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One of the bottlenecks to building semiconductor chips is the increasing cost required to develop chemical plasma processes that form the transistors and memory storage cells1,2. These processes are still developed manually using highly trained engineers searching for a combination of tool parameters that produces an acceptable result on the silicon wafer3. The challenge for computer algorithms is the availability of limited experimental data owing to the high cost of acquisition, making it difficult to form a predictive model with accuracy to the atomic scale. Here we study Bayesian optimization algorithms to investigate how artificial intelligence (AI) might decrease the cost of developing complex semiconductor chip processes. In particular, we create a controlled virtual process game to systematically benchmark the performance of humans and computers for the design of a semiconductor fabrication process. We find that human engineers excel in the early stages of development, whereas the algorithms are far more cost-efficient near the tight tolerances of the target. Furthermore, we show that a strategy using both human designers with high expertise and algorithms in a human first–computer last strategy can reduce the cost-to-target by half compared with only human designers. Finally, we highlight cultural challenges in partnering humans with computers that need to be addressed when introducing artificial intelligence in developing semiconductor processes.

Since advanced technologies were introduced into surgical education, a variety of new programs have been developed. However, a comprehensive review of digital education in general thoracic surgery has not been performed. This narrative review was conducted was to identify the current applications of digital education in general thoracic surgery.A literature search was performed using keywords related to general thoracic surgery and digital education, including e-learning and virtual simulation, up to September 2021. Studies published in English investigating the effect of digital education in general thoracic surgery were included.Thirteen studies met the criteria. The settings were in undergraduate (n = 6) and postgraduate education (residency) (n = 5) and mixed audience with other disciplines (n = 2). Theoretical knowledge (n = 5), technical skills (n = 4), and both knowledge and technical skills (n = 4) were the stated educational objectives for the studies. The didactic materials were transferred to hardware, software, or online platforms and delivered with multimedia materials. Technical skills training for bronchoscopy and chest tube insertion (n = 5) were offered using virtual reality and computer-based simulations. Subjective evaluation was done in 10 studies. Although after the digital education training there was observed improvement in knowledge or skills in 8 studies, studies were not designed to test for superiority compared with controls through randomized controlled studies.This review summarizes the current applications of digital education in general thoracic surgery and helps establish the needs for future studies in this field.

To advance the field of health sciences simulation, research must be of high quality and would benefit from multi-institutional collaboration where centres can leverage and share expertise as well as work together to overcome limits to the generalizability of research findings from single-institution studies. A needs assessment in emergency medicine simulation has illustrated the importance of identifying research priorities in Canada. The main purpose of this study was to identify simulation research priority directions for Canadian simulation centres. The current survey study drew on 16 research priorities developed through a two-round internal Delphi study at McGill University that 15 of 17 simulation centre advisory board members participated in. The final 16 research priorities were then rated by a total of 18 of 24 simulation centre directors and/or delegates contacted from 15 of 19 Royal College of Physicians and Surgeons of Canada-accredited simulation centres in Canada. Results revealed 9 common research priorities that reached 70% or higher agreement for all respondents. We anticipate that our findings can contribute to building a shared vision of priorities, community, and collaboration to enhance health care simulation research quality amongst Canadian simulation centres.

High-power infrared lasers are capable of sealing blood vessels during surgery. A real-time diagnostic feedback system utilizing diffuse optical transmission is characterized by nondestructive identification of vessel seals.For real-time diffuse optical transmission experiments, two approaches were studied. First, a low-power (1.2 mW) visible aiming beam (635 nm) was used for diagnostics, co-aligned with the therapeutic high-power infrared beam (1470 nm). Second, the 1470 nm beam was used simultaneously for both therapy and diagnostics. For both studies, the 1470-nm laser delivered 5 W for 5 seconds for unsuccessful seals (control) versus 30 W for 5 seconds for successful seals, using a linear beam profile (8.4 × 2 mm). Diffuse optical transmission signals were correlated with vessel burst pressures measured using a standard burst pressure setup.Diffuse optical transmission studies using the low-power, 635-nm aiming beam were promising. A decrease in the visible transmitted signal of 59 ± 11% was measured for successful seals versus 23 ± 8% for failed seals (p = 5.4E-8). The use of the high-power, 1470-nm infrared laser for simultaneous therapeutics and diagnostics proved inconsistent and unreliable, due in part to the dynamic and rapid changes in water content and absorption during the seal.A low-power, visible aiming beam, integrated with the therapeutic high-power infrared diode laser, may be used as a real-time diagnostic system for indicating successful laser seals, based on significant changes in optical scattering and diffuse optical transmission between native and coagulated compressed vessels. With further development, this simple and inexpensive optical feedback system may be integrated into a laparoscopic device for laser de-activation upon successful vessel sealing.

