cssi/SciSciGPT-SciSciNet huggingface dataset:
Changing Conceptions of the Opium War as History and Experience

Academic and popular accounts of the Opium War have gone through nearly two centuries of change in focus, view, and scope. My study probes this extensive historiography by tracing the evolvement of our understanding of the war through various phases among which we saw the rise of the “China-centered approach” and the beginning of a new trend towards combining government archives with personal records such as memoirs, personal correspondence, and private journals in research. Based on the observation, I will indicate, despite their undeniable achievements, most of the existing scholarships have paid little attention to the ordinary people in China whose lives were deeply affected by the war. It is high time that we pay more attention to human experience of the Chinese people in order to understand not only the war itself but also the history it helped shape.
Laser-induced ultrafast transport and demagnetization at the earliest time: first-principles and real-time investigation

It is generally believed that there are at least two ways to use an ultrafast laser pulse to demagnetize a magnetic sample. One is to directly photo-demagnetize the system through spin-orbit coupling (SOC), and the other is to utilize ultrafast hot electron transport without SOC. The challenge is that these two processes are entangled on the same time scale. While the experimental results have been inconclusive, theoretical investigations are even scarcer, beyond those earlier studies based on spin superdiffusion. For instance, we do not even know how fast electrons move under laser excitation and how far they move. Here we carry out a first-principles time-dependent calculation to investigate how fast electrons actually move under laser excitation and how large the electron transport affects demagnetization on the shortest time scale. To take into account the transport effect, we implement the intraband transition in our theory. In the bulk fcc Ni, we find the effect of the spin transport on the demagnetization is extremely small, no more than 1%. The collective electron velocity in Ni is 0.4 A fs-1, much smaller than the Fermi velocity, and the collective displacement is no more than 0.1 A. But this does not mean that electrons do not travel fast; instead we find that electron velocities at two opposite crystal momenta cancel each other. We follow the Γ-X line and find a huge dispersion in the velocities in the crystal momentum space. In the Fe/W(1 1 0) thin film, the overall demagnetization is larger than Ni, and the Fermi velocity is higher than Ni. However, the effect of the spin transport is still small in the Fe/W(1 1 0) thin film. Based on our numerical results and existing experimental findings, we propose a different mechanism that can explain two latest experimental results. Our finding sheds new light on the effect of ballistic transport on demagnetization.
Social Learning of Prescribing Behavior Can Promote Population Optimum of Antibiotic Use

The rise and spread of antibiotic resistance causes worsening medical cost and mortality especially for life-threatening bacteria infections, thereby posing a major threat to global health. Prescribing behavior of physicians is one of the important factors impacting the underlying dynamics of resistance evolution. It remains unclear when individual prescribing decisions can lead to the overuse of antibiotics on the population level, and whether population optimum of antibiotic use can be reached through an adaptive social learning process that governs the evolution of prescribing norm. Here we study a behavior-disease interaction model, specifically incorporating a feedback loop between prescription behavior and resistance evolution. We identify the conditions under which antibiotic resistance can evolve as a result of the tragedy of the commons in antibiotic overuse. Furthermore, we show that fast social learning that adjusts prescribing behavior in prompt response to resistance evolution can steer out cyclic oscillations of antibiotic usage quickly towards the stable population optimum of prescribing. Our work demonstrates that provision of prompt feedback to prescribing behavior with the collective consequences of treatment decisions and costs that are associated with resistance helps curb the overuse of antibiotics.
Multi-Institutional Deep Learning Modeling Without Sharing Patient Data: A Feasibility Study on Brain Tumor Segmentation.

Deep learning models for semantic segmentation of images require large amounts of data. In the medical imaging domain, acquiring sufficient data is a significant challenge. Labeling medical image data requires expert knowledge. Collaboration between institutions could address this challenge, but sharing medical data to a centralized location faces various legal, privacy, technical, and data-ownership challenges, especially among international institutions. In this study, we introduce the first use of federated learning for multi-institutional collaboration, enabling deep learning modeling without sharing patient data. Our quantitative results demonstrate that the performance of federated semantic segmentation models (Dice = 0.852) on multimodal brain scans is similar to that of models trained by sharing data (Dice = 0.862). We compare federated learning with two alternative collaborative learning methods and find that they fail to match the performance of federated learning.
New Techniques for Obfuscating Conjunctions

A conjunction is a function \(f(x_1,\dots ,x_n) = \bigwedge _{i \in S} l_i\) where \(S \subseteq [n]\) and each \(l_i\) is \(x_i\) or \(\lnot x_i\). Bishop et al. (CRYPTO 2018) recently proposed obfuscating conjunctions by embedding them in the error positions of a noisy Reed-Solomon codeword and placing the codeword in a group exponent. They prove distributional virtual black box (VBB) security in the generic group model for random conjunctions where \(|S| \ge 0.226n\). While conjunction obfuscation is known from LWE [31, 47], these constructions rely on substantial technical machinery.
Design of Chirped Gratings using Interferometric Lithography

Interferometric lithography with curved wavefronts produces chirped gratings. The chirp can be longitudinal, with the periodicity changing along the grating wavevector, or transverse, with the periodicity changing in the perpendicular direction. The chirp is investigated for a range of configurations, and specific optical systems to generate a wide range of grating chirp parameters are analyzed.
Spatial Analysis of Single Fiber Cells of the Developing Ocular Lens Reveals Regulated Heterogeneity of Gene Expression

