Position Of Cavity Research Articles

Mode selective damping behavior of additively manufactured beam structures

AbstractAdditive manufacturing, with its inherent process-related degrees of freedom, offers significant potential for manufacturing high-performance parts. This allows effects to be integrated that enable completely new solution mechanisms for existing conflicting objectives, which means that the degrees of design freedom make it possible to optimize the application-specific behavior of a part. In addition to the thermal or electrical properties, the dynamic behavior of a part can also be optimized, for example. This article focuses on the integration of the particle damping effect, which can contribute significantly to increased part damping. Unfused powder inside the part leads to energy dissipation through impact and friction mechanisms. However, the particle damping effect is not yet fully explored, lacking essential knowledge for application in product design. Therefore, test specimens with particle dampers, manufactured using laser powder bed fusion by laser beam from 1.2709 tool steel, are investigated, with variations in the position and size of the particle-filled cavities. To determine damping, the samples are freely supported and excited with an impulse. The damping ratio is calculated based on the recorded decay behavior. The results show an increase in damping ratio of up to a factor of 70, with the extent of improvement strongly dependent on the cavity’s volume and, crucially, its position relative to the part’s mode shape. A linear relationship between the damping ratio and the displacement of the volume of the cavities of the beams is shown.

Analysis of the behavior of structures under the effect of progressive rupture of a cavity

Abstract The ground movements related to the presence of old underground cavities are often damaging to structures and infrastructures. Considering these ground movements in calculations will prevent considerable human loss and material damage. Many areas, both in Algeria and in abroad, are prone to instability caused by ground rupture and the phenomenon of sinkhole progression. The objectives of this work are first to numerically simulate the process of cavity collapse and second to analyze the impact of cavity properties on structure stability. A finite element model was established to analyze the influence of several cavity parameters (dimensions, volume, and spacing). Validation of the model relied on comparing numerical results with experimental data from scientific research, as well as those from analytical approaches. Adequate correlation was achieved. The study allowed deriving mathematical equations relating to several parameters, including cavity dimensions and position in the soil, soil characteristics, and footing width. These results will be considered to reduce the risk of surface structure instability.

O-291 Sonographic Symphony: a systematic review and network meta-analysis of the use of 2D, 3D, 4D ultrasound’s influence on embryo transfer outcomes

Abstract Study question To comprehensively evaluate and compare pregnancy and live birth rates following clinical touch, 2D, 3D or 4D ultrasound guided embryo transfer of a blastocyst. Summary answer The use of 3D and 4D ultrasound is not superior to 2D transabdominal ultrasound, but all forms of ultrasound are superior to clinical touch alone. What is known already While several factors contribute to the overall success of embryo transfer, the accurate placement of the embryo within the uterine cavity remains a critical determinant of implantation and subsequent pregnancy. While two-dimensional (2D) ultrasound provides basic imaging during embryo transfer, assisting with catheter placement, three-dimensional (3D) ultrasound adds volume and spatial information, aiding in assessing the endometrial cavity and embryo positioning. Meanwhile, four-dimensional (4D) ultrasound introduces real-time visualisation, offering dynamic insights into embryo movement and potential implantation. Although 2D remains a standard for most transfers, there is a growing interest in leveraging advanced imaging technologies to improve assisted reproductive outcomes. Study design, size, duration We searched bibliographical databases, including the Cochrane Central Register of Controlled Trials, EMBASE and Medline, from inception until August 2023. Randomised controlled trials that compared 2D transabdominal (2D TAUS), 2D transvaginal (2D TVUS), 3D and 4D ultrasound guided embryo transfer with one another or with clinical touch were included. The primary outcome was live birth rate (LBR), and the secondary outcome was clinical pregnancy rate (CPR) per transfer. Participants/materials, setting, methods Two reviewers independently screened selected studies and extracted the data. Pairwise and network meta-analyses (NMA) were conducted according to the technique used. Effect estimates were odds ratio (OR) with 95% confidence interval (CI) for each outcome respectively. Summary estimates were calculated using random-effects methods and quality assessment was performed using GRADE. Main results and the role of chance Twenty-eight trials, reporting data from 10,521 embryo transfer procedures, were included. Four different ultrasound modalities were evaluated: 2D transabdominal guided embryo transfer (2D TAUS) (21 trials), 2D transvaginal guided embryo transfer (2D TVUS) (four trials), 3D transabdominal guided embryo transfer (one trial) and 4D transabdominal guided embryo transfer (one trial). Compared to 2D TAUS, there was no difference in LBR in the network meta-analysis when using 2D TVUS (OR 1.14; 95% CI: 0.75-1.74), 3D ultrasound (OR 0.98; 95% CI: 0.49-1.97) or 4D ultrasound modality (OR 1.28; 95% CI: 0.56- 2.94). The use of clinical touch was associated with lower LBR (OR 0.71; 95% CI: 0.49-1.03). Compared to 2D TAUS, there was no difference in clinical pregnancy rate in the network meta-analysis when using 2D TVUS (OR 1.17; 95% CI: 0.86-1.58), 3D ultrasound (OR 0.97; 95% CI: 0.57-1.63) or 4D ultrasound modality (OR 1.30; 95% CI: 0.71- 2.38). The use of clinical touch was associated with lower CPR (OR 0.74; 95% CI: 0.64-0.85). Limitations, reasons for caution Variability in study designs, methodologies, and participant characteristics across primary studies can complicate the synthesis of results. There was only one study directly comparing 3D and 4D interventions which resulted in sparse data, affecting the precision and reliability of estimates. Wider implications of the findings Published evidence supports the continued use of 2D transabdominal ultrasound guided embryo transfer in routine clinical practice. There is insufficient evidence to support the introduction of 3D and 4D ultrasound when performing embryo transfers. Larger randomised controlled trials specifically assessing the superiority of these modalities are recommended. Trial registration number not applicable