Background Telesimulation helps overcome limitations in time and local expertise by eliminating the need for the learner and educator to be physically co-located, especially important during COVID-19. We investigated whether teaching advanced laparoscopic suturing (ALS) through telesimulation is feasible, effective, and leads to improved suturing in the operating room (OR). Methods In this prospective feasibility study, three previously developed 3D-printed ALS tasks were used: needle handling (NH), suturing under tension (UT), and continuous suturing (CS). General surgery residents (PGY4-5) underwent 1-month of telesimulation training, during which an expert educator at one site remotely trained residents at the other site over 2–3 teaching sessions. Trainees were assessed in the three tasks and in the OR at three time points: baseline(A1), control period(A2), and post-intervention(A3) and completed questionnaires regarding educational value and usability of telesimulation. Paired t-test was used to compare scores between the three assessment points. Results Six residents were included. Scores for UT improved significantly post-intervention A3(568 ± 60) when compared to baseline A1(416 ± 133) (p

Background Surgical peer coaching has been associated with high rates of practice change but remains largely unutilized. The purpose of this study was to survey surgeons internationally to investigate attitudes regarding peer coaching and to identify any international differences to inform the design of future coaching programs. Methods Practicing surgeons in general surgery or related subspecialties were eligible to participate. Invitations to complete the survey were distributed through 13 surgical associations, social media, and personal e-mail invitations. Responses were obtained between June 1st and August 31st, 2020. Results A total of 521 surveys were collected. The majority of participants practiced in North America (263; 50%) with remaining respondents from Asia (81; 16%), Europe (34;7%), South America (21; 4%), Africa (17; 3%), and Oceania (6; 1%). Duration of practice was equally distributed across 4 intervals (0–5 years; 6–15 years; 16–25 years; > 25 years). Respondents most frequently identified as general surgeons (290; 67%) and 325 (75%) were male. Awareness of peer coaching was reported by 275 (53%) respondents, with 197 (44%) never seeking formal feedback from peers. The majority of respondents (372; 84%) would be willing to participate in a peer coaching program, with monthly interactions the most desirable frequency reported (193; 51%). Coaching in the operating room was preferred by most participants (360; 86%). Few respondents (67; 14%) would accept coaching from someone unknown to them. Participants identified key coaching program elements as: feedback kept private and confidential (267; 63%); opportunity to provide feedback to the coach (247; 59%); personalized goal setting (244; 58%); and the option to choose one’s own coach (205; 49%). The most commonly cited potential barrier to participation was logistical constraints (334; 79%). Conclusion This international survey of practicing surgeons demonstrated that peer feedback is rarely used in practice, but there is high interest and acceptance of the peer coaching model for continuous professional development. Findings regarding preferred program structure may be useful to inform the design of future peer coaching programs. Supplementary Information The online version contains supplementary material available at 10.1007/s00464-021-08760-z.

Infrared lasers may provide faster and more precise sealing of blood vessels and with lower jaw temperatures than ultrasonic and electrosurgical devices. This study explores an oscillating or reciprocating side-firing optical fiber method for transformation of a circular laser beam into a linear beam, necessary for integration into a standard 5-mm-diameter laparoscopic device, and for uniform irradiation perpendicular to the vessel length. A servo motor connected to a side-firing, 550-μm-core fiber, provided linear translation of a 2.0-mm-diameter circular beam over either 5 mm or 11 mm scan lengths for sealing small or large vessels, respectively. Laser seals were performed, ex vivo, on a total of 20 porcine renal arteries of 1–6 mm diameter (n = 10 samples for each scan length). Each vessel was compressed to a fixed 0.4-mm-thickness, matching the 1470-nm laser optical penetration depth. Vessels were irradiated with fluences ranging from 636 J/cm(2) to 716 J/cm(2). A standard burst pressure (BP) setup was used to evaluate vessel seal strength. The reciprocating fiber produced mean BP of 554 ± 142 and 524 ± 132 mmHg, respectively, and consistently sealing blood vessels, with all BP above hypertensive (180 mmHg) blood pressures. The reciprocating fiber provides a relatively uniform linear beam profile and aspect ratio, but will require integration of servo motor into a handpiece.

