cssi/SciSciGPT-SciSciNet huggingface dataset:
The central amygdala to periaqueductal gray pathway comprises intrinsically distinct neurons differentially affected in a model of inflammatory pain.

Key points The central nucleus of the amygdala (CeA) encompasses the main output pathways of the amygdala, a temporal lobe structure essential in affective and cognitive dimensions of pain. A major population of neurons in the CeA send projections to the periaqueductal gray (PAG), a key midbrain structure that mediates coping strategies in response to threat or stress. CeA-PAG neurons are topographically organized based on their targeted subregion within the PAG. PAG-projecting neurons in the central medial (CeM) and central lateral (CeL) regions of CeA are intrinsically distinct. CeL-PAG neurons are a homogeneous population of intrinsically distinct neurons while CeM-PAG neurons are intrinsically heterogeneous. Membrane properties of distinct CeM-PAG subtypes are altered in the complete Freund's adjuvant model of inflammatory pain. Abstract A major population of neurons in the central nucleus of amygdala (CeA) send projections to the periaqueductal gray (PAG), a key midbrain structure that mediates coping strategies in response to threat or stress. While the CeA-PAG pathway has proved to be a component of descending anti-nociceptive circuitry, the functional organization of CeA-PAG neurons remains unclear. We identified CeA-PAG neurons in C57BL/6 mice of both sexes using intracranial injection of a fluorescent retrograde tracer into the PAG. In acute brain slices, we investigated the topographical and intrinsic characteristics of retrogradely labelled CeA-PAG neurons using epifluorescence and whole-cell electrophysiology. We also measured changes to CeA-PAG neurons in the complete Freund's adjuvant (CFA) model of inflammatory pain. Neurons in the central lateral (CeL) and central medial (CeM) amygdala project primarily to different regions of the PAG. CeL-PAG neurons consist of a relatively homogeneous population of intrinsically distinct neurons while CeM-PAG neurons are intrinsically heterogeneous. Membrane properties of distinct CeM-PAG subtypes are altered 1 day after induction of the CFA inflammatory pain model. Collectively, our results provide insight into pain-induced changes to a specific population of CeA neurons that probably play a key role in the integration of noxious input with endogenous analgesia and behavioural coping response.
The Efficacy of the Family Check-Up on Children’s Emotional and Behavior Problems in Early Elementary School:

This study reports results of a randomized, controlled trial examining the efficacy of the Family Check-Up (FCU) initiated during kindergarten on teacher report of children’s emotional and behavior...
Well-posedness of fully nonlinear KdV-type evolution equations

We study the well-posedness of the initial value problem for fully nonlinear evolution equations, where f may depend on up to the first three spatial derivatives of u. We make three primary assumptions about the form of a regularity assumption, a dispersivity assumption, and an assumption related to the strength of backwards diffusion. Because the third derivative of u is present in the right-hand side and we effectively assume that the equation is dispersive, we say that these fully nonlinear evolution equations are of KdV-type. We prove the well-posedness of the initial value problem in the Sobolev space , which is close to optimal for the energy estimates we make. The proof relies on gauged energy estimates which follow after making two regularizations, a parabolic regularization and mollification of the initial data. There is evidence that the backward diffusion condition we express is optimal.
The VidaSana Study: Recruitment Strategies for Longitudinal Assessment of Egocentric Hispanic Immigrant Networks.

We disseminate the recruitment strategies used in the five-year VidaSana study (started in 2017) in the Midwest region of the United States, targeting recently arrived Hispanic immigrants. VidaSana aims to follow immigrants within six months of arrival for 24 months to (1) characterize features of networks (personal and community) that improve or undermine dental health; and (2) further refine methods to quantify the evolution of egocentric networks, using social network methodology. We implemented several strategies to promote and recruit potential participants into the study. We collaborate with agents serving Indiana’s Hispanic communities using three levels of visibility. The broad level includes radio advertisements, TV interviews, newspaper advertisements, and targeted Facebook advertisements. Intermediate level visibility includes posting flyers in schools, employment agencies, immigrant welcome centers, and Hispanic businesses; making announcements at church/temple and school events; tabling at community, church and school events; and a pervasive adaptation of our strategies to the requirements of our partners. Lastly, the individualized level includes direct referrals by partners through word of mouth. From the initial 13 months of recruitment (494 screened contacts and 202 recruited participants), the most successful recruitment strategies appear to be a combination of intermediate- and individual-level strategies; specifically, face-to-face recruitment at school events, direct referrals from our community partners, and tabling at community/school/church events. The current interim findings and future final findings will help guide recruitment and retention strategies for studies focused on immigrants in the current climate of heightened immigration regulations and enforcement.
Regional Labor Mobility in Spain

This paper studies the main factors that explain the low regional mobility in Spain, with a view to identifying policy options at the regional and central level to promote labor mobility. The empirical analysis finds that house prices, labor market conditions, and the pervasiveness of labor market duality at the regional level are the main determinants for Spain’s regional mobility, while labor market institutions and policies play an important role at the national level. Policies that facilitate wage setting flexibility and reduce labor market duality could help enhance the functioning of the labor market, thereby promoting labor mobility. There may be also room for policies to incentivize people to move and provide support through targeted active labor market policies.
Retirement choices by state and local public sector employees: the role of eligibility and financial incentives