Effect of Cavity Geometry and Location on Base Pressure in a Suddenly Expanded Flow at Mach 2.0 for Area Ratio 3.24

The primary goal of this study is to use CFD analysis to investigate the impact that a cavity has on the pressure at the base of a structure. In this analysis, we took into account the NPR, the cavity aspect ratio, and the cavity position. In this case, the area ratio is 3.24 and the Mach number is 2.0. Simulations were run with L/D ratios between 1 and 6, and NPRs of 3, 5, 7.8, 9, and 12. The 2-dimensional model was developed using ANSYS Fluent's Design Modeler. The nozzle is operating at Mach 2.0. Base pressure and wall pressure in the duct were the primary research foci. The C-D nozzle was created for this research. ANSYS Fluent was used to verify the CFD findings. When the nozzles are under-expanded and the cavity is at 0.5D, passive control as a cavity is shown to be effective. It appears that 1D is the bare minimum for duct length. Because the shear layer gets reattached to the duct wall at 1D and the boundary layer grows after reattachment, passive control is not observed in the flow process regardless of whether the cavity is located at 1D, 1.5D, 2D, or 3D. An oscillating base pressure is seen at shorter duct lengths. This phenomenon does not occur at longer duct lengths. Whether or not there are cavities in the duct, the flow field is the same.

Experimental study on the temperature control characteristics of graphite foam-based composite phase change materials

Thermal management systems are crucial for ensuring the reliable operation of electronic devices. Heat dissipation using phase change materials (PCMs) is an effective, lightweight method for devices experiencing transient high heat flow. Graphite foam (GF), known for its high thermal conductivity and low density, significantly increases thermal conductivity when combined with PCMs. However, research on the heat transfer characteristics of composite PCMs is limited. This study experimentally investigates the heat dissipation characteristics of a graphite foam-PCM (GF-PCM) composite cooling structure. It explores the impact of factors like the shell's tilt angle, acceleration, and the position of cavities (voids) between the PCM and the shell structure on the transient melting heat transfer of the cooling device under varying thermal source heat flux densities. Results show that using a pure paraffin phase change module, the temperature rise of the heat source increases with the tilt angle, and horizontal placement offers the best heat dissipation and temperature control. The position of the cavity influences heat dissipation; at 30W heating power, a cavity between the heat source and paraffin increases the temperature rise of the heat source by 19.2 %. Furthermore, cavity position is affected by acceleration; at 50W heating power and 3.6g acceleration, the cavity shifts from the top of the module to near the heat source side, increasing its final temperature by 3.7 °C. Acceleration also enhances liquid paraffin convection, significantly affecting paraffin's later melting stage. Adding graphite foam speeds up paraffin melting, reducing the temperature rise of the heat source by 42.8 %, 42.9 %, and 28.3 % at 30W, 40W, and 50W heating powers, respectively. This improvement mitigates the adverse effects of tilt angle, cavities, and uncertainties introduced by acceleration.

