A surgical activity model of laparoscopic cholecystectomy for co-operation with collaborative robots.

BACKGROUND: Laparoscopic cholecystectomy is a very frequent surgical procedure. However, in an ageing society, less surgical staff will need to perform surgery on patients. Collaborative surgical robots (cobots) could address surgical staff shortages and workload. To achieve context-awareness for surgeon-robot collaboration, the intraoperative action workflow recognition is a key challenge. METHODS: A surgical process model was developed for intraoperative surgical activities including actor, instrument, action and target in laparoscopic cholecystectomy (excluding camera guidance). These activities, as well as instrument presence and surgical phases were annotated in videos of laparoscopic cholecystectomy performed on human patients (n = 10) and on explanted porcine livers (n = 10). The machine learning algorithm Distilled-Swin was trained on our own annotated dataset and the CholecT45 dataset. The validation of the model was conducted using a fivefold cross-validation approach. RESULTS: In total, 22,351 activities were annotated with a cumulative duration of 24.9 h of video segments. The machine learning algorithm trained and validated on our own dataset scored a mean average precision (mAP) of 25.7% and a top K = 5 accuracy of 85.3%. With training and validation on our dataset and CholecT45, the algorithm scored a mAP of 37.9%. CONCLUSIONS: An activity model was developed and applied for the fine-granular annotation of laparoscopic cholecystectomies in two surgical settings. A machine recognition algorithm trained on our own annotated dataset and CholecT45 achieved a higher performance than training only on CholecT45 and can recognize frequently occurring activities well, but not infrequent activities. The analysis of an annotated dataset allowed for the quantification of the potential of collaborative surgical robots to address the workload of surgical staff. If collaborative surgical robots could grasp and hold tissue, up to 83.5% of the assistant's tissue interacting tasks (i.e. excluding camera guidance) could be performed by robots.

Ensuring privacy protection in the era of big laparoscopic video data: development and validation of an inside outside discrimination algorithm (IODA).

BACKGROUND: Laparoscopic videos are increasingly being used for surgical artificial intelligence (AI) and big data analysis. The purpose of this study was to ensure data privacy in video recordings of laparoscopic surgery by censoring extraabdominal parts. An inside-outside-discrimination algorithm (IODA) was developed to ensure privacy protection while maximizing the remaining video data. METHODS: IODAs neural network architecture was based on a pretrained AlexNet augmented with a long-short-term-memory. The data set for algorithm training and testing contained a total of 100 laparoscopic surgery videos of 23 different operations with a total video length of 207 h (124 min ± 100 min per video) resulting in 18,507,217 frames (185,965 ± 149,718 frames per video). Each video frame was tagged either as abdominal cavity, trocar, operation site, outside for cleaning, or translucent trocar. For algorithm testing, a stratified fivefold cross-validation was used. RESULTS: The distribution of annotated classes were abdominal cavity 81.39%, trocar 1.39%, outside operation site 16.07%, outside for cleaning 1.08%, and translucent trocar 0.07%. Algorithm training on binary or all five classes showed similar excellent results for classifying outside frames with a mean F1-score of 0.96 ± 0.01 and 0.97 ± 0.01, sensitivity of 0.97 ± 0.02 and 0.0.97 ± 0.01, and a false positive rate of 0.99 ± 0.01 and 0.99 ± 0.01, respectively. CONCLUSION: IODA is able to discriminate between inside and outside with a high certainty. In particular, only a few outside frames are misclassified as inside and therefore at risk for privacy breach. The anonymized videos can be used for multi-centric development of surgical AI, quality management or educational purposes. In contrast to expensive commercial solutions, IODA is made open source and can be improved by the scientific community.

Ultracold neutron storage and transport at the PSI UCN source.

Efficient neutron transport is a key ingredient to the performance of ultracold neutron (UCN) sources, important to meeting the challenges placed by high precision fundamental physics experiments. At the Paul Scherrer Institute's UCN source we have been continuously improving our understanding of the UCN source parameters by performing a series of studies to characterize neutron production and moderation, and UCN production, extraction, and transport efficiency to the beamport. The present study on the absolute UCN transport efficiency completes our previous publications. We report on complementary measurements, namely one on the height-dependent UCN density and a second on the transmission of a calibrated quantity of UCN over a ∼ 16  m long UCN guide section connecting one beamport via the source storage vessel to another beamport. These allow us quantifying and optimizing the performance of the guide system based on extensive Monte Carlo simulations.

Data blinding for the nEDM experiment at PSI.