I analyze the effects of state public pension parameters on the retirement of public employees. Using a panel data set of public sector workers from 12 waves of the Health and Retirement Study, I model the probability of retirement as a function of pension wealth at early and normal retirement eligibility and Social Security coverage in the public sector job. I find that becoming eligible for early retirement, or receiving an early-out offer, significantly increases the probability of retiring. I do not find any effect of retirement wealth levels. These findings suggest that state legislative action to affect retirement decisions and reduce future pension costs would be most effective operating through plan eligibility rules and early-out incentives.
Chapter 7 – Heat Integration

Heating and cooling are among the most common operations in the process industries. Significant quantities of external heating and cooling utilities are used to drive reaction, induce separation, and render units and streams in desirable states of operation. To satisfy the need for heating and cooling, industrial operations require the extensive use of different forms of energy. For instance, fossil fuels are widely used as feedstocks of boilers to generate heating media (e.g., steam, heating oil) or to drive power cycles that drive refrigeration systems. The excessive usage of external heating utilities incurs a substantial economic burden in the form of operating costs, depletes unsustainable energy resources (e.g., fossil fuels), and generates large quantities of greenhouse gas emissions. Consequently, considerable attention has been given to the problem of conserving energy through heat integration and the synthesis of heat-exchange networks (HENs). The basic idea for heat integration is that there are process streams and units that need to be heated and other process streams and units that need to be cooled. Before using external utilities to provide the necessary heating and cooling, heat integration seeks to transfer the heat from the process hot streams and units to the process cold streams and units. The remaining heating and cooling tasks are then fulfilled using the external heating and cooling utilities. This chapter presents the key tools used in identifying rigorous targets for minimum heating and cooling utilities, selecting utilities, and synthesizing HENs that attain the desired targets.
Space-time adaptive processing for airborne radar

Advanced airborne radar systems are required to detect targets in the presence of both clutter and jamming. Ground clutter is extended in both angle and range, and is spread in Doppler frequency because of the platform motion. Space-time adaptive processing (STAP) refers to the simultaneous processing of the signals from an array antenna during a multiple pulse coherent waveform. STAP can provide improved detection of targets obscured by mainlobe clutter, defection of targets obscured by sidelobe clutter, and detection in combined clutter and jamming environments. Fully adaptive STAP is impractical for reasons of computational complexity and estimation with limited data, so partially adaptive approaches are required. The paper presents a taxonomy of partially adaptive STAP approaches that are classified according to the type of preprocessor, or equivalently, by the domain in which adaptive weighting occurs. Analysis of the rank of the clutter covariance matrix in each domain provides insight and conditions for preprocessor design.
A Memoization Framework for Scaling Submodular Optimization to Large Scale Problems

We are motivated by large scale submodular optimization problems, where standard algorithms, which treat the submodular functions in the value oracle model, do not scale. In this paper, we present a new model called the pre-computational complexity model, along with a unifying memoization based framework, which looks at the specific form of the given submodular function. A key ingredient in this framework, is the notion of a precomputed statistic, which is maintained in the course of the algorithms. We show that we can easily integrate this idea into a large class of submodular optimization problems including constrained and unconstrained submodular maximization, minimization, difference of submodular optimization, ratio of submodular optimization and several other related optimization problems. Moreover, memoization can be integrated in both discrete and continuous relaxation flavors of algorithms for these problems. We demonstrate this idea for several commonly occurring submodular functions, and show how the pre-computational model provides significant speedups compared to the value oracle model. Finally, we empirically demonstrate this for large scale machine learning problems of data subset selection and summarization.
Influence of Hydrodynamic Interactions on Stratification in Drying Mixtures

Nonequilibrium molecular dynamics simulations are used to investigate the influence of hydrodynamic interactions on vertical segregation (stratification) in drying mixtures of long and short polymer chains. In agreement with previous computer simulations and theoretical modeling, the short polymers stratify above the long polymers at the top of the drying film when hydrodynamic interactions between polymers are neglected. However, no stratification occurs under the same drying conditions when hydrodynamic interactions are incorporated through an explicit solvent model. Our analysis demonstrates that models lacking hydrodynamic interactions do not faithfully represent stratification in drying mixtures, in agreement with the recent analysis of an idealized model for diffusiophoresis. Hydrodynamic interactions must be incorporated into such models for drying mixtures in future.
The conference effect: National surgery meetings are associated with increased mortality at trauma centers without American College of Surgeons verification.

Background Thousands of physicians attend scientific conferences each year. While recent data indicate that variation in staffing during such meetings impacts survival of non-surgical patients, the association between treatment during conferences and outcomes of a surgical population remain unknown. The purpose of this study was to examine mortality resulting from traumatic injuries and the influence of hospital admission during national surgery meetings. Study design Retrospective analysis of in-hospital mortality using data from the Trauma Quality Improvement Program (2010-2011). Identified patients admitted during four annual meetings and compared their mortality with that of patients admitted during non-conference periods. Analysis included 155 hospitals with 12,256 patients admitted on 42 conference days and 82,399 patients admitted on 270 non-conference days. Multivariate analysis performed separately for hospitals with different levels of trauma center verification by state and American College of Surgeons (ACS) criteria. Results Patient characteristics were similar between meeting and non-meeting dates. At ACS level I and level II trauma centers during conference versus non-conference dates, adjusted mortality was not significantly different. However, adjusted mortality increased significantly for patients admitted to trauma centers that lacked ACS trauma verification during conferences versus non-conference days (OR 1.2, p = 0.008), particularly for patients with penetrating injuries, whose mortality rose from 11.6% to 15.9% (p = 0.006). Conclusions Trauma mortality increased during surgery conferences compared to non-conference dates for patients admitted to hospitals that lacked ACS trauma level verification. The mortality difference at those hospitals was greatest for patients who presented with penetrating injuries.
The Gallerist’s Gambit: Financial Innovation, Tax Law, and the Making of the Contemporary Art Market

