Transanal full-thickness excision for rectal neoplasm: is it advisable to leave the defect open?

PURPOSE: After a full-thickness total wall excision of a rectal tumor, suturing the defect is generally recommended. Recently, due to various contradictory studies, there is a trend to leave the defects open. Therefore, this study aimed to determine whether leaving the defect open is an adequate management strategy compared with suturing it closed based on postoperative outcomes and recurrences. METHODS: A retrospective review of our prospectively maintained database was conducted. Adult patients who underwent transanal surgery for rectal neoplasm in our institution from 1997 to 2019 were analyzed. Patients were divided into two groups: sutured (group A) or unsutured (group B) rectal defect. The primary outcomes were morbidity (early and late) and recurrence. RESULTS: In total, 404 (239 men) patients were analyzed, 143 (35.4%) from group A and 261 (64.6%) from group B. No differences were observed in tumor size, distance from the anal verge or operation time. The overall incidence of complications was significantly higher in patients from group B, which nearly double the rate of group A. With a mean follow-up of 58 (range, 12-96) months, seven patients presented with a rectal stricture, all of them from group B. CONCLUSIONS: We acknowledge the occasional impossibility of closing the defect in patients who undergo local excision; however, when it is possible, the present data suggest that there may be advantages to suturing the defect closed.

Management of odonto-stomatological emergencies during the COVID-19 alarm state in dental clinics in the Autonomous Community of Madrid (CAM), Spain: An observational study.

BACKGROUND: Odontology practice has been severely compromised by the pandemic caused by COVID-19 and Spain is one of the countries with higher incidence. Our aim with this study is to find out the number of cases and type of odonto-stomatological emergencies (OSE) treated in four dental clinics of the Madrid capital area and region (CAM) in the period covered between March 17th and 4th of May. MATERIAL AND METHODS: We search the cases in the demographic/epidemiological databases of the CAM regional government and the Illustrious Official College of Dentists and Stomatologists of the First Region (Madrid). RESULTS: We found that the most prevalent pathology was acute apical periodontitis whereas odontogenic abscess showed the lowest frequency. Prosthetic-orthodontic OSE represented 14% of cases. CONCLUSIONS: In this period of time, the most prevalent pathology acute apical periodontitis, odontogenic abscess reported the lowest frequency and prosthetic-orthodontic treatments were the third in number of cases. Most of OSE were resolved, without referring the patient to a hospital emergency department.

Ultra-wideband Ge-rich silicon germanium mid-infrared polarization rotator with mode hybridization flattening.

In this work we investigate the implementation of ultra-wideband polarization rotator in the mid-infrared spectral region. A new design method of the rotation section is proposed, yielding a polarization rotator with an extinction ratio of at least 15 dB in a wavelength range of 2 µm. For a spectral range wider than 3.8 µm, an extinction ratio of at least 10 dB is achieved for this design. The device is 1660 µm long and the associated insertion loss is below 1.2 dB on the full operational wavelength range. The influence of geometrical parameters with respect to the design method to obtain such a broadband behavior is discussed. Finally, to increase the tolerance to fabrication errors, a tapered rotator design is proposed. Such a device can support up to ± 100 nm fabrication errors and still guarantees remarkable broadband behavior. To the best of our knowledge, this is the first time an integrated polarization rotator is designed to operate for the wavelength range of 4 to 9 µm with a bandwidth exceeding 2 µm.

Graded SiGe waveguides with broadband low-loss propagation in the mid infrared.

Mid-infrared (mid-IR) silicon photonics is expected to lead key advances in different areas including spectroscopy, remote sensing, nonlinear optics or free-space communications, among others. Still, the inherent limitations of the silicon-on-insulator (SOI) technology, namely the early mid-IR absorption of silicon oxide and silicon at λ~3.6 µm and at λ ~8.5 µm respectively, remain the main stumbling blocks that prevent this platform to fully exploit the mid-IR spectrum (λ ~2-20 µm). Here, we propose using a compact Ge-rich graded-index Si1-xGex platform to overcome this constraint. A flat propagation loss characteristic as low as 2-3 dB/cm over a wavelength span from λ = 5.5 µm to 8.5 µm is demonstrated in Ge-rich Si1-xGex waveguides of only 6 µm thick. The comparison of three different waveguides design with different vertical index profiles demonstrates the benefit of reducing the fraction of the guided mode that overlaps with the Si substrate to obtain such flat low loss behavior. Such Ge-rich Si1-xGex platforms may open the route towards the implementation of mid-IR photonic integrated circuits with low-loss beyond the Si multi-phonon absorption band onset, hence truly exploiting the full Ge transparency window up to λ ~15 µm.

