bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical, gasdynamic, and radiative properties of planar surface discharges
Authors: Beverly III R. E. 
Published: July 2002

An investigation was undertaken of the electrical, gasdynamic, and radiative properties of surface discharges intended as intense optical pump sources for lasers. Large-area (≂20–300 cm2), short-pulse (∼1 μs) planar surface discharges were produced across various ceramic and polymer substrates and operated in all of the rare gases, N2, and air at absolute pressures up to 4 atm. Parametric studies of the electrical circuitry and discharge dimensions demonstrate the importance of proper source-driver impedance matching to short-pulse operation and efficient electrical-to-optical energy conversion. Characteristic times for establishment of a conductive discharge gap in the heavy rare gases are consistent with breakdown by the single-stroke leader mechanism. The electrical strength of the gap following discharge remains low for a time which is much greater than the current duration. The delay in recovery is believed to be controlled by continued substrate ablation occurring after the discharge rather than to mechanisms related to plasma expansion or recombination. A shock wave is launched in a direction perpendicular to the dielectric surface while the plasma remains tightly pressed against the substrate. Measured wave velocities can be correlated with the theory of a Chapman–Jouguet detonation despite the fact that the physical processes in a surface discharge depart significantly from those in an optical detonation. Planar surface discharges radiate as Lambertian sources characterized by effective brightness temperatures ≂10 000–20 000 K (visible wavelengths) for specific input energies of ≂1–4 J/cm2. The plasma is not opaque and does not radiate as an ideal blackbody, but shows considerable structure due to line emission from neutral and singly ionized species originating from the gas atmosphere and vaporized substrate material. Line transitions from excited substrate species can greatly enhance the UV radiative output, especially for discharges across perovskite ceramic substrates.
Radiated energy for the rare gases is almost directly proportional to the atomic weight of the gas. Open-shutter photography, performed both perpendicular and parallel to the discharge plane, is used to develop criteria for obtaining uniform, coalesced discharges.
Acetylene: Synergy between theory and experiment
Authors: Lundberg James K. , Field Robert W. , Sherrill C. David , Seidl Edward T. , Xie Yaoming , Schaefer Henry F. 
Published: July 2002

Six anomalous vibronic feature states [∼2 cm−1 full-width at half-maximum (FWHM), each consisting of ∼20 partially resolved eigenstates] have been observed in stimulated emission pumping (SEP) spectra of C2D2. Of the two plausible assignments for these features, the one most consistent with spectroscopic observations would imply that the lowest energy cis-bent triplet state of acetylene has T0≤25 820 cm−1, which is inconsistent with previous ab initio predictions. New higher level ab initio quantum mechanical methods have been used to predict the energy difference between X̃ 1Σg+ ground state and the cis-bent ã 3B2 lowest triplet state of acetylene. In conjunction with a triple zeta plus double polarization plus f function (TZ2Pf) basis set, the coupled cluster including single, double, and linearized triple excitations CCSD(T) method yields T0=ΔE(ã 3B2–X̃ 1Σg+)=30 500 cm−1. The true value of T0 for the ã 3B2 state is estimated to be ∼500 cm−1 higher. At the same level of theory the zero-point levels of the lowest triplet state of the trans-bent (ã 3Bu) and vinylidene (ã 3B2) isomers lie at still higher energies. This result conclusively rules out any triplet assignment for the anomalous feature states. The alternative assignment, as highly excited vibrational levels of the X̃ 1Σg+ state, is surprising in view of the Franck–Condon selectivity, dynamical stability, and nonselective relaxation of this special class of ‘‘bright states’’ observed in the SEP spectra.
Such an assignment would be implausible in the absence of the present ab initio calculations. Previous experimental observations [Lisy and Klemperer, J. Chem. Phys. 72, 3880 (1980) and Wendt, Hippler, and Hunziker, J. Chem. Phys. 70, 4044 (1979)] of acetylene triplet states are discussed and shown to be completely consistent with each other and with the present ab initio ordering of the cis and trans isomeric minima on the T1 potential energy surface: cis ã 3B2 below trans ã 3Bu .
Effect of fluid flow on the fluctuations at the surface of an elastic medium
Authors: Kumaran V. 
Published: July 2002

