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In stationary natural gas engines, lean-burn combustion offers higher engine efficiencies with simultaneous compliance with emission regulations. A prominent problem that one encounters with lean operation is cyclic variations. Advanced ignition systems offer a potential solution as they suppress cyclic variations in addition to extending the lean ignition limit. In this article, the performance of three ignition systems-conventional spark ignition (SI), single-point laser ignition (LI), and prechamber equipped laser ignition (PCLI)-in a single-cylinder natural gas engine is presented. First, a thorough discussion regarding the efficacy of several metrics, besides coefficient of variation of indicated mean effective pressure (COV_IMEP), in representing combustion instability is presented. This is followed by a discussion about the performance of the three ignition systems at a single operational condition, that is, same excess air ratio (λ) and ignition timing (IT). Next, these metrics are compared at the most optimal operational points for each ignition system, that is, at points where λ and IT are optimized to achieve highest efficiency. From these observations, it is noted that PCLI achieves the highest increase in engine efficiency, Δη = 2.1% points, and outperforms the other two methods of ignition. A closer look reveals that the coefficient of variation in ignition delay (COV_ID) was negligible, whereas that in coefficient of variation in combustion duration (COV_CD) was significantly lower by 2.2% points. However, the metrics COV_ID and COV_CD are not well correlated with COV_IMEP.

Certain highly strained hydrocarbons have been identified as potential high energy density fuels, HEDF. The use of these fuels for aviation purposes has implications towards reduced fuel tank size and longer flight range. However, the soot emissions that accompany the burning of these fuels currently limit their use in practical combustion systems. In this study, experiments were conducted to identify possible means of controlling such emissions. A fuel additive approach was followed as the alternative, which is to incorporate mechanical modifications to the engines, is more expensive and difficult to implement. As commercially available HEDF are limited in quantities, heavily sooting benzene was intended to be used as a surrogate fuel. However, due to the experimental difficulties involved in its use, specifically fuel prevaporization and soot formation in large quantities, ethene was used as the fuel. Various fuel additives were tested for their effectiveness by their addition to ethene in a laminar diffusion flame configuration. Laser induced incandescence (LII) and Laser Light Scattering (LLS) were used in characterizing the soot field in these flames. Laser induced fluorescence measurements of OH and PAH species were performed to identify the changes in the soot oxidation and inception processes respectively. Temperature profiles were measured while employing a rapid insertion thermocouple technique to identify the thermal effects. Among the additives that were tested, CH$\\rm\\sb3OH$ and CS$\\sb2$ were found to be the most effective, with soot reductions of the order 60-80% observed upon their addition. A set of systematic experiments that were performed showed minimal effects due to physical influences, such as differential diffusion, variations in thermal diffusivity, dilution and changes in the temperature fields. The chemical interaction by either additive in soot formation processes was observed to be dominant. While the observed changes in OH radical concentrations could not account for the large soot reductions, substantial reductions were observed in PAH species concentrations. Both the additives, i.e., CH$\\rm\\sb3OH$ and CS$\\sb2$ appear to lead to soot suppression by chemical action while following different pathways. With methanol addition, two distinct chemical effects are argued to be operative: (1) increased OH concentrations in the oxidative regions of the flame, and (2) a decrease in H radical superequilibrium due to enhanced H$\\sb2$ formation upon methanol pyrolysis. Similarly, three potential chemical mechanisms leading to soot suppression are argued to be important with CS$\\sb2$ addition: (1) enhanced oxidation by S radicals that result upon CS$\\sb2$ pyrolysis, (2) a decrease in H, OH, and O radical pool superequilibrium, and (3) diminution of surface growth due to a reduction in the number of active sites. However, the relative importance of these chemical mechanisms could not be ascertained due to various experimental limitations.

This paper reports our efforts to develop an instrument, TG-1, to measure particulate emissions from diesel engines in real-time. TG-1 while based on laser-induced incandescence allows measurements at 10 Hz on typical engine exhausts. Using such an instrument, measurements were performed in the exhaust of a 1.7L Mercedes Benz engine coupled to a low-inertia dynamometer. Comparative measurements performed under engine steady state conditions showed the instrument to agree within ±12% of measurements performed with an SMPS. Moreover, the instrument had far better time response and time resolution than a TEOM® 1105. Also, TG-1 appears to surpass the shortcomings of the TEOM instrument, i.e., of yielding negative values under certain engine conditions and, being sensitive to external vibration.

Lean operation of natural gas fired reciprocating engines has been the preferred mode of operation as it allows low NOx emissions and simultaneous high overall efficiencies. In such engines, the operation point is often close to where the ignition boundary and the knock limiting boundary cross-over. While knocking is, to a large extent, limited by engine design, ignition of leanmixtures is limited by the mode of ignition. Since significant benefits can be achieved by extending the lean-ignition limits, many groups have been researching alternate ways to achieve ignition reliably. One of the methods, laser ignition, appears promising as it achieves ignition at high pressures and under lean conditions relatively easily. However, most of the current knowledge about laser ignition is based on measurements performed at room temperature. In this paper, ignition studies on methane-air mixtures under incylinder conditions are presented. A Rapid Compression Machine (RCM) was designed to reproduce typical in-cylinder conditions of high temperature (~ 490°C) and pressure (~ 80 Bar) at the time of ignition. Experiments were performed comparing conventional coil based ignition (CDI) and laser ignition on methane-air mixtures while varying pressure and equivalence ratio systematically. It was observed that substantial gains are likely with the use of laser ignition as it extends the lean-ignition limit to the flammability limit, i.e.,. ϕ = 0.5. On the other hand, conventional CDI ignition could not ignite mixtures leaner than ϕ = 6. Also, faster combustion times and shorter ignition delays were observed in the case of laser ignition. Through scans performed for minimum required laser energies (MRE), it was noted that the measured values were substantially higher than those reported elsewhere. However, the trends of these values indicate that a laser ignition system designed for ϕ = 0.65 will successfully operate under all equivalence ratios of a typical lean-burn engine.