The overprescription of opioids to surgical patients is recognized as an important factor contributing to the opioid crisis. However, the value of prescribing opioid analgesia (OA) vs opioid-free analgesia (OFA) after postoperative discharge remains uncertain.To investigate the feasibility of conducting a full-scale randomized clinical trial (RCT) to assess the comparative effectiveness of OA vs OFA after outpatient general surgery.This parallel, 2-group, assessor-blind, pragmatic pilot RCT was conducted from January 29 to September 3, 2020 (last follow-up on October 2, 2020). at 2 university-affiliated hospitals in Montreal, Quebec, Canada. Participants were adult patients (aged ≥18 years) undergoing outpatient abdominal (ie, cholecystectomy, appendectomy, or hernia repair) or breast (ie, partial or total mastectomy) general surgical procedures. Exclusion criteria were contraindications to drugs used in the trial, preoperative opioid use, conditions that could affect assessment of outcomes, and intraoperative or early complications requiring hospitalization.Patients were randomized 1:1 to receive OA (around-the-clock nonopioids and opioids for breakthrough pain) or OFA (around-the-clock nonopioids with increasing doses and/or addition of nonopioid medications for breakthrough pain) after postoperative discharge.Main outcomes were a priori RCT feasibility criteria (ie, rates of surgeon agreement, patient eligibility, patient consent, treatment adherence, loss to follow-up, and missing follow-up data). Secondary outcomes included pain intensity and interference, analgesic intake, 30-day unplanned health care use, and adverse events. Between-group comparison of outcomes followed the intention-to-treat principle.A total of 15 surgeons were approached; all (100%; 95% CI, 78%-100%) agreed to have patients recruited and adhered to the study procedures. Rates of patient eligibility and consent were 73% (95% CI, 66%-78%) and 57% (95% CI, 49%-65%), respectively. Seventy-six patients were randomized (39 [51%] to OA and 37 [49%] to OFA) and included in the intention-to-treat analysis (mean [SD] age, 55.5 [14.5] years; 50 [66%] female); 40 (53%) underwent abdominal surgery, and 36 (47%) underwent breast surgery. Seventy-five patients (99%; 95% CI, 93%-100%) adhered to the allocated treatment; 1 patient randomly assigned to OFA received an opioid prescription. Seventeen patients (44%) randomly assigned to OA consumed opioids after discharge. Seventy-three patients (96%; 95% CI, 89%-99%) completed the 30-day follow-up. The rate of missing questionnaires was 37 of 3724 (1%; 95% CI, 0.7%-1.4%). All the a priori RCT feasibility criteria were fulfilled.The findings of this pilot RCT support the feasibility of conducting a robust, full-scale RCT to inform evidence-based prescribing of analgesia after outpatient general surgery.ClinicalTrials.gov Identifier: NCT04254679.

Increased stressful experiences are pervasive among healthcare providers (HCPs) during the COVID-19 pandemic. Identifying resources that help mitigate stress is critical to maintaining HCPs’ well-being. However, to our knowledge, no instrument has systematically examined how different levels of resources help HCPs cope with stress during COVID-19. This cross-sectional study involved 119 HCPs (64 nurses and 55 physicians) and evaluated the perceived availability, utilization, and helpfulness of a list of personal, hospital, and healthcare system resources. Participants also reported on their level of burnout, psychological distress, and intentions to quit. Results revealed that HCPs perceived the most useful personal resource to be family support; the most useful hospital resources were a safe environment, personal protective equipment, and support from colleagues; the most useful system resources were job protection, and clear communication and information about COVID. Moreover, HCPs who perceived having more available hospital resources also reported lower levels of psychological distress symptoms, burnout, and intentions to quit. Finally, although training and counseling services were perceived as useful to reduce stress, training was not perceived as widely available, and counseling services, though reported as being available, were underutilized. This instrument helps identify resources that support HCPs, providing implications for healthcare management.

Infrared (IR) lasers have recently been tested as an alternative to electrosurgical and ultrasonic laparoscopic devices for optical sealing of blood vessels. IR laser technology previously demonstrated faster sealing times, reduced thermal spread, and lower device temperatures during experimental studies. However, current commercial laparoscopic devices incorporate electrical impedance and/or temperature sensors as real-time, closed-loop, feedback to indicate successful blood vessel seals. This preliminary study explores an infrared laser system for sealing and optical coherence tomography (OCT) as a potential feedback system for successful vessel seal verification. A 1470-nm diode laser delivered an incident power of 30 W for an irradiation time of 5 s using an 8 × 2 mm linear beam, for creating strong seals in porcine renal blood vessels under compression. After sealing the blood vessels, OCT was performed on unsealed and sealed vessel regions for comparison. Standard vessel burst pressure (BP) measurements confirmed successful seals after OCT. Integrated reflectance intensity in OCT A-scans decreased by an average of 20 ± 6% in sealed versus native vessels of 2.4 ± 0.4 mm diameter. Vessel BP measured 532 ± 239 mmHg, with all vessels (n = 25) recording a successful BP > 180 mmHg (hypertensive blood pressure). Unsealed vessels demonstrated significantly deeper imaging marked by a continuous decay in reflected intensity, while sealed vessels showed subsurface reflectance intensity peaks, immediately followed by a rapid decay in reflectance intensity. These markers are consistent with increased light scattering and decreased optical penetration depth upon thermal coagulation of tissues. A-line OCT data consistently differentiated between sealed and unsealed blood vessel regions. Future work will involve OCT integration into the laparoscopic device for real-time optical feedback during IR laser sealing.