The effect of a linear shear flow of a Newtonian fluid in the region 0&lt;z&lt;∞ on the fluctuations at the surface of an elastic medium of thickness H in the region −H&lt;z&lt;0 is analyzed in the regime Re≫1 and Λ∼1, where Re=ργH2/η is the Reynolds number and Λ=(ργ2H2/E)1/2 is the ratio of the inertial stresses in the fluid and the elastic stresses in the solid. Here ρ and η are the fluid density and viscosity, E is the coefficient of elasticity of the solid, and γ is the mean strain rate in the fluid. A linear analysis is used to determine the effect of the flow on the fluctuations in the surface displacement, and an asymptotic expansion in the small parameter ε=(Λ/Re) is employed. The dynamics in the bulk of the fluid is inviscid in the leading approximation, and the leading order growth rate is imaginary because energy is conserved in the absence of viscous dissipation. There are multiple frequencies of oscillation, all of which satisfy the equations of motion. An increase in the fluid velocity increases the frequency of the downstream traveling waves, and decreases the frequency of the upstream traveling waves. The structure factor for the surface modes of the upstream traveling waves increases with an increase in the fluid velocity because the kinetic energy of the fluctuations decreases due to the lower frequency.
An opposite effect is observed for the downstream traveling waves; in addition, it is observed that the structure factor has a double-peaked structure and reaches zero at an intermediate value at sufficiently high velocities. This is due to a divergence in the ratio of the tangential and normal displacements, and a consequent divergence in the energy required for the normal fluctuations at the surface. There is an O(ε1/2) correction to the growth rate due to the presence of a viscous boundary layer of thickness Hε1/2 in the fluid at the interface. The O(ε1/2) calculation shows that the real part of the growth rate is negative for all values of Λ and wave number k, except along certain lines in the Λ−k parameter space where the real part of the growth rate is zero, because the amplitude of the boundary layer velocity becomes zero along these lines. The real part of the O(ε) correction to the growth rate at these points is negative, indicating the presence of a small stabilizing effect due to the dissipation in the bulk of the fluid and the elastic medium.
Intellectual as Hustler: Researching against the grain of the market
Authors: Smyth John , Hattam Robert 
Published: July 2002

ABSTRACTIn many respects, universities around the world are living through a period of quite extraordinary turmoil as their role and purposes are under serious challenge. In this paper we explore the latest attempt in Australia to push universities even further in the direction of becoming marketised, and we examine what this means in terms of the loss of public space for academics as public intellectuals. In this, we draw some fragments from our own autobiographical experiences in trying to assert what a ‘counter public’ might look like around university research. We find the notion of ‘hustler’ to be a sufficiently playful metaphor around which to begin to frame what happens to knowledge as it is increasingly treated as another commodity.
Continuity and Change in Special School Provision: Some perspectives on local education authority policy‐making
Authors: Croll Paul , Moses Diana 
Published: July 2002

ABSTRACTThe article considers aspects of local authority policy‐making with regard to segregated special school provision for children with special educational needs and the resilience of a separate special school sector, despite a policy climate favouring inclusion. Statistical evidence shows a small but steady trend to more inclusive provsion but very considerable variation between local education authorities (LEAs). The notion of ‘the dominance of structure over ideology’ is used to explore LEA decision‐making processes but is shown to have limited explanatory power. The data suggest that the use of incremental policy development has not resulted in significant long‐term change and that a fundamental policy initiative has been a necessary, though not sufficient, condition of reform. Other factors facilitating reform included a small size of LEA and a preparedness to confront opposition. Strong commitment by key individuals was more important than an overall climate of opinion in securing greater inclusion.
ERBB and P‐glycoprotein inhibitors break resistance in relapsed neuroblastoma models through P‐glycoprotein
Authors: Rösch Lisa , Herter Sonja , Najafi Sara , Ridinger Johannes , Peterziel Heike , Cinatl Jindrich , Jones David T. W. , Michaelis Martin , Witt Olaf , Oehme Ina 
Published: October 2022

