Currently, there is a widespread interest in the different methods of chemical enhanced oil recovery (EOR) as a result of the continuous decline in the conventional oil reserves and the accelerated ...increase in the global energy demand. Surfactant flooding is a well-established method of chemical EOR. This method has proven successful as it increases oil recovery through a combination of mechanisms. These include interfacial tension (IFT) reduction, wettability alteration, foam generation and emulsification. Despite its popularity, surfactant flooding is still challenged by issues including instability under harsh (or normal) reservoir conditions and excessive adsorption. These issues affect the expected oil recovery and thereby reduce the economic returns of EOR projects. Nevertheless, surfactants can be properly selected according to reservoir conditions and rock type. This is usually carried out using surfactant screening methods, which impose limits related to the IFT, surfactant adsorption and other factors under given temperature and salinity conditions. This paper reviews surfactant characterization and phase behavior, the role of surfactants in oil recovery, surfactant adsorption onto reservoir rock, and the application of surfactants in EOR on both laboratory and field scales. Finally, the review presents current research trends and future prospects based on recently published studies in the area of surfactant flooding.
Synthetic biology is bringing together engineers and biologists to design and build novel biomolecular components, networks and pathways, and to use these constructs to rewire and reprogram ...organisms. These re-engineered organisms will change our lives over the coming years, leading to cheaper drugs, 'green' means to fuel our cars and targeted therapies for attacking 'superbugs' and diseases, such as cancer. The de novo engineering of genetic circuits, biological modules and synthetic pathways is beginning to address these crucial problems and is being used in related practical applications.
The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated ...by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobalt-diamine-dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere. The resulting stable and reusable catalysts were active for synthesis of primary, secondary, tertiary, and N-methylamines (more than 140 examples).The reaction couples easily accessible carbonyl compounds (aldehydes and ketones) with ammonia, amines, or nitro compounds, and molecular hydrogen under industrially viable and scalable conditions, offering cost-effective access to numerous amines, amino acid derivatives, and more complex drug targets.
Eukaryotic transcription factors (TFs) perform complex and combinatorial functions within transcriptional networks. Here, we present a synthetic framework for systematically constructing eukaryotic ...transcription functions using artificial zinc fingers, modular DNA-binding domains found within many eukaryotic TFs. Utilizing this platform, we construct a library of orthogonal synthetic transcription factors (sTFs) and use these to wire synthetic transcriptional circuits in yeast. We engineer complex functions, such as tunable output strength and transcriptional cooperativity, by rationally adjusting a decomposed set of key component properties, e.g., DNA specificity, affinity, promoter design, protein-protein interactions. We show that subtle perturbations to these properties can transform an individual sTF between distinct roles (activator, cooperative factor, inhibitory factor) within a transcriptional complex, thus drastically altering the signal processing behavior of multi-input systems. This platform provides new genetic components for synthetic biology and enables bottom-up approaches to understanding the design principles of eukaryotic transcriptional complexes and networks.
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► Zinc fingers can be used to wire orthogonal connections in yeast synthetic circuits ► Zinc finger TF design permits adjustable component properties for modulating outputs ► Protein-protein interactions can be used to engineer cooperativity in zinc finger TFs ► TF component properties can be combinatorially adjusted to reshape signal integration
A library of synthetic eukaryotic transcription factors constructed from modifiable component properties of artificial zinc fingers is capable of modulating outputs and reshaping signal integration.
The K-nearest neighbor (KNN) classifier is one of the simplest and most common classifiers, yet its performance competes with the most complex classifiers in the literature. The core of this ...classifier depends mainly on measuring the distance or similarity between the tested examples and the training examples. This raises a major question about which distance measures to be used for the KNN classifier among a large number of distance and similarity measures available? This review attempts to answer this question through evaluating the performance (measured by accuracy, precision, and recall) of the KNN using a large number of distance measures, tested on a number of real-world data sets, with and without adding different levels of noise. The experimental results show that the performance of KNN classifier depends significantly on the distance used, and the results showed large gaps between the performances of different distances. We found that a recently proposed nonconvex distance performed the best when applied on most data sets comparing with the other tested distances. In addition, the performance of the KNN with this top performing distance degraded only ∼20% while the noise level reaches 90%, this is true for most of the distances used as well. This means that the KNN classifier using any of the top 10 distances tolerates noise to a certain degree. Moreover, the results show that some distances are less affected by the added noise comparing with other distances.
