compositional variation
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2022 ◽  
Vol 169 ◽  
pp. 104220
Author(s):  
Qian Zhang ◽  
Yanlai Han ◽  
Weiqiang Chen ◽  
Yulong Guo ◽  
Mingyu Wu ◽  
...  

2021 ◽  
Author(s):  
Xinxin Zhao ◽  
Qing Lu ◽  
Jingjing Ruan ◽  
Jia Li ◽  
Chengxiang Dai ◽  
...  

Abstract Background: We used textural analysis matrix to examine the spatial distribution of pixel values and detect the compositional variation of repair cartilage with treatment of allogeneic human adipose-derived mesenchymal progenitor cells (haMPCs). Methods: Eighteen patients were divided randomly into three groups with intra-articular injections of haMPCs: the low-dose (1.0×107 cells), mid-dose (2.0×107), and high-dose (5.0×107) group with six patients each. 3D texture analyses based on gray level run-length matrix (GLRLM) of the segmented ROIs on MRI relaxation time maps including T1rho, T2, T2* and R2*. Five GLRLM parameters were analyzed, including run length non-uniformity (RLNonUni), grey level non-uniformity (GLevNonU), long run emphasis (LngREmph), short run emphasis (ShrtREmp) and fraction of image in runs (Fraction). We used the difference before and after treatment (D values) as the object to avoid errors caused by individual differences. Two-tailed Pearson linear correlation analysis was used to investigate correlations between texture parameters and the WOMAC scores. Results: The heterogeneity of spatial distribution of MRI relaxation time mapping pixels from three groups was decreased to varying degrees at 48 weeks after intra-articular injection of haMPCs. Spatial distribution of cartilage relaxation time maps pixels were uneven and layered, especially in T2 maps. Compared with base time, there were significant differences among three dose groups in GLRLM features for T1rho map including RLNonUni, GLevNonU, LngREmph, for T2 map including LngREmph, GLevNonU, ShrtREmp, for T2* map including RLNonUni, GLevNonU, and for R2* map including RLNonUni, GLevNonU. WOMAC pain scores were associated with RLNonUni of T1rho map, GLevNonU of T2 map, LngREmph of T2* map, LngREmph of R2* map and Fraction of T1rho map, whereas no significant correlations in other measurements.Conclusions: MRI texture analysis of cartilage may allow detection of the compositional variation of repair cartilage with treatment of allogeneic haMPCs. This has potential applications in understanding mechanism of stem cells repairing cartilage and assessing response to treatment.Trial registration: Clinicaltrials, NCT02641860. Registered 3 December 2015.https://www.clinicaltrials.gov/ct2/show/NCT02641860


2021 ◽  
Author(s):  
Andrew Lamont Hinton ◽  
Peter J Mucha

The demand for tight integration of compositional data analysis and machine learning methodologies for predictive modeling in high-dimensional settings has increased dramatically with the increasing availability of metagenomics data. We develop the differential compositional variation machine learning framework (DiCoVarML) with robust multi-level log ratio bio-marker discovery for metagenomic datasets. Our framework makes use of the full set of pairwise log ratios, scoring ratios according to their variation between classes and then selecting out a small subset of log ratios to accurately predict classes. Importantly, DiCoVarML supports a targeted feature selection mode enabling researchers to define the number of predictors used to develop models. We demonstrate the performance of our framework for binary classification tasks using both synthetic and real datasets. Selecting from all pairwise log ratios within the DiCoVarML framework provides greater flexibility that can in demonstrated cases lead to higher accuracy and enhanced biological insight.


Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1514
Author(s):  
Iouraouine El Mehdi ◽  
Soraia I. Falcão ◽  
Mustapha Harandou ◽  
Saïd Boujraf ◽  
Ricardo C. Calhelha ◽  
...  

