Are You Wearing a Mask? Detecting If a Person Wears a Mask Using a Wristband.

Coronavirus 2019 (COVID-19) has posed a serious threat to the lives and health of the majority of people worldwide. Since the early days of the outbreak, South Korea's government and citizens have made persistent efforts to provide effective prevention against further spread of the disease. In particular, the participation of individual citizens in complying with the necessary code of conduct to prevent spread of the infection, through measures such as social distancing and mask wearing, is as instrumental as the geographical tracking of the trajectory of the infected. In this paper, we propose an activity recognition method based on a wristband equipped with an IR array and inertial measurement unit (IMU) to detect individual compliance with codes of personal hygiene management, such as mask wearing, which are recommended to prevent the spread of infectious diseases. The results of activity recognition were comparatively analyzed by applying conventional machine learning algorithms and convolutional neural networks (CNNs) to the IMU time series and IR array thermal images collected from 25 subjects. When CNN and 24 × 32 thermal images were used, 97.8% accuracy was achieved (best performance), and when 6 × 8 low-resolution thermal images were used, similar performance with 97.1% accuracy was obtained. In the case of using IMU, the performance of activity recognition was lower than that obtained with the IR array, but an accuracy of 93% was achieved even in the case of applying machine learning algorithms, indicating that it is more suitable for wearable devices with low computational capability.

Entanglement distribution in the quantum symmetric simple exclusion process.

We study the probability distribution of entanglement in the quantum symmetric simple exclusion process, a model of fermions hopping with random Brownian amplitudes between neighboring sites. We consider a protocol where the system is initialized in a pure product state of M particles, and we focus on the late-time distribution of Rényi-q entropies for a subsystem of size ℓ. By means of a Coulomb gas approach from random matrix theory, we compute analytically the large-deviation function of the entropy in the thermodynamic limit. For q>1, we show that, depending on the value of the ratio ℓ/M, the entropy distribution displays either two or three distinct regimes, ranging from low to high entanglement. These are connected by points where the probability density features singularities in its third derivative, which can be understood in terms of a transition in the corresponding charge density of the Coulomb gas. Our analytic results are supported by numerical Monte Carlo simulations.

Consequences of Extended Spectrum Beta-Lactamase-Producing Enterobacteriaceae and Methicillin-Resistant Staphylococcus aureus Carriage in Awaiting Liver Transplant Patients.

Infections in patients with cirrhosis are associated with liver-related complications (LRCs), especially in patients awaiting liver transplantation (LT). The aim of this study was to evaluate the impact of methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamase colonization on infections and LRCs for patients on the wait list and on infections after LT. We retrospectively included 250 of 483 patients with cirrhosis who were placed on the wait list for LT from December 2015 to January 2018. These patients were screened for MRSA or extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBLE) at the time of wait-list placement and after LT. Of the patients, 76% were male with a mean age of 57.5 ± 10 years, and the most frequent cause of liver disease was alcohol (39%). Median Model for End-Stage Liver Disease (MELD) score was 19 (12-28). Only 1 patient was positive for MRSA; 19% of patients (n = 47) had ESBLE fecal carriage at the time of wait-list placement and 15% (n = 37) had it after LT. Infection-free survival on the wait list and after LT, according to fecal carriage status, was not statistically different between 2 groups. LRC-free survival at 6 and 12 months was significantly lower in ESBLE fecal carriage (HR, 1.6; P = 0.04). MELD score >19 (HR, 3.0; P = 0.01) and occurrence of infection during the first 3 months on the wait list (HR, 4.13; P < 0.001) were independent risk factors for LRC occurrence in the multivariate analysis. Our study is the first showing that in a cohort of patients with cirrhosis waiting for LT LRC-free survival was lower in patients with ESBLE fecal carriage but that infection-free survival was not different between the 2 groups.

From Stochastic Spin Chains to Quantum Kardar-Parisi-Zhang Dynamics.

We introduce the asymmetric extension of the quantum symmetric simple exclusion process which is a stochastic model of fermions on a lattice hopping with random amplitudes. In this setting, we analytically show that the time-integrated current of fermions defines a height field that exhibits quantum nonlinear stochastic Kardar-Parisi-Zhang dynamics. Similarly to classical simple exclusion processes, we further introduce the discrete Cole-Hopf (or Gärtner) transform of the height field that satisfies a quantum version of the stochastic heat equation. Finally, we investigate the limit of the height field theory in the continuum under the celebrated Kardar-Parisi-Zhang scaling and the regime of almost-commuting quantum noise.

Universal fluctuations around typicality for quantum ergodic systems.

