Evaluation of National Surgical Practice for Lateral Lymph Nodes in Rectal Cancer in an Untrained Setting.

BACKGROUND: Involved lateral lymph nodes (LLNs) have been associated with increased local recurrence (LR) and ipsi-lateral LR (LLR) rates. However, consensus regarding the indication and type of surgical treatment for suspicious LLNs is lacking. This study evaluated the surgical treatment of LLNs in an untrained setting at a national level. METHODS: Patients who underwent additional LLN surgery were selected from a national cross-sectional cohort study regarding patients undergoing rectal cancer surgery in 69 Dutch hospitals in 2016. LLN surgery consisted of either 'node-picking' (the removal of an individual LLN) or 'partial regional node dissection' (PRND; an incomplete resection of the LLN area). For all patients with primarily enlarged (≥7 mm) LLNs, those undergoing rectal surgery with an additional LLN procedure were compared to those  undergoing only rectal resection. RESULTS: Out of 3057 patients, 64 underwent additional LLN surgery, with 4-year LR and LLR rates of 26% and 15%, respectively. Forty-eight patients (75%) had enlarged LLNs, with corresponding recurrence rates of 26% and 19%, respectively. Node-picking (n = 40) resulted in a 20% 4-year LLR, and a 14% LLR after PRND (n = 8; p = 0.677). Multivariable analysis of 158 patients with enlarged LLNs undergoing additional LLN surgery (n = 48) or rectal resection alone (n = 110) showed no significant association of LLN surgery with 4-year LR or LLR, but suggested higher recurrence risks after LLN surgery (LR: hazard ratio [HR] 1.5, 95% confidence interval [CI] 0.7-3.2, p = 0.264; LLR: HR 1.9, 95% CI 0.2-2.5, p = 0.874). CONCLUSION: Evaluation of Dutch practice in 2016 revealed that approximately one-third of patients with primarily enlarged LLNs underwent surgical treatment, mostly consisting of node-picking. Recurrence rates were not significantly affected by LLN surgery, but did suggest worse outcomes. Outcomes of LLN surgery after adequate training requires further research.

Nonreciprocal Frequency Domain Beam Splitter.

The canonical beam splitter-a fundamental building block of quantum optical systems-is a reciprocal element. It operates on forward- and backward-propagating modes in the same way, regardless of direction. The concept of nonreciprocal quantum photonic operations, by contrast, could be used to transform quantum states in a momentum- and direction-selective fashion. Here we demonstrate the basis for such a nonreciprocal transformation in the frequency domain through intermodal Bragg scattering four-wave mixing (BSFWM). Since the total number of idler and signal photons is conserved, the process can preserve coherence of quantum optical states, functioning as a nonreciprocal frequency beam splitter. We explore the origin of this nonreciprocity and find that the phase-matching requirements of intermodal BSFWM produce an enormous asymmetry (76×) in the conversion bandwidths for forward and backward configurations, yielding ∼25 dB of nonreciprocal contrast over several hundred GHz. We also outline how the demonstrated efficiencies (∼10^{-4}) may be scaled to near-unity values with readily accessible powers and pumping configurations for applications in integrated quantum photonics.

One-stop routing for surgical interventions: a cost-analysis of endoscopic groin repair.

BACKGROUND: Single-visit (SV) totally extraperitoneal (TEP) inguinal hernia repair is an efficient service without impairment of safety or complication rate. Data on the economic impact of this approach are rare. The aim of this study was to compare the costs between the SV TEP and the regular TEP in an employed healthy population from a hospital and societal point of view. METHODS: Retrospectively collected hospital costs and prospectively collected societal costs were obtained from patients treated between July 2016 and January 2018. Outcome measures consisted of all documented institutional care, productivity loss and medical consumption. RESULTS: For analysing the hospital costs, a total of 116 SV patients were matched to 116 regular patients. The hospital costs of a mean SV patient were €1148.78 compared to €1242.84 for a regular patient, with a mean difference of €94.06. Prospective analyses of 50 SV patients and 50 regular patients demonstrated higher societal costs for a mean regular patient (€2188.33) compared to a mean SV patient (€1621.44). The mean total cost difference between a SV TEP repair and a regular TEP repair equalled €660.95 corresponding to a 19.3% decrease in costs. CONCLUSIONS: This comprehensive cost-analysis showed that in an employed, healthy population, the SV TEP repair outprices the regular TEP repair, with savings of €660.95 per patient, reflecting a 19.3% decrease in costs. This routing is mainly interesting from a societal point of view as the difference is mainly impacted by a decrease in societal costs.