Psychological bias towards, or away from, prior measurements or theory predictions is an intrinsic threat to any data analysis. While various methods can be used to try to avoid such a bias, e.g. actively avoiding looking at the result, only data blinding is a traceable and trustworthy method that can circumvent the bias and convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment (nEDM), as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a false signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons within each measurement cycle. The flexible algorithm may be applied twice (or more) to the data, thus providing the option of sequentially applying various blinding offsets for separate analysis steps with independent teams. The subtle manner in which the data are modified allows one subsequently to adjust the algorithm and to produce a re-blinded data set without revealing the initial blinding offset. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable projects elsewhere.

Measurement of the Permanent Electric Dipole Moment of the Neutron.

We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons. Our measurement stands in the long history of EDM experiments probing physics violating time-reversal invariance. The salient features of this experiment were the use of a ^{199}Hg comagnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic-field changes. The statistical analysis was performed on blinded datasets by two separate groups, while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d_{n}=(0.0±1.1_{stat}±0.2_{sys})×10^{-26} e.cm.

Nisin incorporation enhances the inactivation of lactic acid bacteria during the acid wash step of bioethanol production from sugarcane juice.

Bioethanol fermentation is continuously exposed to contamination by Lactic Acid Bacteria (LAB). In this study, the effect of adding nisin (250 mg l-1 ) to the acid wash on the viability of five bacterial contaminants were evaluated both alone and in co-incubation with Saccharomyces cerevisiae. Additionally, fed-batch fermentation was performed using an acid or acid/nisin wash for S. cerevisiae alone and cocultured with the LAB strains. Parameters such as ethanol production, sugar consumption and lactic acid production were monitored. Four model LAB were more susceptible to the acid/nisin wash than the acid wash, and were most susceptible when incubated with yeast. A fifth model LAB was very sensitive to both treatments regardless of the presence of yeast. The addition of nisin to the acid wash lowered the required time for adequate washing and resulted in a higher ethanol production (54·5 ± 0·1 g l-1 ) than the acid wash alone (52·6 ± 0·1 g l-1 ) in a subsequent fermentation. These results indicate the potential benefits of supplementing with nisin to improve the acid wash step of bioethanol fermentations. SIGNIFICANCE AND IMPACT OF THE STUDY: Acid washing by the bioethanol fermentation industry reduces yeast efficiency and selects for contaminant bacteria that are resistant to acid treatments. This study demonstrates that the incorporation of nisin into the acid wash step results in a more potent removal of lactic acid bacteria while significantly shortening the length of time needed for the acid wash.

Observation of Gravitationally Induced Vertical Striation of Polarized Ultracold Neutrons by Spin-Echo Spectroscopy.

We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a |B0|=1 µT magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge of the ambient magnetic field provides an excellent method by which to reconstruct the energy spectrum of a confined ensemble of neutrons. The method takes advantage of the relative dephasing of spins arising from a gravitationally induced striation of stored UCNs of different energies, and also permits an improved determination of the vertical magnetic-field gradient with an exceptional accuracy of 1.1 pT/cm. This novel combination of a well-known nuclear resonance method and gravitationally induced vertical striation is unique in the realm of nuclear and particle physics and should prove to be invaluable for the assessment of systematic effects in precision experiments such as searches for an electric dipole moment of the neutron or the measurement of the neutron lifetime.

A large 'Active Magnetic Shield' for a high-precision experiment: nEDM collaboration.

We present a novel Active Magnetic Shield (AMS), designed and implemented for the n2EDM experiment at the Paul Scherrer Institute. The experiment will perform a high-sensitivity search for the electric dipole moment of the neutron. Magnetic-field stability and control is of key importance for n2EDM. A large, cubic, 5 m side length, magnetically shielded room (MSR) provides a passive, quasi-static shielding-factor of about 105 for its inner sensitive volume. The AMS consists of a system of eight complex, feedback-controlled compensation coils constructed on an irregular grid spanned on a volume of less than 1000 m3 around the MSR. The AMS is designed to provide a stable and uniform magnetic-field environment around the MSR, while being reasonably compact. The system can compensate static and variable magnetic fields up to ±50µT (homogeneous components) and ±5µT/m (first-order gradients), suppressing them to a few µT in the sub-Hertz frequency range. The presented design concept and implementation of the AMS fulfills the requirements of the n2EDM experiment and can be useful for other applications, where magnetically silent environments are important and spatial constraints inhibit simpler geometrical solutions.

The very large n2EDM magnetically shielded room with an exceptional performance for fundamental physics measurements.

