The injection of CO2 into deep geological structures for the purpose of CO2 storage and/or enhanced oil recovery (CO2-EOR) may trigger a series of consecutive chemical reactions (e.g. mineral ...dissolution and asphaltene precipitation) and physical effects (e.g. mechanical compaction and permeability variation). These reactions can significantly impact carbonate reservoirs, due to the presence of highly reactive minerals (e.g. dolomite and calcite), as well as the solvent/precipitation effects of supercritical CO2 on complex crude oil mixtures potentially containing heavy fractions such as wax and asphaltene. A core flooding study has been carried out to evaluate changes in the petrophysical properties of a number of heterogeneous carbonate samples (i.e. limestone and dolostone) after undergoing EOR activities under in situ reservoir conditions. In this study, a number of different measurement techniques are conducted to obtain a comprehensive view of the role that mineral dissolution, mechanical compaction and asphaltene precipitation plays during CO2-EOR in carbonate reservoirs.
The results show that CO2 injection results in higher oil recovery in all the samples evaluated as part of this study. However, early water breakthrough was observed for most samples suggesting a high degree of heterogeneity in the carbonate core samples. In all samples, a decrease in permeability was observed presumably due to asphaltene/resin precipitation and mineral dissolution/precipitation. Chemical analyses of the produced crude oil and scanning electron microscopy images confirmed the precipitation of asphaltene and mineral dissolution that caused permeability reduction. Furthermore, as CO2 concentration in the oil/CO2 mixture increased more asphaltene/resin precipitation was observed. More asphaltene precipitation was observed in higher permeability and more vuggy core samples than in those with intermediate or low permeabilities. This observation can be possibly attributed to relaxation of fluids as they enter the relatively large vugs (with large surface area) from the pore-throats resulting in the flocculation and/or precipitation of asphaltenes. A slight reduction in porosity and pore size was observed in most samples presumably caused by a combination of mineral/asphaltene precipitation and physical compaction.
Overall, the results obtained in this study further highlight the complexities associated with the application of CO2-EOR in underground oil reservoirs where both the crude oil and the rock formation may be expected to interact with the injected fluids. Further research into the underling mechanisms is required.
Reloading of atrophied muscles after hindlimb suspension (HLS) can induce muscle injury and prolong recovery after disuse in old rats, especially in fast contracting muscles. Less is known about the ...responses in mice and whether fast and slow muscles from geriatric mice will respond in a similar fashion to HLS unloading and recovery (HLS + R). Furthermore, while slow muscles undergo atrophy with disuse, they typically are more resistant to sarcopenia than fast contracting muscles. Geriatric (28 mo. of age) male C57BL/6 mice were randomly placed into 3 groups. These included HLS for 14 days n = 9, and HLS followed by 14 days of reloading recovery (HLS + R; n = 9), or normal ambulatory cage controls (n = 9). Control mice were not exposed to unloading. Electrically evoked maximal muscle function was assessed in vivo in anesthetized mice at baseline, after 14 days of HLS or HLS + R. As expected, HLS significantly reduced body weight, wet weight of gastrocnemius and soleus muscles and in vivo maximal force. There were no differences in vivo fatigability of the plantar flexor muscles and overall fiber size. There were only minor fiber type distribution and frequency distribution of fiber sizes that differ between HLS + R and control gastrocnemius and soleus muscles. Soleus muscle wet weight had recovered to control levels after reloading, but type I/IIA fibers in the soleus muscles were significantly smaller after HLS + R than control muscles. In contrast, gastrocnemius muscle wet weight did not recover to control levels after reloading. Plantar flexion muscle force (primarily influenced by the gastrocnemius muscles) did not recover in HLS + R conditions as compared to HLS conditions and both were lower than control force production signaling for apoptosis, autophagy and anabolic markers were not different between control and HLS + R gastrocnemius and soleus muscles in geriatric mice. These results suggest that molecular signaling does not explain attenuated ability to regain muscle wet weight, fiber size or muscle force production after HLS in geriatric mice. It is possible that fluid shifts, reduced blood flow, or shortened muscle fibers which failed to regain control lengths contributed to the attenuation of muscle wet weight after HLS and reloading and this affected force production. Further work is needed to determine if altered/loss of neural activity contributed to the inability of geriatric mice to regain gastrocnemius muscle weight and function after HLS and reloading.