High-power infrared (IR) diode lasers are capable of sealing blood vessels during surgery. This study characterizes an optical feedback system for real-time, nondestructive identification of vessel seals. A low power, red aiming beam (635 nm) was used for diagnostics, co-aligned with a therapeutic high-power IR beam (1470 nm). The IR laser delivered either 30 W for 5 s for successful seals or 5 W for 5 s for unsuccessful seals (control). All studies used a linear beam measuring 8.4 × 2.0 mm. Optical signals for successful and failed seals were correlated with vessel burst pressures (BP) using destructive testing via a standard BP setup. Light scattering increased significantly as vessels were coagulated. Successful seals correlated with a percent decrease in optical transmission signal of 59 ± 11 % and seal failures to a transmission decrease of 23 ± 8% (p < 0.01). With further development, the real-time optical feedback system may be integrated into a laparoscopic device to de-activate the laser upon successful vessel sealing.

Infrared lasers may provide faster sealing of vascular tissues with less collateral thermal damage and lower device temperatures than radiofrequency and ultrasonic devices currently used for surgery. Optical coherence tomography is tested to image native and thermally coagulated blood vessels, as a potential feedback system.

An edited version of this paper was published by AGU. Copyright 2019 American Geophysical Union.

During the period 2005-2014, S&P 500 firms distributed to shareholders more than $3.95 trillion via stock buybacks and $2.45 trillion via dividends — $6.4 trillion in total. These shareholder payouts amounted to over 93% of the firms' net income. Academics, corporate lawyers, asset managers, and politicians point to such shareholder-payout figures as compelling evidence that “short-termism" and “quarterly capitalism" are impairing firms' ability to invest, innovate, and provide good wages.We explain why S&P 500 shareholder-payout figures provide a misleadingly incomplete picture of corporate capital flows and the financial capacity of U.S. public firms. Most importantly, they fail to account for offsetting equity issuances by firms. We show that, taking into account issuances, net shareholder payouts by all U.S. public firms during the period 2005-2014 were in fact only about $2.50 trillion, or 33% of their net income. Moreover, much of these net shareholder payouts were offset by net debt issuances, and thus effectively recapitalizations rather than firm-shrinking distributions. After excluding marginal debt capital inflows, net shareholder payouts by public firms during the period 2005-2014 were only about 22% of their net income. In short, S&P 500 shareholder-payout figures are not indicative of actual capital flows in public firms, and thus cannot provide much basis for the claim that short-termism is starving public firms of needed capital. We also offer three other reasons why corporate capital flows are unlikely to pose a problem for the economy.A prior version of this paper was circulated under the title “Short-Termism and Shareholder Payouts: Getting Corporate Capital Flows Right."

Blood vessel burst pressures were simulated and predicted for sealing and cutting of vessels in a two-step process, using low (

A 1470-nm laser previously demonstrated faster sealing and cutting of blood vessels with lower thermal spread than radiofrequency and ultrasonic surgical devices. This study simulates laser sealing and cutting of vessels in a sequential two-step process, for low (< 25 W), medium (~ 100 W), and high (200 W) power lasers. Optical transport, heat transfer, and tissue damage simulations were conducted. The blood vessel was assumed to be compressed to 400 μm thickness, matching previous experimental studies. A wide range of linear beam profiles (1-5 mm widths and 8-9.5 mm lengths), incident powers (20-200 W) and irradiation times (0.5-5.0 s), were simulated. Peak seal and cut temperatures and bifurcated thermal seal zones were also simulated and compared with experimental results for model validation. Optimal low power laser parameters were: 24W/5s/8x2mm for sealing and 24W/5s/8x1mm for cutting, yielding thermal spread of 0.4 mm and corresponding to experimental vessel burst pressures (BP) of ~450 mmHg. Optimal medium-power laser parameters were: 90 W/1s/9.5x3mm for sealing and 90W/1s/9.5x1mm for cutting, yielding thermal spread of 0.9 mm for BP of ~1300 mmHg. Optimal high-power laser parameters were: 200W/0.5s/9x3mm for sealing and 200W/0.5s/9x1mm for cutting, yielding thermal spread of 0.9 mm and extrapolated to have BP of ~1300 mmHg. All lasers produced seal zones between 0.4-1.5 mm, correlating to high BP of 300-1300 mmHg. Higher laser powers enable shorter sealing and cutting times and higher vessel seal strengths.

