Rhythms

2020 ◽  
Author(s):  
Dennis Khodasevich ◽  
Susan Tsui ◽  
Darwin Keung ◽  
Debra J. Skene ◽  
Micaela E. Martinez
Keyword(s):  
Seasonal Variation ◽  
Circadian Rhythms ◽  
General Population ◽  
Light Exposure ◽  
Circadian Disruption ◽  
Natural Light ◽  
Light Sources ◽  
Four Seasons ◽  
Nighttime Light ◽  
The Impact

AbstractHumans have largely supplanted natural light cycles with a variety of artificial light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. We measured light exposure and wrist temperature among residents of New York City for a full week during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, for all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modeled the impact of morning, afternoon, and nighttime light exposure on the timing of the midline-estimating statistic of rhythm (MESOR). We found that morning light exposure and nighttime light exposure had a significant but opposing impact on MESOR timing. Our results demonstrate that nighttime light can shift/alter circadian rhythms to delay the morning transition from nighttime to daytime physiology, while morning light can lead to earlier onset. Our results demonstrate that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized. Due to the impact of circadian rhythms on health, this is convincing evidence that real-world monitoring of light exposure and circadian rhythms could lead to new advances in personalized medicine.Significance StatementDisruption of circadian rhythms has been linked to various diseases, but the prevalence of circadian disruption among the general population is unknown. Light plays a pivotal role in entraining circadian rhythms to the 24-hour day. Humans have largely supplanted natural light cycles with a variety of electric light sources and by spending large amounts of time indoors. We have shown that individuals experience a pronounced disconnect from natural light cycles. This disconnect includes low daytime light exposure, high levels of light-at-night, and minimal seasonal variation in light exposure. We identified measurable changes in wrist temperature rhythms as a function of differential light exposure during the morning and nighttime hours. Our findings suggest that circadian shifts, and even disruption, may be common in the general population.

An Exploration of the Effects of Photograph Content, Photograph Source, and Price on Consumers’ Online Travel Booking Intentions

2018 ◽  
Vol 59 (1) ◽  
pp. 120-139 ◽  
Author(s):  
Yoojin Shin ◽  
Breffni M. Noone ◽  
Stephani K. A. Robson
Keyword(s):  
Experimental Studies ◽  
Cost Effective ◽  
Information Value ◽  
Consumer Reaction ◽  
Booking Intentions ◽  
Online Travel ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

This research employed two experimental studies to examine the relationship of photograph content with consumers’ online travel booking intentions, the role of photograph source in this relationship, and the impact of photograph content on consumer reaction to price. Study 1’s findings suggest that perceived information value mediates the effect of photograph content on consumers’ booking intentions, with product-focused photographs perceived as being higher in information value than experience-focused photographs. Further, perceived photograph credibility was found to influence consumer reaction to photograph content, with photograph source moderating the photograph content-perceived photograph credibility relationship. Study 2’s findings suggest that photograph content moderates the price–booking intentions relationship. When the price is higher than the average in the market, consumers are likely to rely more heavily on product-focused photographs than on experience-focused photographs to inform the booking decision. Together, the findings of these studies can guide travel marketers in developing cost-effective, photograph-based online content.

Hemodialysis using a Constant Potassium Gradient: Rationale of a Multicenter Study

1995 ◽  
Vol 18 (11) ◽  
pp. 731-734
Author(s):  
B. Redaelli ◽  
D. Limido ◽  
P. Beretta ◽  
M.R. Viganò
Keyword(s):  
Experimental Studies ◽  
Plasma Potassium ◽  
Resting Membrane Potential ◽  
Membrane Hyperpolarization ◽  
Kd Values ◽  
Clinical Consequences ◽  
K Concentration ◽  
The Impact ◽  
The Relationship ◽  
Potassium Gradient

The aim of this study is to evaluate the relationship between two different procedures for potassium removal during hemodialysis (HD) and cardiac arrhythmias. Cell excitability and the transmission of impulses may be influenced by variations of resting membrane potential (RMP). The rapid decrease of plasma potassium during the first two hours of standard HD causes a membrane hyperpolarization. A different K+ kinetic, with a gradual and constant elimination of K+ during HD, may reduce this further unphysiological aspect and its clinical consequences. This can be obtained keeping blood-dialysate K+ gradient as constant as possible with the use of a dialysate K+ concentration (Kd) decreasing during HD. Our experimental studies on various K+ intradialytic gradients seem to indicate as optimal to this purpose K+ gradients of 1.5 mEq/l at the beginning of dialysis, esponentially decreasing during treatment to Kd values of 2.5 mEq/l at the end of dialysis (variable Kd). Patients included in the trial will be submitted to two different methods of treatment with Kd 2 mEq/l and variable Kd, and to a 24 hours ECG the day of dialysis. We will compare the number of intra and interdialytic premature ventricular complexes to evaluate the impact of two different models of potassium removal on arrhythmias.