This essay presents an account of an important moment in the emergence of the market for Pop art that was facilitated in part by a distinctly accommodating legal environment. Although Abstract Expressionism is commonly credited with causing American art’s ascendance onto the world stage immediately after World War II, its international acclaim belied a precarious institutional and financial infrastructure for living American painters. It was only with the following generation of Pop and Minimalist artists that the United States developed a self-sustaining market for the work of contemporary American artists. A significant but largely overlooked factor in that continued success was the ability of art dealers to take advantage of the unique legal and regulatory environment of the 1960s. This essay focuses on the efforts of an enterprising art gallerist, Leo Castelli, to aggressively promote his stable of Pop artists through the development of several financial structures, including some designed to leverage the relatively generous income tax deductions and anemic enforcement regime of the time. In doing so, Castelli not only seeded the ground for the international ascendance of American visual art, but also engineered financial arrangements that fostered the development of a lucrative and resilient art market that endures to this day.
The Manufacture of Northern Fluted Points: A Production Sequence Hypothesis

Recent research has begun to shed light on the role the Northern Fluted Complex (NFC) played in the peopling of the Americas. Our understanding of NFC chronology and origins has increased with the ...
THE SECONDARY STRUCTURE OF TYPE I COLLAGEN N-TELOPEPTIDE AS DEMONSTRATED BY FOURIER TRANSFORM IR SPECTROSCOPY AND MOLECULAR MODELING

The amino-telopeptides of type I collagen have been implicated to have a crucial role in the events of fibril formation. The sequences have been highly conserved in a variety of species. Several proposals have been presented to correlate the sequence with structure and role in fibril formation, but no definite information on telopeptide structure has been deduced. The infrared spectrum of the amide I band, due almost entirely to the C=O stretch vibration of peptide carbonyls, has been a most useful probe for determining the secondary structures of proteins in solution. In the present study, the secondary structure of a synthetic ratα1(I) amino-telopeptide has been investigated in aqueous solution by Fourier transform infrared spectroscopy (FTIRS) using a 9-pass internal reflectance ZnSe prism cell. Conformational changes were monitored as the aqueous solution was heated from 4 to 50°C by observing changes in the frequency position. The amide I band frequency shifted by about 10 cm−1 when the aqueous telopeptide solution was heated from 4–50°C. Deconvolution of the amide I band showed that the major component could be best represented as in a random configuration at 4°C but changed to aβ sheet withβ turns around 30°C. To support these experimental data the telopeptide region was modeled using BIOSYM/MSI software on a Silicon Graphics R-4000,X/Z graphics workstation. The proposed telopeptide structure was energy minimized using DISCOVER CVFF repetitive build and minimize process to reduce steric hindrance and maximize H-bonding. The potential energy surface was quite low and the conformation was stabilized by only 3 H-bonds. This model suggests a telopeptide structure that can be induced to assume a conformation favorable for binding during its interchain interaction at the collagen helix cross-link (N-telopeptide) receptor domain around collagen residue 930.
A new approach to the asymmetric cyclopropanation via a chiral sulfinyl group

High stereoselectivity and high yield are observed in the Michael addition of dimethyl sulfoxonium methylide to an optically pure methyl α-(p-tolylsulfinyl) acrylate. A novel route to the asymmetric synthesis of electrophilic cyclopropanes.
A High-Throughput Fluorescence-Based Assay for Rapid Identification of Petroleum-Degrading Bacteria.

Over the past 100 years, oil spills and long-term waste deposition from oil refineries have significantly polluted the environment. These contaminants have widespread negative effects on human health and ecosystem functioning. Natural attenuation of long chain and polyaromatic hydrocarbons is slow and often incomplete. Bioaugmentation of polluted soils with indigenous bacteria that naturally consume petroleum hydrocarbons could speed up this process. However, the characterization of bacterial crude oil degradation efficiency - which often relies upon expensive, highly specialized gas-chromatography mass spectrometry analyses - can present a substantial bottleneck in developing and implementing these bioremediation strategies. Here, we develop a low-cost, rapid, high-throughput fluorescence-based assay for identifying wild-type bacteria that degrade crude oil using the dye Nile Red. We show that Nile Red fluoresces when in contact with crude oil and developed a robust linear model to calculate crude oil content in liquid cell cultures based on fluorescence intensity (FI). To test whether this assay could identify bacteria with enhanced metabolic capacities to break down crude oil, we screened bacteria isolated from a former Shell Oil refinery in Bay Point, CA, and identified one strain (Cupriavidus sp. OPK) with superior crude oil depletion efficiencies (up to 83%) in only 3 days. We further illustrate that this assay can be combined with fluorescence microscopy to study how bacteria interact with crude oil and the strategies they use to degrade this complex substance. We show for the first time that bacteria use three key strategies for degrading crude oil: biofilm formation, direct adherence to oil droplets, and vesicle encapsulation of oil. We propose that the quantitative and qualitative data from this assay can be used to develop new bioremediation strategies based on bioaugmentation and/or biomimetic materials that imitate the natural ability of bacteria to degrade crude oil.
Total Synthesis of a Mycobactin S, a Siderophore and Growth Promoter of Mycobacterium Smegmatis, and Determination of its Growth Inhibitory Activity against Mycobacterium tuberculosis