A dielectrically modulated vertical TFET-based biosensor considering irregular probe placement and steric hindrance issues

This manuscript presents a comparative biosensing analysis of a dielectrically modulated dual-drain vertical TFET (DD-VTFET) by considering three distinct device arrangements based on the cavity position. DD-VTFETs with single cavity at the source and drain edge are called SC-DD-VTFET and DC-DD-VTFET, respectively, while for SDC-DD-VTFET, dual cavities are created at both the source and drain edge. Asymmetry in cavity position results in different electrostatics for each biosensor, leading to variation in their sensing performance. The on-current sensitivity is found to be lower for the DC-DD-VTFET due to the absence of cavity near the channel-source interface, while the SC-DD-VTFET shows poor performance in terms of ambipolar current sensitivity compared to the SDC-DD-VTFET. Moreover, the study includes the consideration of neutral and charged biomolecules (both positive and negative) with varying dielectric constants of 5, 7, 10 and 12. The sensitivity of partially filled nanogaps with fill-factor (FF) of 42% and 60%, influenced by steric hindrance, are also compared for all three DD-VTFET based biosensors which includes different step profiles of biomolecules, such as concave, convex, increasing, and decreasing. To consider the non-ideal state of the DD-VTFET based biosensors, the effect of irregular placement of the probe within the nano-cavity on different sensitivity parameters for a particular k-value of biomolecules is also analysed using TCAD simulator. Furthermore, the performance of the DD-VTFET based biosensor is quantitatively benchmarked against previously published works available in the literature. For a fully filled cavity with neutral biomolecules having dielectric constant of 12, SDC-DD-VTFET based label-free biosensor provides ON-current and current-switching ratio sensitivities approximately in the order of 105, while the ambipolar current sensitivity of 2.1×103 is observed which makes the sensor equally suitable for sensing the biomolecules even at negative gate bias.

Advances in Aerosol Formulation for Targeted Delivery of Therapeutic Agents from Nose to Brain.

The intricate anatomical and physiological barriers that prohibit pharmaceuticals from entering the brain continue to provide a noteworthy hurdle to the efficient distribution of medications to brain tissues. These barriers prevent the movement of active therapeutic agents into the brain. The present manuscript aims to describe the various aspects of brain-targeted drug delivery through the nasal route. The primary transport mechanism for drug absorption from the nose to the brain is the paracellular/extracellular mechanism, which allows for rapid drug transfer. The transcellular/intracellular pathway involves the transfer across a lipoidal channel, which regulates the entry or exit of anions, organic cations, and peptides. Spectroscopy and PET (positron emission tomography) are two common methods used for assessing drug distribution. MRI (Magnetic resonance imaging) is another imaging method used to assess the efficacy of aerosol drug delivery from nose to brain. It can identify emphysema, drug-induced harm, mucus discharge, oedema, and vascular remodeling. The olfactory epithelium's position in the nasal cavity makes it difficult for drugs to reach the desired target. Bi-directional aerosol systems and tools like the "OptiNose" can help decrease extranasal particle deposition and increase particle deposition efficiency in the primary nasal pathway. Direct medicine administration from N-T-B, however, can reduce the dose administered and make it easier to attain an effective concentration at the site of activity, and it has the potential to be commercialized.

Computer modeling of the interaction of the building underground part with the soil foundation during the karst cavity formation on the example of the administrative and business center construction