Materials development for artificial photosynthesis, in particular, CO2 reduction, has been under extensive efforts, ranging from inorganic semiconductors to molecular complexes. In this report, we ...demonstrate a metal–organic framework (MOF)-coated nanoparticle photocatalyst with enhanced CO2 reduction activity and stability, which stems from having two different functional units for activity enhancement and catalytic stability combined together as a single construct. Covalently attaching a CO2-to-CO conversion photocatalyst ReI(CO)3(BPYDC)Cl, BPYDC = 2,2′-bipyridine-5,5′-dicarboxylate, to a zirconium MOF, UiO-67 (Re n -MOF), prevents dimerization leading to deactivation. By systematically controlling its density in the framework (n = 0, 1, 2, 3, 5, 11, 16, and 24 complexes per unit cell), the highest photocatalytic activity was found for Re3-MOF. Structural analysis of Re n -MOFs suggests that a fine balance of proximity between photoactive centers is needed for cooperatively enhanced photocatalytic activity, where an optimum number of Re complexes per unit cell should reach the highest activity. Based on the structure–activity correlation of Re n -MOFs, Re3-MOF was coated onto Ag nanocubes (Ag⊂Re3-MOF), which spatially confined photoactive Re centers to the intensified near-surface electric fields at the surface of Ag nanocubes, resulting in a 7-fold enhancement of CO2-to-CO conversion under visible light with long-term stability maintained up to 48 h.
Acute myeloid leukemia (AML) is a heterogeneous disease linked to a broad spectrum of molecular alterations, and as such, long-term disease control requires multiple therapeutic approaches. Driven ...largely by an improved understanding and targeting of these molecular aberrations, AML treatment has rapidly evolved over the last 3-5 years. The stellar successes of immunotherapies that harness the power of T cells to treat solid tumors and an improved understanding of the immune systems of patients with hematologic malignancies have led to major efforts to develop immunotherapies for the treatment of patients with AML. Several immunotherapies that harness T cells against AML are in various stages of preclinical and clinical development. These include bispecific and dual antigen receptor-targeting antibodies (targeted to CD33, CD123, CLL-1, and others), chimeric antigen receptor (CAR) T-cell therapies, and T-cell immune checkpoint inhibitors (including those targeting PD-1, PD-L1, CTLA-4, and newer targets such as TIM3 and STING). The current and future directions of these T-cell-based immunotherapies in the treatment landscape of AML are discussed in this review.
The increased detection of small-sized peripheral non-small-cell lung cancer (NSCLC) has renewed interest in sublobar resection in lieu of lobectomy.
We conducted a multicenter, noninferiority, phase ...3 trial in which patients with NSCLC clinically staged as T1aN0 (tumor size, ≤2 cm) were randomly assigned to undergo sublobar resection or lobar resection after intraoperative confirmation of node-negative disease. The primary end point was disease-free survival, defined as the time between randomization and disease recurrence or death from any cause. Secondary end points were overall survival, locoregional and systemic recurrence, and pulmonary functions.
From June 2007 through March 2017, a total of 697 patients were assigned to undergo sublobar resection (340 patients) or lobar resection (357 patients). After a median follow-up of 7 years, sublobar resection was noninferior to lobar resection for disease-free survival (hazard ratio for disease recurrence or death, 1.01; 90% confidence interval CI, 0.83 to 1.24). In addition, overall survival after sublobar resection was similar to that after lobar resection (hazard ratio for death, 0.95; 95% CI, 0.72 to 1.26). The 5-year disease-free survival was 63.6% (95% CI, 57.9 to 68.8) after sublobar resection and 64.1% (95% CI, 58.5 to 69.0) after lobar resection. The 5-year overall survival was 80.3% (95% CI, 75.5 to 84.3) after sublobar resection and 78.9% (95% CI, 74.1 to 82.9) after lobar resection. No substantial difference was seen between the two groups in the incidence of locoregional or distant recurrence. At 6 months postoperatively, a between-group difference of 2 percentage points was measured in the median percentage of predicted forced expiratory volume in 1 second, favoring the sublobar-resection group.
In patients with peripheral NSCLC with a tumor size of 2 cm or less and pathologically confirmed node-negative disease in the hilar and mediastinal lymph nodes, sublobar resection was not inferior to lobectomy with respect to disease-free survival. Overall survival was similar with the two procedures. (Funded by the National Cancer Institute and others; CALGB 140503 ClinicalTrials.gov number, NCT00499330.).
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