cssi/SciSciGPT-SciSciNet huggingface dataset:
Suzuki−Miyaura Cross-Coupling Reactions of Potassium Alkenyltrifluoroborates

We have previously reported that the palladium-catalyzed cross-coupling reaction of air-stable potassium alkenyltrifluoroborates with aryl halides and triflates proceeds readily with good yields. Recent progress in outlining the scope and limitations of such reactions is described herein. The palladium-catalyzed cross-coupling reaction of potassium alkenyltrifluoroborates with aryl and heteroaryl halides and triflates proceeds readily with moderate to excellent yields. The alkenyl cross-coupling reaction can generally be effected using 2 mol % of PdCl2(dppf)·CH2Cl2 as catalyst in i-PrOH−H2O in the presence of t-BuNH2 as the base. A variety of functional groups are tolerated in both partners, and the process is stereospecific with regard to the alkenyltrifluoroborate starting material.
Efficient Online Scalar Annotation with Bounded Support

We describe a novel method for efficiently eliciting scalar annotations for dataset construction and system quality estimation by human judgments. We contrast direct assessment (annotators assign scores to items directly), online pairwise ranking aggregation (scores derive from annotator comparison of items), and a hybrid approach (EASL: Efficient Annotation of Scalar Labels) proposed here. Our proposal leads to increased correlation with ground truth, at far greater annotator efficiency, suggesting this strategy as an improved mechanism for dataset creation and manual system evaluation.
Controversies in Obstructive Sleep Apnea Surgery

Obstructive sleep apnea (OSA) is a common chronic disease characterized by repetitive pharyngeal collapse during sleep. OSA is associated with cardiovascular disease and increased mortality, among other issues. Continuous positive airway pressure (CPAP) is considered first line therapy for OSA, but is not always tolerated. Both non-surgical and surgical alternative management strategies are available for the CPAP intolerant patient. This article explores controversies surrounding airway evaluation, definition of successful treatment, and surgical management of the CPAP intolerant patient with moderate to severe OSA. Controversies specific to maxillomandibular advancement (MMA) are also discussed.
Optimal Learning for Dynamic Coding in Deadline-Constrained Multi-Channel Networks

We study the problem of serving randomly arriving and delay-sensitive traffic over a multi-channel communication system with time-varying channel states and unknown statistics. This problem deviates from the classical exploration-exploitation setting in that the design and analysis must accommodate the dynamics of packet availability and urgency as well as the cost of each channel use at the time of decision. To that end, we have developed and investigated an index-based policy upper confidence bound (UCB)-deadline, which performs dynamic channel allocation decisions that incorporate these traffic requirements and costs. Under symmetric channel conditions, we have proved that the UCB-deadline policy can achieve bounded regret in the likely case where the cost of using a channel is not too high to prevent all transmissions, and logarithmic regret otherwise. In this case, we show that UCB-deadline is order-optimal. We also perform numerical investigations to validate the theoretical fundings, and also compare the performance of the UCB-deadline to another learning algorithm that we propose based on Thompson sampling.
Noise-tolerant Audio-visual Online Person Verification Using an Attention-based Neural Network Fusion

In this paper, we present a multi-modal online person verification system using both speech and visual signals. Inspired by neuroscientific findings on the association of voice and face, we propose an attention-based end-to-end neural network that learns multi-sensory association for the task of person verification. The attention mechanism in our proposed network learns to conditionally select a salient modality between speech and facial representations that provides a balance between complementary inputs. By virtue of this capability, the network is robust to missing or corrupted data from either modality. In the VoxCeleb2 dataset, we show that our method performs favorably against competing multi-modal methods. Even for extreme cases of large corruption or missing data on either modality, our method demonstrates robustness over other unimodal methods.
Implicit Stereotypes: Evidence from Teachers’ Gender Bias

I study whether exposure to teacher stereotypes, as measured by the Gender-Science Implicit Association Test, affects student achievement. I provide evidence that the gender gap in math performance, defined as the score of boys minus the score of girls in standardized tests, substantially increases when students are assigned to math teachers with stronger gender stereotypes. Teacher stereotypes induce girls to underperform in math and self-select into less demanding high schools, following the track recommendation of their teachers. These effects are at least partially driven by lower self-confidence on math ability of girls exposed to gender-biased teachers. Stereotypes impair the test performance of girls, who end up failing to achieve their full potential. I do not detect statistically significant effects on student outcomes of literature teacher stereotypes.
Relating the Approximability of the Fixed Cost and Space Constrained Assortment Problems

Customer choice models are a fundamental tool used by retailers to optimize inventory, pricing, and stocking decisions. One important optimization problem is the assortment problem in which the retailer wants to determine which products to offer to customers to maximize expected revenue. This paper relates two variants of this assortment problem: the space constrained assortment problem, in which the retailer has a limit on the total space of the offered assortment, and the fixed cost assortment problem, in which the retailer incurs a fixed cost for each offered product. In particular, we develop an approximation scheme for the space constrained problem for any random utility choice model that only relies on the ability to solve the corresponding fixed cost assortment problem. We then apply this technique to give the first constant factor approximation scheme for the space constrained assortment problem under a general choice model for vertically differentiated products. Last, we present computational results to show the efficacy of this approach.
Unified Model Formulations for Synchronous Machine Model with Saturation and Arbitrary Rotor Network Representation