Chemotherapy resistance is a persistent clinical problem in relapsed high‐risk neuroblastomas. We tested a panel of 15 drugs for sensitization of neuroblastoma cells to the conventional chemotherapeutic vincristine, identifying tariquidar, an inhibitor of the transmembrane pump P‐glycoprotein (P‐gp/ABCB1), and the ERBB family inhibitor afatinib as the top resistance breakers. Both compounds were efficient in sensitizing neuroblastoma cells to vincristine in trypan blue exclusion assays and in inducing apoptotic cell death. The evaluation of ERBB signaling revealed no functional inhibition, that is, dephosphorylation of the downstream pathways upon afatinib treatment but direct off‐target interference with P‐gp function. Depletion of ABCB1, but not ERRB4, sensitized cells to vincristine treatment. P‐gp inhibition substantially broke vincristine resistance in vitro and in vivo (zebrafish embryo xenograft). The analysis of gene expression datasets of more than 50 different neuroblastoma cell lines (primary and relapsed) and more than 160 neuroblastoma patient samples from the pediatric precision medicine platform INFORM (Individualized Therapy For Relapsed Malignancies in Childhood) confirmed a pivotal role of P‐gp specifically in neuroblastoma resistance at relapse, while the ERBB family appears to play a minor part.
Electrochemical Palladium‐Catalyzed CH Functionalization
Authors: Yang Qi‐Liang , Guo Hai‐Ming , Mei Tian‐Sheng 
Published: October 2022

Abstract
Palladium‐catalyzed site‐selective functionalization of inert CH bonds has emerged as a versatile and transformative synthetic approach in modern organic synthesis, enabling tremendous possibility in the application of drug design, natural products synthesis, and material sciences. Despite significant progress, until recently, the oxidative functionalization of CH bonds predominantly relied on the use of stoichiometric amounts of sacrificial chemical oxidants that lead to the generation of undesired waste, thus compromising the environmental merits deriving from the CH activation chemistry. The recently developed electrooxidative CH functionalization via catalyst control strategy using transition‐metals as redox catalysts and electricity as an environmentally benign oxidant, offers a promising alternative to minimizes waste production, thereby providing a more sustainable and efficient pathway toward the catalytic conversion of CH bonds. In this article, we focus specifically on the progressive discoveries of electrochemical CH bond functionalizations catalyzed by palladium‐based catalysts, highlighting the enormous potential of this exciting field of synthetic chemistry, capable of offering increasingly efficient and sustainable routes for organic syntheses. These pallada‐electrocatalyzed CH bond transformations are presented in terms of CC and C–heteroatom bonds formation.
Palladium‐Catalyzed CH Arylation
Authors: Zhao Yingsheng , Ju Guodong 
Published: October 2022

AbstractCH activation catalyzed by transition metals is one of the more challenging and important research topics in organic chemistry, and direct arylation of the CH bond plays an important role. Recent CH activation developments include considerable progress toward CH arylation. This article summarizes many of the strategies and corresponding mechanistic investigations toward the realization of CH arylation, including directing group, transient directing, extended template strategies, and norbornene as transient mediator strategy.
Pd‐Catalyzed CH Functionalization Leading to Alkene Difunctionalization
Authors: Barve Balaji D. , Kuo Yao‐Haur , Li Wen‐Tai 
Published: October 2022

Abstract
Owing to their natural abundance, alkene has been widely employed in the preparation of various synthetic frameworks and for practical industrial production purposes. Pd‐catalyzed CH functionalization has emerged as one of the most important tools for constructing CC or CX bonds via the generation of different heterocycles, which include pharmaceutically important molecules. Compared with the significant research into transition metal‐catalyzed olefin difunctionalization using activated, preinstalled, and halide substrates, the application of palladium catalysis in CH bond functionalization to afford alkene difunctionalization is less explored, despite being synthetically important. In this article, we provide an overview of recent advancements in olefin difunctionalization resulting from Pd‐catalyzed CH functionalization.
Rhodium(II)‐Carboxylate‐Catalyzed Carbene Transfer Reactions: Toward CH Functionalizations
Authors: Hota Sudhir K. , Meher Prahallad , Murarka Sandip 
Published: October 2022