The developing eye lens presents an exceptional paradigm for spatial transcriptomics. It is composed of highly organized long, slender transparent fiber cells, which differentiate from the edges of the anterior epithelium of the lens (equator), attended by high expression of crystallins, which generates transparency. Every fiber cell, therefore, is an optical unit whose refractive properties derive from its gene activity. Here, we probe this tangible relationship between the gene activity and the phenotype by studying the expression of all known 17 crystallins and 77 other non-crystallin genes in single fiber cells isolated from three states/regions of differentiation, allowing us to follow molecular progression at the single-cell level. The data demonstrate highly variable gene activity in cortical fibers, interposed between the nascent and the terminally differentiated fiber cell transcription. These data suggest that the so-called stochastic, highly heterogeneous gene activity is a regulated intermediate in the realization of a functional phenotype.
A Xylose-Inducible Expression System and a CRISPR Interference Plasmid for Targeted Knockdown of Gene Expression in Clostridioides difficile.

ABSTRACT Here we introduce plasmids for xylose-regulated expression and repression of genes in Clostridioides difficile. The xylose-inducible expression vector allows for ∼100-fold induction of an mCherryOpt reporter gene. Induction is titratable and uniform from cell to cell. The gene repression plasmid is a CRISPR interference (CRISPRi) system based on a nuclease-defective, codon-optimized allele of the Streptococcus pyogenes Cas9 protein (dCas9) that is targeted to a gene of interest by a constitutively expressed single guide RNA (sgRNA). Expression of dCas9 is induced by xylose, allowing investigators to control the timing and extent of gene silencing, as demonstrated here by dose-dependent repression of a chromosomal gene for a red fluorescent protein (maximum repression, ∼100-fold). To validate the utility of CRISPRi for deciphering gene function in C. difficile, we knocked down the expression of three genes involved in the biogenesis of the cell envelope: the cell division gene ftsZ, the S-layer protein gene slpA, and the peptidoglycan synthase gene pbp-0712. CRISPRi confirmed known or expected phenotypes associated with the loss of FtsZ and SlpA and revealed that the previously uncharacterized peptidoglycan synthase PBP-0712 is needed for proper elongation, cell division, and protection against lysis. IMPORTANCEClostridioides difficile has become the leading cause of hospital-acquired diarrhea in developed countries. A better understanding of the basic biology of this devastating pathogen might lead to novel approaches for preventing or treating C. difficile infections. Here we introduce new plasmid vectors that allow for titratable induction (Pxyl) or knockdown (CRISPRi) of gene expression. The CRISPRi plasmid allows for easy depletion of target proteins in C. difficile. Besides bypassing the lengthy process of mutant construction, CRISPRi can be used to study the function of essential genes, which are particularly important targets for antibiotic development.
Bias of OLS Estimators due to Exclusion of Relevant Variables and Inclusion of Irrelevant Variables

In this paper, I discuss three issues related to bias of OLS estimators in a general multivariate setting. First, I discuss the bias that arises from omitting relevant variables. I offer a geometric interpretation of such bias and derive sufficient conditions in terms of sign restrictions that allows us to determine the direction of bias. Second, I show that inclusion of some omitted variables will not necessarily reduce the magnitude of bias as long as some others remain omitted. Third, I show that inclusion of irrelevant variables in a model with omitted variables can also have an impact on the bias of OLS estimators. I use a running example of a simple wage regression to illustrate my arguments.
Tick size, price grids and market performance: Stable matches as a model of market dynamics and equilibrium

Abstract The tick size in a financial market is the minimum allowable difference between ask and bid prices. By the rules of each exchange, no transactions can occur within the tick interval. The impact of tick size is an ongoing controversy which we study by experimental methods, whose simplicity helps distinguish among competing models of complex real-world securities markets. We observe patterns predicted by a matching (cooperative game) model. Because a price grid interferes with a competitive equilibrium and restrictions on order flow interfere with information aggregation, the matching model provides predictions when the competitive model cannot, although their predictions are the same when a competitive equilibrium does exist. Our experiments examine stable allocations, average prices, timing of order flow, information flow and price dynamics. Larger tick size invites more speculation, which in turn increases liquidity. However, increased speculation leads to inefficient trades that otherwise would not have occurred.
National Policy for Regional Development: Historical Evidence from Appalachian Highways

How effective are policies aimed at integrating isolated regions? We answer this question in the context of a highway system in one of the poorest regions in the United States. With construction st...
Modeling Grasp Type Improves Learning-Based Grasp Planning

Different manipulation tasks require different types of grasps. For example, holding a heavy tool like a hammer requires a multifingered power grasp offering stability, while holding a pen to write requires a multifingered precision grasp to impart dexterity on the object. In this paper, we propose a probabilistic grasp planner that explicitly models grasp type for planning high-quality precision and power grasps in real time. We take a learning approach in order to plan grasps of different types for previously unseen objects when only partial visual information is available. This letter demonstrates the first supervised learning approach to grasp planning that can explicitly plan both power and precision grasps for a given object. Additionally, we compare our learned grasp model with a model that does not encode type and show that modeling grasp type improves the success rate of generated grasps. Furthermore, we show the benefit of learning a prior over grasp configurations to improve grasp inference with a learned classifier.
Reactive Modules