Electronic Health Program to Empower Patients in Returning to Normal Activities After General Surgical and Gynecological Procedures: Intervention Mapping as a Useful Method for Further Development.

BACKGROUND: Support for guiding and monitoring postoperative recovery and resumption of activities is usually not provided to patients after discharge from the hospital. Therefore, a perioperative electronic health (eHealth) intervention ("ikherstel" intervention or "I recover" intervention) was developed to empower gynecological patients during the perioperative period. This eHealth intervention requires a need for further development for patients who will undergo various types of general surgical and gynecological procedures. OBJECTIVE: This study aimed to further develop the "ikherstel" eHealth intervention using Intervention Mapping (IM) to fit a broader patient population. METHODS: The IM protocol was used to guide further development of the "ikherstel" intervention. First, patients' needs were identified using (1) the information of a process evaluation of the earlier performed "ikherstel" study, (2) a review of the literature, (3) a survey study, and (4) focus group discussions (FGDs) among stakeholders. Next, program outcomes and change objectives were defined. Third, behavior change theories and practical tools were selected for the intervention program. Finally, an implementation and evaluation plan was developed. RESULTS: The outcome for an eHealth intervention tool for patients recovering from abdominal general surgical and gynecological procedures was redefined as "achieving earlier recovery including return to normal activities and work." The Attitude-Social Influence-Self-Efficacy model was used as a theoretical framework to transform personal and external determinants into change objectives of personal behavior. The knowledge gathered by needs assessment and using the theoretical framework in the preparatory steps of the IM protocol resulted in additional tools. A mobile app, an activity tracker, and an electronic consultation (eConsult) will be incorporated in the further developed eHealth intervention. This intervention will be evaluated in a multicenter, single-blinded randomized controlled trial with 18 departments in 11 participating hospitals in the Netherlands. CONCLUSIONS: The intervention is extended to patients undergoing general surgical procedures and for malignant indications. New intervention tools such as a mobile app, an activity tracker, and an eConsult were developed. TRIAL REGISTRATION: Netherlands Trial Registry NTR5686; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5686.

Higher Recurrence Rate After Endoscopic Totally Extraperitoneal (TEP) Inguinal Hernia Repair With Ultrapro Lightweight Mesh: 5-Year Results of a Randomized Controlled Trial (TULP-trial).

OBJECTIVE: The aim of this study was to determine inguinal hernia recurrence rates 5 years after endoscopic totally extraperitoneal (TEP) inguinal hernia repair when either lightweight or heavyweight mesh was used. BACKGROUND: Recurrence is an important complication of inguinal hernia surgery. Higher recurrence rates of Ultrapro lightweight meshes after TEP repair have been demonstrated, yet data regarding long-term follow-up are limited. METHODS: From 2010 to 2012, 950 male adult patients with primary unilateral hernias were randomized to TEP hernia repair with heavyweight (Prolene) or lightweight (Ultrapro) mesh. Five years postoperatively, the validated PINQ-PHONE telephone questionnaire was carried out. Participants with a positive questionnaire reply were scheduled for a clinical visit. A recurrence was defined as a clinically detectable bulge in the operated groin on physical examination. RESULTS: Data on development of recurrence could be obtained from 790 patients (83.2% 5-year follow-up rate). Four patients presented with a recurrence at the outpatient clinic between 2 and 5 years postoperatively. Thirty-five patients (4.6%) with a positive PINQ-PHONE reply (60.0% lightweight vs 40.0% heavyweight) were physically examined at the outpatient clinic. In 2 patients (lightweight) a recurrence was detected. The total 5-year recurrence rate after TEP hernia repair was 2.4% (3.8% lightweight, 1.1% heavyweight, P = 0.01). A significantly higher recurrence rate for lightweight mesh in primary direct hernias was found (P = 0.003). CONCLUSIONS: The overall recurrence rate 5 years after TEP repair was low. Ultrapro lightweight meshes showed higher recurrence rates than heavyweight meshes and are not recommended for endoscopic TEP inguinal hernia repair.

A Perioperative eHealth Program to Enhance Postoperative Recovery After Abdominal Surgery: Process Evaluation of a Randomized Controlled Trial.

