Four Dibenzofuran-Terminated High-Triplet-Energy Hole Transporters for High-Efficiency and Long-Life Organic Light-Emitting Devices.

The weak stability of a hole-transporter upon approaching the anion state is one of the major bottlenecks for developing long-life organic light-emitting devices (OLEDs). Therefore, in this study, we developed a series of thermally and electrically stable hole-transporters that are end-capped with four dibenzofuran units. These materials exhibit i) high bond dissociation energy (BDE) toward the anion state, ii) a high glass transition temperature (Tg >130 °C), and iii) high triplet energy (ET >2.7 eV), thereby enabling approximately 20 % high external quantum efficiency (EQE) and significantly prolonging the stability of both thermally activated delayed fluorescent (TADF) and phosphorescent OLEDs with an operation lifetime at 50 % (LT50 ) of 20 000-30 000 h at 1000 cd m-2 . In addition, investigating their structure-property relationship revealed that ionization potential (IP ), BDE, and Tg are critical prerequisites for the hole-transporter to prolong lifetime in OLEDs.

Tumor Embolism Through Right-to-Left Shunt Due to Venous Invasion of Esophageal Carcinoma.

A 69-year-old man was admitted to the hospital with right hemiparesis and global aphasia. Perfusion computed tomography imaging revealed ischemic penumbra in the middle cerebral artery territory. Angiography showed left middle cerebral artery occlusion. Mechanical thrombectomy with one pass was performed, and successful recanalization was obtained. Embolic material was retrieved; it contained tumor fragments with atypical keratinizing squamous cell carcinoma. Contrast computed tomography imaging indicated tumor invasion into the superior vena cava, and contrast transcranial Doppler indicated the presence of a right-to-left shunt after the Valsalva maneuver. We diagnosed the patient with acute ischemic stroke of large vessel occlusion due to venous invasion of esophageal carcinoma via a right-to-left shunt. To the best of our knowledge, this is the first case of embolic occlusion resulting from an extracardiac tumor via a right-to-left shunt. Contrast transcranial Doppler potentially detects right-to-left shunts in patients who cannot undergo transesophageal echocardiography.

Radiation exposure in cardiac computed tomography imaging in Mie prefecture in 2021.

PURPOSE: Several effective radiation dose reduction methods have been developed for coronary computed tomography angiography (CTA); however, their use in daily clinical practice remains unknown. We aimed to investigate radiation exposure and the utilization of dose-saving strategies for coronary CTA in hospitals in Mie Prefecture, Japan. MATERIALS AND METHODS: Image acquisition details and dose reports of 30 consecutive cardiac CT examinations performed in 2021 were obtained from 18 hospitals. The inclusion criteria were patients aged 20-80 years who weighed 50-70 kg and underwent coronary CTA using ≥ 64-row multidetector CT. The doses for the overall cardiac CT examination and coronary CTA were analyzed using the dose-length product (DLP) and CT dose index (CTDIvol), respectively. Multivariate analysis was performed to determine independent predictors that affect the radiation dose in coronary CTA. RESULTS: The median DLP of cardiac CT was 774 (interquartile range [IQR]: 538-1119) mGy*cm, and the median CTDIvol of coronary CTA was 33 (IQR: 25-48) mGy. The 75th percentile values of DLP for cardiac CT and that of CTDIvol for coronary CTA were slightly lower than the values recorded in the Japan Diagnostic Reference Level (DRLs) 2020 report (1285 mGy*cm and 66.4 mGy, respectively) but were substantially higher than those reported in a previous large international dose survey (402 mGy*cm and 24 mGy, respectively). Iterative reconstruction was performed during all examinations. Only six hospitals (33%) used a low tube potential (≤ 100 kVp), and nine hospitals (50%) used electrocardiogram-triggered prospective scanning. Multivariate analysis revealed low heart rate, low tube potential, and use of electrocardiogram-triggered prospective scanning as independent predictors of CTDIvol ≤ 24 mGy (p < 0.001, respectively). CONCLUSION: As of 2021, low tube potential and prospective scanning are underutilized, whereas iterative reconstruction is used in every coronary CTA in Mie Prefecture. Further efforts to optimize the radiation exposure from cardiac CT scans are necessary.

Microvascular Dysfunction in Patients with Idiopathic Dilated Cardiomyopathy: Quantitative Assessment with Phase Contrast Cine MR Imaging of the Coronary Sinus.

PURPOSE: The purposes of this study were to compare global coronary flow reserve (CFR) between patients with idiopathic dilated cardiomyopathy (DCM) and risk-matched controls using cardiac MRI (CMR), and to evaluate the relationship between global CFR and CMR left ventricular (LV) parameters. METHODS: Twenty-six patients with DCM and 26 risk-matched controls who underwent comprehensive CMR examination, including stress-rest coronary sinus flow measurement by phase contrast (PC) cine CMR were retrospectively studied. LV peak global longitudinal, radial, and circumferential strains (GLS, GRS, and GCS) were determined by feature tracking. RESULTS: Patients with DCM had significantly lower global CFR compared with the risk-matched controls (2.87 ± 0.86 vs. 4.03 ± 1.47, P = 0.001). Among the parameters, univariate linear regression analyses revealed significant correlation of global CFR with LV end-diastolic volume index (r = -0.396, P = 0.045), LV mass index (r = -0.461, P = 0.018), GLS (r = -0.558, P = 0.003), and GRS (r = 0.392, P = 0.047). Multiple linear regression analysis revealed GLS as the only independent predictor of global CFR (standardized ß = -0.558, P = 0.003). CONCLUSION: Global CFR was significantly impaired in patients with idiopathic DCM and independently associated with LV GLS, suggesting that microvascular dysfunction may contribute to deterioration of LV function in patients with idiopathic DCM.

