Enhancing Diamond Color Center Fluorescence via Optimized Configurations of Plasmonic Core-Shell Nanoresonator Dimers.

Numerical optimization of silica-metal core-shell nanoresonator dimer geometries was realized to maximize the fluorescence of the NV and SiV diamond color centers. The configurations combine the advantages stemming from the elongation and reduced metal volume of hollow spheroids and the wide tunability and good antenna efficiency due to hybridization of composite modes on the core-shell dimers. The optimized coupled dimers sustain plasmonic modes that maximize the fluorescence by ensuring the simultaneous enhancement of excitation and emission. Asymmetry is advantageous in terms of good enhancement with a compromised corrected quantum efficiency. The directional fluorescence can be significantly increased in the optimized asymmetrically coupled dimer configurations.

Crater formation and deuterium production in laser irradiation of polymers with implanted nano-antennas.

Recent validation experiments on laser irradiation of polymer foils with and without implanted golden nanoparticles are discussed. First we analyze characteristics of craters, formed in the target after its interaction with the laser beam. Preliminary experimental results show significant production of deuterons when both the energy of laser pulse and concentration of nanoparticles are high enough. We consider the deuteron production via the nuclear transmutation reactions p+C→d+X where protons are accelerated by the Coulomb field generated in the target plasma. We argue that maximal proton energy can be above threshold values for these reactions and the deuteron yield may noticeably increase due to presence of nanoparticles.

Plasmonically Enhanced Superradiance of Broken-Symmetry Diamond Color Center Arrays Inside Core-Shell Nanoresonators.

Superradiance was demonstrated in broken-symmetry arrays of SiV diamond color centers embedded into concave plasmonic nanoresonators. The coupled configurations, including the diamond-silver (bare) and diamond-silver-diamond (coated) nanoresonators' geometry parameters as well as the emitters' azimuthal orientation and distance from the metal, were numerically optimized. An objective function consisting of the total fluorescence enhancement multiplied by the corrected emission quantum efficiency was used to design nanoresonators that promote superradiance. A larger total fluorescence enhancement was achieved via a larger number of emitters in both geometries, in coated spherical and in bare ellipsoidal nanoresonators. The superradiance performance was better in the case of a smaller number of emitters in bare spherical and coated ellipsoidal nanoresonators and in the case of a larger number of emitters in coated spherical and bare ellipsoidal nanoresonators. Ellipsoidal geometry is advantageous independent of composition and seeding. The configurations optimal for non-cooperative fluorescence enhancement and superradiance are coincidental. A radiative rate enhancement proportional to the number of emitters was found in wide spectral regions; therefore, superradiance implies N-fold enhancements coexist at excitation and emission. In ellipsoidal nanoresonators, the better superradiance achieved via a smaller quality-factor is accompanied by larger frequency pulling.

Active Individual Nanoresonators Optimized for Lasing and Spasing Operation.

Plasmonic nanoresonators consisting of a gold nanorod and a spherical silica core and gold shell, both coated with a gain layer, were optimized to maximize the stimulated emission in the near-field (NF-c-type) and the outcoupling into the far-field (FF-c-type) and to enter into the spasing operation region (NF-c*-type). It was shown that in the case of a moderate dye concentration, the nanorod has more advantages: smaller lasing threshold and larger slope efficiency and larger achieved intensities in the near-field in addition to FF-c-type systems' smaller gain and outflow threshold, earlier dip-to-peak switching in the spectrum and slightly larger far-field outcoupling efficiency. However, the near-field (far-field) bandwidth is smaller for NF-c-type (FF-c-type) core-shell nanoresonators. In the case of a larger dye concentration (NF-c*-type), although the slope efficiency and near-field intensity remain larger for the nanorod, the core-shell nanoresonator is more advantageous, considering the smaller lasing, outflow, absorption and extinction cross-section thresholds and near-field bandwidth as well as the significantly larger internal and external quantum efficiencies. It was also shown that the strong-coupling of time-competing plasmonic modes accompanies the transition from lasing to spasing occurring, when the extinction cross-section crosses zero. As a result of the most efficient enhancement in the forward direction, the most uniform far-field distribution was achieved.

Few-cycle localized plasmon oscillations.

The generation of few-cycle laser pulses proved to be a key enabling technology in strong-field physics and ultrafast science. The question naturally arises whether one can induce few-cycle localized plasmon oscillations in optical near-fields. Here, we perform a comparative study of different plasmonic nanoresonators illuminated by few-cycle pulses. We analyze the number of cycles (NOC) of the plasmonic field, the near-field enhancement (NFE) as well as the figure of merit NFE/NOC. The pulse length dependence of these quantities is also investigated. Throughout the inspected pulse-length interval silica-gold and silica-silver core-shell monomers have the potential to preserve the NOC of the incoming pulse, silver bow-ties result in the highest NFE, whereas gold core-shell dimers have the highest NFE/NOC. Based on the analysis, silver bow-ties, gold core-shell and silver nanorod dimers proved to be the most suitable for few-cycle near-field amplification.

Superradiant diamond color center arrays coupled to concave plasmonic nanoresonators.