Abstract

The direct CH functionalizations have garnered immense popularity in the chemical community as they offer novel strategic approaches to introduce new functional entities into small organic molecules. One of the most promising reaction technologies for CH functionalization is the dirhodium carboxylate‐catalyzed insertion of transient metal carbenes into CH bonds. Over the years, this area has witnessed tremendous growth and dirhodium carboxylates have evolved as powerful catalysts allowing site‐ and stereoselective CH insertion reactions. This article delineates all these developments made in the last 10 years in the field of rhodium(II) carboxylate‐catalyzed intra‐ and intermolecular insertion of metal carbenes into Csp
2
H and Csp
3
H bonds with representative examples. A particular emphasis has been given to illustrate the effectiveness of dirhodium catalysts in controlling the site‐ and stereoselectivity in CH insertions of a diverse variety of substrates, including applications in the synthesis and late‐stage functionalization of biologically active compounds, pharmaceuticals, and natural products.
Ruthenium‐Catalyzed C–Heteroatom Bond Formation Through C(sp
2
)H Functionalization
Authors: Song Li‐Rui , (Ruthy) Zhang Ruisi , Lu Heng , Zhang Ao 
Published: October 2022

Abstract

This article describes recent advances in C–heteroatom bond formation via ruthenium‐catalyzed proximal or remote C(sp
2
)H functionalization. This ruthenium catalysis is particularly fascinating not only because of the low cost of the metal, but also because it allows for a wide range of transformations. The excellent reactivity of the ruthenium catalysts is attributed to the highly active CH ruthenated intermediate, which can perform oxidative addition or electrophilic substitution at the ortho position as well as radical addition at distal meta or para positions. Diverse strongly or weakly coordinating directing groups, such as
N
‐containing heterocycles, aldehydes, ketones, carboxylic acids, amides, sulfamides, carbamates, and phosphines, can assist the ruthenium‐catalyzed functionalization of ortho, meta, and even, para positions via CN, CO, C–halogen, CSi, CS/Se, and CB bond‐forming reactions. Typically, [RuCl
2
(
p
‐cymene)]
2
is used for C–heteroatom bond construction, but the octahedral Ru catalysts RuHCl(CO)(PPh
3
)
3
and Ru
3
(CO)
12
have been used for
ortho
CSi and
meta
CN bond formation, respectively. In addition, this article details representative applications of Ru‐catalyzed C(sp
2
)H functionalization in the preparation and late‐stage modification of important synthetic building blocks and pharmaceuticals.
Ni‐Catalyzed C(sp
2
)H Bond Functionalization: Trifluoromethylation, Thiolation, and Selenylation
Authors: Garg Nidhi , Garai Bholanath , Sundararaju Basker 
Published: October 2022

Abstract

This article is intended to provide a concise review of the seminal work on nickel‐catalyzed direct “sp
2
” CH bond functionalizations, with a particular focus on trifluoromethylation, thiolation, and selenylation. The current mechanistic hypotheses were described for a deeper understanding that should aid in the future design of various other efficient transformations. We anticipate that the continued research in this area should help to extend applications in late‐stage functionalization of various bioactive molecules.
Transition Metal‐Catalyzed CH Functionalizations Using a Transient Directing Group Approach
Authors: Das Animesh , Aditya Netai , Maji Biplab 
Published: October 2022

Abstract
Transition metal‐catalyzed CH bond functionalization reactions are among the cutting‐edge synthetic tool for step‐economical construction of complex‐molecular architectures. In this realm, the key challenge lies in harnessing the site‐selective activation of the inert CH bonds. Although covalently tethered directing groups rendered reliable results in obtaining positional selectivity, their preinstallation and removal entail multiple steps restricting their applicability. An alternative approach is developed to fill this gap where a transient ligand enables the formation of the directing group in situ and dissociates after the reaction's completion. This strategy is widely known as the transient directing group (TDG) approach. Diverse functionalization such as arylation, alkylation, amination, halogenation, etc., could be achieved using TDG as a powerful means. Moreover, asymmetric functionalization has also been realized utilizing this technique. However, this strategy remained only applicable to aldehydes, ketones, amines, and phenol substrates.
α‐Functionalization of Aliphatic Carboxylic Acid Equivalents via Direct CH Oxidation
Authors: Rahaman Ajijur , Gupta Aniket , Kumar Jogendra , Bhadra Sukalyan 
Published: October 2022