BACKGROUND: Electronic health (eHealth) interventions have proven effective, but implementation in clinical practice is difficult. More research focusing on the implementation process of eHealth interventions is necessary. OBJECTIVE: The objective of this study was to describe the process evaluation of a perioperative eHealth intervention, aiming to enhance recovery after laparoscopic abdominal surgery. METHODS: A process evaluation was carried out alongside a multicenter randomized controlled trial. Patients aged between 18 and 75 years who were scheduled for a laparoscopic cholecystectomy, hernia inguinal surgery, or laparoscopic adnexal surgery were included. The eHealth intervention comprised a website and mobile phone app with the possibility to develop a personalized convalescence plan, a section with information about the surgical procedure and the recovery period, the possibility to ask questions via an electronic consultation (eConsult), and an activity tracker. The process evaluation was carried out using the model of Linnan and Steckler, measuring components such as reach, dose delivered, dose received, fidelity, and participants' attitudes. Implementation scores were calculated based on the average of the four components. Quantitative data were collected by means of an electronic questionnaire, a logistic database, a weblog, and medical files. Qualitative data were collected by conducting interviews with a subsample of the study participants. RESULTS: A total of 344 of the 863 eligible patients were included in the study, which accounted for a reach of 39.9%, and 173 participants were randomized to the intervention group. The implementation scores of the different functions of the intervention ranged between 60% and 65%. The website, mobile phone app, and activity tracker were rated 7.3 to 7.6 on a scale of 1 to 10. Almost all participants who were interviewed about the eConsult function rated it as being of additional value if combined with the usual care but not as a replacement for usual care. CONCLUSIONS: Although participants were overall satisfied with the intervention, the implementation scores of the different functions of the intervention were fair. More research is needed to evaluate the barriers and facilitators for implementation of this perioperative eHealth intervention in normal practice outside study setting. TRIAL REGISTRATION: Netherlands Trial Registry NTR4699; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4699 (Archived by WebCite at http://www.webcitation.org/6vr02V4KK).

Designing graphene absorption in a multispectral plasmon-enhanced infrared detector.

We have examined graphene absorption in a range of graphene-based infrared devices that combine either monolayer or bilayer graphene with three different gate dielectrics. Electromagnetic simulations show that the optical absorption in graphene in these devices, an important factor in a functional graphene-based detector, is strongly dielectric-dependent. These simulations reveal that plasmonic excitation in graphene can significantly influence the percentage of light absorbed in the entire device, as well as the graphene layer itself, with graphene absorption exceeding 25% in regions where plasmonic excitation occurs. Notably, the dielectric environment of graphene has a dramatic influence on the strength and wavelength range over which the plasmons can be excited, making dielectric choice paramount to final detector tunability and sensitivity.

Silicon photonic transceiver circuit for high-speed polarization-based discrete variable quantum key distribution.

We demonstrate a silicon photonic transceiver circuit for high-speed discrete variable quantum key distribution that employs a common structure for transmit and receive functions. The device is intended for use in polarization-based quantum cryptographic protocols, such as BB84. Our characterization indicates that the circuit can generate the four BB84 states (TE/TM/45°/135° linear polarizations) with >30 dB polarization extinction ratios and gigabit per second modulation speed, and is capable of decoding any polarization bases differing by 90° with high extinction ratios.

Single photon detection in a waveguide-coupled Ge-on-Si lateral avalanche photodiode.

We examine gated-Geiger mode operation of an integrated waveguide-coupled Ge-on-Si lateral avalanche photodiode (APD) and demonstrate single photon detection at low dark count for this mode of operation. Our integrated waveguide-coupled APD is fabricated using a selective epitaxial Ge-on-Si growth process resulting in a separate absorption and charge multiplication (SACM) design compatible with our silicon photonics platform. Single photon detection efficiency and dark count rate is measured as a function of temperature in order to understand and optimize performance characteristics in this device. We report single photon detection of 5.27% at 1310 nm and a dark count rate of 534 kHz at 80 K for a Ge-on-Si single photon avalanche diode. Dark count rate is the lowest for a Ge-on-Si single photon detector in this range of temperatures while maintaining competitive detection efficiency. A jitter of 105 ps was measured for this device.

Long-term Results of a Randomized Double-blinded Prospective Trial of a Lightweight (Ultrapro) Versus a Heavyweight Mesh (Prolene) in Laparoscopic Total Extraperitoneal Inguinal Hernia Repair (TULP-trial).