We present a formal model for concurrent systems. The model represents synchronous and asynchronous components in a uniform framework that supports compositional (assume-guarantee) and hierarchical (stepwise-refinement) design and verification. While synchronous models are based on a notion of atomic computation step, and asynchronous models remove that notion by introducing stuttering, our model is based on a flexible notion of what constitutes a computation step: by applying an abstraction operator to a system, arbitrarily many consecutive steps can be collapsed into a single step. The abstraction operator, which may turn an asynchronous system into a synchronous one, allows us to describe systems at various levels of temporal detail. For describing systems at various levels of spatial detail, we use a hiding operator that may turn a synchronous system into an asynchronous one. We illustrate the model with diverse examples from synchronous circuits, asynchronous shared-memory programs, and synchronous message-passing protocols.
Mendel's Laws†

Gregor Mendel's experiments with peas lead to the development of two laws that describe, in quantitative terms, trait distributions in the offspring of a mating. The first, which still forms the fundamental basis behind much of genetics, is the law of segregation. In modern terms, this law states that each individual, as a parent, transmits to an offspring, exactly one randomly chosen allele of the two present at each locus in the individual. The second law, or law of independence, describes the joint behavior of more than one gene. This law states that alleles at one locus segregate independently of alleles at other loci. This proposition is now known to be false for genes on the same chromosome, but still, usually adequately describes the inheritance patterns of multiple genes, other than those on the same chromosome. Keywords: segregation; assortment; inheritance pattern; transmission; linkage; diploid; gamete
Semiparametric competing risks regression under interval censoring using the R package intccr.

Abstract Background and Objective: Competing risk data are frequently interval-censored in real-world applications, that is, the exact event time is not precisely observed but is only known to lie between two time points such as clinic visits. This type of data requires special handling because the actual event times are unknown. To deal with this problem we have developed an easy-to-use open-source statistical software. Methods: An approach to perform semiparametric regression analysis of the cumulative incidence function with interval-censored competing risks data is the sieve maximum likelihood method based on B-splines. An important feature of this approach is that it does not impose restrictive parametric assumptions. Also, this methodology provides semiparametrically efficient estimates. Implementation of this methodology can be easily performed using our new R package intccr. Results: The R package intccr performs semiparametric regression analysis of the cumulative incidence function based on interval-censored competing risks data. It supports a large class of models including the proportional odds and the Fine–Gray proportional subdistribution hazards model as special cases. It also provides the estimated cumulative incidence functions for a particular combination of covariate values. The package also provides some data management functionality to handle data sets which are in a long format involving multiple lines of data per subject. Conclusions: The R package intccr provides a convenient and flexible software for the analysis of the cumulative incidence function based on interval-censored competing risks data.
Pubertal influences on neural activation during risky decision-making in youth with ADHD and disruptive behavior disorders

Abstract Objective Risk-taking during adolescence is a leading cause of mortality; Neuroscience research examining pubertal effects on decision-making is needed to better inform interventions, particularly among youth with attention-deficit/hyperactivity (ADHD) and disruptive behavior disorders (DBD), who are particularly prone to risky decision-making. We examined effects of pubertal development on risky decision-making and neural activation during decision-making among youth with ADHD/DBDs. Method Forty-six 11–12-year-olds (29.4% girls; 54.9% white; Tanner M(SD) = 2.08(1.32)) who met DSM-5 criteria for ADHD/DBD completed the Balloon Analog Risk Task (BART) during fMRI scanning. We examined effects of Tanner stage, sex, and age on risky decision-making (mean wager at which individuals stopped balloon inflation) and neural activation in the middle frontal gyrus and the ventral striatum during the choice and outcome phases of decision-making. Results Those in earlier pubertal stages made riskier decisions during the BART compared to those in later Tanner stages (β=-0.62, p = .02). Later pubertal stage was associated with greater activation in the left middle frontal gyrus (β=0.61, p = .03) during the choice phase and in the right ventral striatum in response to rewards (β=0.59, p = .03). Conclusion Youth with ADHD/DBD in later stages of puberty, regardless of age, show greater ventral striatal activation in response to rewards.
APPROACH TO UTERINE ARTERY OCCLUSION AT MYOMECTOMY

Video abstract summary Objective To demonstrate three approaches to uterine artery occlusion at time of myomectomy as a blood-sparing intra-operative technique and review available evidence in the literature. Study methods We proceed with a step-by-step explanation of the procedure with surgical video footage and discuss the available literature on its effectiveness. Results A step-wise approach is applied prior to beginning the myomectomy portion of the procedure which includes the following: 1) selecting the appropriate approach to uterine artery occlusion (lateral vs. posterior vs. anterior) based on individual anatomy; 2) identifying relevant anatomy and important landmarks for the procedure 3) isolating the uterine artery and identifying the ureter; 4) occluding the uterine artery. A recent systematic review and meta-analysis supports uterine artery occlusion as a technique to reduce blood loss and blood transfusion, while minimally increasing operative times. Conclusion(s) Uterine artery occlusion can be performed by three different approaches, as have been demonstrated in this video, and is an effective measure at reducing intra-operative blood loss, albeit at the cost of slightly longer operative times.
Neuropilin-1 Regulates the Secondary CD8 T Cell Response to Virus Infection