Superradiantly enhanced emission of SiV diamond color centers was achieved via numerically optimized concave plasmonic nanoresonators. Advantages of different numbers of SiV color centers, diamond-silver (bare) and diamond-silver-diamond (coated) core-shell nanoresonator types, spherical and ellipsoidal geometries were compared. Indistinguishable superradiance is reached via four color centers, which is accompanied by line-width narrowing except in a coated ellipsoidal nanoresonator that outperforms its bare counterpart in superradiance. Seeding of both spherical and bare ellipsoidal nano-resonators with six color centers results in larger fluorescence enhancement and better overridden superradiance thresholds simultaneously. Both phenomena are the best optimized in a six color centers seeded ellipsoidal bare nanoresonator according to the pronounced bad-cavity characteristics.

Utility of drain fluid amylase measurement on the first postoperative day after distal pancreatectomy.

BACKGROUND: Early exclusion of a postoperative pancreatic fistula (POPF) may facilitate earlier drain removal in selected patients after distal pancreatectomy. The purpose of this study was to evaluate the role of first postoperative day drain fluid amylase (DFA1) measurement to predict POPF. METHODS: Patients in whom DFA1 was measured after distal pancreatectomy were identified from a prospectively maintained database over a five-year period. A cut-off value of DFA1 was derived using ROC analysis, which yielded sensitivity and negative predictive value of 100% for excluding POPF. RESULTS: DFA1 was available in 53 of 138 (38%) patients who underwent distal pancreatectomy. 19 of 53 patients (36%) developed a pancreatic fistula (Grade A - 15, Grade B - 3, Grade C - 1). Median DFA1 was significantly higher in those who developed a pancreatic fistula (5473; range 613-28,450) compared those without (802; range 57-2350). p < 0.0001. Using ROC analysis, a DFA1 less than 600 excluded pancreatic fistula with a sensitivity of 100% (AUROC of 0.91; SE = 0.04, p < 0.001). CONCLUSION: First postoperative day drain fluid amylase measurement may have a role in excluding pancreatic fistula after distal pancreatectomy. Such patients may be suitable for earlier drain removal.

Long-term Patient-reported Outcomes After Laparoscopic Fenestration of Symptomatic Liver Cysts.

BACKGROUND: Laparoscopic fenestration is the treatment of choice for symptomatic liver cysts. Despite the benefits of minimally invasive surgery, there is limited data on long-term outcomes after laparoscopic fenestration, in terms of symptom recurrence and quality of life. The purpose of this study was to evaluate long-term patient-reported outcomes and satisfaction following this procedure. METHODS: All patients who underwent laparoscopic liver cyst fenestration in a single center between 2001 and 2012 were identified from a prospectively maintained database. Long-term patient-reported outcomes including symptom relief and quality of life were prospectively evaluated by a structured telephone interview. RESULTS: A total of 98 patients underwent laparoscopic liver cyst fenestration. The median follow-up was 62 months (range, 22 to 173 mo). Follow-up data was available in 48 patients. Four patients developed radiologically confirmed evidence of recurrence with 3 undergoing further surgery. No mortality was reported in the series. Four complications occurred and the median postoperative length of hospital stay was 2 days (range, 1 to 7 d). Thirty-nine patients received immediate symptomatic relief with 98% reporting long-term satisfaction. RESULTS: Laparoscopic liver cyst fenestration is associated with low morbidity and long-term alleviation of symptoms. This should be considered the treatment modality of choice in managing patients with nonparasitic cysts.

Inflammatory lymphangiogenesis in a rat transplant model of interstitial fibrosis and tubular atrophy.

We have previously reported de novo lymphangiogenesis in human renal allograft nephrectomy specimens that exhibited interstitial fibrosis and tubular atrophy (IFTA). This study examined whether a similar pathology developed in an experimental model of renal transplantation in the rat. Renal transplants were carried out in rats comprising both isografts (Lewis kidneys → Lewis rats) and allografts (Fisher kidneys → Lewis rats). Animals were immunosuppressed in the immediate postoperative period and sacrificed at 12 months. Experimental readouts included lymphatic vessel number and location, inflammatory cell infiltration, interstitial fibrosis, renal function, blood pressure and proteinuria. Rat allografts demonstrated the characteristic features of IFTA with increased macrophage and T cell infiltration and scattered B cells aggregates. Rat allografts exhibited impaired renal function and proteinuria. Although there was no difference in the number of perivascular lymphatic vessels, there was a striking 18-fold increase in the number of interstitial lymphatic vessels in renal allografts. Furthermore, the lymphatic vessel number correlated with the extent of interstitial fibrosis. This rat allograft model of IFTA demonstrates a marked increase in the number of interstitial lymphatic vessels and mirrors previous work in failing human renal allografts.

Restorative and rejection-associated lymphangiogenesis after renal transplantation: friend or foe?

The review focuses on lymphangiogenesis as a possible contributor to interstitial fibrosis leading to chronic renal transplant injury, which culminates in the loss of 5% transplants annually. The process of lymphatic reconnection after renal transplantation and the mechanisms and mediators of lymphangiogenesis are explored in the context of new specific lymphatic markers. In addition, potentially exciting research avenues are examined, with the specific aim of determining whether new lymphatic formation is beneficial or detrimental to the transplanted kidney.