A general total synthesis of mycobactins, represented by a mycobactin S, was achieved by a convergent approach. Two hydroxamic acid residues, 28 and 40b, were prepared from commercially available Nα-Cbz-l-lysine via dimethyldioxirane oxidations. Cyclization of hydroxylamine 34 to a seven-membered hydroxamic acid, 35, was mediated by DCC, DMAP, and DMAP·HCl. The use of a [2-(trimethylsilyl)ethoxy]methyl group as a hydroxyl protecting group for Nα-Cbz-Ne-hydroxy-Ne-palmitoyl-l-lysine methyl ester (28) was critical for this synthesis. Biological tests indicated that the synthetic mycobactin S was a potent growth inhibitor of Mycobacterium tuberculosis H37Rv, though it differs in only one stereogenic center from mycobactin T, the siderophore growth promoter of M. tuberculosis.
An unusual labilization of a 4‐(trifluoromethyl)thiazole

N-2-Chloro-4-(trifluoromethyl)-5-thiazolyl-N',N'-diethylurea 5 has been found to undergo a facile labilization of the trifluoromethyl group under mild conditions. The reaction relies on the assistance of the nitrogen substitution at the 4-position of the thiazole ring. Treatment of 5 with triethylamine and either methanol or methanethiol replaced the trifluoromethyl group with a methyl ester or a trimethylorthothio ester respectively at room temperature. Combination of 5 with diethylamine led to an unusual thiazolidine with two exocyclic double bonds, 8
Synthesis, Structure, and Chemical Vapor Deposition Studies of Molecular Precursors to NbP Films

Treatment of niobium pentachloride with cyclohexylphosphine and phenylphosphine in dichloromethane afforded octachlorotetrakis(cyclohexylphosphine)diniobium(IV) (85%) and octachlorotetrakis(phenylp...
Facile synthesis of C-aryl glycals from sugar-derived lactones

Abstract A general entry to C(1) aryl-substituted glycals from the corresponding sugar lactones is described. This approach features one-pot access to aryl glycals. A variety of aryllithium reagents can be used and the method is compatible with various 2-deoxysugar lactones.
Mechanism of Action of Methotrexate Against Zika Virus.

Zika virus (ZIKV), which is associated with microcephaly in infants and Guillain-Barre syndrome, reemerged as a serious public health threat in Latin America in recent years. Previous high-throughput screening (HTS) campaigns have revealed several potential hit molecules against ZIKV, including methotrexate (MTX), which is clinically used as an anti-cancer chemotherapy and anti-rheumatoid agent. We studied the mechanism of action of MTX against ZIKV in relation to its inhibition of dihydrofolate reductase (DHFR) in vitro using Vero and human neural stem cells (hNSCs). As expected, an antiviral effect for MTX against ZIKV was observed, showing up to 10-fold decrease in virus titer during MTX treatment. We also observed that addition of leucovorin (a downstream metabolite of DHFR pathway) rescued the ZIKV replication impaired by MTX treatment in ZIKV-infected cells, explaining the antiviral effect of MTX through inhibition of DHFR. We also found that addition of adenosine to ZIKV-infected cells was able to rescue ZIKV replication inhibited by MTX, suggesting that restriction of de novo synthesis adenosine triphosphate (ATP) pools suppresses viral replication. These results confirm that the DHFR pathway can be targeted to inhibit replication of ZIKV, similar to other published results showing this effect in related flaviviruses.
Recent Developments in Organocatalyzed Electroorganic Chemistry

This highlight review focuses on the integration of organocatalysis and electrosynthesis. Specifically, we detail recent advances involving the use of organocatalysts to alter substrate redox poten...
A NOVEL SYNTHESIS OF THE ANTIPSYCHOTIC AGENT ZIPRASIDONE

Abstract A new synthesis of the antipsychotic ziprasidone from 2,5-dichloro-4-nitrotoluene 3 is presented. The nitro group in 3 was used to activate the ortho-chlorine for displacement and the methyl group for enamine formation and introduction of the piperazinyl moiety.
Resolving the Insertion Sites of Polymorphic Duplications Reveals a HERC2 Haplotype under Selection

Polymorphic duplications in humans have been shown to contribute to phenotypic diversity. However, the evolutionary forces that maintain variable duplications across the human genome are largely unexplored. We developed a linkage-disequilibrium based method to detect insertion sites of polymorphic duplications not represented in reference genomes. This method also allows resolution of haplotypes harboring the duplications. Using this approach, we conducted genome-wide analyses and identified the insertion sites of 22 common polymorphic duplications. We found that the majority of these duplications is intrachromosomal and only one of them is an interchromosomal insertion. Further characterization of these duplications revealed significant associations to blood and skin phenotypes. On the basis of population genetics analyses, we found that the duplication of a well-characterized pigmentation-related region, including the HERC2 gene, may be selected against in European populations. We further demonstrated that the haplotype harboring this duplication significantly affects the expression of the HERC2P9 gene in multiple tissues. Our study sheds light onto the evolutionary impact of understudied polymorphic duplications in human populations and presents methodological insights for future studies.
Synthesis of pyrroles through coupling of enyne-hydrazones with Fischer carbene complexes.