Memristive behaviour of Si-Al oxynitride thin films: the role of oxygen and nitrogen vacancies in the electroforming process.

The resistive switching properties of silicon-aluminium oxynitride (SiAlON) based devices have been studied. Electrical transport mechanisms in both resistance states were determined, exhibiting an ohmic behaviour at low resistance and a defect-related Poole-Frenkel mechanism at high resistance. Nevertheless, some features of the Al top-electrode are generated during the initial electroforming, suggesting some material modifications. An in-depth microscopic study at the nanoscale has been performed after the electroforming process, by acquiring scanning electron microscopy and transmission electron microscopy images. The direct observation of the devices confirmed features on the top electrode with bubble-like appearance, as well as some precipitates within the SiAlON. Chemical analysis by electron energy loss spectroscopy has demonstrated that there is an out-diffusion of oxygen and nitrogen ions from the SiAlON layer towards the electrode, thus forming silicon-rich paths within the dielectric layer and indicating vacancy change to be the main mechanism in the resistive switching.

Isoflurane disrupts excitatory neurotransmitter dynamics via inhibition of mitochondrial complex I.

BACKGROUND: The mechanisms of action of volatile anaesthetics are unclear. Volatile anaesthetics selectively inhibit complex I in the mitochondrial respiratory chain. Mice in which the mitochondrial complex I subunit NDUFS4 is knocked out [Ndufs4(KO)] either globally or in glutamatergic neurons are hypersensitive to volatile anaesthetics. The volatile anaesthetic isoflurane selectively decreases the frequency of spontaneous excitatory events in hippocampal slices from Ndufs4(KO) mice. METHODS: Complex I inhibition by isoflurane was assessed with a Clark electrode. Synaptic function was measured by stimulating Schaffer collateral fibres and recording field potentials in the hippocampus CA1 region. RESULTS: Isoflurane specifically inhibits complex I dependent respiration at lower concentrations in mitochondria from Ndufs4(KO) than from wild-type mice. In hippocampal slices, after high frequency stimulation to increase energetic demand, short-term synaptic potentiation is less in KO compared with wild-type mice. After high frequency stimulation, both Ndufs4(KO) and wild-type hippocampal slices exhibit striking synaptic depression in isoflurane at twice the 50% effective concentrations (EC50). The pattern of synaptic depression by isoflurane indicates a failure in synaptic vesicle recycling. Application of a selective A1 adenosine receptor antagonist partially eliminates isoflurane-induced short-term depression in both wild-type and Ndufs4(KO) slices, implicating an additional mitochondria-dependent effect on exocytosis. When mitochondria are the sole energy source, isoflurane completely eliminates synaptic output in both mutant and wild-type mice at twice the (EC50) for anaesthesia. CONCLUSIONS: Volatile anaesthetics directly inhibit mitochondrial complex I as a primary target, limiting synaptic ATP production, and excitatory vesicle endocytosis and exocytosis.

Ge-rich graded-index Si1-xGex waveguides with broadband tight mode confinement and flat anomalous dispersion for nonlinear mid-infrared photonics.