We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute, which features an interior cubic volume with each side of length 2.92 m, thus providing an accessible space of 25 m3. The MSR has 87 openings of diameter up to 220 mm for operating the experimental apparatus inside and an intermediate space between the layers for housing sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1 m3 below 100 pT and a field below 600 pT in the entire inner volume, up to 4 cm to the walls. The quasi-static shielding factor at 0.01 Hz measured with a sinusoidal 2 µT peak-to-peak signal is about 100 000 in all three spatial directions and increases rapidly with frequency to reach 108 above 1 Hz.

The design of the n2EDM experiment: nEDM Collaboration.

We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.

Yeast Derived LysA2 Can Control Bacterial Contamination in Ethanol Fermentation.

Contamination of fuel-ethanol fermentations continues to be a significant problem for the corn and sugarcane-based ethanol industries. In particular, members of the Lactobacillaceae family are the primary bacteria of concern. Currently, antibiotics and acid washing are two major means of controlling contaminants. However, antibiotic use could lead to increased antibiotic resistance, and the acid wash step stresses the fermenting yeast and has limited effectiveness. Bacteriophage endolysins such as LysA2 are lytic enzymes with the potential to contribute as antimicrobials to the fuel ethanol industries. Our goal was to evaluate the potential of yeast-derived LysA2 as a means of controlling Lactobacillaceae contamination. LysA2 intracellularly produced by Pichia pastoris showed activity comparable to Escherichia coli produced LysA2. Lactic Acid Bacteria (LAB) with the A4α peptidoglycan chemotype (L-Lys-D-Asp crosslinkage) were the most sensitive to LysA2, though a few from that chemotype were insensitive. Pichia-expressed LysA2, both secreted and intracellularly produced, successfully improved ethanol productivity and yields in glucose (YPD60) and sucrose-based (sugarcane juice) ethanol fermentations in the presence of a LysA2 susceptible LAB contaminant. LysA2 secreting Sacharomyces cerevisiae did not notably improve production in sugarcane juice, but it did control bacterial contamination during fermentation in YPD60. Secretion of LysA2 by the fermenting yeast, or adding it in purified form, are promising alternative tools to control LAB contamination during ethanol fermentation. Endolysins with much broader lytic spectrums than LysA2 could supplement or replace the currently used antibiotics or the acidic wash.

Creative lysins: Listeria and the engineering of antimicrobial enzymes.

Cell wall lytic enzymes have been of increasing interest as antimicrobials for targeting Gram-positive spoilage and pathogenic bacteria, largely due to the development of strains resistant to antibiotics and bacteriophage therapy. Such lysins show considerable promise against Listeria monocytogenes, a primary concern in food-processing environments, but there is room for improvement via protein engineering. Advances in antilisterial applications could benefit from recent developments in lysin biotechnology that have largely targeted other organisms. Herein we present various considerations for the future development of lysins, including environmental factors, cell physiology concerns, and dynamics of protein architecture. Our goal is to review key developments in lysin biotechnology to provide a contextual framework for the current models of lysin-cell interactions and highlight key considerations for the characterization and design of novel lytic enzymes.

Magnetic Field Stabilization for Magnetically Shielded Volumes by External Field Coils.

For highly sensitive magnetic measurements, e.g., a measurement of the neutron electric dipole moment (EDM), the magnetic field has to be stable in time on a level below picoTesla. One of several measures we employ to achieve this uses an external field coil system which can stabilize the ambient external field at a predefined value. Here we report on the construction and characterization of such a system in the magnetic test facility at PSI. The system actively stabilizes the field along the axis of the EDM experiment by means of four coils in a Helmholtz-like configuration. Additional coils serve to compensate for transverse ambient field components. Because of the long integration times in the EDM experiment (about 100 s or more) only slow disturbances have to be corrected for. The performance of the system has been measured using static and moving magnetic sources and suppression factors in excess of 200 have been observed.

Investigation of Solid D 2 for UCN Sources.

Solid deuterium (sD2) will be used for the production of ultra-cold neutrons (UCN) in a new generation of UCN sources. Scattering cross sections of UCN in sD2 determine the source yield but until now have not been investigated. We report first results from transmission and scattering experiments with cold, very cold and ultra-cold neutrons on sD2 along with light transmission and Raman scattering studies showing the influence of the sD2 crystal properties.

Glycemic response in children with insulin-dependent diabetes mellitus after high- or low-glycemic-index breakfast.