Abstract
The α‐functionalization of aliphatic carboxylic acids and equivalents thereof including amides and esters is among the highly important synthetic transformations of organic synthesis. Traditional approaches are largely dominated by enolate chemistry demanding (over) stoichiometric quantity of a strong base with respect to the carbonyl precursor to obtain a nucleophilic enolate equivalent and an electrophilic coupling partner to form a new CC and/or C–heteroatom bond. Modern progresses demonstrate that the α‐CH bond of carboxylic acids, amides, esters, and other synthons can be also triggered in the presence or absence of a transition metal catalyst under oxidative conditions. The external oxidant is known to play a crucial role in the α‐CH bond oxidation process. The current article describes the oxidative α‐CH bond functionalizations of carboxylic acids/equivalents by nucleophiles using transition metal catalysts or organic mediators. Consequently, (i) α‐CH transformations with the participation of an enolate equivalent from the carboxylate counterpart; (ii) Lewis acid‐catalyzed α‐functionalization approaches; (iii) α‐functionalization with concomitant decarboxylation, etc. are beyond the scope of this article.
Annulative π‐Extension (APEX) of Indole to Carbazole Through CH Activation
Authors: Das Pritha , Dinda Enakshi , Jana Ranjan 
Published: October 2022

Abstract
The annulative π‐extension (APEX) reaction through CH bond activation has emerged as a powerful technique for the rapid synthesis of fused aromatic systems from simple aromatic compounds in a single operation. This cutting‐edge technology can transform the conventional, tedious multistep protocols into a user‐friendly one‐pot procedure for the synthesis of functionalized materials useful in high‐tech materials for material science applications, bioimaging for biomedical research, and agro‐ and pharmaceutical industries. Furthermore, CH activation strategy does not require prefunctionalization steps, which allows for the late‐stage modification of the functional molecule to achieve requisite molecular properties. Owing to their unique photophysical properties, carbazoles are widely used in photovoltaic cells, biomedical imaging, fluorescent polymer, organic light‐emitting diodes (OLEDs), liquid crystals, etc. They are also ubiquitously found in many natural products, agrochemicals, and privileged medicinal scaffolds. Hence, π‐extension of indole to carbazole via CH functionalization has proven as a straightforward and robust technique in the past decades. The fundamental mechanistic aspect behind this cascade π‐extension strategy is the facile electrophilic metalation at the C‐3 position of the indole moiety, 1,2‐ migration, and electrocyclization. Furthermore, acid‐catalyzed electrocyclization under metal‐free conditions has also been explored.
Iron‐Catalyzed Heterocycle Synthesis by CH Functionalization
Authors: Sekar Govindasamy , Sundaravelu Nallappan , Nair Vysakh V. 
Published: October 2022

Abstract

The synthetic perspective of CH activation was first revealed using ruthenium catalysis and is now extensively studied by the use of several other transition metals. Iron‐catalyzed CH functionalization reactions have gained paramount attention in organic synthesis due to their low cost, low toxicity, and good functional group tolerance. Recently, iron‐catalyzed CH bond functionalization has achieved significant progress in the synthesis of heterocycles through CH activation followed by inter/intramolecular cyclization reactions on treatment with various electrophiles. This article mainly focuses on iron‐catalyzed C–heteroatom bond (CN, CO, CS, etc.) formation through sp
2
and sp
3
CH functionalization to access biologically valuable heterocycles and their mechanistic insights.
Cp*Co(III)‐Catalyzed CH Functionalization Mediated by Oxidizing Directing Groups toward the Synthesis of Heterocycles
Authors: Aher Yogesh N. , Mondal Bhaskar , Pawar Amit B. 
Published: October 2022

Abstract
The utilization of oxidizing directing group for CH activation/functionalization is a unique strategy for the synthesis of a versatile range of heterocycles under redox‐neutral conditions. In this approach, the directing group plays a dual role; controls the product selectivity through its chelation property, and a part of the directing group functions as an internal oxidant. The oxidizing property of the directing groups is due to the oxidizing ability of the NO, NN, NS, NCl bonds. Overall, this synthetic strategy precludes the need for external oxidants, thereby making the process environmentally benign. This article describes significant developments in this area focusing on the Cp*Co(III)‐catalyzed CH functionalization using the oxidizing directing group strategy for the synthesis of heterocycles. The emphasis has been given to the scope and generality of the reactions along with their mechanistic understanding.