Numerous models and formulations have been used to study synchronous machines in different applications. Herein, a unified derivation of the various model formulations, which support direct interface to external circuitry in a variety of scenarios, is presented. A synchronous machine model with magnetizing path saturation including cross-saturation and an arbitrary rotor network representation is considered. This model has been extensively experimentally validated and includes most existing machine models as special cases. Derivations of the standard voltage-in, current-out formulation as well as formulations in which the stator and/or the field windings are represented in a voltage-behind-reactance form are presented in a unified manner, including the derivation of a field-only voltage-behind-reactance formulation. The formulations are compared in a variety of simulation scenarios to show the relative advantages in terms of time steps, run time, and accuracy. It has been demonstrated that selection of the formulation with the most suitable interface for the simulation scenario has better accuracy, fewer time steps, and less run time.
Porcine Circovirus 2 Uses a Multitude of Weak Binding Sites To Interact with Heparan Sulfate, and the Interactions Do Not Follow the Symmetry of the Capsid.

Porcine circovirus 2 (PCV2) is the smallest pathogenic virus capable of autonomous replication within its host. Infections result in immunosuppression and subsequent death of the host and are initiated via the attachment of the PCV2 icosahedral capsid to heparan sulfate (HS) and chondroitin sulfate B (CSB) glycosaminoglycans on the cell surface. However, the underlying mechanism of structural recognition remains to be explored. Using heparin, a routinely used analog of heparan sulfate, we demonstrate that increasing lengths of heparin exhibit a greater affinity toward PCV2. Our competition assays indicate that dextran sulfate (8 kDa) has a higher affinity for PCV2 than heparin (12 kDa), chondroitin sulfate B (41 kDa), hyaluronic acid (1.6 MDa), and dextran (6 kDa). This suggests that polymers high in sulfate content are capable of competing with the PCV2-heparan sulfate interaction and, thus, have the potential to inhibit PCV2 infection. Finally, we visualized the interaction between heparin and the PCV2 capsid using cryo-electron microscopy single-particle analysis, symmetry expansion, and focused classification. The image reconstructions provide the first example of an asymmetric distribution of heparin on the surface of an icosahedral virus capsid. We demonstrate that each of the 60 capsid subunits that generate the T=1 capsid can bind heparin via one of five binding sites. However, not all of the binding sites were occupied by heparin, and only one-third to two-thirds of the binding sites were occupied. The binding sites are defined by arginine, lysine, and polar amino acids. Mutating the arginine, lysine, and polar amino acids to alanine diminished the binding capacity of PCV2 to heparin.IMPORTANCE It has been demonstrated that porcine circovirus 2 (PCV2) attaches to cells via heparan sulfate (HS) and chondroitin sulfate B (CSB) glycosaminoglycans; however, the underlying structural mechanism describing the HS/CSB recognition by PCV2 remains to be explored. We used cryo-electron microscopy with single-particle analysis, symmetry expansion, and focused classification to visualize the interaction between the PCV2 capsid and heparin, an analog of heparan sulfate, to better than 3.6-A resolution. We observed that the interaction between PCV2 and heparin does not adhere to the icosahedral symmetry of the capsid. To the best of our knowledge, this is the first example where the interaction between heparin and an icosahedral capsid does not follow the symmetry elements of the capsid. Our findings also suggest that anionic polymers, such as dextran sulfate, may act to inhibit PCV2 infection.
Mergeable dictionaries

A data structure is presented for the Mergeable Dictionary abstract data type, which supports the operations Predecessor-Search, Split, and Merge on a collection of disjoint sets of totally ordered data. While in a typical mergeable dictionary (e.g. 2-4 Trees), the Merge operation can only be performed on sets that span disjoint intervals in keyspace, the structure here has no such limitation. A data structure which can handle arbitrary Merge operations in O(log n) amortized time in the absence of Split operations was presented by Brown and Tarjan [2]. A data structure which can handle both Split and Merge operations in O(log2 n) amortized time was presented by Farach and Thorup [4]. In contrast, our data structure supports all operations, including Split and Merge, in O(log n) amortized time, thus showing that interleaved Merge operations can be supported at no additional cost vis-a-vis disjoint Merge operations.
A CRITICAL GUIDE TO CASE SERIES REPORTS

Objective Provide guidance to investigators and authors regarding appropriate conduct and reporting of case-series studies. Summary of background data Evidence-based practice has provided a substantial contribution to advancing clinical science. Many study designs have been critically examined, and the quality of the research literature has improved. A common study design in musculoskeletal medicine is the case series: a description of the course of patients over time. Case series can provide valuable information as to: case definition, trend analyses regarding outcomes, and clues as to causation. Case series cannot be used to draw inferences regarding treatment effect. Methods Examination of previous work on identification of characteristics of high quality study designs such as cohort studies; extending this work to case series. Results We identified draft characteristics that good case series studies should address: clearly defined study question; well- described study population; well-described intervention; use of validated outcome measures; appropriate statistical analyses; well-described results; discussion/conclusions supported by the data presented; funding sources acknowledged. Conclusions We propose these measures to authors and journal editors as one mechanism to improve the quality of the case series study.
Model for a Noise-Matched Phased Array Feed