The coupling of enyne-imines with Fischer carbene complexes leads to the formation of alkenylpyrrole derivatives. Maximum yields of pyrrole adducts were obtained using N,N-dimethylhydrazones. A mechanism involving alkyne insertion followed by nucleophilic attack of the imine nitrogen at the intermediate alkenylcarbene complex was proposed.
Simulation of spontaneous G protein activation reveals a new intermediate driving GDP unbinding.

Activation of heterotrimeric G proteins is a key step in many signaling cascades. However, a complete mechanism for this process, which requires allosteric communication between binding sites that are ~30 A apart, remains elusive. We construct an atomically detailed model of G protein activation by combining three powerful computational methods: metadynamics, Markov state models (MSMs), and CARDS analysis of correlated motions. We uncover a mechanism that is consistent with a wide variety of structural and biochemical data. Surprisingly, the rate-limiting step for GDP release correlates with tilting rather than translation of the GPCR-binding helix 5. β-Strands 1 - 3 and helix 1 emerge as hubs in the allosteric network that links conformational changes in the GPCR-binding site to disordering of the distal nucleotide-binding site and consequent GDP release. Our approach and insights provide foundations for understanding disease-implicated G protein mutants, illuminating slow events in allosteric networks, and examining unbinding processes with slow off-rates.
Face-localized bonding models for borane cage ligands in transition metal coordination chemistry

Abstract Substitution of a borane vertex by an isolobal transition metal vertex in a deltahedron can change the shape and apparent electron count. More specifically, in many metallaborane deltahedra with 9, 10, and 11 vertices some transition metal units are found to occur at degree 6 vertices. In the case of 9- and 10-vertex deltahedra this requires a change in the shape of the deltahedron from the metal-free closo borane deltahedra having only degree 4 and 5 vertices to alternative so-called isocloso deltahedra having a single degree 6 vertex. The change in electron count from 2 n +2 skeletal electrons for metal-free borane closo deltahedra having the maximum number of degree 4 and 5 vertices to 2 n skeletal electrons for metallaborane isocloso deltahedra with the metal at a single degree 6 vertex can be rationalized by a major change in the skeletal bonding topology from globally delocalized in the closo deltahedra to face-localized in the isocloso deltahedra. In this model the skeletal bonding in closo deltahedra with n vertices can be constructed from n two-center two-electron surface bonds and a single n -center core bond whereas the entire skeletal bonding in isocloso deltahedra can arise from n three-center two-electron bonds in n of the 2 n −4 faces. The isocloso metallaboranes with n vertices can be considered to be metal complexes of an open borane ligand having all triangular faces except for a single hexagonal face, which forms a hexahapto bond to the transition metal vertex similar to the hexahapto arenemetal bonds in arene metal complexes. The 10-vertex deltahedra (C 5 H 5 M) 2 C 2 B 6 H 8 (M=Co, Fe) discovered by Hawthorne and co-workers in the 1970s provide an early example of a structurally characterized closo / isocloso deltahedral pair of the same stoichiometry in which the cobalt derivative has the 2 n +2 skeletal electrons and geometry of the closo 10-vertex deltahedron (the bicapped square antiprism) whereas the iron derivative has only 2 n skeletal electrons and the different geometry of the isocloso 10-vertex deltahedron with one of the iron atoms at the unique degree 6 vertex.
Preparation of 6-, 7-, and 8-substituted derivatives of 2-Oxa-1,3,4,10-tetraazacyclopenta[b]fluoren-9-one

The preparation of a variety of derivatives of 2-oxa-1,3,4,10-tetraazacyclopenta[b]fluoren-9-one 1 is described. A series of substituted indan-1-ones were prepared and oxidized with N-bromosuccinimide and dimethyl sulfoxide to the corresponding ninhydrin derivatives. Cyclization of the ninhydrins with furazan-3,4-diamine yielded the target tetracycles. Appropiate choice of substituents in ninhydrins led to a preference for one regioisomer in the target tetracycles. This permitted the synthesis of a variety of 8-substituted hetero-cycles. In those instances where isomer formation was possible, structural assignments were confirmed by X-ray crystallography.
1,3,4-Oxadiazoles with SF5-containing substituents

Abstract 1,3,4-Oxadiazoles containing a combination of SF 5 -perfluoroalkyl, SF 5 -alkyl, polynitroalkyl and perfluoroalkyl substituents have been synthesized by cyclization (dehydration) of the corresponding diacyl hydrazines. The properties of oxadiazoles with SF 5 -perfluoroalkyl substituents are compared with those of similar oxadiazoles containing the corresponding perfluoroalkyl substituent (CF 3 in place of SF 5 ).
Enantioselective Cyclization of Alkene Radical Cations

Enantiomerically enriched β-(diphenylphosphatoxy)nitroalkanes undergo radical ionic fragmentation, induced by tributyltin hydride and AIBN in benzene at reflux, to give alkene radical cations in contact radical ion pairs. These contact ion pairs are trapped intramolecularly by amines to give pyrrolidines and piperidines with significant enantioselectivity (∼60% ee), indicative of cyclization competing effectively with equilibration within the ion pairs. Use of an intramolecular N-propargylamine as a nucleophile provides an enantiomerically enriched pyrrolizidine skeleton via a tandem polar/radical crossover sequence.
Mosaic mutations in blood DNA sequence are associated with solid tumor cancers.