Neuropilin-1 (Nrp1) plays important roles in axonal guidance in neurons and in the growth of new blood vessels. There is also a growing appreciation for roles played by neuropilin-1 in the immune response. This molecule is important for the function of regulatory T cells; however, roles in other T cell populations have not been identified. Here, we show that neuropilin-1 is expressed during the peak of the antiviral CD8 T cell response during murine gammaherpesvirus infection. Using a conditional knockout model, we deleted Nrp1 either before infection or after CD8 T cell memory had been established. We found that deletion of Nrp1 skewed the acute CD8 T cell response toward a memory precursor-like phenotype; however, the ensuing resting memory response was similar regardless of Nrp1 expression. Interestingly, Nrp1 deletion had differing effects on the recall response depending on the timing of deletion. When deleted before infection, Nrp1 deficiency inhibited the secondary response. Deletion just prior to reexposure to virus led to an enhanced secondary response. Interestingly, these effects were observed only in mice infected with a persistent strain of murine gammaherpesvirus and not with a nonpersistent mutant strain. These data highlight a multifaceted role for neuropilin-1 in memory CD8 T cell differentiation, dependent upon the stage of the T cell response and characteristics of the infectious agent. Several therapeutic anticancer therapies focus on inhibition of Nrp1 to restrict tumor growth, and so knowledge of how Nrp1 blockade may affect the CD8 T cell response will provide a better understanding of treatment consequences.IMPORTANCE CD8 T cell responses are critical to control both virus infections and tumors. The ability of these cells to persist for long periods of time can result in lifelong immunity, as relatively small populations of cells can expand rapidly to counter reexposure to the same insult. Understanding the molecules necessary for this rapid secondary expansion is critical if we are to develop therapies that can provide lifelong protection. This report shows an important and complex role for the molecule neuropilin-1 in the secondary response. Several cancer therapies targeting neuropilin-1 are in development, and this work will lead to better understanding of the effect these therapies could have upon the protective CD8 T cell response.
The role of financial conditions in portfolio choices: The case of insurers

Abstract Many institutional investors depend on the returns they generate to fund their operations and liabilities. How do these investors’ financial conditions affect the management of their portfolios? We address this issue using the insurance industry because insurers are large investors for which detailed portfolio data are available, and can face financial shocks from exogenous weather events which help us establish causality. Among corporate bonds, for which we can control for regulatory treatment, results suggest that when Property & Casualty (P&C) insurers become more constrained due to operating losses, they shift towards safer bonds. The effect of losses on allocations is likely to be causal because it holds when instrumenting for losses with weather shocks. The change in allocations following losses is larger for smaller or worse-rated insurers and during the financial crisis, suggesting that the shift toward safer securities is driven by concerns about financial flexibility. The results highlight the importance of financial conditions in institutional investors’ portfolio decisions.
Normal T1 relaxometry and extracellular volume of the pancreas in subjects with no pancreas disease: correlation with age and gender

Determine normal T1 and extracellular volume (ECV) of the pancreas in subjects with no pancreas disease and correlate with age and gender. We imaged 120 healthy subjects (age range 20–78 years) who are on annual screening with MRI/MRCP for the possibility of pancreatic cancer. Subjects had a predisposition to develop pancreatic cancer, but no history of pancreas disease or acute symptoms. Equal number (n = 60) of subjects were scanned on either 1.5 T or 3 T scanner using dual flip angle spoiled gradient echo technique incorporating fat suppression and correction for B1 field inhomogeneity. Optimization of imaging parameters was performed using a T1 phantom. ECV was calculated using pre- and post-contrast T1 of the pancreas and plasma. Regression analysis and Mann–Whitney tests were used for statistical analysis. Median T1 on 1.5 T was 654 ms (IQR 608–700); median T1 on 3 T was 717 ms (IQR 582–850); median ECV on 1.5 T was 0.28 (IQR 0.21–0.33), and median ECV on 3 T was 0.25 (IQR 0.19–0.28). Age had a mild positive correlation with T1 (r = 0.24, p = 0.009), but not with ECV (r = 0.06, p = 0.54). T1 and ECV were similar in both genders (p > 0.05). This study measured the median T1 and ECV of the pancreas in subjects with no pancreas disease. Pancreas shows longer T1 relaxation times in older population, whereas extracellular fraction remains unchanged. Median T1 values were different between two magnet strengths; however, no difference was seen between genders and ECV fractions.
Preparation of unsubstituted dipyridine‐dibarbituric acid ylide through dimerization of pyridin‐2‐ylmethylenepyrimidinetrione as a reactive intermediate

Preparation of 5,5′-(pyridin-2-ylmethylene)dipyrimidinetrione from barbituric acid and 2-pyridinecarbox-aldehyde in any polar solvent is a straightforward synthetic procedure, while preparation of the dipyridine-dibarbituric acid ylide from the same starting materials is sensitive to the reaction media, pH, and temperature. For both products, the formation of the reactive intermediate 2-pyridin-2-ylmethylenepyrimidinetrione is certain and this intermediate is a cross road for the reaction to be directed in one way or other. The experimental evidence for the formation of this important intermediate, as well as synthetic procedures for the preparation of both condensation products are presented.
The prevalence and impact of transient species in ecological communities