We present a model for a noise-matched phased array feed (PAF) system and compare model predictions with the measurement results. The PAF system consists of an array feed, a receiver, a beamformer, and a parabolic reflector. The novel aspect of our model is the characterization of the PAF system by a single matrix. This characteristic matrix is constructed from the open-circuit voltage covariance (OCVC) at the output of the PAF due to a signal from the observing source, ground spillover noise, sky background noise, and (low-noise) amplifier (LNA) noise. The best signal-to-noise ratio (SNR) on the source achievable with the PAF system will be the maximum eigenvalue of the characteristic matrix. The voltage covariance due to signal and spillover noise is derived by applying the Lorentz reciprocity theorem. The receiver noise covariance and noise temperature are obtained in terms of Lange invariants such that they are suitable for noise matching the array feed. The model predictions are compared with the measured performance of a 1.4 GHz, 19-element, dual-polarized PAF on the Robert C. Byrd Green Bank Telescope. We show that the model predictions, obtained with an additional noise contribution due to the measured losses ahead of the LNA, compare well with the measured ratio of system temperature to aperture efficiency as a function of frequency and as a function of offset from the boresight. Furthermore, our modeling indicates that the bandwidth over which this ratio is optimum can be improved by a factor of at least two by noise matching the PAF with the LNA.
ADVERSE EVENTS AND MODES OF FAILURE RELATED TO THE IMPELLA PERCUTANEOUS LEFT VENTRICULAR ASSIST DEVICES: A RETROSPECTIVE ANALYSIS OF THE MAUDE DATABASE

Robust data on the commonly reported complications and failure modes associated with Impella (Abiomed Inc, Danvers, MA) is limited. We analyzed the post-marketing surveillance data from the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database to assess these
Facilitating en/counters with special education’s cloak of benevolence in professional learning to eliminate racial disproportionality in special education

Despite the U.S. government’s funding and provision of technical assistance as a prevailing approach to remedy special education racial disproportionality, and considerable research on the explanat...
Many-Body Localization in the Presence of a Central Qudit

We consider a many-body localized system coupled globally to a central $d$-level system. Under an appropriate scaling of $d$ and $L$, we find evidence that the localized phase survives. We argue for two possible thermalizing phases, depending on whether the qudit becomes fully ergodic. This system provides one of the first examples of many-body localization in the presence of long-range (nonconfining) interactions.
Respiration Enhances TDP-43 Toxicity, but TDP-43 Retains Some Toxicity in the Absence of Respiration

The trans-activating response DNA-binding protein 43 (TDP-43) is a transcriptional repressor and splicing factor. TDP-43 is normally mostly in the nucleus, although it shuttles to the cytoplasm. Mutations in TDP-43 are one cause of familial amyotrophic lateral sclerosis. In neurons of these patients, TDP-43 forms cytoplasmic aggregates. In addition, wild-type TDP-43 is also frequently found in neuronal cytoplasmic aggregates in patients with neurodegenerative diseases not caused by TDP-43 mutations. TDP-43 expressed in yeast causes toxicity and forms cytoplasmic aggregates. This disease model has been validated because genetic modifiers of TDP-43 toxicity in yeast have led to the discovery that their conserved genes in humans are amyotrophic lateral sclerosis genetic risk factors. While how TDP-43 is associated with toxicity is unknown, several studies find that TDP-43 alters mitochondrial function. We now report that TDP-43 is much more toxic when yeast are respiring than when grown on a carbon source where respiration is inhibited. However, respiration is not the unique target of TDP-43 toxicity because we found that TDP-43 retains some toxicity even in the absence of respiration. We found that H2O2 increases the toxicity of TDP-43, suggesting that the reactive oxygen species associated with respiration could likewise enhance the toxicity of TDP-43. In this case, the TDP-43 toxicity targets in the presence or absence of respiration could be identical, with the reactive oxygen species produced by respiration activating TDP-43 to become more toxic or making TDP-43 targets more vulnerable.
A new minority? International JD students in US law schools

This Article reveals the significance of a new and growing minority group within US law schools—international students in the Juris Doctor (JD) program. While international students have received some attention in legal education scholarship, it mostly has been focused on their participation in the context of programs specially designed for this demographic (e.g. postgraduate programs like the LLM and SJD). Drawing from interview data with fifty-eight international JD students across seventeen graduating US law schools, our research reveals the rising importance of international students as actors within a more mainstream institutional context. In examining the ways these students navigate their law school environments, we find that although international status often impacts identity and participation, not all students encounter its impact similarly. Particularly, while some students use the identity to their advantage, others cannot escape negative implications, even with effort. This is consistent with other scholarship on minority students, and adds to a growing literature that uses their socialization experiences to better understand professional stratification. To unpack these different ways of “being international,” we borrow from Goffman’s theorization of stigma to suggest illustrative variations in the ways international students experience their environments. In doing so, we offer an introductory landscape to better understand this growing population and hope this enables new insights to theorize about other kinds of minority experience.
Collective dynamics of microtubule-based 3D active fluids from single microtubules

