Field-scale monitoring of nitrate leaching in agriculture: assessment of three methods.

Deterioration of groundwater quality due to nitrate loss from intensive agricultural systems can only be mitigated if methods for in-situ monitoring of nitrate leaching under active farmers' fields are available. In this study, three methods were used in parallel to evaluate their spatial and temporal differences, namely ion-exchange resin-based Self-Integrating Accumulators (SIA), soil coring for extraction of mineral N (Nmin) from 0 to 90 cm in Mid-October (pre-winter) and Mid-February (post-winter), and Suction Cups (SCs) complemented by a HYDRUS 1D model. The monitoring, conducted from 2017 to 2020 in the Gäu Valley in the Swiss Central Plateau, covered four agricultural fields. The crop rotations included grass-clover leys, canola, silage maize and winter cereals. The monthly resolution of SC samples allowed identifying a seasonal pattern, with a nitrate concentration build-up during autumn and peaks in winter, caused by elevated water percolation to deeper soil layers in this period. Using simulated water percolation values, SC concentrations were converted into fluxes. SCs sampled 30% less N-losses on average compared to SIA, which collect also the wide macropore and preferential flows. The difference between Nmin content in autumn and spring was greater than nitrate leaching measured with either SIA or SCs. This observation indicates that autumn Nmin was depleted not only by leaching but also by plant and microbial N uptake and gaseous losses. The positive correlation between autumn Nmin content and leaching fluxes determined by either SCs or SIA suggests autumn Nmin as a useful relative but not absolute indicator for nitrate leaching. In conclusion, all three monitoring techniques are suited to indicate N leaching but represent different transport and cycling processes and vary in spatio-temporal resolution. The choice of monitoring method mainly depends (1) on the project's goals and financial budget and (2) on the soil conditions. Long-term data, and especially the combination of methods, increase process understanding and generate knowledge beyond a pure methodological comparison.

Impact of physiological pacing on functional mitral regurgitation in systolic dysfunction: Initial echocardiographic remodeling findings after His bundle pacing.

BACKGROUND: Although His bundle pacing (HBP) has been shown to improve left ventricular ejection fraction (LVEF), its impact on mitral regurgitation (MR) remains uncertain. OBJECTIVES: The aim of this study was to evaluate change in functional MR after HBP in patients with left ventricular (LV) systolic dysfunction. METHODS: Paired echocardiograms were retrospectively assessed in patients with reduced LVEF (<50%) undergoing HBP for pacing or resynchronization. The primary outcomes assessed were change in MR, LVEF, LV volumes, and valve geometry pre- and post-HBP. MR reduction was characterized as a decline in ≥1 MR grade post-HBP in patients with ≥grade 3 MR at baseline. RESULTS: Thirty patients were analyzed: age 68 ± 15 years, 73% male, LVEF 32% ± 10%, 38% coronary artery disease, 33% history of atrial fibrillation. Baseline QRS was 162 ± 31 ms: 33% left bundle branch block, 37% right bundle branch block, 17% paced, and 13% narrow QRS. Significant reductions in LV end-systolic volume (122 mL [73-152 mL] to 89 mL [71-122 mL], P = .006) and increase in LV ejection fraction (31% [25%-37%] to 39% [30%-49%], P < .001) were observed after HBP. Ten patients had grade 3 or 4 MR at baseline, with reduction in MR observed in 7. In patients with at least grade 3 MR at baseline, reduction in LV volumes, improved mitral valve geometry, and greater LV contractility were associated with MR reduction. Greater reduction in paced QRS width was present in MR responders compared to non-MR responders (-40% vs -25%, P = .04). CONCLUSIONS: In this initial detailed echocardiographic analysis in patients with LV systolic dysfunction, HBP reduced functional MR through favorable ventricular remodeling.

Physiological optimization of robotic endoscopic epicardial CRT-D implantation using multielectrode electroanatomic mapping.

Multielectrode epicardial mapping during robotic implantation of cardiac resynchronization-defibrillator system. Robotically assisted endoscopic implantation of cardiac implantable devices is well documented to be both feasible and safe, and this technique provides particular benefit in patients with limited vascular access. In a patient meeting Class I indication for cardiac resynchronization therapy with defibrillator and inaccessible vascular access, we describe in this case an optimization strategy for intraoperative left ventricular lead placement utilizing robotic epicardial electroanatomic mapping as well as the feasibility of implanting a totally epicardial biventricular cardioverter-defibrillator system.

Treatment of Knee Meniscus Pathology: Rehabilitation, Surgery, and Orthobiologics.

The meniscal tear treatment paradigm traditionally begins with conservative measures such as physical therapy and referral for operative management for persistent or mechanical symptoms. As a result, the partial meniscectomy is performed more than any other orthopedic procedure in the United States. This treatment paradigm has shifted because recent literature has supported the attempt to preserve or repair the meniscus whenever possible given its importance for the structural integrity of the knee joint and the risk of early osteoarthritis associated after meniscus excision. Choosing an appropriate management strategy depends on multiple factors such as patient demographics and location of the tear. Physical therapy remains a first-line treatment for knee pain secondary to meniscus tear and should be pursued in the setting of acute and chronic knee pain. Furthermore, there is a growing amount of evidence showing that elderly patients with complex meniscus tears in the setting of degenerative arthritis should not undergo arthroscopic surgery. Direct meniscus repair remains an option in ideal patients who are young, healthy, and have tears near the more vascular periphery of the meniscus but it is not suitable for all patients. Use of orthobiologics such as platelet-rich plasma and mesenchymal stem cells have shown promise in augmenting surgical repairs or as standalone treatments, although research for their use in meniscal tear management is limited.