Transient species occur infrequently in a community over time and do not maintain viable local populations. Because transient species interact differently than non-transients with their biotic and abiotic environment, it is important to characterize the prevalence of these species and how they impact our understanding of ecological systems. We quantified the prevalence and impact of transient species in communities using data on over 19,000 community time series spanning an array of ecosystems, taxonomic groups, and spatial scales. We found that transient species are a general feature of communities regardless of taxa or ecosystem. The proportion of these species decreases with increasing spatial scale leading to a need to control for scale in comparative work. Removing transient species from analyses influences the form of a suite of commonly studied ecological patterns including species-abundance distributions, species-energy relationships, species-area relationships, and temporal turnover. Careful consideration should be given to whether transient species are included in analyses depending on the theoretical and practical relevance of these species for the question being studied.
A reexamination of the reactions of 2,3-dichloro-1,4-naphthoquinone with thioamides

2,3-Dichloro-1,4-naphthoquinone reacts with thioamides and thiourea to give mixtures of condensed thiazoles and thianthrenes.
An efficient and simple aqueous N-heterocyclization of aniline derivatives: microwave-assisted synthesis of N-aryl azacycloalkanes.

An efficient and clean synthesis of N-aryl azacycloalkanes from alkyl dihalides and aniline derivatives has been achieved using microwave irradiation in an aqueous potassium carbonate medium. The phase separation can simplify the product isolation and reduce usage of volatile organic solvents.
Synthesis, Characterization, and Bonding of Two New Heteropolychalcogenides: α-CsCu(SxSe4-x) and CsCu(SxSe6-x)

The Cs-Cu-Q (Q = S, Se) system has been investigated using copper metal, cesium chloride, and alkali-metal polychalcogenide salts under mild hydrothermal reaction conditions. Heteropolychalcogenide salts and mixtures of known polysulfide and polyselenide salts have been used as reagents. The reaction products contain the alpha-CsCuQ(4) and CsCuQ(6) structures. The alpha-CsCuQ(4) phase exhibits a smooth transition in lattice parameters from the pure sulfur to the pure selenium phases, based on Vegard's law. The CsCuQ(6) phase has been prepared as the pure sulfur analog and a selenium rich analog. The single-crystal structures of the disordered compounds alpha-CsCuS(2)Se(2) (P2(1)2(1)2(1), Z = 4, a = 5.439(1) A, b = 8.878(2) A, c = 13.762(4) A) and CsCuS(1.6)Se(4.4) (Po, Z = 2, a = 11.253(4) A, b = 11.585(2) A, c = 7.211(2) A, alpha = 92.93 degrees, beta = 100.94 degrees, gamma = 74.51 degrees ) have been solved using a correlated-site occupancy model. These disordered structures display a polychalcogenide geometry in which the sulfur atoms prefer positions that are bound to copper. The optical absorption spectra of these materials have been investigated. The optical band gap varies as a function of the sulfur-selenium ratio. Extended Huckel crystal orbital calculations have been performed to investigate the electronic structure and bonding in these compounds in an attempt to explain the site distribution of sulfur and selenium.
Strong Decays of Hybrid Mesons from the Heavy Quark Expansion of QCD

We calculate the strong decays of hybrid mesons to conventional mesons for all the lowest lying JPC hybrids of flavour uū, dd, ss, cc and bb. A decay operator developed from the heavy quark expansion of quantum chromodynamics is employed. We show that the selection rule that hybrid mesons do not decay to identical S-wave mesons, found in other models, is preserved. We predict decays of charmonium hybrids, discuss decays of JPC=1−+ exotic isovector hybrids of various masses, and interpret the π(1800) as a hybrid meson.
Discovery of the tungsten carbonyl-catalyzed endo-selective alkynyl alcohol cycloisomerization reaction: applications to stereoselective syntheses of d-olivose, d-olivose disaccharide substructures of landomycin and mithramycin

Abstract An account of the discovery of the tungsten carbonyl-catalyzed endo -selective cycloisomerization of alkynyl alcohols to dihydropyrans is described. The utility of this new chemical transformation involving tungsten vinylidene catalytic intermediates is demonstrated in stereoselective syntheses of disaccharide substructures 26 – 28 of the landomycin and mithramycin families of anticancer antibiotics.
Reactions of ethyl diazoacetate with β-methylfurans

Abstract Reactions of β-methylfuran and 2,4-dimethylfuran with ethyl diazoacetate in the presence of [Rh2(OAc)4] catalyst, followed by iodine-induced isomerization, yielded furan ring-unravelled products. The results are compared with those of α-methylfurans.
Synthesis of novel aromatic macrolactones via ring closing metathesis of substituted phenylalkanoic acid allylic esters

Stable aromatic macrolactones have been synthesized and characterized from 2- and 3-substituted phenylalkanoic acid systems in modest yields.
Numerical simulations of bouncing jets

Bouncing jets are fascinating phenomenons occurring under certain conditions when a jet impinges on a free surface. This e ect is observed when the fluid is Newtonian and the jet falls in a bath undergoing a solid motion. It occurs also for non-Newtonian fluids when the jets falls in a vessel at rest containing the same fluid. We investigate numerically the impact of the experimental setting and the rheological properties of the fluid on the onset of the bouncing phenomenon. Our investigations show that the occurrence of a thin lubricating layer of air separating the jet and the rest of the liquid is a key factor for the bouncing of the jet to happen. The numerical technique that is used consists of a projection method for the Navier-Stokes system coupled with a level set formulation for the representation of the interface. The space approximation is done with adaptive finite elements. Adaptive refinement is shown to be very important to capture the thin layer of air that is responsible for the bouncing.
The reaction of methyl 3-amino-4-cyano-5-methylthiothiophene-2-carboxylate with dmad. A new synthesis of polyfunctionalized quinolines