Self-organization of kinesin-driven, microtubule-based 3D active fluids relies on the collective dynamics of single microtubules. However, the connection between macroscopic fluid flows and microscopic motion of microtubules remains unclear. In this work, the motion of single microtubules was characterized by means of 2D gliding assays and compared with the flows of 3D active fluids. While the scales of the two systems differ by ∼1000×, both were driven by processive, non-processive or an equal mixture of both molecular motor proteins. To search for the dynamic correlation between both systems, the motor activities were tuned by varying temperature and ATP concentration, and the changes in both systems were compared. Motor processivity played an important role in active fluid flows but only when the fluids were nearly motionless; otherwise, flows were dominated by hydrodynamic resistance controlled by sample size. Furthermore, while the motors’ thermal reaction led active fluids to flow faster with increasing temperature, such temperature dependence could be reversed by introducing temperature-varying depletants, emphasizing the potential role of the depletant in designing an active fluid's temperature response. The temperature response of active fluids was nearly immediate (≲10 s). Such a characteristic enables active fluids to be controlled with a temperature switch. Overall, this work not only clarifies the role of temperature in active fluid activity, but also sheds light on the underlying principles of the relationship between the collective dynamics of active fluids and the dynamics of their constituent single microtubules.
Measuring global economic activity

A number of economic studies have used a proxy for world real economic activity derived from shipping costs. This measure turns out to depend on a normalization that has substantive consequences, of which users of the index had been unaware prior to this paper. This paper further evaluates this and alternative measures in terms of treatment of trends, coherence with world output, and correlation with commodity prices. I conclude that measures derived from world industrial production offer a better indicator of global real economic activity.
Cyber risk and insurance for transportation infrastructure

Abstract While advances in information technology and interconnectivity have improved efficiency for transportation infrastructure, they have also created higher risk associated with cyber systems. The objective of this study is to inform transportation policy and management in the U.S. by identifying barriers to a robust cyber insurance market and improved cyber resilience for transportation infrastructure. This is accomplished through a mixed-methods approach involving analysis of U.S. cyber incident data for transportation systems and a series of interviews with transportation infrastructure managers and insurers. Contributions include new insights into the nature of cyber risk for transportation infrastructure and recommendations on research needs to improve cyber risk management and insurance. Results indicate that the annual number of transport-related companies affected by cyber incidents and the associated costs are on the rise. The most common incidents involve data breaches, while incidents involving privacy violation have the highest average loss per incident. Cyber risk assessment, mitigation and security measures, and insurance are being implemented to varying degrees in transportation infrastructure systems but are generally inadequate. Infrastructure managers do not currently have the tools to rigorously assess and manage cyber risk. Limited data and models also inhibit the accurate modeling of cyber risk for insurance purposes. Even after improved tools and modeling are developed, insurance purchase can be an important risk management strategy to allow transportation infrastructure systems to recover from cyber incidents.
The entity-relationship model: toward a unified view of data

A data model, called the entity-relationship model, is proposed. This model incorporates some of the important semantic information about the real world. A special diagrammatic technique is introduced as a tool for database design. An example of database design and description using the model and the diagrammatic technique is given. Some implications for data integrity, information retrieval, and data manipulation are discussed.The entity-relationship model can be used as a basis for unification of different views of data: the network model, the relational model, and the entity set model. Semantic ambiguities in these models are analyzed. Possible ways to derive their views of data from the entity-relationship model are presented.
N-centered hexazirconium chloride clusters: excision and redox chemistry.

The tightly cross-linked solid Zr6Cl15N yields [(Zr6NCl12)Cl6]3- upon heating with bis(triphenylphosphine)iminium chloride (PPNCl), in MeCN at 90 °C. Purple solutions containing [(Zr6NCl12)Cl6]3- were obtained and characterized with 15N NMR. Cyclic voltammetric (CV) measurements on the series of [(Zr6ZCl12)Cl6]n- cluster ions (Z = Be, B, C, and N) in acetonitrile reveal that these cluster ions exhibit multiple reversible redox waves at potentials that can be systematically understood, including a reversible redox wave corresponding to the [(Zr6NCl12)Cl6]3-/4- couple. Preparation of the reduced cluster ion, [(Zr6NCl12)Cl6]4-, (with 15 cluster-bonding electrons) was achieved by reduction of [(Zr6NCl12)Cl6]3- with (C5(CH3)5)2Co. Several new N-centered cluster complexes: (PPN)3[(Zr6NCl12)Cl6]·CH2Cl2, [(C5(CH3)5)2Co+]3[(Zr6NCl12)Cl6], and (Et4N)4[(Zr6NCl12)Cl6]·2CH3CN have been isolated and structurally characterized.
Substitution of benzylic hydroxyl groups with vinyl moieties using vinylboron dihalides.

