Primary oil recovery from fractured unconventional formations, such as shale or tight sands, is typically less than 10%. The development of an economically viable enhanced oil recovery (EOR) ...technique applicable to unconventional liquid reservoirs (ULRs) would lead to tremendous increases in domestic oil production. Although injection techniques such as waterflooding and CO2 EOR have proven profitable in conventional formations for decades, EOR in ULRs presents a far more difficult challenge. The extremely low permeability and mixed wettability of unconventional formations are the foremost obstacles to success. Because of the challenges associated with water-based EOR techniques (a.k.a., chemical EOR) in shale, several nonaqueous injection fluids have been considered, including CO2, natural gas, and (to a lesser degree) nitrogen. All these fluids have significantly lower viscosities than water, allowing them to more easily penetrate shale nanopores. Unlike water, they also each possess some degree of miscibility with oil, which enables the gas to extract oil through a combination of mechanisms. Based on laboratory-scale experimentation, CO2 and rich natural gas (methane-rich natural gas containing high concentrations of ethane, propane, and butane) are the most promising EOR fluids. The interpretation of results from field tests in the Bakken and Eagle Ford formations have been complicated by interference of frac-hits or well-bashing caused by hydraulic fracturing at nearby wells. In this review we cover mechanisms, laboratory experiments, numerical simulations, and field tests involving high-pressure CO2, natural gas, ethane, nitrogen, and water.
The proliferative and invasive nature of malignant cancers drives lethality. In glioblastoma, these two processes are presumed mutually exclusive and hence termed "go or grow." We identified a ...molecular target that shuttles between these disparate cellular processes-the molecular motor KIF11. Inhibition of KIF11 with a highly specific small-molecule inhibitor stopped the growth of the more treatment-resistant glioblastoma tumor-initiating cells (TICs, or cancer stem cells) as well as non-TICs and impeded tumor initiation and self-renewal of the TIC population. Targeting KIF11 also hit the other arm of the "go or grow" cell fate decision by reducing glioma cell invasion. Administration of a KIF11 inhibitor to mice bearing orthotopic glioblastoma prolonged their survival. In its role as a shared molecular regulator of cell growth and motility across intratumoral heterogeneity, KIF11 is a compelling therapeutic target for glioblastoma.
The Rh(I)-catalyzed allenic Pauson–Khand reaction (APKR) is an efficient, redox-neutral method of synthesizing α-acyloxy cyclopentenones. An enantioselective APKR could provide access to chiral, ...nonracemic α-acyloxy and α-hydroxy cyclopentenones and their corresponding redox derivatives, such as thapsigargin, a cytotoxic natural product with potent antitumor activity. Rapid scrambling of axial chirality of allenyl acetates in the presence of Rh(I) catalysts enables the conversion of racemic allene to enantiopure cyclopentenone product in a dynamic kinetic asymmetric transformation (DyKAT). A combined experimental and computational approach was taken to develop an effective catalytic system to achieve the asymmetric transformation. The optimization of the denticity, and steric and electronic properties of the ancillary ligand (initially (S)-MonoPhos, 58:42 er), afforded a hemilabile bidentate (S)-MonoPhos-alkene-Rh(I) catalyst that provided α-acyloxy cyclopentenone product in up to 14:86 er. Enantioselectivity of the Rh(I)-(S)-MonoPhos-alkene catalyst was rationalized using ligand-substrate steric interactions and distortion energies in the computed transition states. This asymmetric APKR of allenyl acetates is a rare example of a Type I DyKAT reaction of an allene, the first example of DyKAT in a cyclocarbonylation reaction, and the first catalyst-controlled enantioselective APKR.
For 2 weeks in the summer of 2018, K-12 science, technology, engineering, and mathematics (STEM) teachers (n = 40) attended a professional development (PD) that included four sessions focused on ...computer science modeling with follow-up academic year sessions; however, overall, the teachers did not incorporate or utilize modeling means or how as the instructors intended. The purpose of the study is to examine why this occurred, and the authors looked at the teachers’ modeling discourse. Using two theories to connect to practice (terministic screens, and schema theory), the authors collected data via the surveys, interviews, and email reflections. The authors analyzed the results via coding to explore participants’ concept of models and the potential difficulties of implementing computer modeling in their classrooms. Findings show that the term model was interpreted differently by the PD’s faculty team and participants. Further, the authors found that the majority of presenters held differing theories of models than the participants. Participant concepts of models did improve slightly after the PD, but lingering model concepts caused confusion with the anticipated PD results. Conclusions include five general modeling concepts which are presented and explained. Implications are provided showcasing articulated keys for delivering PD that assists in eliminating discursive and theoretical issues. Included are considerations for STEM teacher educators, PD providers, and K-12 teachers. The main study limitations include mixed K-12 teaching participants, distance between participants, a self-selected population, and non-generalizable findings based on qualitative work. Future directions are outlined.