The reaction of methyl 3-amino-4-cyano-5-methylthiothiophene-2-carboxy- late (2), which was prepared by the reaction of bis(methylthio)methy- lenepropanedinitrile (1) with methyl thioglycolate followed by dimethyl acetylenedicarboxylate (DMAD) in the presence of potassium carbonate in dimethyl sulfoxide gave the polyfunctionalized quinoline, pentamethyl 4-amino-5-mercaptoquinoline-2,3,6,7,8-pentacarboxylate (3). The oxida- tion of (3) with iodine in DMSO provided the novel ring system in the form of the derivative, pentamethyl 2H-isothiazolo[3,4,5-de]quinoline- 3,4,6,7,8-pentacarboxylate (4)
Intrinsic charm in B-meson decays

Abstract Light cone hadron wave functions support Fock states of arbitrarily high particle number: their heavy quark content arises naturally through QCD interactions. We discuss what role c c pairs, intrinsic to a hadron's structure, can play in B-meson decays. The effects can be prominent in hadronic decays for which the tree-level contributions are Cabibbo-suppressed, as in B → πK decay, and they mimic “charming penguin” contributions.
A Facile Perfluoroallylation of Olefins

The addition of F-allyl iodide to terminal alkenes is induced by a catalytic amount of copper powder in the absence of solvent at room temperature to 50 °C to give the corresponding 1:1 adducts in good yields. A variety of functional groups such as trimethylsilyl, alkyl, epoxy, ester, hydroxyl, bromo, ether, and phosphonate are tolerated in the addition reaction. This reaction also worked well with internal olefins such as cyclohexene, cyclopentene, and 4-octene. Reaction with dienes gives the corresponding linear adduct and cyclization adduct depending on the chain length of the dienes. With 1,7-octadiene, a bis(perfluoroallyl) product is formed, while a tetrahydrofuran derivative is obtained with diallyl ether. Reduction of the adducts with zinc in the presence of nickel dichloride in moist THF or zinc in moist DMF affords the perfluoroallyl derivatives. The adduct reacts with zinc in DMF to form a zinc reagent which couples with organic electrophiles in the presence of CuBr.
A convenient microwave-assisted arylstannane generation-Stille coupling protocol

An efficient methodology for the synthesis of complex pyridin-3-yl-phenyl biaryl systems is described; microwave irradiation greatly enhances the rate of the two Pd-catalyzed key steps: formation of the stannane partner and its subsequent Stille coupling with a range of highly functionalized pyridines. Besides being fast and high yielding, this process also allows diversification of the pyridine at a late stage.
Neural systems of cognitive demand avoidance

Cognitive effort is typically aversive, evident in people's tendency to avoid cognitively demanding tasks. The 'cost of control' hypothesis suggests that engagement of cognitive control systems of the brain makes a task costly and the currency of that cost is a reduction in anticipated rewards. However, prior studies have relied on binary hard versus easy task subtractions to manipulate cognitive effort and so have not tested this hypothesis in "dose-response" fashion. In a sample of 50 participants, we parametrically manipulated the level of effort during fMRI scanning by systematically increasing cognitive control demands during a demand-selection paradigm over six levels. As expected, frontoparietal control network (FPN) activity increased, and reward network activity decreased, as control demands increased across tasks. However, avoidance behavior was not attributable to the change in FPN activity, lending only partial support to the cost of control hypothesis. By contrast, we unexpectedly observed that the de-activation of a task-negative brain network corresponding to the Default Mode Network (DMN) across levels of the cognitive control manipulation predicted the change in avoidance. In summary, we find partial support for the cost of control hypothesis, while highlighting the role of task-negative brain networks in modulating effort avoidance behavior.
Vagus nerve stimulation promotes gastric emptying by increasing pyloric opening measured with magnetic resonance imaging.

BACKGROUND Vagus nerve stimulation (VNS) is an emerging electroceutical therapy for remedying gastric disorders that are poorly managed by pharmacological treatments and/or dietary changes. Such therapy seems promising as the vagovagal neurocircuitry modulates the enteric nervous system to influence gastric functions. METHODS Here, the modulatory effects of left cervical VNS on gastric emptying in rats were quantified using a (i) feeding protocol in which the animal voluntarily consumed a postfast, gadolinium-labeled meal and (ii) a non-invasive imaging method to measure antral motility, pyloric activity and gastric emptying based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing pipelines. KEY RESULTS Vagus nerve stimulation significantly accelerated gastric emptying (sham vs VNS: 29.1% ± 1.5% vs 40.7% ± 3.9% of meal emptied per 4 hours), caused a greater relaxation of the pyloric sphincter (sham vs VNS: 1.5 ± 0.1 vs 2.6 ± 0.4 mm2 cross-sectional area of lumen), and increased antral contraction amplitude (sham vs VNS: 23.3% ± 3.0% vs 32.5% ± 3.0% occlusion), peristaltic velocity (sham vs VNS: 0.50 ± 0.02 vs 0.67 ± 0.03 mm s-1 ), but not its contraction frequency (sham vs VNS: 6.1 ± 0.2 vs 6.4 ± 0.2 contractions per minute, P = .22). The degree to which VNS relaxed the pylorus was positively correlated with gastric emptying rate (r = .5887, P < .001). CONCLUSIONS & INFERENCES The MRI protocol employed in this study is expected to enable advanced preclinical studies to understand stomach pathophysiology and its therapeutics. Results from this study suggest an electroceutical treatment approach for gastric emptying disorders using cervical VNS to control the degree of pyloric sphincter relaxation.
Synthesis and 13C NMR spectra of cis- and trans-{2-(haloaryl)-2-[(1H-imidazol)-1-yl]methyl]}-1,3-dioxolane-4-methanols

