313 research outputs found
A new semi-analytical flow model for multi-branch well testing in natural gas hydrates
This paper presents a new semi-analytical solution and the related methodology to analyze the pressure behavior of multi-branch wells produced from natural gas hydrates. For constant bottom-hole pressure production, the transient flow solution is obtained by Laplace transforms. The interference among various branches is investigated using the superposition principle. A simplified form of the proposed model is validated using published analytical solutions. The complete flow profile can be divided into nine distinct regimes: wellbore storage and skin, vertical radial flow, linear flow, pseudo-radial flow, composite flow, dissociated flow, transitional flow, improvement flow and stress-sensitive flow. A wellâs multi-branch structure governs the vertical radial and the linear flow regimes. In our model, a dynamic interface divides the natural gas hydrates deposit into dissociated and non-dissociated regions. Natural gas hydrates formation properties govern the compositeeffect, dissociated, transitional, and improvement flow regimes. A dissociation coefficient governs the difference in flow resistance between dissociated and non-dissociated natural gas hydrates regions. The dissociated-zone radius affects the timing of these flow regimes. Conversion of natural gas hydrates to natural gas becomes instantaneous as the dissociation coefficient increases. The pressure derivative exhibits the same features as a homogeneous formation. The natural gas hydrates parameter values in the Shenhu area of the South China Sea cause the prominent dissociated flow regime to conceal the later transitional and improvement flow regimes. Due to the maximum practical well-test duration limitation, the first five flow regimes (through composite flow) are more likely to appear in practice than later flow regimes.Cited as: Chu, H., Zhang, J., Zhang, L., Ma, T, Gao Y., Lee, W. J. A new semi-analytical flow model for multi-branch well testing in natural gas hydrates. Advances in Geo-Energy Research, 2023, 7(3): 176-188. https://doi.org/10.46690/ager.2023.03.0
Cross-Modal Attention Effects in the Vestibular Cortex during Attentive Tracking of Moving Objects
The midposterior fundus of the Sylvian fissure in the human brain is central to the cortical processing of vestibular cues. At least two vestibular areas are located at this site: the parietoinsular vestibular cortex (PIVC) and the posterior insular cortex (PIC). It is now well established that activity in sensory systems is subject to cross-modal attention effects. Attending to a stimulus in one sensory modality enhances activity in the corresponding cortical sensory system, but simultaneously suppresses activity in other sensory systems. Here, we wanted to probe whether such cross-modal attention effects also target the vestibular system. To this end, weused a visual multiple-object tracking task. By parametrically varying the number of tracked targets, we could measure the effect of attentional load on the PIVC and the PIC while holding the perceptual load constant. Participants performed the tracking task during functional magnetic resonance imaging. Results show that, compared with passive viewing of object motion, activity during object tracking was suppressed in the PIVC and enhanced in the PIC. Greater attentional load, induced by increasing the number of tracked targets, was associated with a corresponding increase in the suppression of activity in the PIVC. Activity in the anterior part of the PIC decreased with increasing load, whereas load effects were absent in the posterior PIC. Results of a control experiment show that attention-induced suppression in the PIVC is stronger than any suppression evoked by the visual stimulus per se. Overall, our results suggest that attention has a cross-modal modulatory effect on the vestibular cortex during visual object tracking
Biophysical Phenotyping and Modulation of ALDH+ Inflammatory Breast Cancer StemâLike Cells
