scholarly journals Plankton blooms in vortices: the role of biological and hydrodynamic timescales

2007 ◽  
Vol 14 (4) ◽  
pp. 443-454 ◽  
Author(s):  
M. Sandulescu ◽  
C. López ◽  
E. Hernández-García ◽  
U. Feudel

Abstract. We study the interplay of hydrodynamic mesoscale structures and the growth of plankton in the wake of an island, and its interaction with a coastal upwelling. Our focus is on a mechanism for the emergence of localized plankton blooms in vortices. Using a coupled system of a kinematic flow mimicking the mesoscale structures behind the island and a simple three component model for the marine ecosystem, we show that the long residence times of nutrients and plankton in the vicinity of the island and the confinement of plankton within vortices are key factors for the appearance of localized plankton blooms.

2019 ◽  
Vol 26 (11) ◽  
pp. 800-818
Author(s):  
Zujian Xiong ◽  
Xuejun Li ◽  
Qi Yang

Pituitary Tumor Transforming Gene (PTTG) of human is known as a checkpoint gene in the middle and late stages of mitosis, and is also a proto-oncogene that promotes cell cycle progression. In the nucleus, PTTG works as securin in controlling the mid-term segregation of sister chromatids. Overexpression of PTTG, entering the nucleus with the help of PBF in pituitary adenomas, participates in the regulation of cell cycle, interferes with DNA repair, induces genetic instability, transactivates FGF-2 and VEGF and promotes angiogenesis and tumor invasion. Simultaneously, overexpression of PTTG induces tumor cell senescence through the DNA damage pathway, making pituitary adenoma possessing the potential self-limiting ability. To elucidate the mechanism of PTTG in the regulation of pituitary adenomas, we focus on both the positive and negative function of PTTG and find out key factors interacted with PTTG in pituitary adenomas. Furthermore, we discuss other possible mechanisms correlate with PTTG in pituitary adenoma initiation and development and the potential value of PTTG in clinical treatment.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1283
Author(s):  
Vasileios Ziogas ◽  
Georgia Tanou ◽  
Giasemi Morianou ◽  
Nektarios Kourgialas

Among the various abiotic stresses, drought is the major factor limiting crop productivity worldwide. Citrus has been recognized as a fruit tree crop group of great importance to the global agricultural sector since there are 140 citrus-producing countries worldwide. The majority of citrus-producing areas are subjected to dry and hot summer weather, limited availability of water resources with parallel low-quality irrigation water due to increased salinity regimes. Citrus trees are generally classified as “salt-intolerant” with high water needs, especially during summer. Water scarcity negatively affects plant growth and impairs cell metabolism, affecting the overall tree growth and the quality of produced fruit. Key factors that overall attempt to sustain and withstand the negative effect of salinity and drought stress are the extensive use of rootstocks in citriculture as well as the appropriate agronomical and irrigation practices applied. This review paper emphasizes and summarizes the crucial role of the above factors in the sustainability of citriculture.


2021 ◽  
Vol 2 (2) ◽  
pp. 274-292
Author(s):  
Sarah James ◽  
Edith Joseph

The instability of iron artefacts is rooted in salt contamination during burial and damages associated with exposure to alternative oxygen levels and high relative humidity once excavated. While a combination of chemical and mechanical treatments is utilised to remove the harmful ions (chlorides, sulphur species) and excess bulky corrosion products, these methods can be hazardous for conservation staff’s health, have limited success, or require extensive treatment times. Bio-based treatments provide a potentially greener alternative for removing damaging corrosion and creating biogenic mineral passivation layers, thus remediating concerns over costs, duration, and health and safety. Pseudomonas putida mt-2 (KT2440) is capable of utilising iron under certain conditions and for phosphating mild steel; however, applications have not been made in the cultural heritage sector. To address the potential of using bacteria for conservation purposes, Pseudomonas was assessed for both the bioremediation of salt contaminates and the production of a passivation layer suitable for iron artefacts, with specific conservation concerns in mind. Key factors for optimisation include the role of agitation, chloride content, and oxygen content on bacterial growth and biomineralisation. The initial results indicate a growth preference, not reliance, for NaCl and agitation with partial success of bioconversion of a mineral source.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Tong Shen ◽  
Jing-Lin Liu ◽  
Chu-Yi Wang ◽  
Youlutuziayi Rixiati ◽  
Shi Li ◽  
...  

AbstractThe mechanisms and key factors involved in tumor environments for lung metastasis of CRC are still unclear. Here, using clinical samples from lung metastases of CRC patients, we found that intestinal immune network for IgA production was significantly dysregulated in lung metastases of CRC. Single-cell RNA sequencing discovered a subtype of B cells positive for Erbin, one member of the leucine-rich repeat and PDZ domain (LAP) family, was involved in the lung metastases. Erbin deletion in B cells suppressed lung metastasis of CRC in vivo. And, deletion of Erbin in B cells enhanced the killing effects of CD8+ T cells on tumor cells. Mechanistically, Erbin knockout attenuated TGFβ-mediated suppression of migration of CXCR5+ IgA+ cells and STAT6-mediated PD1 expression. Our study uncovered a key role of Erbin in regulating PD1+ IgA+ B cells in lung metastasis of CRC. Targeting Erbin as well as combined use of neutralizing B cells and antibodies neutralizing PD1 suppresses lung metastasis of CRC in mice, suggesting the potential option for treatment of lung metastasis of CRC.


