Tetrakis(-heterocyclic Carbene)-Diboron(0): Double Single-Electron-Transfer Reactivity.

The use of 1,3,4,5-tetramethylimidazol-2-ylidene (IMe) to coordinate with diatomic B species afforded a tetrakis(-heterocyclic carbene)-diboron(0) [(IMe)B-B(IMe)] (). The singly bonded B moiety therein possesses a valence electronic configuration 1σ1π1π* with four vacant molecular orbitals (1σ*, 2σ, 1π', 1π'*) coordinated with IMe. Its unprecedented electronic structure is analogous to the energetically unfavorable planar hydrazine with a D symmetry.

Fibrotic Plaque and Microvascular Dysfunction Predict Early Cardiac Allograft Vasculopathy Progression After Heart Transplantation: The Early Post Transplant Cardiac Allograft Vasculopathy Study.

Background: Early cardiac allograft vasculopathy (CAV) prognostication is needed to improve long-term outcomes after heart transplantation. We characterized first year posttransplant coronary anatomic-physiologic alterations to determine predictors of early CAV progression.

Methods: Heart transplant recipients at 2 institutions (enrolled January 2018 to March 2021) underwent prospective evaluation 3 and 12-month posttransplant with angiography and left anterior descending artery intravascular ultrasound, optical coherence tomography, fractional flow reserve, coronary flow reserve, and index of microcirculatory resistance measurements.

-Phosphinoamidinato Silylene- and Phosphine-Borylborylene Complexes.

This work describes a straightforward method to synthesize a borylborylene without proceeding via the rearrangement of a diborene. An amidinato amidosilylene [LSiNMe] (L = PhC(NBu)) and PMe were reacted with an -phosphinoamidinato diborane and KC to form a stable silylene-borylborylene and a persistent phosphine-borylborylene , respectively. Compound is stable as the borylene center is well stabilized by the silylene donor and boryl substituent, whereas compound is unstable in solution due to labile PMe.

A Pyridine-Stabilized N-Phosphinoamidinato N-Heterocyclic Carbene-Diboravinyl Cation: Boron Analogue of Vinyl Cation.

A boron analogue of vinyl cation, pyridine-stabilized N-phosphinoamidinato N-heterocyclic carbene (NHC)-diboravinyl cation 2 , was synthesized by displacement of bromide in diborene 1 with excess pyridine. Experimental and computational studies showed that the positive charge is mainly at the B-B skeleton with delocalization to the pyridine ligand. One of the main modes of reactivity is through the B=B double bond alongside activation of the pyridine substituent, where the B center is the predominant nucleophilic center and the predominant electrophilic center is either the activated pyridine para position or the B center, illustrating the presence of diborene cation A, borylene-borenium cation B and diborene-pyridinium cation C resonance structures in cation 2 .

Quantitative T1ρ MRI of the Head and Neck Discriminates Carcinoma and Benign Hyperplasia in the Nasopharynx.

Background And Purpose: T1ρ imaging is a new quantitative MR imaging pulse sequence with the potential to discriminate between malignant and benign tissue. In this study, we evaluated the capability of T1ρ imaging to characterize tissue by applying T1ρ imaging to malignant and benign tissue in the nasopharynx and to normal tissue in the head and neck.

Materials And Methods: Participants with undifferentiated nasopharyngeal carcinoma and benign hyperplasia of the nasopharynx prospectively underwent T1ρ imaging.

Measurements of the Absolute Branching Fractions of B^{±}→K^{±}X_{cc[over ¯]}.

A study of the two-body decays B^{±}→X_{cc[over ¯]}K^{±}, where X_{cc[over ¯]} refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424  fb^{-1}. The absolute determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B^{+}→X(3872)K^{+} at the 3σ level.

Early Detection of Cancer: Evaluation of MR Imaging Grading Systems in Patients with Suspected Nasopharyngeal Carcinoma.

Background And Purpose: We evaluated modifications to our contrast-enhanced MR imaging grading system for symptomatic patients with suspected nasopharyngeal carcinoma, aimed at improving discrimination of early-stage cancer and benign hyperplasia. We evaluated a second non-contrast-enhanced MR imaging grading system for asymptomatic patients from nasopharyngeal carcinoma plasma screening programs.