This work explores the use of Ge-rich graded-index Si1-xGex rib waveguides as building blocks to develop integrated nonlinear optical devices for broadband operation in the mid-IR. The vertical Ge gradient concentration in the waveguide core renders unique properties to the guided optical mode, providing tight mode confinement over a broadband mid-IR wavelength range from λ = 3 µm to 8 µm. Additionally, the gradual vertical confinement pulls the optical mode upwards in the waveguide core, overlapping with the Ge-rich area where the nonlinear refractive index is larger. Moreover, the Ge-rich graded-index Si1-xGex waveguides allow efficient tailoring of the chromatic dispersion curves, achieving flat anomalous dispersion for the quasi-TM optical mode with D ≤ 14 ps/nm/km over a ~1.4 octave span while retaining an optimum third-order nonlinear parameter, γeff. These results confirm the potential of Ge-rich graded-index Si1-xGex waveguides as an attractive platform to develop mid-IR nonlinear approaches requiring broadband dispersion engineering.

Compact focusing grating couplers for silicon horizontal slot waveguides.

In this Letter, we present the design, simulation (2D and 3D), fabrication, and experimental characterization of compact and fully etched focusing gratings for a horizontal slot waveguide based on a silicon nitride layer sandwiched between amorphous silicon and a silicon-on-insulator. The measured coupling losses are about 4 dB with a 3 dB bandwidth of 38 nm. The fully etched configuration allows the fabrication in a single lithography step.

A model for lymphocyte activation in open versus laparoscopic surgery in colorectal cancer patients in enhanced recovery after surgery (ERAS) protocols.

PURPOSE: Given the high mortality and morbidity associated with colon cancer worldwide and the advantages inherent to the use of the laparoscopy technique with respect to open surgery in oncological colorectal surgery, a study was designed to observe and compare the lymphocyte activation model between open surgery (OS) and laparoscopic surgery (LS) for this type of patient as part of an ERAS protocol. METHODS: A prospective study was conducted with 38 patients who underwent surgery due to colorectal disease and were included in an ERAS protocol. The patients were divided into two groups: G1 (patients who had undergone OS; n = 19) and G2 (patients who had undergone LS; n = 19). The lymphocyte activation model was studied at three times: immediately prior to surgery and on post-operative days 1 and 3 (POD0, POD1 and POD3). RESULTS: The Th lymphocyte activation markers studied (CD25, CD69, HLADR) exhibited a significantly higher mean value on POD0 for CD69 in OS than in LS (p = 0.037) and a significantly lower mean HLADR value on POD3 for OS than for LS (p = 0.040). No statistically significant differences were observed in either the evolution or in the mean values for the intracellular cytokines studied responsible for a Th1, Th2 or Th17 response. A Th1 response pattern was observed in both OS and LS. CONCLUSIONS: The lymphocyte activation model in OS and LS is a Th1 response in both cases. The findings for the Th lymphocyte activation markers could indicate a better preserved immunity in LS with respect to OS.

A systematic review of sugammadex vs neostigmine for reversal of neuromuscular blockade.

We reviewed systematically sugammadex vs neostigmine for reversing neuromuscular blockade. We included 17 randomised controlled trials with 1553 participants. Sugammadex reduced all signs of residual postoperative paralysis, relative risk (95% CI) 0.46 (0.29-0.71), p = 0.0004 and minor respiratory events, relative risk (95% CI) 0.51 (0.32-0.80), p = 0.0034. There was no difference in critical respiratory events, relative risk (95% CI) 0.13 (0.02-1.06), p = 0.06. Sugammadex reduced drug-related side-effects, relative risk (95% CI) 0.72 (0.54-0.95), p = 0.02. There was no difference in the rate of postoperative nausea or the rate of postoperative vomiting, relative risk (95% CI) 0.94 (0.79-1.13), p = 0.53, and 0.87 (0.65-1.17), p = 0.36 respectively.

A multicentre comparison of a fast track or conventional postoperative protocol following laparoscopic or open elective surgery for colorectal cancer surgery.