2021 ◽  
Vol 13 (15) ◽  
pp. 8441
Author(s):  
Michal Hrivnák ◽  
Peter Moritz ◽  
Marcela Chreneková

The COVID-19 pandemic has exposed new aspects of sustainable entrepreneurship and the resilience of SMEs in the conditions of individual countries. This empirical study contributes to entrepreneurship sustainability literature and business resilience literature by estimating the impact of various utilized internal crisis management tools and state compensation measures on retaining the pre-crisis levels of employment after two waves of the pandemic on the conditions of a V4 country. The study adopts an econometric approach towards assessing the influence of key factors of mitigating the problems caused by the pandemic, and the results suggest a crucial role of digitalization, internal policies optimizing variable costs, and utilization of direct governmental supportive measures to compensate for restrictions in force for employment retention in knowledge-intensive SMEs. According to the results, knowledge-intensive SMEs appears to have increased resilience towards economic shocks due to the capability to swiftly change the management of ventures to adapt to a crisis.


Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 436
Author(s):  
Dimitra C. Lazaridou ◽  
Anastasios Michailidis ◽  
Marios Trigkas

The role of a forest sector in the transition to a circular economy (CE) is critical. Therefore, the purpose of this study is to summarize the main findings of the most important published articles and to provide insights on the interdisciplinary space at the interface of concepts related to a forest-based CE. Moreover, it attempts to assess the challenges raised from adopting the CE in forest sector. Through a systematic literature review, 69 scientific publications were selected and evaluated by two sights: (i) a descriptive analysis and (ii) a cluster analysis of the keywords related to the forest-based CE. The study highlights the need for additional survey on optimizing the interaction between forest ecosystem services and circular economy. Further discussion is also needed about the relations of the key factors associated with the forest-based circular economy, as they emerged from the cluster analysis and the co-occurrence network map.


2012 ◽  
Vol 302 (11) ◽  
pp. H2166-H2177 ◽  
Author(s):  
G. Frazziano ◽  
H. C. Champion ◽  
P. J. Pagano

Pulmonary vessel constriction results from an imbalance between vasodilator and vasoconstrictor factors released by the endothelium including nitric oxide, endothelin, prostanoids, and reactive oxygen species (ROS). ROS, generated by a variety of enzymatic sources (such as mitochondria and NADPH oxidases, a.k.a. Nox), appear to play a pivotal role in vascular homeostasis, whereas elevated levels effect vascular disease. The pulmonary circulation is very sensitive to changes in the partial pressure of oxygen and differs from the systemic circulation in its response to this change. In fact, the pulmonary vessels contract in response to low oxygen tension, whereas systemic vessels dilate. Growing evidence suggests that ROS production and ROS-related pathways may be key factors that underlie this differential response to oxygen tension. A major emphasis of our laboratory is the role of Nox isozymes in cardiovascular disease. In this review, we will focus our attention on the role of Nox-derived ROS in the control of pulmonary vascular tone.


2014 ◽  
Vol 458 (2) ◽  
pp. 187-193 ◽  
Author(s):  
María Fernández-Velasco ◽  
Silvia González-Ramos ◽  
Lisardo Boscá

Emerging evidence points to the involvement of specialized cells of the immune system as key drivers in the pathophysiology of cardiovascular diseases. Monocytes are an essential cell component of the innate immune system that rapidly mobilize from the bone marrow to wounded tissues where they differentiate into macrophages or dendritic cells and trigger an immune response. In the healthy heart a limited, but near-constant, number of resident macrophages have been detected; however, this number significantly increases during cardiac damage. Shortly after initial cardiac injury, e.g. myocardial infarction, a large number of macrophages harbouring a pro-inflammatory profile (M1) are rapidly recruited to the cardiac tissue, where they contribute to cardiac remodelling. After this initial period, resolution takes place in the wound, and the infiltrated macrophages display a predominant deactivation/pro-resolution profile (M2), promoting cardiac repair by mediating pro-fibrotic responses. In the present review we focus on the role of the immune cells, particularly in the monocyte/macrophage population, in the progression of the major cardiac pathologies myocardial infarction and atherosclerosis.


2021 ◽  
pp. 205943642110226
Author(s):  
Yanyan Hong

India has long been known for its prestigious Mumbai-based film industry, namely Bollywood, and remains by far the largest producer of films in the world. With the growing global reach of Indian cinema, this study looks at an intriguing Indian-film fever over the last decade in the newly discovered market of China. Through examining key factors that make Indian films appealing to Chinese and exploring the opportunities and challenges of Indian cinema in China, this article draws upon insights gained from the narratives of local audiences. Data were collected from semi-structured interviews with 32 Indian-film audiences residing across 14 different cities in mainland China. Thematic analysis identified the following five appealing factors, which explain why the Chinese enjoy Indian films: content-driven story, social values, star power, audience reviews and cultural connections. While a comprehensive list of opportunities was derived showing the potential future of Bollywood in China, results found that China’s unique institutional context and an ongoing India–China geopolitical tensions also present challenges, which in turn add to the overall complexity of films’ success in the Chinese market. This article argues the powerful role of Bollywood in bridging cultures and improving India–China ties, as Indian films have made Chinese people more aware of India in a favourable way.


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