In restrained urban conditions of Moscow, the accomplishment of complex urban construction projects is complicated by the choice of construction sites, as well as by lack of methods for computer modeling of the interaction of high-rise and unique buildings and structures with the probable formation of karst cavities in the current regulatory documents. The overall profitability of the project is under the great impact of it, therefore a reliable accounting of karts-suffusion processes is a priority issue in designing buildings and structures, especially if it concerns the unique and high-rise ones. The authors analyze the results of the calculations of the forecast assessment of the impact of a karst cavity probable formation on the subsurface parts of building of the administrative and business center construction in flat and spatial formulation. In spatial formulation different positions of the potential karst cavities are considered; their locations were chosen according to standard procedures and were guided by the results of geological and geophysical research. It has been reviewed the formation of arch over a karst cavity in a 2D and 3D formulation in the condition of different location of the karst cavities in plan and by depth of occurrence. It has been made methodological recommendations for determining the predicted bore of the karst cavity, for taking into account the frame stiffness of the aboveground part of the building, for defining the principles of a karst cavity modeling, as well as for the choice of assessment criteria of stability of cover mass above the potential cavity. The discovered differences in the results of 2D and 3D settings permit to make a conclusion that solving the problem in a flat formulation contributes to the overestimation of karst processes danger and, therefore, to the excess in anti-karst measures included in the project.

Cavity preparation model in rat maxillary first molars: A pilot study

Objective: To conduct a standardized method for cavity preparation on the palatal surface of rat maxillary molars and to introduce a standardized method for tooth correct alignment within the specimen during the wax embedding procedure to better detect cavity position within the examined slides. Materials and methods: Six male Wistar rats, aged 4-6 weeks, were used. The maxillary molars of three animals were sectioned in the frontal plane to identify the thickness of hard tissue on the palatal surface of the first molar which was (250-300µm). The end-cutting bur (with a cutting head diameter of 0.2mm) was suitable for preparing a dentinal cavity (70-80µm) depth. Cavity preparation was then performed using the same bur on the tooth surface in the other three animals. Rats are then euthanized before dissecting, fixing, and demineralizing the teeth. For better alignment of teeth samples during the waxing procedure, K-file endodontic instrument size #8 was dipped in Indian ink. The file tip was inserted on the jaw bone at the buccal side of the tooth in a region opposed to the prepared cavity on the palatal side. Moreover, a small Dycal applicator instrument was used to mark the jaw bone on the mesial side of teeth samples as an orientation for the cutting surface. Results: Well-defined sections were obtained with a clear cavity extension within dentin and without any signs of pulp exposure in all samples. Conclusion: This pilot was conducted to perform an easy procedure for cavity preparation in rat molar teeth to obtain a clear histopathological section.

Detection of erosion damage on airfoils by means of thermographic flow visualization

Cavity-type defects on a wind turbine rotor blade due to erosion lead to an sub-optimal boundary layer flow behavior and result in a reduced annual energy production. To enable an indirect defect detection from far distances, with no contact and no wind turbine stop, the thermographic visualization of the defect wake flow is studied. Experimental investigations and complementary flow simulations on two different airfoil shapes show that the detection is possible above a critical Reynolds number. Furthermore, the wake flow depends on multiple influencing quantities such as the airfoil geometry and the associated chord Reynolds number as well as the cavity position, the cavity shape and the associated cavity Reynolds number. Adjacent cavities can also influence the wake flow behavior. For instance, the cavity position has an influence on the turbulent flow region even after the natural laminar–turbulent flow transition line, and many cavities close to each other shift the transition line towards the leading edge. With increasing aspect ratio as well as increasing inflow velocity, the wake flow turbulence and, thus, the visibility of the wake in the thermographic images becomes higher. However, even if the wake flow from the cavity to the transition line is not continuously visible, a change in the natural transition can still be observed. As a result, thermographic flow visualization enables the indirect detection of cavity-type defects on airfoils and can provide further information about the cavity features.

Predicting evolutions of pulse characteristics along cavity position in passively mode-locked fiber laser via SSA-LSTM approach

Ultrashort pulse evolution along the cavity position is an extremely complicated computational process in passively mode-locked fiber laser systems. Herein, we present a data-driven model to predict the complex intracavity evolution of pulse characteristics along the cavity position using an integrated sparrow search algorithm (SSA) and long short-term memory (LSTM) approach instead of numerically calculating the nonlinear Schrödinger equation (NLSE). Furthermore, the proposed model is compared with a separate LSTM network. The results predicted from the network agree well with those of the NLSE simulation. Moreover, the SSA-LSTM model exhibits excellent predictive performance.