The purpose of this study was to explore how undergraduate college students formed partnerships in informal educational teams to design and build an interdisciplinary, ill-defined, integrated ...science, technology, engineering, and mathematics (STEM) project and translate it to lessons taught to a pre-collegiate student (e.g., K-12 in the US) audience. The authors pursued two research questions: (a) How does an authentic research project provide space for integrating STEM disciplines? (b) How does an authentic research project impact partnerships among team members? Nine undergraduate college students were accepted into the 2020 cohort, forming three teams of three undergraduates each. Teams were roughly composed of one engineering major, one science major, and one education major. Methods of data collection included interviews and field notes. Data were analyzed by assessing the level of partnership achieved based on an already established model. Results indicate that all teams progressed through pre-partnership to at least the partnership (little p) level. Two partnership dimensions achieved the highest (big P) level: one of perception of benefit and one of products and activities. The results have implications that integration of STEM disciplines and forming partnerships could be related, and that building teamwork skills results in products of higher quality. The results are linked to previous research and recommendations for more effective partnerships are provided.
This paper describes the Radio Occultation Processing Package, ROPP, a product of the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF) developed by a large number of ...scientists over many years. A brief review of the concepts, functionality and structure of ROPP is followed by more detailed descriptions of its key capabilities. Example results from a full chain of processing using some of the ROPP tools are presented. Some current and prospective uses of ROPP are given. Instructions on how to access the code and its supporting documentation are provided.
Cellular automata models have emerged as a valuable tool in corrosion management. This manuscript provides an overview of the application of cellular automata models in corrosion research, ...highlighting their benefits and contributions to understanding the complex nature of corrosion processes. Cellular automata models offer a computational approach to simulating corrosion behavior at the microscale, capturing the intricate interactions between electrochemical reactions, material properties, and environmental factors and generating a new vision of predictive maintenance. It reviews the key features of cellular automata, such as the grid-based representation of the material surface, the definition of state variables, and the rules governing cell-state transitions. The ability to model local interactions and emergent global behavior makes cellular automata particularly suitable for simulating corrosion processes. Finally, cellular automata models offer a powerful and versatile approach to studying corrosion processes, expanding models that can continue to enhance our understanding of corrosion and contribute to the development of effective corrosion prevention and control strategies.
Ubiquitin-mediated proteolysis is a key regulatory process in cell cycle progression. The Skp1-Cul1-F-box (SCF) and anaphase-promoting complex (APC) ubiquitin ligases target numerous components of ...the cell cycle machinery for destruction. Throughout the cell cycle, these ligases cooperate to maintain precise levels of key regulatory proteins, and indirectly, each other. Recently, we have identified the deubiquitinase USP37 as a regulator of the cell cycle. USP37 expression is cell cycle-regulated, being expressed in late G1 and ubiquitinated by APCCdh1 in early G1. Here we report that in addition to destruction at G1, a major fraction of USP37 is degraded at the G2/M transition, prior to APC substrates and similar to SCFβTrCP substrates. Consistent with this hypothesis, USP37 interacts with components of the SCF in a βTrCP-dependent manner. Interaction with βTrCP and subsequent degradation is phosphorylation-dependent and is mediated by the Polo-like kinase (Plk1). USP37 is stabilized in G2 by depletion of βTrCP as well as chemical or genetic manipulation of Plk1. Similarly, mutation of the phospho-sites abolishes βTrCP binding and renders USP37 resistant to Plk1 activity. Expression of this mutant hinders the G2/M transition. Our data demonstrate that tight regulation of USP37 levels is required for proper cell cycle progression.
Background: USP37 regulates S-phase progression and is degraded in late M/G1.
Results: USP37 undergoes biphasic degradation during G2 and late M/G1.
Conclusion: SCFβTrCP and APCCdh1 coordinately regulate USP37 during the cell cycle.
Significance: Precise regulation of USP37 activity is required for cell cycle progression.
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