Materials And Methods: Dedicated nasopharyngeal MR imaging before (plain scan system) and after intravenous contrast administration (current and modified systems) was reviewed in patients from a nasopharyngeal carcinoma-endemic region, comprising 383 patients with suspected disease without nasopharyngeal carcinoma and 383 patients with nasopharyngeal carcinoma.

Extraction of form Factors from a Four-Dimensional Angular Analysis of B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}.

An angular analysis of the decay B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}, ℓ∈{e,μ}, is reported using the full e^{+}e^{-} collision data set collected by the BABAR experiment at the ϒ(4S) resonance. One B meson from the ϒ(4S)→BB[over ¯] decay is fully reconstructed in a hadronic decay mode, which constrains the kinematics and provides a determination of the neutrino momentum vector. The kinematics of the semileptonic decay is described by the dilepton mass squared, q^{2}, and three angles.

Search for B^{+}→K^{+}τ^{+}τ^{-} at the BaBar Experiment.

We search for the rare flavor-changing neutral current process B^{+}→K^{+}τ^{+}τ^{-} using data from the BABAR experiment. The data sample, collected at the center-of-mass energy of the ϒ(4S) resonance, corresponds to a total integrated luminosity of 424  fb^{-1} and to 471×10^{6}  BB[over ¯] pairs. We reconstruct one B meson, produced in the ϒ(4S)→B^{+}B^{-} decay, in one of many hadronic decay modes and search for activity compatible with a B^{+}→K^{+}τ^{+}τ^{-} decay in the rest of the event.

Routine vs extended outpatient EEG for the detection of interictal epileptiform discharges.

Objective: To compare the yield of epileptiform abnormalities on 30-minute recordings with those greater than 45 minutes.

Methods: We performed a prospective observational cross-sectional study of all outpatient routine EEGs comparing the rate of interictal epileptiform discharges (IEDs) and clinical events during the initial 30 minutes (routine) with those occurring in the remaining 30-60 minutes (extended). A relative increase of 10% was considered clinically significant.

Observation of B→D(*) π^(+)π^(-)ℓ^(-)ν Decays in e^(+)e^(-) Collisions at the Υ(4S) Resonance.

We report on measurements of the decays of B¯ mesons into the semileptonic final states B¯→D^(*)π^(+)π^(-)ℓ^(-)ν¯, where D^(*) represents a D or D^(*) meson and ℓ^(-) is an electron or a muon. These measurements are based on 471×10^(6) BB ¯ pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R_{π^{+}π^{-}}^{(*)}=B(B[over ¯]→D^{(*)}π^{+}π^{-}ℓ^{-}ν[over ¯])/B(B[over ¯]→D^{(*)}ℓ^{-}ν[over ¯]) using events in which the second B meson is fully reconstructed.

Role of miR-195 in aortic aneurysmal disease.

Rationale: Abdominal aortic aneurysms constitute a degenerative process in the aortic wall. Both the miR-29 and miR-15 families have been implicated in regulating the vascular extracellular matrix.

Objective: Our aim was to assess the effect of the miR-15 family on aortic aneurysm development.

Observation of time-reversal violation in the B0 meson system.

Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral B mesons into definite flavor states (B(0) or B(0)), and J/ψK(L)(0) or ccK(S)(0) final states (referred to as B(+) or B(-)), allow comparisons between the probabilities of four pairs of T-conjugated transitions, for example, B(0) → B(-) and B(-) → B(0), as a function of the time difference between the two B decays. Using 468 × 10(6) BB pairs produced in Υ(4S) decays collected by the BABAR detector at SLAC, we measure T-violating parameters in the time evolution of neutral B mesons, yielding ΔS(T)(+) = -1.

Precision measurement of the B → Xs γ photon energy spectrum, branching fraction, and direct CP asymmetry A(CP)((B → X(s+d)γ).

The photon spectrum in the inclusive electromagnetic radiative decays of the B meson, B → X(s)γ plus B → X(d)γ, is studied using a data sample of (382.8 ± 4.2) × 10(6)Υ(4S) → BB decays collected by the BABAR experiment at SLAC.

Evidence for an excess of B→D*τ(-)ν(τ) decays.

Based on the full BABAR data sample, we report improved measurements of the ratios R(D(*))=B(B[over ¯]→D(*)τ(-)ν[over ¯](τ))/B(B[over ¯]→D(*)ℓ(ℓ)(-)ν[over ¯](ℓ)), where ℓ is either e or μ. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D)=0.