Significance: Water is a primary absorber of infrared (IR) laser energy, and urinary stones are immersed in fluid in the urinary tract and irrigated with saline during IR laser lithotripsy. Laser-induced vapor bubbles, formed during lithotripsy, contribute to the stone ablation mechanism and stone retropulsion effects. Aim: Introduction of a surfactant may enable manipulation of vapor bubble dimensions and duration, potentially for more efficient laser lithotripsy. Approach: A surfactant with concentrations of 0%, 5%, and 10% was tested. A single pulse from a thulium fiber laser with wavelength of 1940 nm was delivered to the surfactant through a 200-μm-core optical fiber, using a wide range of laser parameters, including energies of 0.05 to 0.5 J and pulse durations of 250 to 2500 μs. Results: Bubble length, width, and duration with surfactant increased on average by 29%, 17%, and 120%, compared with water only. Conclusions: Our study demonstrated successful manipulation of laser-induced vapor bubble dimensions and duration using a biocompatible and commercially available surfactant. With further study, use of a surfactant may potentially improve the “popcorn” technique of laser lithotripsy within the confined space of the kidney, enable non-contact laser lithotripsy at longer working distances, and provide more efficient laser lithotripsy.

AI is becoming ubiquitous, revolutionizing many aspects of our lives. In surgery, it is still a promise. AI has the potential to improve surgeon performance and impact patient care, from post-operative debrief to real-time decision support. But, how much data is needed by an AI-based system to learn surgical context with high fidelity? To answer this question, we leveraged a large-scale, diverse, cholecystectomy video dataset. We assessed surgical workflow recognition and report a deep learning system, that not only detects surgical phases, but does so with high accuracy and is able to generalize to new settings and unseen medical centers. Our findings provide a solid foundation for translating AI applications from research to practice, ushering in a new era of surgical intelligence.

Surgery is defined as the branch of medicine concerned with the treatment of disease, injury, and deformity by operation or manipulation. (Stedman’s Medical Dictionary, 28th edition).

Background/Introduction Obesity is an important risk factor associated with poor cardiovascular and metabolic outcomes. Dietary, medical, and surgical weight loss strategies are often unsuccessful, unsustainable or accompanied by risks. Pre-clinical and early case series reported that transcatheter bariatric embolotherapy (TBE) of the left gastric artery reduces weight, by reducing “hunger” hormones from the gastric fundus. We studied TBE in a double-blind, sham procedure, first in human RCT of patients (pts) with obesity, and following completion of the initial study we asked subjects to return after 2 years post-embolization for further evaluation. Purpose The purpose of this extension study was to assess the long-term weight loss and other outcomes in subjects who underwent TBE for weight loss. Methods In the initial RCT subjects were randomized 1:1 to either a Sham (skin nick & 1 hr wait) or TBE following IV Propofol sedation. All pts received Lifestyle Therapy (behavioral and diet education); these staff following the pts were also blinded to treatment. Subjects completed the initial study when reaching the 1 year-follow-up visit. Subjects were then invited to return to the weight loss clinic at 2 years post-embolization for further evaluation on weight loss, blood pressure, pre-diabetic clinical status, satiety, and quality of life. Results A total of 44 pts (age 45.5±9.8; 36/8 M/F; BMI 39.6±3.8) were enrolled, of which 40 pts were randomized equally to groups, with no major complications. Mild, transient epigastric pain was seen, but EGDs showed no major abnormalities. Weight loss was improved with TBE by 6 mo, and maintained over the full 12 mo by both intention-to-treat and per-protocol analyses. At 2 years post-embolization, subjects treated with TBE demonstrated a mean 9% TBWL and 25% EBWL. Conclusion(s) Bariatric embolization is safe and when used along with lifestyle therapy, results in clinically significant weight loss. Long-term data demonstrates evidence that subjects treated with TBE continue to maintain their weight loss up to 2 years post-treatment. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Endobar Solutions LLC