Recent understanding of the causal role of blood-detectable somatic protein-truncating DNA variants in leukemia prompts questions about the generalizability of such observations across cancer types. We used the cancer genome atlas exome sequencing (~8000 samples) to compare 22 different cancer phenotypes with more than 6000 controls using a case–control study design and demonstrate that mosaic protein truncating variants in these genes are also associated with solid-tumor cancers. The absence of these cancer-associated mosaic variants from the tumors themselves suggest these are not themselves tumor drivers. Through analysis of different cancer phenotypes we observe gene-specificity for mosaic mutations. We confirm a specific link between PPM1D and ovarian cancer, consistent with previous reports linking PPM1D to breast and ovarian cancer. Additionally, glioblastoma, melanoma and lung cancers show gene specific burdens of mosaic protein truncating mutations. Taken together, these results extend existing observations and broadly link solid-tumor cancers to somatic blood DNA changes. Increased risk for solid tumors linked to mutations detected in blood samples that shorten the coding sequence of their genes. Mark Daly and colleagues from the Broad Institute in Cambridge, Massachusetts, USA, used large genomic databases to test whether having blood cells both with and without genetic variants predicted to shorten the encoded protein—a phenomenon known as mosaic protein-truncating variants (PTVs)—was associated with developing a range of solid-tumor cancers. They studied DNA from around 8,000 people with cancer and 6,000 healthy controls. Other studies have shown that mosaic PTVs precede and predict the development of leukemia. In this study, the scientists not only confirmed previous reports linking these variants to breast and ovarian cancer but also extended the association to include tumors of the brain, skin and lungs. These results broadly connect cancer to blood DNA changes.
CONVERGENT PREPARATION OF 1,6-LINKED C-DISACCHARIDES VIA OLEFIN METATHESIS

Abstract The DCC mediated coupling reaction of 3,4,6-tri- O -benzyl-1,2-dideoxy- d -arabino-hex-1-enitol ( 5a ) with a variety of sugar based carboxylic acids 6a-d gave esters 7a-d in good yield. Methylenation of the formed esters led to the acyclic enol ethers 8a-d and exposure to the Schrock molybdenum catalyst 1 in warm toluene, in the box, gave the target C -disaccharide glycals 9a-d in good yield. The 1,6-linked gluco based C -disaccharide glycal 9a was converted to the 2-deoxy-β- gluco -derivative 10a and the corresponding and gluco β- gluco-C -disaccharide 13 .
[Mn(en)3]CdSnTe4 and [Mn(en)3]Ag6Sn2Te8 : New intermetallic tellurides synthesized in superheated organic medium

Two intermetallic tellurides, Mn(en)3]CdSnTe4 (I) and [Mn(en)3]Ag6Sn2Te8 (II), have been synthesized in superheated ethylenediamine solutions at 180 °C. Single-crystal X-ray diffraction analyses show that I crystallizes in triclinic crystal system, space group P1 (No. 1) with lattice parameters a = 9.134(2) A, b = 10.085(3) A, c = 12.691(3) A, α = 73.52(2)°, β = 86.05(2)°, γ = 76.43(2)°, V = 1089.7(5) A3, and Z = 2 and II belongs to trigonal (rhombohedral) crystal system, space group R3m (No. 166) with a = 8.9590(9) A, c = 34.795(2) A, V = 2418.6(4) A3, and Z = 3. Both compounds possess new structure types. The structure of I is composed of one-dimensional Zintl chains of alternating edge-sharing MTe4 (M = Cd, Sn) tetrahedra and [Mn(en)3]2+ complex cations that are between the chains. The structure of II contains two-dimensional double layers of Ag6Sn2Te82- formed by connecting two single honeycomb-like layers through M−Te bonds (M = Ag, Sn). The double layers are separated by the [Mn(en)3]2+ templates. ...
Solvent Effects on Carbocation−Nucleophile Combination Reactions: A Comparison of π-Nucleophilicity in Aqueous and Organic Solvents

The following selectivities are reported for partitioning of the α-(N,N-dimethylthiocarbamoyl)-4-methoxybenzyl carbocation 1+ between nucleophilic addition of π-nucleophiles and a solvent of 50:50 (v:v) acetonitrile/water at 25 °C (nucleophile, kNu/ks): pyrrole, 23 M-1; 2-methoxythiophene, ≈2 M-1. No nucleophile adducts (<2% of total products) were detected from the reaction of this carbocation in the same solvent containing the following carbon nucleophiles: thiophene (0.10 M), furan (0.10 M), ethyl 1-propenyl ether (0.10 M), amd 1-cyclohexenyl trimethylsilyl ether (0.01 M). These results show that only π-nucleophiles with Mayr nucleophilicity parameters greater than N ≈ 6 are sufficiently reactive to compete with nucleophilic aqueous solvents for addition to 1+, and they provide support for a simple relationship between the Ritchie N+ scale of nucleophilicity in water and the Mayr N scale of nucleophilicity in weakly polar nonnucleophilic solvents.2,3 Our data require a large effective molarity for th...
Synthesis of Silirenes by Palladium-Catalyzed Transfer of Silylene from Siliranes to Alkynes