scholarly journals Unified Theory for Flexural Strengthening of Masonry with Composites

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 680 ◽  
Author(s):  
Giancarlo Ramaglia ◽  
Francesco Fabbrocino ◽  
Gian Lignola ◽  
Andrea Prota
Keyword(s):  
Experimental Studies ◽  
Flexural Behavior ◽  
Strongly Correlated ◽  
General Validity ◽  
Flexural Strengthening ◽  
Strain Relationship ◽  
Low Efficiency ◽  
The Impact ◽  
The Relationship ◽  
Further Development

Recent calamitous events have shown the fragility of the existing masonry buildings. Many of them are heritage structures, such as churches and monumental buildings. Therefore, optimized strengthening strategies are necessary. Experimental studies performed on masonry elements strengthened with composite systems have shown the performance of these materials. However, further development is necessary to optimize the intervention strategies. In fact, due to the lack of general validity models, the design is usually based on prescriptive approaches according to manufacturers’ broad instructions, often producing systems with low efficiency and overestimations of the amount of reinforcement. In this paper a generalized approach is proposed to assess the flexural behavior of masonry sections strengthened with composites. The proposed theory has allowed performance of a sensitivity analysis assessing the impact both of the mechanical parameters of masonry and of the strengthening system. In particular, the impact of several constitutive relationships of composites (linear, bilinear, or trilinear) have been evaluated in terms of ultimate behavior of the strengthened masonry. For strengthening systems more compatible with the masonry substrate, the form of the stress–strain relationship becomes a key aspect. For such cases, the modeling of the reinforcement plays a fundamental role and the form of the relationship is strongly correlated to the type of reinforcement selected, e.g., organic versus inorganic matrix.

scholarly journals Microbiota and Immune-Mediated Skin Diseases—An Overview

2019 ◽  
Vol 7 (9) ◽  
pp. 279 ◽  
Author(s):  
Adrian Catinean ◽  
Maria Adriana Neag ◽  
Andrei Otto Mitre ◽  
Corina Ioana Bocsan ◽  
Anca Dana Buzoianu
Keyword(s):  
Autoimmune Diseases ◽  
Beneficial Effect ◽  
Skin Diseases ◽  
Experimental Studies ◽  
Immune Mediated ◽  
The Impact ◽  
The Relationship

In recent years, increased attention has been paid to the relationship between microbiota and various diseases, especially immune-mediated diseases. Because conventional therapy for many autoimmune diseases is limited both in efficacy and safety, there is an increased interest in identifying nutraceuticals, particularly probiotics, able to modulate the microbiota and ameliorate these diseases. In this review, we analyzed the research focused on the role of gut microbiota and skin in immunity, their role in immune-mediated skin diseases (IMSDs), and the beneficial effect of probiotics in patients with this pathology. We selected articles published between 2009 and 2019 in PubMed and ScienceDirect that provided information regarding microbiota, IMSDs and the role of probiotics in these diseases. We included results from different types of studies including observational and interventional clinical trials or in vivo and in vitro experimental studies. Our results showed that probiotics have a beneficial effect in changing the microbiota of patients with IMSDs; they also influence disease progression. Further studies are needed to better understand the impact of new therapies on intestinal microbiota. It is also important to determine whether the microbiota of patients with autoimmune diseases can be manipulated in order to restore homeostasis of the microbiota.

scholarly journals Understanding the Impact of Transformational Leadership on Project Success: A Meta-Analysis Perspective

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Na Zhao ◽  
Dongjiao Fan ◽  
Yun Chen
Keyword(s):  
Transformational Leadership ◽  
Project Success ◽  
Driving Forces ◽  
Meta Analysis ◽  
Cultural Background ◽  
Eastern Culture ◽  
Project Construction ◽  
Primary Driver ◽  
The Impact ◽  
The Relationship

This paper aims to systematically analyze the reasons for the differences in the relationship between transformational leadership (TL) and project success and apply meta-analysis to summarize which dimensions of TL are the main driving forces for project success. Adopting the meta-analysis approach, we investigated 31 independent studies (N = 6475) and studied the theoretical moderators of this relationship from the perspectives of mediating variables, cultural background, and document type to test whether the moderating effects can explain the inconsistent research results. The results reveal that TL positively affects project success and leadership charm is the primary driver of TL. Also, the existence of a mediating mechanism has a more significant impact on the success of the leading project. Meanwhile, compared with project construction under the Western cultural background, countries with Eastern culture are more inclined to use a people-oriented philosophy for project management to promote project success. This research provides an empirical perspective to help project leaders select management talents, regulate leaders’ words and deeds, and cultivate technical and soft leadership skills. Besides, this paper proposes a unique and nuanced view of the relationship between TL and project success, enhancing people’s understanding of the TL’s role in influencing project success.

Sign in / Sign up

Export Citation Format

Share Document