To examine the effects of various carbohydrate foods on postprandial glycemia in diabetic children, we fed a mixed, isocaloric diet containing either high- or low-glycemic-index (GI) breakfast foods to 22 children with poorly controlled insulin-dependent diabetes mellitus (IDDM) and measured blood sugar response with and without adjustment of insulin doses. We found that IDDM children fed a high-GI meal showed a significantly higher serum glucose level than those fed a low-GI meal. However, such differences were not seen when the preprandial dose of regular insulin was adjusted to the amount of carbohydrate in feedings. Thus, as long as proper adjustment of insulin is made, the type of carbohydrate in a single mixed meal does not appear to have a significant effect on the postprandial glycemic response in children with long-standing poorly controlled IDDM.

Parental health beliefs as a cause of nonorganic failure to thrive.

Parental misconceptions and health beliefs concerning what constitutes a normal diet for infants is reported as a cause for failure to thrive. There were seven patients (four boys, three girls), 7 to 22 months of age, who were evaluated for poor weight gain and linear growth. They were only consuming 60% to 94% of the recommended caloric intake for age and sex. The children's caloric intake had been restricted by their parents. They were concerned that the children would become obese, develop atherosclerosis, become junk food dependent, and/or develop eating habits that the parents believed were unhealthy. The parents instituted diets consistent with health beliefs currently in vogue and recommended by the medical community for adults who are at risk for cardiovascular disease. These diets caused the infants to experience inadequate weight gain and have a decreased linear growth rate. With nutritional counseling, all food restrictions were removed, the caloric intake was increased to 94% to 147% of the recommended intake for age. The weight gain rate increased significantly (P less than .05) from 0.1 +/- 0.1 kg/mo to 0.4 +/- 0.3 kg/mo, and the linear growth rate increased significantly (P less than .05) from 0.4 +/- 0.4 cm/mo to 1.0 +/- 0.6 cm/mo within 3 months of therapy. Exaggerated concerns about excessive food intake in childhood and/or concern about the sequelae of eating an improper diet has resulted in this entity of failure to thrive due to parental health beliefs.

KARMEN time anomaly: search for a neutral particle of mass 33.9 MeV in pion decay

We have searched for the pion decay pi(+)-->&mgr;+X, where X is a neutral particle of mass 33.905 MeV. This process was suggested by the KARMEN Collaboration to explain an anomaly in their observed time distribution of neutrino induced reactions. Having measured the muon momentum spectrum of charged pions decaying in flight, we find no evidence for this process and place an upper limit on the branching fraction eta

Ferret mothers provide more anogenital licking to male offspring: possible contribution to psychosexual differentiation.

European ferret (Mustela putorius furo) mothers displayed significantly higher levels of anogenital licking (AGL) towards male as opposed to female kits in tests given on postpartum (P) days 6, 12, and 15. In these tests the entire litter was removed from the nestbox for 10 min, whereupon individual male and female kits were reintroduced to the mother in a counterbalanced order. In a second study an analysis of videotapes, sampled over the 24 h of several days, showed that mothers provided significantly more AGL to males than to females on P15, with a similar trend being observed on P1 and P8. This difference was no longer present on P22. In neither experiment was any sex difference observed in the amount of maternal licking of other (nonanogenital) body parts or in maternal carrying behavior received by kits. These results are comparable to those previously published for rat and gerbil, and further emphasize the possible contribution of sex differences in maternal stimulation, especially AGL, to the development of sexually dimorphic features of brain and behavioral development in different mammalian orders.

Reciprocal inhibition in the forearm during voluntary contraction and thinking about movement.

The regulatory mechanism for the interaction of agonist and antagonist muscles is not still clear. In these studies we investigated reciprocal inhibition during voluntary contraction and thinking about movement by using transcranial magnetic stimulation (TMS) and the H reflex technique. Magnetic stimuli, with intensities 10% above threshold, were delivered at the scalp under 3 experimental conditions; at rest, during voluntary isometric weak contraction and during thinking about movement. Surface EMG responses were taken from extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles in 14 normal subjects. Inhibitions of antagonist muscles induced by thinking about agonist movement occurred in 8 ECR and 10 FCR muscles, but most of them were not statistically significant. H reflexes were obtained from the FCR muscles in 10 normal subjects under the same conditions. Voluntary wrist extension and thinking about wrist extension produced inhibition of the H reflex in the FCR muscles. Reciprocal inhibition of antagonist muscles may occur at the cortical and spinal cord levels. The excitability of motoneurons has effects on the H reflex amplitude. Motor evoked potential (MEP) response to TMS might be affected by the combination of input from the motor cortex and the spinal cord. TMS may evoke simultaneous facilitatory and inhibitory volleys to antagonist muscles. This may explain why the inhibitions in the TMS study were weaker than those in the H reflex study.