Cavity evolution of ventilated vehicle launch under a rolling condition

The unsteady development of the tail cavity of a vehicle after it leaves a tube often causes adverse effects, most notably an impact load on the vehicle when the cavity ruptures. The rolling of the launch platform can alter the development of the tail cavity, significantly altering the influence of the impact load on the motion and attitude of the vehicle. The present study employs the shear stress transport k-w model, the volume of fluid multiphase flow model, the Schnerr–Sauer cavity model, and the overlapping mesh technique to conduct numerical simulations of the underwater launching process of a ventilated vehicle under both stationary and rolling boundaries. A comparative analysis is conducted to examine the evolution of the cavity shape, pressure distribution, and collapse-induced load in the tail cavity under various conditions after vehicle launch. The findings suggest that the rolling of the tube induces an asymmetrical development of the shoulder cavity lengths and widths on both the windward and leeward sides, with the result of a lower peak pressure at the cavity closure position compared with that under stationary conditions. The rolling of the tube reduces the internal velocity within the tail cavity, elevates the rupture position of the tail cavity, delays the tail cavity rupture, impacts the timing of the force peak occurrence in the vertical direction of the vehicle, reduces the high pressure at the point of tail cavity rupture, and modifies the post-rupture structural characteristics of the tail cavity.

Evolution of demarcation line after pneumatic retinopexy—a case report

BackgroundDemarcation line in a rhegmatogenous retinal detachment (RD) is a classic finding noted in chronic cases. In this case report, we describe a case of evolution of post-operative demarcation line after pneumatic retinopexy (PnR) in a subtotal rhegmatogenous RD.Case descriptionA 31-year-old male diagnosed with acute, subtotal, macula-off rhegmatogenous RD in the left eye of 15-day duration underwent PnR on the same day. His presenting visual acuity was 6/48 in the left eye. Transconjunctival cryopexy was performed to the retinal break at the same sitting and 0.5 cc of 100% perfluoroproprane (C3F8) gas was injected in the vitreous cavity and right lateral position was advised to the patient.ResultA pigmentary demarcation line was noted extending the nasal part of the macula along the most dependent part of the detachment on the immediate post-operative day and was more obviously visible on the 2nd and then on the 11th post-operative day. The visual acuity at the last follow-up visit improved to 6/18. Successful reattachment of the retina was noted on the last follow-up visit.ConclusionPost-operative demarcation lines after RD surgery could develop due to subretinal migration of pigments and along the most-dependent part depending upon post-operative positioning of the patient. Careful post-operative positioning, particularly in macula splitting RDs could be important to avoid pigment accumulation along the foveal area.

Effectiveness of Structure Teaching Programme on Knowledge Regarding Prevention of Uterine Prolapse Among House Wife

Uterine prolaspe is a common reproductive health problem in low- income countries like napal. Physical symptoms of this condition influence women’s quality of life. Current data insufficiently determine women’s awareness of this condition health care seeking practices for uterine prolapsed in India are inadequate. Uterine prolapsed is falling or sliding of the uterus from its normal position in the pelvic cavity into the vaginal canal uterine prolapsed occurs most commonly in women who have one or more vaginal birth & in Caucasian women’s and Other condition associated with an increased risk of problems with the supportive tissues of the uterus include obesity & chronic coughing or straining .obesity place additional strain on the supportive muscles of the pelvis as does excessive coughing caused by lung conditions such as chronic bronchitis & asthma chronic constipation & the pushing associated with it causes weakness in the muscles. The that the mean knowledge score of pretest 8.8 mean post test knowledge score 15.56 mean difference of 7.16 stander deviation was2.37 and stander error 0.47 T-value is 13,82 Table value 2.4 .at degree of freedom 29 and level of 0.p<0.005 and this shows that there was significant in knowledge score in pre test and post test.