OBJECTIVE: The aim of the randomized clinical trial was to compare the 2 years of clinical outcomes of a lightweight (Ultrapro) vs a heavyweight (Prolene) mesh for laparoscopic total extraperitoneal (TEP) inguinal hernia repair. BACKGROUND: Lightweight meshes reduce postoperative pain and stiffness in open anterior inguinal hernia repair. The discussion about a similar benefit for laparoscopic repair is ongoing, but concerns exist about higher recurrence rates. METHODS: Between March 2010 and October 2012, male patients who presented with a primary, reducible unilateral inguinal hernia who underwent day-case TEP repair were eligible. Outcome parameters included chronic pain, recurrence, foreign body feeling, and quality of life scores. RESULTS: During the study period, 950 patients were included. One year postoperatively the presence of relevant pain (Numeric Rating Score 4-10) was significantly higher in the lightweight mesh group (2.9%) compared with the heavyweight mesh group (0.7%) (P = 0.01), and after 2 years this difference remained significant (P = 0.03). There were 4 (0.8%) recurrent hernias in the heavyweight mesh group and 13 (2.7%) in the lightweight group (P = 0.03). No differences in foreign body feeling or quality of life scores were detected. CONCLUSIONS: In TEP hernia surgery, there was no benefit of lightweight over heavyweight meshes observed 2 years postoperatively.

High performance waveguide-coupled Ge-on-Si linear mode avalanche photodiodes.

We present experimental results for a selective epitaxially grown Ge-on-Si separate absorption and charge multiplication (SACM) integrated waveguide coupled avalanche photodiode (APD) compatible with our silicon photonics platform. Epitaxially grown Ge-on-Si waveguide-coupled linear mode avalanche photodiodes with varying lateral multiplication regions and different charge implant dimensions are fabricated and their illuminated device characteristics and high-speed performance is measured. We report a record gain-bandwidth product of 432 GHz for our highest performing waveguide-coupled avalanche photodiode operating at 1510nm. Bit error rate measurements show operation with BER< 10-12, in the range from -18.3 dBm to -12 dBm received optical power into a 50 Ω load and open eye diagrams with 13 Gbps pseudo-random data at 1550 nm.

Highly directional thermal emission from two-dimensional silicon structures.

We simulate, fabricate, and characterize near perfectly absorbing two-dimensional grating structures in the thermal infrared using heavily doped silicon (HdSi) that supports long wave infrared surface plasmon polaritons (LWIR SPP's). The devices were designed and optimized using both finite difference time domain (FDTD) and rigorous coupled wave analysis (RCWA) simulation techniques to satisfy stringent requirements for thermal management applications requiring high thermal radiation absorption over a narrow angular range and low visible radiation absorption over a broad angular range. After optimization and fabrication, characterization was performed using reflection spectroscopy and normal incidence emissivity measurements. Excellent agreement between simulation and experiment was obtained.

Feasibility of enhanced recovery programme in various patient groups.

INTRODUCTION: An accelerated multi-modal rehabilitation programme may improve the recuperation and reduce the complication rate in patients undergoing colorectal surgery. The aim of this study was to see whether fast-track recovery is feasible in various patient groups. PATIENTS AND METHODS: Data on all patients operated for intestinal pathology from July 2006-April 2008 were prospectively collected for this prospective study. All included patients entered a multi-modal rehabilitation programme. Peri- and postoperative complications and readmissions, pathology reports and operation characteristics were recorded prospectively. RESULTS: Three hundred and forty-eight patients underwent colorectal surgery. No difference in readmission rate was found between various patient groups. The only significant differences after multivariate regression analysis were in re-operation rate and length of stay in favour of the elective surgery group. CONCLUSIONS: Fast-track modalities can be introduced with a low complication rate in all patient groups. Length of stay in elderly patients averages 10 days, implying that this group cannot be considered as "fast track", although the same protocol can also be applied in this group. Better organization of the aftercare might however considerably change the length of stay of elderly patients, since postoperative complications do not differ between old and young patients.

Observation of Rabi splitting from surface plasmon coupled conduction state transitions in electrically excited InAs quantum dots.