Palladium-catalyzed reactions of cis-1,1-di-tert-butyl-2,3-dimethylsilirane with disubstituted alkynes produced thermally stable silirenes in high yields (81−86%). Alkyl-, aryl-, trimethylsilyl-, and heteroatom-substituted alkynes were employed. The silirenes reacted with phenylacetylene and <3 mol % of PdCl2(PPh3)2 to produce trisubstituted siloles. A common catalytic cycle involving palladasilacyclobutene accounts for both the formation of silirene and the trisubstituted silole. The palladium-catalyzed extrusion of silylene effectively transfers silylene from one strained ring (a silirane) to form another strained ring (a silirene) and represents an unusual metal-mediated process.
An efficient synthesis of geminal di-sulfones

A simple and efficient method for the synthesis of gem-disulfones is reported. This method is based on protection of one of the central acidic hydrogens of bis(methylsulfonyl)methane as a thioether followed by formation of the dianion and selective alkylation of the methyl group. Alkylation of one of the methyl groups was demonstrated as well as alkylation of both methyl groups with the same or different alkyl groups. Removal of the thioether moiety furnished the desired substituted disulfones.
An efficient, enantioselective synthesis of branched polyhydroxylated pyrrolidines†

Abstract The enantioselective synthesis of branched polyhydroxylated pyrrolidines from a novel α-methylene bicyclic lactam (4b) is described.
Enantioselective synthesis of tropanes by reaction of rhodium-stabilized vinylcarbenoids with pyrroles

Abstract Rhodium(II) catalyzed decomposition of vinyldiazomethanes containing either (R)-pantolactone or (S)-lactate as chiral auxiliary in the presence of N-(tert-butoxycarbonyl)pyrrole resulted in an enantioselective entry to tropanes by a tandem cyclopropanation/Cope rearrangement.
Amino Acid-Derived Iodobenzene Dicarboxylates: Reagents for Oxidative Conversion of Alkenes to Amino Acid Esters

New amino acid-derived iodobenzene dicarboxylates were prepared by the reaction of (diacetoxyiodo)benzene with N-protected natural amino acids. These compounds in the presence of iodide anion can be used as reagents for β-iodocarboxylation of alkenes leading to the respective amino acid esters.
Stereochemistry of the cyclization-rearrangement of (+)-copalyl diphosphate to (-)-abietadiene catalyzed by recombinant abietadiene synthase from Abies grandis.

Syntheses and enzymatic cyclizations of 8α-hydroxy-17-nor copalyl diphosphate (8a), (15R)-[15-2H1] 8b, and (15R,17E)-[15-3H1,17-2H1] copalyl diphosphate ([2H,3H] 2) catalyzed by recombinant abietad...
Crystallization and spectroscopic properties of electron-beam-deposited, chromium-doped, forsterite films

A sol−gel prepared, chromium-doped, magnesium- and silicon-containing oxide mixture was used as a target material for the electron-beam deposition of 1.2 μm thick chromium-doped forsterite films onto single-crystal quartz substrates. The stoichiometry of the target materials was adjusted to compensate for the disparate volatilities of the component oxides. X-ray diffraction revealed that the as-deposited films were amorphous, and the refractive indices of the films revealed that they were near full density. Heating the films to 650 °C produced isolated crystallites of forsterite that ranged in size from 50 to 250 nm in an amorphous matrix (by TEM). Only films that had been heated to 725 °C and above revealed Cr4+ emissions.
Experimental Designs for Selecting Molecules from Large Chemical Databases

Recent developments in high-throughput screening and combinatorial chemistry have generated interest in experimental design methods to select subsets of molecules from large chemical databases. In this manuscript three methods for selecting molecules from large databases are described: edge designs, spread designs, and coverage designs. Two algorithms with linear time complexity that approximate spread and coverage designs are described. These algorithms can be threaded for multiprocessor systems, are compatible with any definition of molecular distance, and may be applied to very large chemical databases. For example, ten thousand molecules were selected using the maximum dissimilarity approximation to a spread design from a sixty-dimensional simulated molecular database of one million molecules in approximately 6 h on a UNIX workstation.
Lewis Acid-Promoted Reactions of Styrenyl Systems with Benzoquinone Bisimines: New Regioselective Syntheses of Substituted 2-Aryl-2,3-dihydroindoles and 2-Arylindoles

BF3-promoted reactions of 2-alkoxy-1-(N-benzoyl)-4-(N-benzenesulfonyl)-1,4-benzoquinone bisimines (2/3) with β-methylstyrenes yield trans-5-(N-benzoylamino)-6-alkoxy-2-aryl-3-methyl-2,3-dihydroindoles (4/5) or 3-(N-benzoylamino)-6-aryl-7-methyl-4,8-dioxobicyclo[3.2.1]oct-2-enes (6) regio- and stereoselectively. The former are produced in reactions with styrenes bearing alkoxy substituents, whereas with neutral or electron deficient styrenes, the latter are found. As applications of this new methodology to the synthesis of biologically interesting molecules, reactions of 2H-chromenes and 7-methoxy-N-toluenesulfonyl-1,2-dihydroquinoline with the bisimines have been developed as routes to substituted aza- and diazapterocarpans. Syntheses of 2-arylindoles via oxidation of the dihydroindoles 4 are also reported.
The total synthesis of bistratamides F–I

