We investigate theoretically high-harmonic generation (HHG) in bulk crystals exposed to intense midinfrared lasers with photon energies smaller than the band gap. The two main mechanisms, interband ...and intraband HHG, are explored. Our analysis indicates that the interband current neglected so far is the dominant mechanism for HHG. Saddle point analysis in the Keldysh limit yields an intuitive picture of interband HHG in solids similar to atomic HHG. Interband and intraband HHG exhibit a fundamentally different wavelength dependence. This signature can be used to experimentally distinguish between the two mechanisms in order to verify their importance.
First-in-man studies of leadless pacemakers have demonstrated high rates of implant success, and safety and efficacy objectives were achieved. Outside of the investigational setting, there are ...concerns, particularly over cardiac effusion and perforation, device dislodgement, infection, telemetry, and battery issues.
The acute performance of the Micra transcatheter pacemaker from a worldwide Post-Approval Registry is reported.
The registry is an ongoing prospective single-arm observational study designed to assess the safety and effectiveness of Micra in the post-approval setting. The safety end point was system- or procedure-related major complications at 30 days post implant. We compared the major complication rate with that of the 726 patients from the investigational study. Electrical performance was also characterized.
The device was successfully implanted in 792 of 795 registry patients (99.6%) by 149 implanters at 96 centers in 20 countries. Through 30 days post implant, a total of 13 major complications occurred in 12 patients, for a major complication rate of 1.51% (95% confidence interval, 0.78%-2.62%). Major complications included cardiac effusion/perforation (1, 0.13%), device dislodgement (1, 0.13%), and sepsis (1, 0.13%). After adjusting for baseline differences, the rate of major complications in the registry trended lower than the investigational trial (odds ratio, 0.58, 95% confidence interval, 0.27-1.25; P = .16). Early pacing capture thresholds were low and stable.
Performance of the Micra transcatheter pacemaker in a real-world setting demonstrates a high rate (99.6%) of implant success and low rate (1.51%) of major complications through 30 days post implant. In particular, the rates of pericardial effusion, device dislodgement, and infection were low, reinforcing the positive results seen in the investigational study.
Abstract The aim of this study was to evaluate the value of microvascular obstruction (MO) and infarct size as a percentage of left ventricular mass (IS%LV), as measured by contrast-enhanced cardiac ...magnetic resonance, in predicting major cardiovascular adverse events (MACE) at 2 years in patients with ST-segment elevation myocardial infarction reperfused by primary percutaneous coronary intervention. Individual data from 1,025 patients were entered into the pooled analysis. MO was associated with the occurrence of MACE, defined as a composite of cardiac death, congestive heart failure, and myocardial re-infarction (adjusted hazard ratio: 3.74; 95% confidence interval: 2.21 to 6.34). IS%LV ≥25% was not associated with MACE (adjusted hazard ratio: 0.90; 95% confidence interval: 0.59 to 1.37). The authors conclude that MO is an independent predictor of MACE and cardiac death, whereas IS%LV is not independently associated with MACE.
The band structure of matter determines its properties. In solids, it is typically mapped with angle-resolved photoemission spectroscopy, in which the momentum and the energy of incoherent electrons ...are independently measured. Sometimes, however, photoelectrons are difficult or impossible to detect. Here we demonstrate an all-optical technique to reconstruct momentum-dependent band gaps by exploiting the coherent motion of electron-hole pairs driven by intense midinfrared femtosecond laser pulses. Applying the method to experimental data for a semiconductor ZnO crystal, we identify the split-off valence band as making the greatest contribution to tunneling to the conduction band. Our new band structure measurement technique is intrinsically bulk sensitive, does not require a vacuum, and has high temporal resolution, making it suitable to study reactions at ambient conditions, matter under extreme pressures, and ultrafast transient modifications to band structures.