Substitution of benzylic hydroxyl groups with vinyl moieties using vinylboron dihalides has been achieved. The reaction provides a novel method for preparing stereodefined alkenyl halides.
A Novel Copper(I/II) Oxophosphate Chloride with a Quasi-One-Dimensional μ4-Oxo-Bridged Copper(II) Chain. Crystal Structure and Magnetic Properties of [Na2CuII3(PO4)2][CuIOCl]

In a continuing search for mixed-valence copper phosphate compounds, crystals of a novel copper(I/II) oxophosphate chloride, Na2Cu4P2O9Cl, have been grown in a low-temperature eutectic flux of 23% NaCl and 77% CuCl (mp = 315 °C). The title compound crystallizes in an orthorhombic lattice, Cmcm (No. 63), with a = 13.614 (2) A, b = 10.385 (2) A, c = 6.372 (2) A, and V = 900.8 A3; Z = 4. This new compound is a welcome addition to the small family of electronically distinct copper phosphates. The extended structure exhibits an interesting quasi-one-dimensional chain consisting of fused tetrahedra of copper(II) atoms centered by a μ4-oxo-bridging oxygen atom. This mixed framework is composed of [Cu(2)IIO6]−[Cu(1)IIO4Cl]−[Cu(3)IO2Cl3] fused polyhedra. The Cu2+ centers are closely spaced, 3.03−3.19 A, creating an environment conducive to a magnetic transition at ∼5 K associated with the diffused antiferromagnetic coupling starting at 220 K. In this paper, the synthesis, thermal properties, and bond valence analy...
Density Functional Calculations of Small Anionic Clusters of Group III Nitrides

In this paper, we study the changes in the structural, vibrational, bonding, and electronic properties of small clusters of the group III nitrides when an electron is added to the neutral clusters. The results, based on density functional calculations, reveal that the addition of an electron induces significant structural changes in the neutral cluster configurations. The atomic charge analysis suggests that the added electron is located over the metallic atoms in dimers and trimers and equally shared by metal and nitrogen atoms in monomers. The calculated electron affinity values depend on both the cations and the structural configuration in these clusters.
Excited electronic states and internal conversion in cyanocobalamin

Abstract Cyanocobalamin (CNCbl) is a paradigm system for the study of excited electronic states and biological cofactors including the B 12 vitamers. The photophysics of CNCbl has been thoroughly investigated using both ultrafast spectroscopy and time dependent density functional theory (TD-DFT). Here we review the spectroscopic and theoretical investigations of CNCbl with emphasis on the nature of S 1 , the lowest excited electronic state, and extend the spectroscopic measurements to include the ultraviolet region of the spectrum. Ultrafast transient absorption measurements in the visible αβ band region and in the mid-infrared led to assignment of the S 1 state to a ligand-to-metal charge transfer (LMCT) with lengthened axial bonds and a ∼3 kcal/mol barrier for internal conversion to the ground state. The present measurements encompassing the γ band region of the spectrum provide further support for the assignment of the S 1 state. The experiments are in good agreement with the results of TD-DFT calculations which confirm the expected lengthening of the axial bonds in S 1 and account for the observed barrier for internal conversion back to the ground state.
On the use of the experimentally determined enzyme inhibition constant as a measure of absolute binding affinity.

Abstract Defined as a state function representing an inhibitor's absolute affinity for its target enzyme, the experimentally determined enzyme inhibition constant (Ki) is widely used to rank order binding affinities of different inhibitors for a common enzyme or different enzymes for a common inhibitor and to benchmark computational approaches to predicting binding affinity. Herein, we report that adsorption of bis(7)-tacrine to the glass container surface increased its Ki against Electrophorus electricus acetylcholinesterase (eeAChE) to 3.2 ± 0.1 nM (n = 5) compared to 2.9 ± 0.4 pM (n = 5) that was determined using plastic containers with other assay conditions kept the same. We also report that, due to binding or “adsorption” of bis(7)-tacrine to the inactive eeAChE, the bis(7)-tacrine Ki increased from 2.9 ± 0.4 pM (n = 5) to 734 ± 70 pM (n = 5) as the specific eeAChE activity decreased from 342 U/mg to 26 U/mg while other assay conditions were kept the same. These results caution against using Kis to rank order binding potencies, define selectivity, or benchmark computational methods without knowing detailed assay conditions.
Testing an Optimally Weighted Combination of Common and/or Rare Variants with Multiple Traits

Recently, joint analysis of multiple traits has become popular because it can increase statistical power to identify genetic variants associated with complex diseases. In addition, there is increasing evidence indicating that pleiotropy is a widespread phenomenon in complex diseases. Currently, most of existing methods test the association between multiple traits and a single genetic variant. However, these methods by analyzing one variant at a time may not be ideal for rare variant association studies because of the allelic heterogeneity as well as the extreme rarity of rare variants. In this article, we developed a statistical method by testing an optimally weighted combination of variants with multiple traits (TOWmuT) to test the association between multiple traits and a weighted combination of variants (rare and/or common) in a genomic region. TOWmuT is robust to the directions of effects of causal variants and is applicable to different types of traits. Using extensive simulation studies, we compared the performance of TOWmuT with the following five existing methods: gene association with multiple traits (GAMuT), multiple sequence kernel association test (MSKAT), adaptive weighting reverse regression (AWRR), single-TOW, and MANOVA. Our results showed that, in all of the simulation scenarios, TOWmuT has correct type I error rates and is consistently more powerful than the other five tests. We also illustrated the usefulness of TOWmuT by analyzing a whole-genome genotyping data from a lung function study.
Comparison of electrophilic amination reagents for N-amination of 2-oxazolidinones and application to synthesis of chiral hydrazones.