Abstract The total synthesis of bistratamides F–I ( 2 – 5 ) have been achieved in overall yields of 3, 10, 13, and 27%, respectively. The thiazole substructure was prepared utilizing a MnO 2 oxidation of a thiazoline, synthesized from a Val-Cys dipeptide using bis(triphenyl)oxodiphosphonium trifluoromethanesulfonate. The serine-based oxazole substructure was prepared from a Val-Ser dipeptide using literature methods. The threonine-derived oxazole substructure was synthesized from a ketoamide dipeptide using the bisphosphonium salt employed for thiazoline preparation. Most of the amide bonds were formed using HBTU and HOBt in the presence of DIEA. The final macrocyclization step was accomplished efficiently by PyBOP and DMAP in all cases.
The Hydrovinylation Reaction: A New Highly Selective Protocol Amenable to Asymmetric Catalysis

Carbon-carbon bond forming reaction is arguably the most important type of bond construction in organic chemistry; yet, paucity of methods for the stereoselective incorporation of abundantly available carbon feedstocks such as CO, CO2, HCN, or simple olefins to prochiral substrates is one of the major limitations in this area.1 One potentially important class of such reactions is the cationic [Ni-H]+-catalyzed olefin dimerization reaction.2,3 There had been only limited success in finding an enantioselective variation of this reaction partly because of the competing oligomerization of starting olefins and isomerization of the primary products (eq 1). In this paper we report our initial
Asymmetric Synthesis of (−)-Trichodiene. Generation of Vicinal Stereogenic Quaternary Centers via the Thio-Claisen Rearrangement

The use of chiral bicyclic lactams, in their thiocarbonyl form 9, has been shown to serve as important intermediates for producing α-quaternary alkyl derivatives 8, which were readily transformed into the title compound (−)-1. The reversibility of the thio-Claisen rearrangement, 15⇌8, was clearly demonstrated and appears to be unprecedented. Solvent effects to alter the equilibrium position were studied and found to have only a moderate, but beneficial effect. The title compound was obtained in 14% overall yield in 10 steps from bicyclic lactam, 9.
Stereoselective dimerization of benzylic amines derived from indoline

Treatment of benzylic amines derived from 2-(acyloxymethyl)-5-nitroindolines with sodium hexamethyl-disilazide leads to dimeric products resulting from deprotonation in the benzylic position, oxidation of the resulting carbanion to radical by the nitroarene moiety of another molecule, and stereoselective radical recombination. Only those two of six possible diastereoisomers are formed in which the recombination takes place from the less hindered face in the more stable conformation of the presumably near-planar radical.
Reagent control of stereochemistry in allylic additions to chiral aldehydes with CpMo(NO)(X)(2‐methallyl) complexes of high enantiomeric purity

Reactions of (R)- and (S)-CpMo(NO)(η 3 -methally)X(X=camphorsulfonate, Cl, Br, I) with chiral α-substituted aldehydes yield homoallylic alcohols with high diastereoselectivity. Reactions of (R)- and (S)-CpMo(NO)(η 3 -methallyl)L S [L S =(LS)-(+)-10-camphorsulfonate] with D-glyceraldehyde acetonide yield the corresponding homoallylic alcohols in >98% diastereomeric excess. Reactions with racemic 2-phenyl-propionaldehyde and nonracemic 3-benzyoxy-2-methylpropanol are also considered and show that there is very high reagent control of stereochemistry in additions to the carbonyl group
Waterbowls: Reducing Impacting Droplet Interactions by Momentum Redirection

Superhydrophobic surfaces can dramatically reduce the transport of mass or energy from impacting droplets by making them bounce off. Such transport processes are dependent on both the contact time ...
An optimal test for the additive model with discrete or categorical predictors

In multivariate nonparametric regression, the additive models are very useful when a suitable parametric model is difficult to find. The backfitting algorithm is a powerful tool to estimate the additive components. However, due to complexity of the estimators, the asymptotic p value of the associated test is difficult to calculate without a Monte Carlo simulation. Moreover, the conventional tests assume that the predictor variables are strictly continuous. In this paper, a new test is introduced for the additive components with discrete or categorical predictors, where the model may contain continuous covariates. This method is also applied to the semiparametric regression to test the goodness of fit of the model. These tests are asymptotically optimal in terms of the rate of convergence, as they can detect a specific class of contiguous alternatives at a rate of $$n^{-1/2}$$ . An extensive simulation study and a real data example are presented to support the theoretical results.
Star Formation: Chemistry as a Probe of Embedded Protostars

The embedded phase of star formation is the crucial phase where most of the stellar mass is assembled. Velocity-resolved spectra reveal an infalling envelope, bipolar outflows, and perhaps an infant circumstellar disk – all locked together in a cosmic dance of gravitational collapse and magnetic winds. Densities and temperatures change by orders of magnitude as the protostar evolves, driving a chemistry as exotic as it is fascinating. I will review two examples of how to exploit chemistry and molecular spectroscopy to study the physics of low-mass star formation: energetic feedback and episodic accretion.