Abstract Background Patients with nonischemic dilated cardiomyopathy (DCM) may be at lower risk for ventricular arrhythmias compared with those with ischemic cardiomyopathy (ICM). In addition, DCM ...has been identified as a predictor of positive response to cardiac resynchronization therapy (CRT). Objectives The aim of this study was to investigate the impact of an additional implantable cardioverter-defibrillator over CRT, according to underlying heart disease, in a large study group of primary prevention patients with heart failure. Methods This was an observational, multicenter, European cohort study of 5,307 consecutive patients with DCM or ICM, no history of sustained ventricular arrhythmias, who underwent CRT implantation with (n = 4,037) or without (n = 1,270) a defibrillator. Propensity-score and cause-of-death analyses were used to compare outcomes. Results After a mean follow-up period of 41.4 ± 29.0 months, patients with ICM had better survival when receiving CRT with a defibrillator compared with those who received CRT without a defibrillator (hazard ratio for mortality adjusted on propensity score and all mortality predictors: 0.76; 95% confidence interval CI: 0.62 to 0.92; p = 0.005), whereas in patients with DCM, no such difference was observed (hazard ratio: 0.92; 95% CI: 0.73 to 1.16; p = 0.49). Compared with recipients of defibrillators, the excess mortality in patients who did not receive defibrillators was related to sudden cardiac death in 8.0% among those with ICM but in only 0.4% of those with DCM. Conclusions Among patients with heart failure with indications for CRT, those with DCM may not benefit from additional primary prevention implantable cardioverter-defibrillator therapy, as opposed to those with ICM.
The objective of this study was to characterize the association between body condition score (BCS) and BCS change (ΔBCS), determined by an automated camera system at multiple time points, and the ...subsequent pregnancy per first artificial insemination (P/AI1) of Holstein cows. A retrospective observational study was completed using data collected from 11,393 lactations in 7,928 Holstein cows calving between April 2019 and March 2021 in a commercial dairy operation located in Colorado. Cows were classified as primiparous or multiparous. Scores generated by BCS cameras at dry-off, calving, 21 days in milk (DIM), 56 DIM, and first artificial insemination were selected for the analyses and subsequently categorized as low (≤lower quartile), moderate (interquartile range), and high (≥upper quartile). Changes in BCS were calculated by periods of interest as change from dry-off to calving (multiparous cows); change from calving to 21 DIM; change from calving to 56 DIM; and change from calving to first artificial insemination and assigned into categories as large loss of BCS (top 25% of cows losing BCS); moderate loss (bottom 75% of cows losing BCS); no change (ΔBCS = 0); or gain of BCS (ΔBCS > 0). Data were examined in primiparous and multiparous cows separately using logistic regression and time-to-event analyses. Initial univariable models were followed by multivariable models that considered calving season, occurrence of disease, and milk yield up to 60 DIM as covariables. The logistic regression analyses indicated that in both parity groups the associations between BCS category and P/AI1 were more evident at 21 DIM, 56 DIM, and first artificial insemination, with lower odds of P/AI1 in cows in the low BCS category. Likewise, cows with large loss in BCS between calving and 21 DIM, calving and 56 DIM, and calving and first artificial insemination had lower odds of P/AI1 compared with other categories of ΔBCS within the same period of interest. Similarly, survival analyses evidenced that cows in the low BCS category required more time to get pregnant. In agreement, differences in the dynamics of the average daily BCS during the first 90 DIM were evident when cows were grouped by first AI outcome (pregnant vs. nonpregnant) and by their time to pregnancy category (<90 DIM; 91–150 DIM; or >150 DIM), with cows with reduced fertility showing lower BCS up to 90 DIM. Overall, low BCS and more pronounced reductions in BCS occurring closer to first artificial insemination resulted in lower odds of pregnancy per artificial insemination.
Although the implantable cardioverter-defibrillator (ICD) remains the main therapy for Brugada syndrome (BrS), it does not reduce life-threatening ventricular arrhythmia. Based on pathophysiologic ...mechanisms, hydroquinidine (HQ) has been suggested for effective prevention of arrhythmia.
The purpose of this study was to provide evidence-based data supporting HQ use to prevent life-threatening ventricular arrhythmia in high-risk patients with BrS.
We performed a prospective multicenter randomized (HQ vs placebo) double-blind study with two 18-month crossover phases in patients with BrS and implanted with an ICD.