Comparison of several hydroxylamine-based electrophilic ammonia equivalents in the N-amination of 2-oxazolidinones revealed that O-(p-nitrobenzoyl)hydroxylamine (NbzONH2) and sodium hydride in dioxane is a superior reagent combination for this purpose. Practical preparations of a variety of chiral N-acylhydrazones by this method gave yields ranging from 45 to 95%. Methods for exchange or removal of the aldehyde component have been developed, making this a general route to chiral N-acylhydrazones of interest for asymmetric synthesis applications.
Porphyrins with exocyclic rings. Part 4. An improved one step synthesis of cyclopenta[b]pyrroles†‡

Cyclopentanone condensed with phenylhydrazones 5, or oximes 6, in the presence of zinc dust, sodium propionate and propionic acid at 150° to give cyclopenta[b]pyrroles 7 in good yields. This chemistry was extended to the synthesis of pyrrolic products from 1-indanone, 2-indanone and 2-methylcyclopentanone. Benzyl 3-methylcyclopenta[b]pyrrole-2-carboxylate was found to react regioselectively with lead tetraacetate to give the corresponding 6-acetoxy derivative and subsequent acid-catalyzed condensations with 5-unsubsti-tuted pyrrole-2-carboxylates afforded a series of synthetically valuable dipyrroles 18a-c.
Enantiocontrol in catalytic metal carbene reactions

New catalysts and applications for carbon-carbon bond construction are described, providing access to lignan lactones, GABA analogs, and other compounds of biological interest.
Dynamics of human telomerase recruitment depend on template- telomere base pairing.

The reverse transcriptase telomerase adds telomeric repeats to chromosome ends to counteract telomere shortening and thereby assures genomic stability in dividing human cells. Key parameters in telomere homeostasis are the frequency with which telomerase engages the chromosome end and the number of telomeric repeats it adds during each association event. To study telomere elongation in vivo, we have established a live-cell imaging assay to track individual telomerase ribonucleoproteins in CRISPR-edited HeLa cells. Using this assay and the drug imetelstat, which is a competitive inhibitor of telomeric DNA binding, we demonstrate that stable association of telomerase with the single-stranded overhang of the chromosome end requires telomerase-DNA base pairing. Furthermore, we show that telomerase processivity contributes to telomere elongation in vivo. Together, these findings provide new insight into the dynamics of telomerase recruitment and the importance of processivity in maintaining telomere length in human cancer cells.
Expansion of the rich structures and magnetic properties of neptunium selenites: soft ferromagnetism in Np(SeO3)2.

Two new neptunium selenites with different oxidation states of the metal centers, NpIV(SeO3)2 and NpVIO2(SeO3), have been synthesized under mild hydrothermal conditions at 200 °C from the reactions of NpO2 and SeO2. Np(SeO3)2 crystallizes as brown prisms (space group P21/n, a = 7.0089(5) A, b = 10.5827(8) A, c = 7.3316(5) A, β = 106.953(1)°); whereas NpO2(SeO3) crystals are garnet-colored with an acicular habit (space group P21/m, a = 4.2501(3) A, b = 9.2223(7) A, c = 5.3840(4) A, β = 90.043(2)°). Single-crystal X-ray diffraction studies reveal that the structure of Np(SeO3)2 features a three-dimensional (3D) framework consisting of edge-sharing NpO8 units that form chains that are linked via SeO3 units to create a 3D framework. NpO2(SeO3) possesses a lamellar structure in which each layer is composed of NpO8 hexagonal bipyramids bridged via SeO32– anions. Bond-valence sum calculations and UV-vis-NIR absorption spectra support the assignment of tetravalent and hexavalent states of neptunium in Np(SeO3)2 a...
A Framework to Assess Debt Sustainability and Fiscal Risks under the Belt and Road Initiative

This paper provides a framework to assess the impact of infrastructure investment expected under the Belt and Road Initiative (BRI) on the debt vulnerabilities of countries that are located on BRI transport and connectivity corridors in the absence of comprehensive and consistent information on investments and financing terms. Key assumptions relate to the amount of public and publicly guaranteed (PPG) debt financing and its terms, the size and sectoral type of identified BRI investment, and the expected impact of growth in the medium and long term of that investment. BRI debt financing is expected significantly increase PPG debt in a number of countries. The paper provides estimates for both the medium and the long term. In the medium term, defined as the period 2019-2023, debt financing of BRI investment is expected to be fully disbursed while the full growth impact of BRI related infrastructure is not entirely realized. In this initial phase, around one-third of assessed BRI-recipient countries are estimated to face elevated debt vulnerabilities post- BRI, several of which have already high debt vulnerabilities. The impact of BRI on public debt would improve over the longer term under the assumption of a sustained negative interest rate-growth differential and in the absence of the materialization of BRI related fiscal risks. Still, debt to GDP ratio is expected to remain higher in one-third of countries (11 out of 30 with available data).
StePHOX, a new family of optically active, tunable phosphine–oxazoline ligands: syntheses and applications