The venom from Apis mellifera intermissa, the main honey bee prevailing in Morocco, has been scarcely studied, despite its known potential for pharmacological applications. In the present work, we investigated the composition, the anti-inflammatory activity, and the venom’s cytotoxic properties from fifteen honey bee venom (HBV) samples collected in three regions: northeast, central, and southern Morocco. The chemical assessment of honey bee venom was performed using LC-DAD/ESI/MSn, NIR spectroscopy and AAS spectroscopy. The antiproliferative effect was evaluated using human tumor cell lines, including breast adenocarcinoma, non-small cell lung carcinoma, cervical carcinoma, hepatocellular carcinoma, and malignant melanoma. Likewise, we assessed the anti-inflammatory activity using the murine macrophage cell line. The study provides information on the honey bee venom subspecies’ main components, such as melittin, apamin, and phospholipase A2, with compositional variation depending on the region of collection. Contents of toxic elements such as cadmium, chromium, and plumb were detected at a concentration below 5 ppm, which can be regarded as safe for pharmaceutical use. The data presented contribute to the first study in HBV from Apis mellifera intermissa and highlight the remarkable antiproliferative and anti-inflammatory effects of HBV, suggesting it to be a candidate natural medicine to explore.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1740
Author(s):  
Patrick Bustrel Choungo Nguekeng ◽  
Prasad Hendre ◽  
Zacharie Tchoundjeu ◽  
Marie Kalousová ◽  
Armelle Verdiane Tchanou Tchapda ◽  
...  

Vitellaria paradoxa (C.F.Gaertn.) is a multi-purpose tree species distributed in a narrow band across sub-Saharan Africa. The species is integrated into cropping and agroforestry systems as a nutritional and economic resource, which provides a range of environmental services. Integration of the species into land-use systems provides an essential source of livelihoods and income for local populations. The economic potential of the shea butter tree derives from its edible products, which also serve cosmetic and pharmaceutical applications. To understand the current state of knowledge about V. paradoxa, this paper summarizes information about the ecology, population structure, and genetic diversity of the species, also considering compositional variation in the pulp and kernels, management practices, and efforts towards its domestication. Despite the great potential of the shea butter tree, there are some gaps in the understanding of the genetics of the species. This review presents up-to-date information related to the species for further domestication and breeding purposes.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3448
Author(s):  
Seid Tiku Mereta ◽  
Pieter Lemmens ◽  
Luc De Meester ◽  
Peter L. M. Goethals ◽  
Pieter Boets

The present study investigates the relative importance of human disturbance, local environmental and spatial factors on variations in bird community composition in natural Ethiopian wetlands with high biodiversity conservation value. We quantified bird abundances, local environmental variables and human disturbances at 63 sites distributed over ten wetlands in two subsequent years. Variation partitioning analyses were used to explore the unique and shared contributions of human disturbance, local environmental variables and spatial factors on variations in community compositions of wetland bird species. Local environmental variables explained the largest amount of compositional variation of wetland bird species. Productivity-related variables were the most important local environmental variables determining bird community composition. Human disturbance was also an important determinant for wetland bird community composition and affected the investigated communities mainly indirectly through its effect on local environmental conditions. Spatial factors only played a minor role in variations in bird community composition. Our study highlights the urgent need for integrated management approaches that consider both nature conservation targets and socio-economic development of the region for the sustainable use and effective conservation of wetland resources.


2021 ◽  
Vol 116 (8) ◽  
pp. 1825-1848
Author(s):  
Wei Li ◽  
Nigel J. Cook ◽  
Gui-Qing Xie ◽  
Jing-Wen Mao ◽  
Cristiana L. Ciobanu ◽  
...  