Among the 50 patients enrolled (mean age 47.0 ± 11.4 years, 42 84% male), 26 (52%) fully completed both phases. Thirty-four (68%) presented HQ-related side effects, mainly gastrointestinal, which led to discontinuation of the therapy in 13 (26%). HQ lengthened the QTc interval (409 ± 32 ms vs 433 ± 37 ms; P = .027) and increased repolarization dispersion as evaluated by Tpe max in precordial leads (89 ± 15 ms vs 108 ± 27 ms; P <.0001) with no significant changes in J-point elevation. During the 36-month follow-up, 1 appropriate ICD shock (0.97% event per year), 1 self-terminating ventricular fibrillation, and 1 inappropriate ICD shock occurred under placebo therapy. No arrhythmic events were reported under HQ therapy.
Although HQ seems to be effective in preventing life-threatening ventricular arrhythmia, it could not be an alternative for ICD implantation. Its frequent side effects greatly reduce its probable compliance and therefore do not reveal a significant effect. HQ increases repolarization dispersal with no changes in BrS pattern, which could indicate a more complex action of HQ than its I
blocking effect alone.
Structural changes during annealing of high-density amorphous ice were studied with both neutron and x-ray diffraction. The first diffraction peak was followed from the high- to the low-density ...amorphous form. Changes were observed to occur through a series of intermediate forms that appear to be metastable at each anneal temperature. Five distinct amorphous forms were studied with neutron scattering, and many more forms may be possible. Radial distribution functions indicate that the structure evolves systematically between 4 and 8 angstroms. The phase transformations in low-temperature liquid water may be much more complex than currently understood.
Modifications in left atrial (LA) flow velocities after left atrial appendage (LAA) exclusion have been shown in animal and ex vivo models. In a substudy of PROTECT AF (Percutaneous Closure of the ...Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients With Atrial Fibrillation), an objective improvement in quality of life was observed after LAA closure.
The purpose of this study was to investigate the impact of LAA closure on LA transport function.
Comprehensive transthoracic echocardiography evaluation (2-dimensional 2D/3-dimensional 3D, 2D speckle tracking) was prospectively performed before and after LAA closure (at discharge and 45 days after procedure) in 33 patients.
LAA closure was associated with a significant improvement in LA reservoir function at discharge and 45 days after the procedure with (1) increased maximum LA volume index, (2) increased 2D-LA reservoir volume and expansion index, and (3) increased 2D speckle tracking-derived peak atrial longitudinal strain (PALS) (27.9 ± 14 and 26 ± 12.6 vs 21.7 ± 10.7%, P <.0001). LAA closure was also associated with a significant improvement in LA contractile function with (1) increased LA ejection fraction and (2) increased speckle tracking-derived peak atrial contraction strain (PACS) in sinus rhythm patients (19.1 ± 6.8 and 18.1 ± 5.4 vs 14.4 ± 6.4%, P = .0006). Conversely, the slope of the relation between PACS and PALS remained unchanged (0.5 ± 0.27 and 0.53 ± 0.3 vs 0.5 ± 0.25, P = .99), thus arguing for an improvement in LA contractile function secondary to a Frank-Starling effect rather than a modification in its intrinsic contractility.
LAA closure was associated with an improvement in LA mechanical function. These changes appeared to be related to a modification in loading conditions, that is, a Frank-Starling effect.
Dysfunction of microRNA (miRNA) metabolism is thought to underlie diseases affecting motoneurons. One miRNA, miR-218, is abundantly and selectively expressed by developing and mature motoneurons. ...Here we show that mutant mice lacking miR-218 die neonatally and exhibit neuromuscular junction defects, motoneuron hyperexcitability, and progressive motoneuron cell loss, all of which are hallmarks of motoneuron diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. Gene profiling reveals that miR-218 modestly represses a cohort of hundreds of genes that are neuronally enriched but are not specific to a single neuron subpopulation. Thus, the set of messenger RNAs targeted by miR-218, designated TARGET²¹⁸, defines a neuronal gene network that is selectively tuned down in motoneurons to prevent neuromuscular failure and neurodegeneration.
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