Associating the Severity of Emphysema with Coronary Flow Reserve and Left Atrial Conduit Function for the Emphysema Patients with Known or Suspected Coronary Artery Disease.

PURPOSE: Pulmonary emphysema may associate with ischemic heart disease through systemic microvascular abnormality as a common pathway. Stress cardiovascular MR (CMR) allows for the assessment of global coronary flow reserve (CFR). The purpose of this study was to evaluate the association between the emphysema severity and the multiple MRI parameters in the emphysema patients with known or suspected coronary artery disease (CAD). METHODS: A total of 210 patients with known or suspected CAD who underwent both 3.0T CMR including cine CMR, stress and rest perfusion CMR, stress and rest phase-contrast (PC) cine CMR of coronary sinus, and late gadolinium enhancement (LGE) CMR, and lung CT within 6 months were studied. Global CFR, volumes and functions of both ventricles and atria, and presence or absence of myocardial ischemia and infarction were evaluated. Emphysema severity was visually determined on lung CT by Goddard method. RESULT: Seventy nine (71.0 ± 7.9 years, 75 male) of 210 patients with known or suspected CAD had emphysema on lung CT. Goddard score was significantly correlated with CFR (r = -0.246, P = 0.029), left ventricular end-diastolic volume index (LV EDVI) (r = -0.230, P = 0.041), right ventricular systolic volume index (RV SVI) (r = -0.280, P = 0.012), left atrial (LA) total emptying volume index (r = -0.269, P = 0.017), LA passive emptying volume index (r = -0.309, P = 0.006), LA systolic strain (Es) (r = -0.244, P = 0.030), and LA conduit strain (Ee) (r = -0.285, P = 0.011) in the patients with emphysema. Multiple linear regression analysis revealed LA conduit function was independently associated with emphysema severity as determined by Goddard method (beta = -0.361, P = 0.006). CONCLUSION: LA conduit function independently associates with emphysema severity in the emphysema patients with known or suspected CAD after adjusting age, sex, smoking, and the CMR indexes including CFR. These findings suggest that impairment of LA function predominantly occurs prior to the reduction of the CFR in the emphysema patients with known or suspected CAD.

A single-molecule enzymatic assay in a directly accessible femtoliter droplet array.

The enzyme assay in a femtoliter chamber array is a simple and efficient method for concentrating the reaction product; it greatly improves the detection sensitivity down to the single-molecule level. However, in previous methods, controlling the initiation and termination of the reaction in each chamber is difficult once enclosed. Furthermore, the recovery of the enzyme and product is also difficult. To overcome these drawbacks, we developed a femtoliter droplet array in which the individual droplets are fixed on the substrate and are directly accessible from outside. A hydrophilic-in-hydrophobic micropatterned surface was used for the preparation of the droplets. When the aqueous solution on the surface is exchanged with oil, the hydrophilic surface retains the aqueous solution, and more than 10(6) dome-shaped droplets that are usable for further assay can be prepared simultaneously. The curvature radius of the droplet obeys the Young-Laplace equation, and the volume can be precisely controlled by the micropipette, which applies pressure into the droplet. Changing the pressure makes the addition, collection, and exchange of the aqueous content for individual droplets possible. Using these advantages, we successfully measured the kinetic parameters of the single-molecule enzyme ß-galactosidase and rotary motor protein F(1)-ATPase enclosed in a droplet.

Large-scale femtoliter droplet array for digital counting of single biomolecules.

We present a novel device employing one million femtoliter droplets immobilized on a substrate for the quantitative detection of extremely low concentrations of biomolecules in a sample. Surface-modified polystyrene beads carrying either zero or a single biomolecule-reporter enzyme complex are efficiently isolated into femtoliter droplets formed on hydrophilic-in-hydrophobic surfaces. Using a conventional micropipette, this is achieved by sequential injection first with an aqueous solution containing beads, and then with fluorinated oil. The concentration of target biomolecules is estimated from the ratio of the number of signal-emitting droplets to the total number of trapped beads (digital counting). The performance of our digital counting device was demonstrated by detecting a streptavidin-ß-galactosidase conjugate with a limit of detection (LOD) of 10 zM. The sensitivity of our device was >20-fold higher than that noted in previous studies where a smaller number of reactors (fifty thousand reactors) were used. Such a low LOD was achieved because of the large number of droplets in an array, allowing simultaneous examination of a large number of beads. When combined with bead-based enzyme-linked immunosorbent assay (digital ELISA), the LOD for the detection of prostate specific antigen reached 2 aM. This value, again, was improved over that noted in a previous study, because of the decreased coefficient of variance of the background measurement determined by the Poisson noise. Our digital counting device using one million droplets has great potential as a highly sensitive, portable immunoassay device that could be used to diagnose diseases.