Background/Introduction Obesity and its comorbid conditions (i.e. type II diabetes mellitus, atrial fibrillation, coronary artery disease, hypertension, etc...) is a growing burden globally, however, the current treatments (i.e. bariatric surgery, intragasrtic balloons and/or pharmaceutical therapy) pose substantial risks or are contraindicated for various populations. Transcatheter bariatric embolotherapy of left gastric artery by reducing “hunger” hormones from the gastric fundus is a procedure for weight loss that has been growing in prominence over the last several years, however, to date no randomized-controlled trial has been conducted until our study. We studied TBE in a double-blind, sham procedure, first in human RCT of patients (pts) with obesity. Purpose The purpose of this study was to assess the safety and efficacy of TBE for weight loss in obese patients as well as to evaluate metabolic changes. Methods After IV propofol, eligible pts (age 21–60; BMI 35–50 kg/m2) were randomized 1:1 to Sham (skin nick & 1 hr wait) or TBE. All pts received Lifestyle Therapy (behavioral and diet education). Study staff following the pts were also blinded to treatment. Blood samples for gastrointestinal hormones were collected in EDTA tubes containing a protease inhibitor cocktail and frozen per local laboratory standards. All collected samples were assessed together in two batches at the end of the study. The hormones analyzed included ghrelin, GIP, GLP-1, Visfatin, resistin, PAI-1 (total), Leptin, and C-Peptide. An Oral Glucose Tolerance Test (OGTT) and a diabetes assay was performed at baseline and at 6- and 12-months post-intervention. Note, while diabetes was an exclusion criterion for this study, pre-diabetes was not. Results 44 pts were enrolled, of which 40 pts were randomized equally to the groups, with no major complications in either group. TBE demonstrated superior weight loss over the control group at 6- and 12-months post-intervention in both intention-to-treat and per-protocol analyses. At 6 and 12 months, the TBE group demonstrated a clinically meaningful decrease in glucose 1-hour post-fasting by OGTT. GIP levels in the TBE group increased at a mean of 21%, indicative of an improvement in pre-diabetic milieu. Circulating plasma visfatin levels decreased 20% at 6 months and 26% at 12 months in the TBE group indicating a decrease in body fat. C-Peptide levels were noticeably increased in the TBE group at 6 months possibly indicating improvements in insulin sensitivity and beta-cell function. Conclusion(s) TBE is safe and results in clinically significant weight loss and demonstrated a positive effect on glucose homeostasis in pre-diabetic patients. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Endobar Solutions, LLC

Suture ligation of vascular tissues is slow and skill intensive. Ultrasonic (US) and radiofrequency (RF) devices enable more rapid vascular tissue ligation to maintain hemostasis, than sutures and mechanical clips, which leave foreign objects in the body and require exchange of instruments. However, US and RF devices are limited by excessive collateral thermal damage to adjacent tissues, and high jaw temperatures that require a long time to cool. A novel alternative method using infrared (IR) laser energy is being developed for more rapid and precise sealing of vessels. This study describes design, modeling, and initial testing of several optical beam shaping geometries for integration into the standard jaws of a laparoscopic device. The objective was to transform the circular laser beam into a linear beam, for uniform, cross-irradiation and sealing of blood vessels. Cylindrical mirrors organized in a staircase geometry provided the best spatial beam profile.Clinical Relevance—This study explored several optical designs for potential integration into the standard jaws of a laparoscopic vessel sealing device, transforming a circular laser beam into a linear beam for sealing of vascular structures.

Using previously described functional techniques for some non--perturbative, gauge invariant, renormalized QCD processes, a simplified version of the amplitudes --- in which forms akin to Pomerons naturally appear --- provides fits to ISR and LHC--TOTEM $pp$ elastic scattering data. Those amplitudes rely on a specific function $\varphi (\vec b)$ which describes the fluctuations of the transverse position of quarks inside hadrons., Comment: 23 pages, 12 figures. arXiv admin note: text overlap with arXiv:1611.02691

At tidewater glaciers, plume dynamics affect submarine melting, fjord circulation, and the mixing of meltwater. Models often rely on buoyant plume theory to parameterize plumes and submarine melting; however, these parameterizations are largely untested due to a dearth of near-glacier measurements. Here, we present a high-resolution ocean survey by ship and remotely-operated boat near the terminus of Kangerlussuup Sermia in west Greenland. These novel observations reveal the 3D structure and transport of a near-surface plume, originating at a large undercut conduit in the glacier terminus, that is inconsistent with axisymmetric plume theory, the most common representation of plumes in ocean-glacier models. Instead, the observations suggest a wider upwelling plume – a ‘truncated’ line plume of ∼200 m width – with higher entrainment and plume-driven melt compared to the typical axisymmetric representation. Our results highlight the importance of a subglacial outlet's geometry in controlling plume dynamics, with implications for parameterizing the exchange flow and submarine melt in glacial fjord models.