Syntheses and 13C nmr spectra of a number of cis and trans 2-(haloaryl)-2-[(1H-imidazol-1-yl)rnethyl]-4-(hydroxymethyl)-1,3-dioxolanes are described. The haloaryl groups are 2,4-dichloro, 2,4-difluoro-, 4-chloro-and 4-bromophenyl. In these series, some of the cis compounds become available through crystalline bromo benzoates 5. Separations of some trans isomers are achieved through fractional crystallizations of imidazolyl benzoate nitrates 6. Stereochemical assignments are based primarily on one major 13C chemical shift difference, namely that of C-4 of the 1,3-dioxolane ring, the chemical shift of the trans isomers being 1.0-2.5 ppm downfield from that of the cis isomers.
The cytosporones, new octaketide antibiotics isolated from an endophytic fungus.

Organic extracts from cultures of endophytic fungi collected in the Guanacaste Conservation Area of Costa Rica were screened for antibiotic activity. Two endophytes CR200 (Cytospora sp.) and CR146 (Diaporthe sp.) were found to have potent antibiotic activity. Bioassay-guided fractionation of the extracts from these fungi led to the identification of cytosporones D and E, antibacterial active trihydroxybenzene lactones, and three related but inactive metabolites. The five new octaketides were characterized using X-ray crystallography and NMR.
Practical and Provably Secure Onion Routing.

In an onion routing protocol, messages travel through several intermediaries before arriving at their destinations, they are wrapped in layers of encryption (hence they are called "onions"). The goal is to make it hard to establish who sent the message. It is a practical and widespread tool for creating anonymous channels. For the standard adversary models --- network, passive, and active --- we present practical and provably secure onion routing protocols. Akin to Tor, in our protocols each party independently chooses the routing paths for his onions. For security parameter $\lambda$, our differentially private solution for the active adversary takes $O(\log^2\lambda)$ rounds and requires every participant to transmit $O(\log^{4} \lambda)$ onions in every round.
Chemical Synthesis of Microporous Nonoxide Ceramics from Polysilazanes

In a search for a generic synthesis methodology to produce microporous, nonoxide ceramics, pyrolysis of silicon-based preceramic polymers has been studied in inert (He or Ar) and reactive (NH3) atmospheres over the temperature range 25−1300 °C. Pyrolysis of polysilazanes in an inert atmosphere in the absence of additives produced only low-density, nonmicroporous solids. However, four successful approaches to induce microporosity were developed, involving controlled reaction of selected low molecular weight polysilazane preceramic polymers. The first method employs the formation of colloidal polysilazane mixtures with micron-size particles of ceramics such as Si3N4, SiC, and AlN, followed by their pyrolysis in He or NH3 to form a ceramic−ceramic composite. The second method involves the synthesis of a nanoscale, polysilazane-stabilized metal colloid of a noble or transition metal and its conversion to a metal− or cermet−ceramic composite by pyrolysis in He or NH3. In the third method, a polysilazane is pyr...
A facile one‐pot synthesis of 2,5‐disubstituted oxazoles using iodobenzene diacetate

A facile one-pot synthesis of oxazoles 1a-h is described that utilizes readily available aromatic α-methyl ketones and a safe hypervalent iodine reagent, iodobenzene diacetate.
“Azaphilic addition” of methyl lithium to 3,6‐bisalkylthio‐1,2,4,5‐tetrazines: A remarkable dichotomy

A new type of «azaphilic addition» reaction of methyl lithium to 3,6-bisalkylthio-1,2,4,5-tetrazines has been discovered. Methyl lithium adds at the tetrazine nitrogen of 1 affording 4 while nitrogen nucleophiles displace tetrazine alkylthio groups at carbon affording 3. The structures of the N-alkyl products were determined by 1 H- and 13 C-nmr and uv experiments. Reversing the order of methyl lithium addition caused the formation of a bicyclic tetrazine 6. Grignard reagents add in the same fashion as methyl lithium
Resting-State fMRI Dynamics and Null Models: Perspectives, Sampling Variability, and Simulations.