This manuscript reports the development and validation of the three-dimensional Grit Scale (3-D Grit Scale). The psychometric measure developed has three factors, Perseverance-Commitment (PC), Interest-Passion (IP), and Goal-directed Resilience (GR) through a series of five studies; study 1 ( n  = 409) for item analysis, study 2 ( n  = 334) for exploratory factor analysis, study 3 ( n  = 514) for confirmatory factor analysis and study 4 ( n  = 214) and 5 ( n  = 107) to assess the validity. The sample included students and working professionals aged between 18 and 25, residing in different parts of India. Exploratory and confirmatory factor analyses indicated that the scale excellently fits in the three-correlated factor model and the two-level hierarchical model indexing grit as a total of three first-order factors. The final 17-item 3-D Grit Scale showed adequate internal consistency (Cronbach’s α  = 0.86), and split-half reliability (Spearman-brown = 0.80, Guttman = 0.80). Validation studies showed that the scores of the 3-D Grit Scale were moderately correlated with (a) 12 item grit scale (Duckworth et al., 2007) and the brief resilience scale (smith et al., 2008), indicating good concurrent and convergent validities (b) conscientiousness revealing that both the constructs are mutually exclusive.

Phosphatidylinositol 3′-OH kinase (PI3K)-Akt and transcription factor NF-κB are important molecules involved in the regulation of cell proliferation, apoptosis, and oncogenesis. Both PI3K-Akt and Nuclear Factor-kappaB (NF-κB) are involved in the development and progression of prostate cancer, however, the crosstalk and molecules connecting these pathway remains unclear. A multilevel system representation of the PI3K-Akt and NF-κB pathways was constructed to determine which signaling components contribute to adaptive behavior and coordination. In silico experiments conducted using PI3K-Akt and NF-κB, mathematical models were modularized using biological functionality and were validated using a cell culture system. Our analysis demonstrates that a component representing the IκB kinase (IKK) complex can coordinate these two pathways. It is expected that interruption of this molecule could represent a potential therapeutic target for prostate cancer.

Mechanistic studies of deregulated ERG in prostate cancer and other cancers continue to enhance its role in cancer biology and its utility as a biomarker and therapeutic target. Here, we show that ERG, through its physical interaction with androgen receptor, induces AR aggregation and endoplasmic reticulum stress in the prostate glands of ERG transgenic mice. Histomorphological alterations and the expression of ER stress sensors Atf6, Ire1α, Perk, their downstream effectors Grp78/BiP and eIF2α in ERG transgenic mouse prostate glands indicate the presence of chronic ER stress. Transient activation of apoptotic cell death during early age correlated well with the differential regulation of ER stress sensors, in particular Perk. Epithelial cells derived from ERG transgenic mouse prostates have increased prostasphere formation with resistance to radiation induced cell death. Continued activation of cell survival factors, Atf6 and Ire1α during chronic ER stress due to presence of ERG in prostate epithelium induces survival pathways and provides a selection pressure in the continuum of ERG dependent neoplastic process. These novel insights will enhance the understanding of the mechanistic functions of ERG in prostate tumor biology and towards development of early targeted therapeutic strategies for prostate cancer.

\"Blurred Boundaries: The Discourse of Corruption, the Culture of Politics, and the Imagined State,\" by Akhil Gupta, first appeared in print in 1995 in the pages of American Ethnologist. It went on to become one of the most important and influential articles of recent decades. We talked with Akhil Gupta about how the argument put forward in \"Blurred Boundaries\" came to be. Our conversation touched on the background of the article and the difficulties in getting it published; the relationship of the article to postcolonial scholarship, subaltern studies, feminist studies, and the then emerging literature on globalization; its relationship with other theorists of the state through themes such as Eurocentrism, reification, fantasy, fetishism, and the role of culture in the analysis of the state; and future directions in research on the state, among them, examining emotion and affect, studying the most powerful bureaucracies in nation-states, and developing the emergent literature on corruption.

Macromolecular complexes are essential functional units in nearly all cellular processes, and their atomic-level understanding is critical for elucidating and modulating molecular mechanisms. The Protein Data Bank (PDB) serves as the global repository for experimentally determined structures of macromolecules. Structural data in the PDB offer valuable insights into the dynamics, conformation, and functional states of biological assemblies. However, the current annotation practices lack standardised naming conventions for assemblies in the PDB, complicating the identification of instances representing the same assembly. In this study, we introduce a method leveraging resources external to PDB, such as the Complex Portal, UniProt and Gene Ontology, to describe assemblies and contextualise them within their biological settings accurately. Employing the proposed approach, we assigned standard names to over 90% of unique assemblies in the PDB and provided persistent identifiers for each assembly. This standardisation of assembly data enhances the PDB, facilitating a deeper understanding of macromolecular complexes. Furthermore, the data standardisation improves the PDB’s FAIR attributes, fostering more effective basic and translational research and scientific education.