Improvements in the design of nest cavities to attract cephalopods and crustaceans in a green artificial reef unit according to tridimensional hydrodynamic criteria – Application to the Ares-Betanzos estuary

Installing artificial reefs (ARs) on the seabed creates a hard substrate that alters water flow and causes different species to settle. For this reason, by applying hydrodynamics to ARs, a useful tool is created for analysing these reefs so that there is adequate nutrient circulation and a propitious habitat for benthic and pelagic fauna. Using hydrodynamic criteria to characterise the velocity field, the present work aims to propose a methodology for positioning nest cavities within an AR unit in which different species will settle. Biological considerations, such as nutrient supply as well as the most suitable size and shape for the nest cavities, are taken into account. A state-of-the-art 3D shallow water model is validated and applied to the Ares-Betanzos estuary (NW Spain), where the installation of an AR group has recently been proposed. This coastal body, with a complex 3D hydrodynamic structure, was achieved under representative average conditions in absence of winds, which in turn greatly differs both in space and time throughout a spring-neap tidal cycle. A 3D CFD (Computational Fluid Dynamics) tool is applied to model food delivery on the AR. Moreover, the optimal geometry and position of nest cavities are established through a created indicator, ARnest cavity position, in order to provide sufficient nutrient circulation. It was found that the most appropriate shape for the nest cavities is cylindrical and a diameter of 200–300 mm is the most appropriate size. In terms of the ideal positions for the nest cavities, these depend on the orientation of the AR with respect to the current velocity. One of the orientations analysed leads to sufficient nutrient supply to the whole AR, while the other orientation analysed leads to sufficient nutrient supply to the high and mid positions at the front face, mid and low positions at the back face and all positions along the lateral faces.

Identification of Underground Artificial Cavities Based on the Bayesian Convolutional Neural Network.

The development of underground artificial cavities plays an important role in the exploitation of urban spatial resources. As the rapidly growing number of underground artificial cavities with different depths and scales increases, the detection and identification of underground artificial cavities has become a key issue in underground engineering studies. Geophysical techniques have been widely used for the construction, management, and maintenance of underground artificial cavities. In this study, we present two identification methods for underground artificial cavities. Apparent resistivity imaging is the most popular technique for quickly identifying underground artificial cavities, using the forward simulation results of a three-dimensional earth model and comparing these with the preset positions of artificial cavities, as demonstrated in the experiment. To further improve the efficiency of underground artificial cavity identification, we developed a fast recognition approach for underground artificial cavities based on the Bayesian convolutional neural network (BCNN). Compared to a traditional convolutional neural network, the performance of the BCNN method was greatly improved in terms of the classification accuracy and efficiency of identifying underground artificial cavities with apparent resistivity image datasets.

Vibration response and safety control for blasting vibration of the existing tunnel with defects

Current studies on blasting construction of small clear-distance tunnels have not considered the impact of existing tunnel lining defects when establishing safety controls. This paper offers a series of study results based on the blasting project of a new tunnel adjacent to the existing defect Xinling tunnel to thoroughly examine the dynamic response, safety control standards, and measures of the existing defect tunnel. First, structural models were developed to investigate the influence of the presence or absence of specific defects (like lining cracks and cavities behind the lining) on the dynamic response of the current tunnel lining to identify the most unfavorable defect distribution. Then, establish safety control standards for intact linings and those with the most unfavorable defects. Eventually, two types of control measures, single safe charge and reasonable delay time, were studied based on the established safety control standards. In particular, the most adverse position of cracks was the wall facing the explosion, the rise in depth was more unfavorable for vibration response, and the impact of the longitudinal crack was restricted to the vicinity of the crack. While the vault was the most adverse cavity position, the rise in cavity area was more damaging, and the influence range varied with longitudinal cavity length. Moreover, the impact of cracks was mainly evident in the amplification effect of stress at the crack region. In contrast, cavities had varied degrees of amplification effects on the vibration velocity and stress response and a relatively extensive influence range. Safety control research was conducted, when the tunnel was intact, with a right wall crack, a vault cavity, and both vault cavity and crack for this project, the peak particle velocity (PPV) of the safety control standard for vibration velocity was 13, 10, 13, and 8 cm/s, respectively, and the respective single safe charge could be adjusted at 64, 53, 37, and 25 kg. However, the presence of different defects had a relatively negligible effect on the reasonable delay time; 25 ms was recommended for existing tunnel lining with and without the defect.