AIM: The introduction of multimodal or fast track (FT) rehabilitation and laparoscopy in colorectal surgery has improved patient recovery and shortened hospital stay (HS). This study aimed to determine the influence of laparoscopic or open surgery on the postoperative recovery of colorectal cancer patients having a conventional care (CC) or FT protocol in the postoperative period. METHOD: A multicentre prospective study was controlled with a retrospective group. The prospective group included 300 patients having elective colorectal resection for cancer. The retrospective control group included 201 patients with the same characteristics who were treated before the introduction of the programme. The patients were divided into four groups including laparoscopy + FT, open surgery + FT, laparoscopy + CC, and open surgery + CC. The primary end-points were HS and morbidity. Secondary end-points included mortality and reoperation rates. RESULTS: The overall median HS was 7 days. The median HS for laparoscopy + FT was 5 days, open + FT 6 days, laparoscopy + CC 9 days and open + CC 10 days (P < 0.001). In the regression model the laparoscopy + FT group had the greatest reduction in HS (P < 0.001). A significant reduction in HS was observed in the laparoscopy + FT group compared with laparoscopy + CC (P < 0.001). The overall patient morbidity was 30.6%. The logistic regression model adjusted for propensity score showed no statistically significant differences between the study groups regarding all other end-points. CONCLUSION: Colorectal cancer patients who underwent laparoscopic surgery within a multimodal rehabilitation protocol experienced the shortest HS and the lowest morbidity.

Er-doped light emitting slot waveguides monolithically integrated in a silicon photonic chip.

An integrated erbium-based light emitting diode has been realized in a waveguide configuration allowing 1.54 µm light signal routing in silicon photonic circuits. This injection device is based on an asymmetric horizontal slot waveguide where the active slot material is Er(3+) in SiO2 or Er(3+) in Si-rich oxide. The active horizontal slot waveguide allows optical confinement, guiding and lateral extraction of the light for on-chip distribution. Light is then coupled through a taper section to a passive Si waveguide terminated by a grating which extracts (or inserts) the light signal for measuring purposes. We measured an optical power density in the range of tens of µW/cm(2) which follows a super-linear dependence on injected current density. When the device is biased at high current density, upon a voltage pulse (pump signal), free-carrier and space charge absorption losses become large, attenuating a probe signal by more than 60 dB/cm and thus behaving conceptually as an electro-optical modulator. The integrated device reported here is the first example, still to be optimized, of a fundamental block to realize an integrated silicon photonic circuit with monolithic integration of the light emitter.

Combined transposition of internal obturator and superficial gluteal muscles for perineal hernia treatment in dogs: 17 cases (2017-2020).

OBJECTIVES: To report the results of the combined transposition of the internal obturator muscle and superficial gluteal muscle for perineal hernia treatment in dogs. MATERIALS AND METHODS: Retrospective case series of dogs treated with this technique from November 2017 to May 2020, including pre- and post-operative clinical findings, outcome and complications. RESULTS: Seventeen dogs were included in the study. Twelve dogs were presented with unilateral perineal hernia and five dogs with bilateral perineal hernias. Mean duration of clinical signs before presentation was 9 months. All perineal hernias were successfully repaired using a transposition of the internal obturator muscle to cover the ventral aspect of the perineal hernia and the superficial gluteal muscle to cover the dorsal aspect of the hernia with minimal tension. All dogs regained normal defecation within 24 hours post-surgery. Average follow-up time was 16 months. No recurrence of clinical signs or rectal deviation was observed. Five dogs developed a superficial minor partial necrosis of the T-shaped incision and two had surgical site infections. CLINICAL SIGNIFICANCE: Perineal herniorrhaphy using a combined transposition of the internal obturator and the superficial gluteal muscles is feasible and offered excellent results in this cohort of dogs. It may be considered as a technique for repairing chronic and extensive unilateral and bilateral perineal hernias.

Electrical pump & probe and injected carrier losses quantification in Er doped Si slot waveguides.

Electrically driven Er(3+) doped Si slot waveguides emitting at 1530 nm are demonstrated. Two different Er(3+) doped active layers were fabricated in the slot region: a pure SiO(2) and a Si-rich oxide. Pulsed polarization driving of the waveguides was used to characterize the time response of the electroluminescence (EL) and of the signal probe transmission in 1 mm long waveguides. Injected carrier absorption losses modulate the EL signal and, since the carrier lifetime is much smaller than that of Er(3+) ions, a sharp EL peak was observed when the polarization was switched off. A time-resolved electrical pump & probe measurement in combination with lock-in amplifier techniques allowed to quantify the injected carrier absorption losses. We found an extinction ratio of 6 dB, passive propagation losses of about 4 dB/mm, and a spectral bandwidth > 25 nm at an effective d.c. power consumption of 120 µW. All these performances suggest the usage of these devices as electro-optical modulators.