Abstract A new class of optically active phosphine–oxazoline ligands has been synthesized wherein backbone chirality of these new ligands is installed by a Sharpless asymmetric dihydroxylation. Different backbone protecting groups as well as different substitution patterns on the oxazoline ring were studied. These ligands were tested in allylic substitution (with ee's up to 97%) and asymmetric Tsuji allylation.
Probabilistic adaptation in changing microbial environments

Microbes growing in animal host environments face fluctuations that have elements of both randomness and predictability. In the mammalian gut, fluctuations in nutrient levels and other physiological parameters are structured by the host's behavior, diet, health and microbiota composition. Microbial cells that can anticipate environmental fluctuations by exploiting this structure would likely gain a fitness advantage (by adapting their internal state in advance). We propose that the problem of adaptive growth in structured changing environments, such as the gut, can be viewed as probabilistic inference. We analyze environments that are "meta-changing": where there are changes in the way the environment fluctuates, governed by a mechanism unobservable to cells. We develop a dynamic Bayesian model of these environments and show that a real-time inference algorithm (particle filtering) for this model can be used as a microbial growth strategy implementable in molecular circuits. The growth strategy suggested by our model outperforms heuristic strategies, and points to a class of algorithms that could support real-time probabilistic inference in natural or synthetic cellular circuits.
Cell-associated heparin-like molecules modulate the ability of LDL to regulate PCSK9 uptake

Proprotein convertase subtilisin/kexin type 9 (PCSK9) targets the LDL receptor (LDLR) for degradation, increasing plasma LDL and, consequently, cardiovascular risk. Uptake of secreted PCSK9 is required for its effect on the LDLR, and LDL itself inhibits this uptake, though how it does so remains unclear. In this study, we investigated the relationship between LDL, the PCSK9:LDLR interaction, and PCSK9 uptake. We show that LDL inhibits binding of PCSK9 to the LDLR in vitro more impressively than it inhibits PCSK9 uptake in cells. Furthermore, cell-surface heparin-like molecules (HLMs) can partly explain this difference, consistent with heparan sulfate proteoglycans (HSPGs) acting as coreceptors for PCSK9. We also show that HLMs can interact with either PCSK9 or LDL to modulate the inhibitory activity of LDL on PCSK9 uptake, with such inhibition rescued by competition with the entire PCSK9 prodomain, but not its truncated variants. Additionally, we show that the gain-of-function PCSK9 variant, S127R, located in the prodomain near the HSPG binding site, exhibits increased affinity for HLMs, potentially explaining its phenotype. Overall, our findings suggest a model where LDL acts as a negative regulator of PCSK9 function by decreasing its uptake via direct interactions with either the LDLR or HLMs.
Electrocatalysis and Charge-Transfer Reactions at Redox-Modified Zeolites

When aluminosilicate zeolites, which are microporous crystalline scaffolds, intersect with electrochemistry, new opportunities arise for control of ion- and electron-transfer reactions. In this Account, we describe how zeolites modified with either redox solutes or nanocrystalline particles (which when electrified behave as nanoelectrodes) give rise to new reaction products for old catalytic schemes, improve catalytic turnovers relative to the zeolite-free electrocatalyst, and generate practical amounts of electrosynthesized product at nanoelectrode-modified zeolites. The electrochemical reactions driven at redox-modified zeolites demonstrate the ability of the truncated topography of the zeolite boundary to affect charge-transfer reactions.
N-(α-Aminoalkyl)benzotriazoles: Novel “Nonstabilized” α-Aminocarbanion Synthons

C−Benzotriazole bonds were selectively transformed to give the corresponding α-aminocarbanions when N-(α-aminoalkyl)benzotriazoles were reacted with either Li/LiBr or SmI2 in the presence of representative electrophiles. The ranges of applicability of the two reagents complement each other, and together the two protocols provide a general route from readily available crystalline starting materials to a variety of “nonstabilized” α-aminocarbanions that can be trapped in moderate to good yields.
ENANTIOSELECTIVE APPROACHES TO AMINOCYCLOPENTITOLS : A TOTAL SYNTHESIS OF (+)-6-EPITREHAZOLIN AND A FORMAL TOTAL SYNTHESIS OF (+)-TREHAZOLIN

Potent inhibitors of trehalase, such as trehazolin and its congeners, represent an attractive approach to the design of effective new insect control agents. In this report, enantioselective total syntheses of (−)-6-epitrehazolin and (+)-trehazolin were achieved using the asymmetric heterocycloaddition between [(benzyloxy)methyl]cyclopentadiene and the acylnitroso compound arising from in situ oxidation of (S)-mandelohydroxamic acid with tetrabutylammonium periodate. Further functionalization of the resulting 3,4,5-trisubstituted cyclopentene, either involving osmylation or epoxidation of the double bond, efficiently created pentasubstituted cyclopentanes. Introduction of the quaternary carbon in both synthesis targets was achieved via stereoselective osmylation of an intermediate 2,3,4,5-substituted 1-methylenecyclopentane.
GNE: a deep learning framework for gene network inference by aggregating biological information