Cancer stemâlike cells (CSCs) have been shown to initiate tumorigenesis and cancer metastasis in many cancer types. Although identification of CSCs through specific marker expression helps define the CSC compartment, it does not directly provide information on how or why this cancer cell subpopulation is more metastatic or tumorigenic. In this study, the functional and biophysical characteristics of aggressive and lethal inflammatory breast cancer (IBC) CSCs at the singleâcell level are comprehensively profiled using multiple microengineered tools. Distinct functional (cell migration, growth, adhesion, invasion and selfârenewal) and biophysical (cell deformability, adhesion strength and contractility) properties of ALDH+ SUM149 IBC CSCs are found as compared to their ALDHâ nonâCSC counterpart, providing biophysical insights into why CSCs has an enhanced propensity to metastasize. It is further shown that the cellular biophysical phenotype can predict and determine IBC cellsâ tumorigenic ability. SUM149 and SUM159 IBC cells selected and modulated through biophysical attributesâadhesion and stiffnessâshow characteristics of CSCs in vitro and enhance tumorigenicity in in vivo murine models of primary tumor growth. Overall, the multiparametric cellular biophysical phenotyping and modulation of IBC CSCs yields a new understanding of IBCâs metastatic properties and how they might develop and be targeted for therapeutic interventions.This study comprehensively profiles the biophysical characteristics of inflammatory breast cancer stemâlike cells to delineate the soâcalled âbiophysical phenotypeâ of the model of the most metastatic breast cancer subtype. Evidence indicates that the cellular biophysical phenotype can predict and determine cancer cellsâ tumorigenic ability.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/1/smll201802891_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/2/smll201802891.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/3/smll201802891-sup-0001-S1.pd
Enhancing mHealth Technology in the Patient-Centered Medical Home Environment to Activate Patients With Type 2 Diabetes: A Multisite Feasibility Study Protocol.
BackgroundThe potential of mHealth technologies in the care of patients with diabetes and other chronic conditions has captured the attention of clinicians and researchers. Efforts to date have incorporated a variety of tools and techniques, including Web-based portals, short message service (SMS) text messaging, remote collection of biometric data, electronic coaching, electronic-based health education, secure email communication between visits, and electronic collection of lifestyle and quality-of-life surveys. Each of these tools, used alone or in combination, have demonstrated varying degrees of effectiveness. Some of the more promising results have been demonstrated using regular collection of biometric devices, SMS text messaging, secure email communication with clinical teams, and regular reporting of quality-of-life variables. In this study, we seek to incorporate several of the most promising mHealth capabilities in a patient-centered medical home (PCMH) workflow.ObjectiveWe aim to address underlying technology needs and gaps related to the use of mHealth technology and the activation of patients living with type 2 diabetes. Stated differently, we enable supporting technologies while seeking to influence patient activation and self-care activities.MethodsThis is a multisite phased study, conducted within the US Military Health System, that includes a user-centered design phase and a PCMH-based feasibility trial. In phase 1, we will assess both patient and provider preferences regarding the enhancement of the enabling technology capabilities for type 2 diabetes chronic care management. Phase 2 research will be a single-blinded 12-month feasibility study that incorporates randomization principles. Phase 2 research will seek to improve patient activation and self-care activities through the use of the Mobile Health Care Environment with tailored behavioral messaging. The primary outcome measure is the Patient Activation Measure scores. Secondary outcome measures are Summary of Diabetes Self-care Activities Measure scores, clinical measures, comorbid conditions, health services resource consumption, and technology system usage statistics.ResultsWe have completed phase 1 data collection. Formal analysis of phase 1 data has not been completed. We have obtained institutional review board approval and began phase 1 research in late fall 2016.ConclusionsThe study hypotheses suggest that patients can, and will, improve their activation in chronic care management. Improved activation should translate into improved diabetes self-care. Expected benefits of this research to the scientific community and health care services include improved understanding of how to leverage mHealth technology to activate patients living with type 2 diabetes in self-management behaviors. The research will shed light on implementation strategies in integrating mHealth into the clinical workflow of the PCMH setting.Trial registrationClinicalTrials.gov NCT02949037. https://clinicaltrials.gov/ct2/show/NCT02949037. (Archived by WebCite at http://www.webcitation.org/6oRyDzqei)
AluScan: a method for genome-wide scanning of sequence and structure variations in the human genome