Theoretical and Experimental Study of CaMgSi Thermoelectric Properties.

Pure CaMgSi was successfully synthesized by mechanical milling, followed by spark plasma sintering. Rietveld refinement was used to calculate the structural parameters, where a crystallite size (D XRD) of 79 nm was estimated. This value was confirmed by the Williamson-Hall analysis. Transmission electron microscopy was used to analyze the microstructure, revealing the presence of extensive interfaces, nanoparticles, and a high crystallinity. First-principles calculations were performed with the WIEN2k package, finding a band gap of 0.27 eV. The thermoelectric properties were determined combining experimental measurements and theoretical results from the BoltzTraP code. The highest value of the electronic figure of merit (ZT e) was 1.67 at 415 K. However, when the lattice thermal contribution (k L) is considered, the highest value of the figure of merit (ZT) was 0.144 at 644 K.

Metal-nitride-oxide-semiconductor light-emitting devices for general lighting.

The potential for application of silicon nitride-based light sources to general lighting is reported. The mechanism of current injection and transport in silicon nitride layers and silicon oxide tunnel layers is determined by electro-optical characterization of both bi- and tri-layers. It is shown that red luminescence is due to bipolar injection by direct tunneling, whereas Poole-Frenkel ionization is responsible for blue-green emission. The emission appears warm white to the eye, and the technology has potential for large-area lighting devices. A photometric study, including color rendering, color quality and luminous efficacy of radiation, measured under various AC excitation conditions, is given for a spectrum deemed promising for lighting. A correlated color temperature of 4800K was obtained using a 35% duty cycle of the AC excitation signal. Under these conditions, values for general color rendering index of 93 and luminous efficacy of radiation of 112 lm/W are demonstrated. This proof of concept demonstrates that mature silicon technology, which is extendable to low-cost, large-area lamps, can be used for general lighting purposes. Once the external quantum efficiency is improved to exceed 10%, this technique could be competitive with other energy-efficient solid-state lighting options.

Blue-green to near-IR switching electroluminescence from Si-rich silicon oxide/nitride bilayer structures.

Blue-green to near-IR switching electroluminescence (EL) has been achieved in a metal-oxide-semiconductor light emitting device, where the dielectric has been replaced by a Si-rich silicon oxide/nitride bilayer structure. To form Si nanostructures, the layers were implanted with Si ions at high energy, resulting in a Si excess of 19%, and subsequently annealed at 1000 °C. Transmission electron microscopy and EL studies allowed ascribing the blue-green emission to the Si nitride related defects and the near-IR band with the emission of the Si-nanoclusters embedded into the SiO(2) layer. Charge transport analysis is reported and allows for identifying the origin of this two-wavelength switching effect.

Efficiency and outcomes of harmonic device in transanal endoscopic microsurgery compared with monopolar scalpel.

INTRODUCTION: An important fact when facing new technologies is their cost for the Health Publishes. The purpose of this paper is to compare the costs of performing TEM with harmonic scalpel and classic monopolar scalpel and to analyze complications. METHODS: Operation time, blood loss, and hospital stay were recorded to determine the cost of the TEM procedure. We also recorded early and late complications. Patients were divided in two groups: harmonic scalpel group (UC) and monopolar scalpel group (MS). RESULTS: TEM for curative intention was used in 330 rectal tumors from January 1997 to January 2010. A total of 229 patients met the criteria for this study: UC group (n = 87) and MS group (n = 142). Patients from the UC group developed fewer complications (16%) than patients from the MS group (23%). The difference of mean stay between groups was 1.5 days (95% confidence interval, 0.7; 2.2 days; P < 0.001) in favor of the UC group. CONCLUSIONS: Harmonic scalpel provides a safer, easier, and more precise surgical section through clean, bloodless, and better visualized operative field. The additional cost of UC was compensated with the decrease in the health resources (mainly hospital stay).