•The consequences of disuse followed by reloading were studied in geriatric mice.•Soleus muscle mass recovered to control levels following reloading after disuse.•Gastrocnemius muscle mass and force failed to recover with reloading after disuse.•Molecular signaling for apoptosis or autophagy could not account for failure to recover muscle mass or function.•Disuse followed by reloading did not amplify muscle dysfunction and loss associated with aging-induced sarcopenia.
To study the mechanisms of relapse in acute lymphoblastic leukemia (ALL), we performed whole-genome sequencing of 103 diagnosis-relapse-germline trios and ultra-deep sequencing of 208 serial samples ...in 16 patients. Relapse-specific somatic alterations were enriched in 12 genes (NR3C1, NR3C2, TP53, NT5C2, FPGS, CREBBP, MSH2, MSH6, PMS2, WHSC1, PRPS1, and PRPS2) involved in drug response. Their prevalence was 17% in very early relapse (<9 months from diagnosis), 65% in early relapse (9-36 months), and 32% in late relapse (>36 months) groups. Convergent evolution, in which multiple subclones harbor mutations in the same drug resistance gene, was observed in 6 relapses and confirmed by single-cell sequencing in 1 case. Mathematical modeling and mutational signature analysis indicated that early relapse resistance acquisition was frequently a 2-step process in which a persistent clone survived initial therapy and later acquired bona fide resistance mutations during therapy. In contrast, very early relapses arose from preexisting resistant clone(s). Two novel relapse-specific mutational signatures, one of which was caused by thiopurine treatment based on in vitro drug exposure experiments, were identified in early and late relapses but were absent from 2540 pan-cancer diagnosis samples and 129 non-ALL relapses. The novel signatures were detected in 27% of relapsed ALLs and were responsible for 46% of acquired resistance mutations in NT5C2, PRPS1, NR3C1, and TP53. These results suggest that chemotherapy-induced drug resistance mutations facilitate a subset of pediatric ALL relapses.
•Chemotherapy-induced mutagenesis may cause drug resistance mutations in ALL, leading to relapse.
•Thiopurines in particular likely cause drug resistance mutations in NT5C2, NR3C1, and TP53.
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Mitochondria Initiate and Regulate Sarcopenia Alway, Stephen E; Mohamed, Junaith S; Myers, Matthew J
Exercise and sport sciences reviews,
04/2017, Letnik:
45, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present the hypothesis that an accumulation of dysfunctional mitochondria initiates a signaling cascade leading to motor neuron and muscle fiber death and culminating in sarcopenia. Interactions ...between neural and muscle cells that contain dysfunctional mitochondria exacerbate sarcopenia. Preventing sarcopenia will require identifying mitochondrial sources of dysfunction that are reversible.
Today’s business customers expect sellers not only to respond effectively to their expressed needs but also to understand their business sufficiently well to proactively address their latent and ...future needs. Yet, research shows that many firms underestimate, misunderstand, or overlook these customer expectations. To draw clarity to this discrepancy, this study explores the notion of proactive customer orientation and examines the degree to which this capability offers an opportunity for competitive advantage. While research in recent years has explored the role of proactive customer orientation in new product performance, empirical investigation in this stream of market orientation literature is significantly underdeveloped. We assess the impact of the proactive customer orientation construct on value creation by taking a novel approach that examines the proactive customer orientation → value → satisfaction → loyalty chain using data from 800 business customers in India, Singapore, Sweden, the United Kingdom, and the United States. We find that, relative to other firm capabilities, proactive customer orientation is the most consistent driver of customer value across our multinational data set. Results also show robust effects for the interaction of proactive and responsive customer orientation to create superior value. Several moderating conditions further frame the impact of this capability: intense levels of customer value change, a global relationship scope, and a transnational relationship structure. Overall, findings significantly advance the understanding of the proactive dimension within market orientation and provide marketers with insights for voice of the customer processes.
Aquatic chemical sensors have experienced rapid development in recent years largely due to advances in the fields of nanotechnology. Accurate in situ monitoring of nutrients is fundamental to ...understanding the biogeochemistry of aquatic ecosystems and is necessary for the sustainable utilization of water resources. Although many sensor technologies can achieve nM detection levels, quality assurance and reliability for long-term sensing in complex environments is still lacking. Furthermore, some sensors suffer from sensitivity to high background ion concentration. This review aims to address these challenges by highlighting recent improvements in aquatic chemical sensors to monitor nitrate (NO3−), nitrite (NO2−), ammonium (NH4+), and phosphate (PO43−) ion concentrations in water. The review critically analyses and compares the performance of these chemical sensors with a particular emphasis on their capability for long-term in situ water monitoring. We also provide an overview on some crucial problems significantly affecting the analytical performance of the sensors. Finally, this review details some recommendations and future directions for improving sensing accuracy and robustness.