We demonstrate strong coupling between a surface plasmon and intersublevel transitions in self-assembled InAs quantum dots. The surface plasmon mode exists at the interface between the semiconductor emitter structure and a periodic array of holes perforating a metallic Pd/Ge/Au film that also serves as the top electrical contact for the emitters. Spectrally narrowed quantum-dot electroluminescence was observed for devices with varying subwavelength hole spacing. Devices designed for 9, 10, and 11 µm wavelength emission also exhibit a significant spectral splitting. The association of the splitting with quantum-dot Rabi oscillation is consistent with results from a calculation of spontaneous emission from an interacting plasmonic field and quantum-dot ensemble. The fact that this Rabi oscillation can be observed in an incoherently excited, highly inhomogeneously broadened system demonstrates the utility of intersublevel transitions in quantum dots for investigations of coherent transient and quantum coherence phenomena.

Ultra compact 45 GHz CMOS compatible Germanium waveguide photodiode with low dark current.

We present a compact 1.3 × 4 µm2 Germanium waveguide photodiode, integrated in a CMOS compatible silicon photonics process flow. This photodiode has a best-in-class 3 dB cutoff frequency of 45 GHz, responsivity of 0.8 A/W and dark current of 3 nA. The low intrinsic capacitance of this device may enable the elimination of transimpedance amplifiers in future optical data communication receivers, creating ultra low power consumption optical communications.

Scaling of optical forces in dielectric waveguides: rigorous connection between radiation pressure and dispersion.

We show that eigenmodes of dielectric optical waveguides exert surface dilation forces on waveguide boundaries owing to radiation pressure, and we develop an exact scaling law relating modal dispersion of an arbitrary dielectric waveguide to the magnitude of optical forces generated by radiation pressure. This result points to highly dispersive waveguides as an optimal choice for the generation of large optical forces in nano-optomechanical systems. Exact agreement with ab initio calculations is demonstrated.

Microwave response in a topological superconducting quantum interference device.

Photon detection at microwave frequency is of great interest due to its application in quantum computation information science and technology. Herein are results from studying microwave response in a topological superconducting quantum interference device (SQUID) realized in Dirac semimetal Cd3As2. The temperature dependence and microwave power dependence of the SQUID junction resistance are studied, from which we obtain an effective temperature at each microwave power level. It is observed the effective temperature increases with the microwave power. This observation of large microwave response may pave the way for single photon detection at the microwave frequency in topological quantum materials.

Tailoring optical forces in waveguides through radiation pressure and electrostrictive forces.

Radiation pressure is known to scale to large values in engineered micro and nanoscale photonic waveguide systems. In addition to radiation pressure, dielectric materials also exhibit strain-dependent refractive index changes, through which optical fields can induce electrostrictive forces. To date, little attention has been paid to the electrostrictive component of optical forces in high-index contrast waveguides. In this paper, we examine the magnitude, scaling, and spatial distribution of electrostrictive forces through analytical and numerical models, revealing that electrostrictive forces increase to large values in high index-contrast waveguides. Similar to radiation pressure, electrostrictive forces increase quadratically with the optical field. However, since electrostrictive forces are determined by the material photoelastic tensor , the sign of the electrostrictive force is highly material-dependent, resulting in cancellation with radiation pressure in some instances. Furthermore, our analysis reveals that the optical forces resulting from both radiation pressure and electrostriction can scale to remarkably high levels (i.e., greater than 10(4)(N/m(2))) for realistic guided powers. Additionally, even in simple rectangular waveguides, the magnitude and distribution of both forces can be engineered at the various boundaries of the waveguide system by choice of material system and geometry of the waveguide. This tailorability points towards novel and simple waveguide designs which enable selective excitation of elastic waves with desired symmetries through engineered stimulated Brillouin scattering processes in nanoscale waveguide systems.

Electrical power generation from moderate-temperature radiative thermal sources.

Moderate-temperature thermal sources (100° to 400°C) that radiate waste heat are often the by-product of mechanical work, chemical or nuclear reactions, or information processing. We demonstrate conversion of thermal radiation into electrical power using a bipolar grating-coupled complementary metal-oxide-silicon (CMOS) tunnel diode. A two-step photon-assisted tunneling charge pumping mechanism results in separation of charge carriers in pn-junction wells leading to a large open-circuit voltage developed across a load. Electrical power generation from a broadband blackbody thermal source has been experimentally demonstrated with converted power densities of 27 to 61 microwatts per square centimeter for thermal sources between 250° and 400°C. Scalable, efficient conversion of radiated waste heat into electrical power can be used to reduce energy consumption or to power electronics and sensors.