The topological landscape of gene interaction networks provides a rich source of information for inferring functional patterns of genes or proteins. However, it is still a challenging task to aggregate heterogeneous biological information such as gene expression and gene interactions to achieve more accurate inference for prediction and discovery of new gene interactions. In particular, how to generate a unified vector representation to integrate diverse input data is a key challenge addressed here. We propose a scalable and robust deep learning framework to learn embedded representations to unify known gene interactions and gene expression for gene interaction predictions. These low- dimensional embeddings derive deeper insights into the structure of rapidly accumulating and diverse gene interaction networks and greatly simplify downstream modeling. We compare the predictive power of our deep embeddings to the strong baselines. The results suggest that our deep embeddings achieve significantly more accurate predictions. Moreover, a set of novel gene interaction predictions are validated by up-to-date literature-based database entries. The proposed model demonstrates the importance of integrating heterogeneous information about genes for gene network inference. GNE is freely available under the GNU General Public License and can be downloaded from GitHub ( https://github.com/kckishan/GNE ).
2-Lithio-N-BOC-thiazolidines as chiral acyl anion synthons: evaluation of facial stereoselectivity in the addition of chiral organolithiums to aldehydes

Abstract Deprotonation of N- BOC-thiazolidines having an isopropyl group in the 4- or 5-position affords chiral organolithiums that add to aldehydes in excellent yields. The relative and absolute configurations at both new stereocenters of the major and minor isomers were deduced. Mechanistic considerations suggest that each organolithium adds with a high degree of diastereoselectivity. We also demonstrated, as proof of principle, that further elaboration of the addition products into α-hydroxyaldehydes and glycols can be achieved.
Preparation and crystal structure of methyl [12-acetyl-8-ethyl]-bacteriopheophorbide d. – A new bacteriochlorophyll derivative

Reaction of methyl bacteriopheophorbide d 2 in tetrahydrofuran with sodium methoxide led to oxidation of the ethyl side chain at position 12 to afford an acetyl group. Experiments with 18O2 suggest a mechanism via abstraction of a proton and reaction of the secondary radical formed with molecular oxygen. The implications of this mechanism for the biosynthesis of the bacteriochlorophylls are discussed. The 12-acetyl compound 3 was investigated by X-ray crystallography.
Chemistry and electronic structure of iron-based superconductors

The solid state provides a richly varied fabric for intertwining chemical bonding, electronic structure, and magnetism. The discovery of superconductivity in iron pnictides and chalcogenides has revealed new aspects of this interplay, especially involving magnetism and superconductivity. Moreover, it has challenged prior thinking about high-temperature superconductivity by providing a set of materials that differ in many crucial aspects from the previously known cuprate superconductors. Here we review some of what is known about the superconductivity and its interplay with magnetism, chemistry, and electronic structure in Fe-based superconductors.
Total Synthesis of Q Base (Queuine)

Abstract The total synthesis of Q Base (Queuine) has been accomplished in eleven steps from ribose. Mitsunobu reaction of nosyl protected amine 12 with known cyclopentenol 7, derived from ribose, gave 13, the first key intermediate in the synthesis. The pyrrolo[2,3-d]pyrimidine ring system of Q Base was built via a cyclocondensation reaction between a β-aminobromoaldehyde 16, derived from the Mitsunobu product 13, and 2,4-diamino-6-hydroxypyrimidine. Deprotection of the product from the cycloccondensation reaction (17) gave Q Base.
Physical origin of giant excitonic and magneto-optical responses in two-dimensional ferromagnetic insulators

The recent discovery of magnetism in atomically thin layers of van der Waals crystals has created great opportunities for exploring light-matter interactions and magneto-optical phenomena in the two-dimensional limit. Optical and magneto-optical experiments have provided insights into these topics, revealing strong magnetic circular dichroism and giant Kerr signals in atomically thin ferromagnetic insulators. However, the nature of the giant magneto-optical responses and their microscopic mechanism remain unclear. Here, by performing first-principles GW and Bethe-Salpeter equation calculations, we show that excitonic effects dominate the optical and magneto-optical responses in the prototypical two-dimensional ferromagnetic insulator, CrI3. We simulate the Kerr and Faraday effects in realistic experimental setups, and based on which we predict the sensitive frequency- and substrate-dependence of magneto-optical responses. These findings provide physical understanding of the phenomena as well as potential design principles for engineering magneto-optical and optoelectronic devices using two-dimensional magnets.
Aqueous Catalysis: Methylrhenium Trioxide (MTO) as a Homogeneous Catalyst for the Diels−Alder Reaction

The title compound proves to be an effective and efficient catalyst for the Diels−Alder reaction when the dienophile is an α,β-unsaturated ketone or aldehyde. It is especially effective in water. Equal amounts of any such dienophile and any of six representative dienes (isoprene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, cyclopentadiene, 1,2,3,4,5-pentamethylcyclopentadiene, and 1,3-cyclohexadiene) were used, along with 1% MTO. The reactions gave usually >90% isolated yield of the cycloaddition product except for the larger dienophiles. Nearly exclusively, there was formed one product isomer, the same one that usually predominates. The reactions were often run in chloroform (mostly) and in other organic solvents. A select number were carried out in water, where the reactions gave a greater product yield in a considerably shorter time. Water, itself, is known to enhance the rates of Diels−Alder reactions, but MTO exerts an additional accelerating effect. Kinetics studies were carried out to show...