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•It is critical to continuously monitor quality water that is in contact with different nutrients.•This work reviews sensor developed to monitor nitrate, nitrite, ammonium, and phosphate ions.•The analytical performance of different sensors has been compared and contrasted.•The challenges facing the different types of chemical nutrients sensors are discussed.•Finally, future outlook and suggestions for improving the sensors’ performance were provided.
Research in collaborative interorganizational relationships has typically focused on the value of these relationships to a specific supply chain partner. Furthermore, the phenomenon has rarely been ...explored in a global setting. Using primary data from 126 cross-border dyads, we investigate the influence of relational learning on the relationship performance of both the buyer and the supplier, testing the contention that both members (1) benefit from relational learning efforts and (2) enjoy equal pieces of the benefits pie. We find that three specific types of relational learning (information sharing, joint sensemaking, and knowledge integration) influence relationship performance, and that these dimensions of relational learning affect supply chain partners in different ways. We draw conclusions regarding the relative value of relational learning for both buyers and suppliers.
Abstract
Motivation
Recent single-cell DNA sequencing technologies enable whole-genome sequencing of hundreds to thousands of individual cells. However, these technologies have ultra-low sequencing ...coverage (<0.5× per cell) which has limited their use to the analysis of large copy-number aberrations (CNAs) in individual cells. While CNAs are useful markers in cancer studies, single-nucleotide mutations are equally important, both in cancer studies and in other applications. However, ultra-low coverage sequencing yields single-nucleotide mutation data that are too sparse for current single-cell analysis methods.
Results
We introduce SBMClone, a method to infer clusters of cells, or clones, that share groups of somatic single-nucleotide mutations. SBMClone uses a stochastic block model to overcome sparsity in ultra-low coverage single-cell sequencing data, and we show that SBMClone accurately infers the true clonal composition on simulated datasets with coverage at low as 0.2×. We applied SBMClone to single-cell whole-genome sequencing data from two breast cancer patients obtained using two different sequencing technologies. On the first patient, sequenced using the 10X Genomics CNV solution with sequencing coverage ≈0.03×, SBMClone recovers the major clonal composition when incorporating a small amount of additional information. On the second patient, where pre- and post-treatment tumor samples were sequenced using DOP-PCR with sequencing coverage ≈0.5×, SBMClone shows that tumor cells are present in the post-treatment sample, contrary to published analysis of this dataset.
Availability and implementation
SBMClone is available on the GitHub repository https://github.com/raphael-group/SBMClone.
Supplementary information
Supplementary data are available at Bioinformatics online.
Face coverings constitute an important strategy for containing pandemics, such as COVID-19. Infection from airborne respiratory viruses including Severe Acute Respiratory Syndrome Coronavirus 2 ...(SARS-CoV-2) can occur in at least three modes; tiny and/or dried aerosols (typically < 1.0 μm) generated through multiple mechanisms including talking, breathing, singing, large droplets (> 0.5 μm) generated during coughing and sneezing, and macro drops transmitted via fomites. While there is a growing number of studies looking at the performance of household materials against some of these situations, to date, there has not been any systematic characterization of household materials against all three modes.
A three-step methodology was developed and used to characterize the performance of 21 different household materials with various material compositions (e.g. cotton, polyester, polypropylene, cellulose and blends) using submicron sodium chloride aerosols, water droplets, and mucous mimicking macro droplets over an aerosol-droplet size range of ~ 20 nm to 0.6 cm.
Except for one thousand-thread-count cotton, most single-layered materials had filtration efficiencies < 20% for sub-micron solid aerosols. However, several of these materials stopped > 80% of larger droplets, even at sneeze-velocities of up to 1700 cm/s. Three or four layers of the same material, or combination materials, would be required to stop macro droplets from permeating out or into the face covering. Such materials can also be boiled for reuse.
Four layers of loosely knit or woven fabrics independent of the composition (e.g. cotton, polyester, nylon or blends) are likely to be effective source controls. One layer of tightly woven fabrics combined with multiple layers of loosely knit or woven fabrics in addition to being source controls can have sub-micron filtration efficiencies > 40% and may offer some protection to the wearer. However, the pressure drop across such fabrics can be high (> 100 Pa).
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