Over 6.5 million women in the United States suffer from female stress urinary incontinence (SUI). Only ~200,000 women choose surgery. There may be a role for a non-surgical, minimally invasive procedure that provides thermal shrinkage/remodeling of submucosal collagen in the endopelvic fascia. This study describes design, characterization, and preliminary testing of a novel probe with integrated contact cooling for potential use in transvaginal laser treatment of SUI. Laser energy at a deeply penetrating, near-infrared wavelength of 1075 nm was delivered through a 600-μm-core fiber optic patchcord into a 90° side-firing probe head (19 × 22 mm) with integrated flow cell and sapphire window cooled to −2°C by circulating an alcohol-based solution. An inflatable balloon attached to the probe insured contact with vaginal wall. A force sensor and thermocouples monitored pressure and temperature. Thermal lesions were created in vaginal tissue of three cadavers (power = 4.6–6.4 W; spot diameter = 5.2 mm; time = 30 s). Thermal lesion areas measured 3.1–4.6 mm(2), while preserving the vaginal wall to a depth of 0.8–1.1 mm. Consistent tissue contact and cooling was maintained using the force sensors. Preliminary cadaver studies demonstrated subsurface treatment of endopelvic fascia with partial preservation of the vaginal wall. Future studies will optimize parameters for thermal remodeling with further tissue surface preservation.

Background and Objectives A non-surgical method is being developed for treating female stress urinary incontinence by laser thermal remodeling of subsurface tissues with applied surface tissue cooling. Computer simulations of light transport, heat transfer, and thermal damage in tissue were performed, comparing transvaginal and transurethral approaches. Study Design/Materials and Methods Monte Carlo (MC) simulations provided spatial distributions of absorbed photons in the tissue layers (vaginal wall, endopelvic fascia, and urethral wall). Optical properties (n,μa,μs,g) were assigned to each tissue at λ = 1064 nm. A 5-mm-diameter laser beam and incident power of 5 W for 15 seconds was used, based on previous experiments. MC output was converted into absorbed energy, serving as input for finite element heat transfer simulations of tissue temperatures over time. Convective heat transfer was simulated with contact probe cooling temperature set at 0°C. Variables used for thermal simulations (κ,c,ρ) were assigned to each tissue layer. MATLAB code was used for Arrhenius integral thermal damage calculations. A temperature matrix was constructed from ANSYS output, and finite sum was incorporated to approximate Arrhenius integral calculations. Tissue damage properties (Ea,A) were used to compute Arrhenius sums. Results For the transvaginal approach, 37% of energy was absorbed in the endopelvic fascia target layer with 0.8% deposited beyond it. Peak temperature was 71°C, the treatment zone was 0.8-mm-diameter, and 2.4 mm of the 2.7-mm-thick vaginal wall was preserved. For transurethral approach, 18% energy was absorbed in endopelvic fascia with 0.3% deposited beyond the layer. Peak temperature was 80°C, treatment zone was 2.0-mm-diameter, and 0.6 mm of 2.4-mm-thick urethral wall was preserved. Conclusions Computer simulations suggest that transvaginal approach is more feasible than transurethral approach. Lasers Surg. Med. © 2016 Wiley Periodicals, Inc.

Previous studies have shown that reflectance imaging at wavelengths greater than 1200-nm can be used to image demineralization on tooth occlusal surfaces with high contrast and without the interference of stains. In addition, these near-IR imaging systems can be integrated with laser ablation systems for the selective removal of carious lesions. Higher wavelengths, such as 1950-nm, yield higher lesion contrast due to higher water absorption and lower scattering. In this study, a point-to-point scanning system employing diode and fiber lasers operating at 1450, 1860, 1880, and 1950-nm was used to acquire reflected light images of the tooth surface. Artificial lesions were imaged at these wavelengths to determine the highest lesion contrast. Near-IR images at 1880-nm were used to demarcate lesion areas for subsequent selective carious lesion removal using a new compact air-cooled CO2 laser prototype operating at 9.3-µm. The highest lesion contrast was at 1950-nm and the dual NIR/CO2 laser system selectively removed the simulated lesions with a mean loss of only 12-µm of sound enamel.