Abstract Yuhengtang is a representative slate-hosted Au deposit in the Jiangnan orogenic belt, South China, with a reserve of ~55 t Au and an average grade of ~3.9 g/t. Gold mineralization is characterized by veinlet and disseminated ores comprising native gold, auriferous pyrite, and arsenopyrite. Paragenesis of the Yuhengtang deposit can be divided into three stages. Pre-ore stage 1 is composed of bedding-parallel layers of pyrite in slate of the Neoproterozoic Banxi Group. Main ore stage 2 represents the Au mineralization stage, and two distinct types of mineralization can be distinguished: visible Au-arsenopyrite-pyrite in quartz veinlets and auriferous arsenopyrite-pyrite disseminated within altered slate. Post-ore stage 3 consists of quartz-pyrite-calcite-ankerite veins. In this study, we integrate electron microprobe, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and high-resolution ion microprobe (SHRIMP) analyses to document textural, isotopic, and compositional variation among texturally complex pyrite and arsenopyrite assemblages in veinlet and disseminated ores. Additionally, LA-ICP-MS sulfur isotope mapping of pyrite highlights the covariation behavior between trace elements and sulfur isotopes at the grain scale, thus allowing the factors controlling sulfur isotope fractionation in hydrothermal Au deposits to be constrained. Pyrite, of sedimentary origin (stage 1), hosts negligible Au (<1.6 ppm) but is enriched in δ34S (15.6–25.8‰). Pyrite and arsenopyrite from stage 2 veinlet mineralization both display porous and dissolution-reprecipitation textures, have low Au concentrations (<4 and <78 ppm, respectively), and show a large variation in δ34S (–2.7 to 14.7‰ and –10.3 to 12.1‰, respectively). Pyrite and arsenopyrite from disseminated mineralization are, in contrast, characterized by oscillatory zoning textures and homogeneous appearance in backscattered electron (BSE) images, respectively, and are obvious by their relatively high contents of invisible Au (up to 90 and 263 ppm, respectively) and restricted range of δ34S values (0–5.3‰). These data suggest that magmatic-hydrothermal fluids contribute most of the Au and S budget in the Yuhengtang Au deposit. The major differences between veinlet and disseminated mineralization in terms of texture, trace element concentrations, and δ34S signatures of pyrite and arsenopyrite reflect contrasting mechanisms of Au precipitation and an evolution of physicochemical parameters of the ore-forming processes, particularly fO2 and the intensity of fluid-rock interaction. Pyrite from stage 3 appears homogeneous in BSE images yet displays a wide variation in δ34S values (1.2–31.4‰), further highlighting the controlling role played by physicochemical condition (i.e., pressure) on the δ34S signature of sulfides. Results of the coupled LA-ICP-MS sulfur and trace element mapping reveal that some zoned pyrite grains from stage 2 formed via overgrowth of Au-rich, light δ34S (2.4‰) hydrothermal rims onto Au-poor, heavy δ34S (18.1–18.5‰) sedimentary cores. All results support that multiple depositional mechanisms within a dynamic mineral system were responsible for Au concentration and define the specific textural, compositional, and sulfur isotope signatures of sulfides in coexisting vein/veinlet and disseminated mineralization. The new data highlight the ore-forming processes-based interpretation for ore genesis and underpin the importance of performing complementary in situ mineralogical analyses to elucidate the source and evolution of ore-forming fluids and enable correct interpretation of the architecture of the hydrothermal Au system.


2021 ◽  
Vol 923 (1) ◽  
pp. 29
Author(s):  
Xiaoshu Wu ◽  
Jun Cui ◽  
Dandan Niu ◽  
Zhipeng Ren ◽  
Yong Wei

Abstract The Martian ionosphere plays a crucial role in driving the interactions of the planet with solar photons and solar wind particles. The variations of the dayside Martian ionosphere with several controlling factors, including the solar extreme ultraviolet radiation, the background atmosphere, and the underlying thermal structure, have been the topic of extensive research in terms of electron distribution. In contrast, how the ionospheric composition varies has not been systematically investigated, a topic that is attempted in this study based on photochemical equilibrium computations performed at 100–200 km altitude, including a large number of reactions. Our calculations reveal the following compositional variations as natural outcomes of the ionospheric chemistry on Mars. (1) With increasing solar irradiance, the proportions of the majority of nonterminal ions are enhanced at the expense of reduced proportions of terminal ions, including O 2 + , HCO+, NO+, and H3O+. (2) At high electron temperatures, the proportion of NO+ is modestly reduced, whereas the proportions of the other species are nearly unaffected. (3) The response of the ionospheric composition to the upper atmospheric composition is complicated, showing the strong negative response of many trace ions to ambient CO2, O, and CO, as well as the strong positive response of protonated ions to H2, nitrogen-bearing ions to N and N2, water-group ions to H2O, and HO 2 + to O2. As an application of the model results, the recent ion measurements made on board the Mars Atmosphere and Volatile Evolution are used to provide hints about the realistic composition of the Martian upper atmosphere.


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