Studies of resting state functional MRI (rs-fRMI) are increasingly focused on “dynamics”, or on those properties of brain activation that manifest and vary on timescales shorter than the scan’s full duration. This shift in focus has led to a flurry of interest in developing hypothesis testing frameworks and null models applicable to the dynamical setting. Thus far however, these efforts have been weakened by a number of crucial shortcomings that are outlined and discussed in this short paper. We focus here on aspects of recently proposed null models that, we argue, are poorly formulated relative to the hypotheses they are designed to test, i.e. their potential role in separating functionally relevant BOLD signal dynamics from noise or intermittent background and maintenance type processes is limited by factors that are fundamental rather than merely quantitative or parametric. In this short position paper, we emphasize that (1) serious care must be exercised in building null models for rs-fMRI dynamics from distributionally stationary univariate or multivariate timeseries, i.e. timeseries whose values are each independently drawn from one pre-specified probability distribution; and (2) measures such as kurtosis that quantify over-concentration of observed values in the far tails of some reference distribution may not be particularly suitable for capturing signal features most plausibly contributing to functionally relevant brain dynamics. Other metrics targeted, for example, at capturing the epochal temporal variation that contributes heavily to dynamic functional connectivity estimates and is and often taken as a signature of brain responsiveness to stimuli or experimental tasks, could play a more scientifically clarifying role. As we learn more about the phenomenon of functionally relevant brain dynamics and its imaging correlates, scientifically meaningful null hypotheses and well-tuned null models will naturally emerge. We also revisit the important concept of distributional stationarity, discuss how it manifests within realizations versus across multiple realizations, and provide guidance on the benefits and limitations of employing this type of stationarity in modeling the absence of functionally relevant temporal dynamics in resting state fMRI. We hope that the discussions herein are useful, and promote thoughtful consideration of these important issues.
Substituted ethyl 2‐acyl‐3‐amino‐6‐methylthieno[2,3‐b]pyridine‐4‐carboxylates as synthons for novel heterocycles

The triethylamine-catalyzed reaction of 4-substituted ethyl 2-acyl-3-amino-6-methylthieno[2,3-b]pyridine-4-carboxylates IIIa-h with 2,2,6-trimethyl-4H-1,3-dioxin-4-one IV gave 4-substituted ethyl 3-acetyl-2-hydroxy-7-methylthieno[2,3-b:4,5-b′]dipyridine-9-carboxylates Va-h. Some of the thienodipyridines (V) reacted with excess IV to give 5-substituted ethyl 3-acetyl-4,8-dimethyl-2-oxo-2H-pyrano[2,3-b]-pyrido[3′,2′:4,5]thieno[2,3-e]pyridine-10-carboxylates VI.
[H2NMe2]CuZrCl6: Hydrogen-Bond Induced Distortions in a Copper Zirconium Chloride Analogue of a Thiophosphate

The copper(I) zirconium(IV) halide, [H2NMe2]CuZrCl6 (1), has been synthesized, and its single-crystal X-ray structure was determined. The crystal undergoes a phase transition at −60 °C giving a room-temperature structure with a = 10.1105(6) A, b = 9.9463(5) A, c = 12.7254(8) A, β = 110.287(5)° in the monoclinic space group C2/c, Z = 4, and a low-temperature structure (−116 °C) with a = 10.234(2) A, b = 9.427(1) A, c = 12.691(2) A, β = 109.90(2)° in the monoclinic space group P21/c, Z = 4. [H2NMe2]CuZrCl6 is constructed from unique one-dimensional chains with zirconium and copper in alternating octahedral and tetrahedral coordination environments, respectively. The structural relationship between (CuCl4)3- and (PS4)3- is demonstrated by the analogy of this structure to that of KNiPS4. The phase transition, which occurs at approximately −60 °C, results in altered configurations of the dimethylammonium to metal−chloride hydrogen bonding. In addition, a remarkable distortion in the cuprous chloride tetrahedra...
Stannous chloride-mediated reductive cyclization-rearrangement of nitroarenyl ketones.

Cyclization products are produced in excellent yields from using standard reaction conditions for nitroarene reduction to aminoarene with SnCl2. Thus, 4-methyl-2-(2-nitrobenzyl)-2H-1,4-benzothiazin-3(4H)-one (2b) upon treatment with SnCl2 in ethanol did not produce the expected aniline derivative. Instead, 6-methyl-11a, 12-dihydro-6H-quino[3,2-b][1,4]benzothiazine (3) was produced in excellent yield, presumably via novel Sn (IV)-mediated amidine formation from the initial aniline reduction product. Under identical reaction conditions, 2-(2-nitrophenyl)-thiochroman-4-one (6) produces ethyl 5,11-dihydrodibenzo[b,e][1,4]thiazepin-11-ylacetate (7). A novel semipinacol rearrangement is proposed to account for this extensive skeletal rearrangement. Aniline derivative (14) (from 6 treated with FeSO4·7H2O) forms 12-ethoxy-11,12-dihydro-6H-6,12-methanodibenzo[b,f][1,5]thiazocine (15) upon treatment with SnCl2 in ethanol. Thiophene analogues of 6 and 14 (18 and 19, respectively) react similarly, forming the analogo...
Z ′ bosons, the NuTeV anomaly, and the Higgs boson mass

Fits to the precision electroweak data that include the NuTeV measurement are considered in family universal, anomaly free U(1) extensions of the Standard Model. In data sets from which the hadronic asymmetries are excluded, some of the Z′ models can double the predicted value of the Higgs boson mass, from ∼60 to ∼120 GeV, removing the tension with the LEP II lower bound, while also modestly improving the χ 2 confidence level. The effect of the Z′ models on both m H and the χ 2 confidence level is increased when the NuTeV measurement is included in the fit. Both the original NuTeV data and a revised estimate by the PDG are considered.