<p>Abstract</p> <p>Background</p> <p>To complement next-generation sequencing technologies, there is a pressing need for efficient pre-sequencing capture methods with reduced costs and DNA requirement. The Alu family of short interspersed nucleotide elements is the most abundant type of transposable elements in the human genome and a recognized source of genome instability. With over one million Alu elements distributed throughout the genome, they are well positioned to facilitate genome-wide sequence amplification and capture of regions likely to harbor genetic variation hotspots of biological relevance.</p> <p>Results</p> <p>Here we report on the use of inter-Alu PCR with an enhanced range of amplicons in conjunction with next-generation sequencing to generate an Alu-anchored scan, or 'AluScan', of DNA sequences between Alu transposons, where Alu consensus sequence-based 'H-type' PCR primers that elongate outward from the head of an Alu element are combined with 'T-type' primers elongating from the poly-A containing tail to achieve huge amplicon range. To illustrate the method, glioma DNA was compared with white blood cell control DNA of the same patient by means of AluScan. The over 10 Mb sequences obtained, derived from more than 8,000 genes spread over all the chromosomes, revealed a highly reproducible capture of genomic sequences enriched in genic sequences and cancer candidate gene regions. Requiring only sub-micrograms of sample DNA, the power of AluScan as a discovery tool for genetic variations was demonstrated by the identification of 357 instances of loss of heterozygosity, 341 somatic indels, 274 somatic SNVs, and seven potential somatic SNV hotspots between control and glioma DNA.</p> <p>Conclusions</p> <p>AluScan, implemented with just a small number of H-type and T-type inter-Alu PCR primers, provides an effective capture of a diversity of genome-wide sequences for analysis. The method, by enabling an examination of gene-enriched regions containing exons, introns, and intergenic sequences with modest capture and sequencing costs, computation workload and DNA sample requirement is particularly well suited for accelerating the discovery of somatic mutations, as well as analysis of disease-predisposing germline polymorphisms, by making possible the comparative genome-wide scanning of DNA sequences from large human cohorts.</p
Convergence Analysis for Mathematical Programs with Distributionally Robust Chance Constraint
Oral Pathobiont Activates Anti-Apoptotic Pathway, Promoting both Immune Suppression and Oncogenic Cell Proliferation.
Chronic periodontitis (CP) is a microbial dysbiotic disease linked to increased risk of oral squamous cell carcinomas (OSCCs). To address the underlying mechanisms, mouse and human cell infection models and human biopsy samples were employed. We show that the \u27keystone\u27 pathogen Porphyromonas gingivalis, disrupts immune surveillance by generating myeloid-derived dendritic suppressor cells (MDDSCs) from monocytes. MDDSCs inhibit CTLs and induce FOXP3â+â
Synthesis and Characterization of Glomerate GaN Nanowires
Glomerate GaN nanowires were synthesized on Si(111) substrates by annealing sputtered Ga2O3/Co films under flowing ammonia at temperature of 950 °C. X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy and Fourier transformed infrared spectra were used to characterize the morphology, crystallinity and microstructure of the as-synthesized samples. Our results show that the samples are of hexagonal wurtzite structure. For the majority of GaN nanowires, the length is up to tens of microns and the diameter is in the range of 50â200 nm. The growth process of the GaN nanowires is dominated by CoâGaâN alloy mechanism
Discovery and characterization of small molecules that target the Ral GTPase
The Ras-like GTPases RalA and B are important drivers of tumor growth and metastasis. Chemicals that block Ral function would be valuable as research tools and for cancer therapeutics. Here, we used protein structure analysis and virtual screening to identify drug-like molecules that bind a site on the GDP-form of Ral. Compounds RBC6, RBC8 and RBC10 inhibited Ral binding to its effector RalBP1, Ral-mediated cell spreading in murine fibroblasts and anchorage-independent growth of human cancer cell lines. Binding of RBC8 derivative BQU57 to RalB was confirmed by isothermal titration calorimetry, surface plasma resonance and 15N-HSQC NMR. RBC8 and BQU57 show selectivity for Ral relative to Ras or Rho and inhibit xenograft tumor growth similar to depletion of Ral by siRNA. Our results show the utility of structure-based discovery for development of therapeutics for Ral-dependent cancers
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