484. ROBOTIC ASSISTED PRONE ESOPHAGECTOMY USING VERSIUS PLATFORM: A PROMISING APPROACH

Abstract Background Esophagectomy for cancer is a complex procedure with high morbidity. Minimally invasive approach offers the benefits of minimal access across the different fields required during this operation. Robotic surgery is becoming an integral part of modern practice. It holds the potential of more precision especially in narrow thoracic space. Currently, Many Robotic platforms exist. This video aims to demonstrate the feasibility of Robotic Mc Keown esophagectomy in the prone position using Versius platform. Methods 56 years old male patient presented with grade I dysphagia of 3 months duration. His complete assessment revealed an 11 cm long invasive non keratinizing squamous cell carcinoma located in the mid esophagus (cT3N1M0). Marked regressive course of the lesion occurred with neoadjuvant chemoradiation. Robotic assisted Mc Keown esophagectomy was performed in the prone position. Thoracic phase was performed with the robotic approach. Bed side units and Port placement is illustrated in the video. The abdominal phase was accomplished laparoscopically. Finally, the stomach was pulled up and the esophagogastric anastomosis was done in the neck. Results No intraoperative adverse events were encountered. The improved vision, dexterity and articulation of instruments facilitated the identification of the thoracic duct, ligation of azygos vein tributaries and dissection of the recurrent laryngeal lymph nodes. Instrument clash was insignificant due to patient’s wide chest cavity and optimal positioning of ports and bed side units improving ergonomics. The operative time of the thoracic phase was 310 min. Blood loss was 300 mL. The postoperative course was uneventful except for chest infection which improved on conservative measures. The length of stay was 18 days. Pathology revealed complete clinical response with 0/25 lymph node yield. Conclusion Robotic assisted esophagectomy is feasible and can be safely performed using Versius robotic platform. The enhanced visualization and articulation enabled meticulous dissection of the recurrent laryngeal lymph nodes. Patient positioning, optimal port and bed side units placement were keys to achieving minimal instrument clash. Further research is needed to confirm these findings and to compare the long-term oncological outcomes and cost effectiveness of this modality. Video links: https://we.tl/t-rpkTHvNlXI or https://drive.google.com/drive/folders/1tOsFPrEBUHBpVn8C9jF7BGoNxlYPuBjq?usp=sharing.

Cavity Quantum Optomechanical Nonlinearities and Position Measurement beyond the Breakdown of the Linearized Approximation.

Several optomechanics experiments are now entering the highly sought nonlinear regime where optomechanical interactions are large even for low light levels. Within this regime, new quantum phenomena and improved performance may be achieved; however, a corresponding theoretical formalism of cavity quantum optomechanics that captures the nonlinearities of both the radiation-pressure interaction and the cavity response is needed to unlock these capabilities. Here, we develop such a nonlinear cavity quantum optomechanical framework, which we then utilize to propose how position measurement can be performed beyond the breakdown of the linearized approximation. Our proposal utilizes optical general-dyne detection, ranging from single to dual homodyne, to obtain mechanical position information imprinted onto both the optical amplitude and phase quadratures and enables both pulsed and continuous modes of operation. These cavity optomechanical nonlinearities are now being confronted in a growing number of experiments, and our framework will allow a range of advances to be made in, e.g., quantum metrology, explorations of the standard quantum limit, and quantum measurement and control.

Engineering Porous Silicon-Based Microcavity for Chemical Sensing.

In this article, the authors theoretically and experimentally investigated ways to improve the efficiency of porous silicon (PS)-based optical microcavity sensors as a 1D/2D host matrix for electronic tongue/nose systems. The transfer matrix method was used to compute reflectance spectra of structures with different [nLnH] sets of low nL and high nH bilayer refractive indexes, the cavity position λc, and the number of bilayers Nbi. Sensor structures were prepared by electrochemically etching a silicon wafer. The kinetics of adsorption/desorption processes of ethanol-water-based solution was monitored in real time with a reflectivity probe-based setup. It was theoretically and experimentally demonstrated that the sensitivity of the microcavity sensor is higher for structures with refractive indexes in the lower range (and the corresponding porosity values in the upper range). The sensitivity is also improved for structures with the optical cavity mode (λc) adjusted toward longer wavelengths. The sensitivity of a distributed Bragg reflector (DBR) with cavity increases for a structure with cavity position λc in the long wavelength region. The full width at half maximum (fwhmc) of the microcavity is smaller and the quality factor of microcavity (Qc) is higher for the DBR with a larger number of structure layers Nbi. The experimental results are in good agreement with the simulated data. We believe that our results can help in developing rapid, sensitive, and reversible electronic tongue/nose sensing devices based on a PS host matrix.