Zusammenfassung: Nausea und Erbrechen sind häufig. Sie können eine physiologische Antwort auf ein exogenes Toxin sein, aber auch Ausdruck einer organischen, psychischen oder funktionellen Erkrankung. Trotz der Fülle der Differenzialdiagnose gelingt es meist durch sorgfältige Anamnese und wenige Untersuchungen, den Auslöser zu finden. Die Ursachen akuter Beschwerden unterscheiden sich teilweise von denen chronischer. Bei Frauen im gebärfähigen Alter ist eine Schwangerschaft auszuschließen. Eine symptomatische Therapie kann bereits zu Beginn eingeleitet werden. Die Klärung chronischer Ursachen ist schwieriger. Funktionstests wie die Messung der Magenentleerung ergänzen die Diagnostik. Sie sollen nur in spezialisierten Zentren mit entsprechender Erfahrung durchgeführt werden. Ruminieren und Regurgitation sind von Erbrechen abzugrenzen. Findet sich keine Ursache für die Beschwerden, kann von einer funktionellen Erkrankung ausgegangen werden

Background: Despite widespread implementation of policies to address mistreatment, the proportion of medical students who experience mistreatment during clinical training is significantly higher than the proportion of students who report mistreatment. Understanding barriers to reporting mistreatment from students’ perspectives is needed before effective interventions can be implemented to improve the clinical learning environment. Objective: We explored medical students’ reasons for not reporting perceived mistreatment or abuse experienced during clinical clerkships at the David Geffen School of Medicine at UCLA (DGSOM). Design: This was a sequential two-phase qualitative study. In the first phase, we analyzed institutional survey responses to an open-ended questionnaire administered to the DGSOM graduating classes of 2013–2015 asking why students who experienced mistreatment did not seek help or report incidents. In the second phase, we conducted focus group interviews with third- and fourth-year medical students to explore their reasons for not reporting mistreatment. In total, 30 of 362 eligible students participated in five focus groups. On the whole, 63% of focus group participants felt they had experienced mistreatment, of which over half chose not to report to any member of the medical school administration. Transcripts were analyzed via inductive thematic analysis. Results: The following major themes emerged: fear of reprisal even in the setting of anonymity; perception that medical culture includes mistreatment; difficulty reporting more subtle forms of mistreatment; incident is not important enough to report; reporting process damages the student–teacher relationship; reporting process is too troublesome; and empathy with the source of mistreatment. Differing perceptions arose as students debated whether or not reporting was beneficial to the clinical learning environment. Conclusions: Multiple complex factors deeply rooted in the culture of medicine, along with negative connotations associated with reporting, prevent students from reporting incidents of mistreatment. Further research is needed to establish interventions that will help identify mistreatment and change the underlying culture.

Previous studies have shown that reflectance imaging at wavelengths greater than 1200-nm can be used to image demineralization on tooth occlusal surfaces with high contrast and without the interference of stains. In addition, these near-IR imaging systems can be integrated with laser ablation systems for the selective removal of carious lesions. Higher wavelengths, such as 1950-nm, yield higher lesion contrast due to higher water absorption and lower scattering. In this study, a point-to-point scanning system employing diode and fiber lasers operating at 1450, 1860, 1880, and 1950-nm was used to acquire reflected light images of the tooth surface. Artificial lesions were imaged at these wavelengths to determine the highest lesion contrast. Near-IR images at 1880-nm were used to demarcate lesion areas for subsequent selective carious lesion removal using a new compact air-cooled CO2 laser prototype operating at 9.3-μm. The highest lesion contrast was at 1950-nm and the dual NIR/CO2 laser system selectively removed the simulated lesions with a mean loss of only 12-μm of sound enamel.

A nonsurgical laser procedure is being developed for treatment of female stress urinary incontinence (SUI). Previous studies in porcine vaginal tissues, ex vivo, as well as computer simulations, showed the feasibility of using near-infrared laser energy delivered through a transvaginal contact cooling probe to thermally remodel endopelvic fascia, while preserving the vaginal wall from thermal damage. This study explores optical properties of vaginal tissue in cadavers as an intermediate step towards future pre-clinical and clinical studies. Optical clearing of tissue using glycerol resulted in a 15–17% increase in optical transmission after 11 min at room temperature (and a calculated 32.5% increase at body temperature). Subsurface thermal lesions were created using power of 4.6 – 6.4 W, 5.2-mm spot, and 30 s irradiation time, resulting in partial preservation of vaginal wall to 0.8 – 1.1 mm depth.

The fermionic Green’s functions of QCD exhibit an unexpected property of effective locality, which appears to be exact, involving no approximation. This property is nonperturbative, resulting from a full integration of the elementary gluonic degrees of freedom of QCD. Recalling, correcting, and extending the derivations of effective locality, focus is put on the way nonabelian gauge invariance gets realized in the fermionic nonperturbative regime of QCD.