For a quantum system in a macroscopically large volume V, prepared in a pure state and subject to maximally noisy or ergodic unitary dynamics, the reduced density matrix of any sub-system v≪V is almost surely totally mixed. We show that the fluctuations around this limiting value, evaluated according to the invariant measure of these unitary flows, are captured by the Gaussian unitary ensemble (GUE) of random matrix theory. An extension of this statement, applicable when the unitary transformations conserve the energy but are maximally noisy or ergodic on any energy shell, allows to decipher the fluctuations around canonical typicality. According to typicality, if the large system is prepared in a generic pure state in a given energy shell, the reduced density matrix of the sub-system is almost surely the canonical Gibbs state of that sub-system. We show that the fluctuations around the Gibbs state are encoded in a deformation of the GUE whose covariance is specified by the Gibbs state. Contact with the eigenstate thermalization hypothesis is discussed.

Open Quantum Symmetric Simple Exclusion Process.

We present the solution to a model of fermions hopping between neighboring sites on a line with random Brownian amplitudes and open boundary conditions driving the system out of equilibrium. The average dynamics reduces to that of the symmetric simple exclusion process. However, the full distribution encodes for a richer behavior, entailing fluctuating quantum coherences which survive in the steady limit. We determine exactly the steady statistical distribution of the system state. We show that the out-of-equilibrium quantum coherence fluctuations satisfy a large-deviation principle, and we present a method to recursively compute exactly the large-deviation function. As a by-product, our approach gives a solution of the classical symmetric simple exclusion process based on fermion technology. Our results open the route towards the extension of the macroscopic fluctuation theory to many-body quantum systems.

Enhanced Recovery in Liver Transplantation: A Feasibility Study.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) programmes after surgery are effective in reducing length of stay, functional recovery and complication rates in liver surgery (LS) with the indirect advantage of reducing hospitalisation costs. Preoperative comorbidities, challenging surgical procedures and complex post-operative management are the points that liver transplantation (LT) shares with LS. Nevertheless, there is little evidence regarding the feasibility and safety of ERAS programmes in LT. METHODS: We designed a pilot, small-scale, feasibility study to assess the impact on hospital stay, protocol compliance and safety of an ERAS programme tailored for LT. The ERAS arm was compared with a 1:2 match paired control arm with similar characteristics. All patients with MELD <25 were included. A dedicated LT-tailored protocol was derived from publications on ERAS liver surgery. RESULTS: Ten patients were included in the Fast-Trans arm. It was observed a 47% reduction of the total LOS, as compared to the control arm: 9.5 (9.0-10.5) days versus 18.0 (14.3-24.3) days, respectively, p <0.001. The protocol achieved 72.9% compliance. No differences were observed in terms of post-operative complications or readmission rates after discharge between the two arms. Overall, it was observed a reduction of length of stay in ICU and surgical ward in the Fast-Trans arm compared with the control arm. CONCLUSION: Considered the main points in common between LS and LT, this small-scale study suggests that the application of an ERAS programme tailored to the LT setting is feasible. Further testing will be appropriate to generalise these findings.

Ischemic-type biliary lesions: A leading indication of liver retransplantation with excellent results.

BACKGROUND: Liver retransplantation (RLT) is the only life-saving treatment option for patients with a failing graft, but it remains a major challenge because of inferior outcomes and technical difficulties. METHODS: This study aimed to evaluate the outcomes of and risk factors for adult RLT in a single center, focusing on the etiology of graft failure. Between 1987 and 2011, 1592 liver transplants (LTs) and 143 RLTs (9%) were performed at our institution. RESULTS: The 1-, 5- and 10-year patient survival rates after RLT were 60%, 52% and 39%, and the graft survival rates were 55%, 46% and 32%. The 90-day mortality rate was 32%, mainly due to septic complications (45% of deaths). Ischemic-type biliary lesions (ITBL) were the leading indication for RLT (23%), and patient survival was significantly better in patients retransplanted for ITBL than for any other indication (P<0.02). Indications other than ITBL (P=0.015), the transfusion of more than 7 units (P=0.006) and preoperative dialysis (P=0.005) were the three parameters associated with poor survival after RLT. CONCLUSION: Patients with ITBL benefit the most from elective RLT.

Hydrodynamic Diffusion in Integrable Systems.

We show that hydrodynamic diffusion is generically present in many-body, one-dimensional interacting quantum and classical integrable models. We extend the recently developed generalized hydrodynamic (GHD) to include terms of Navier-Stokes type, which leads to positive entropy production and diffusive relaxation mechanisms. These terms provide the subleading diffusive corrections to Euler-scale GHD for the large-scale nonequilibrium dynamics of integrable systems, and arise due to two-body scatterings among quasiparticles. We give exact expressions for the diffusion coefficients. Our results apply to a large class of integrable models, including quantum and classical, Galilean and relativistic field theories, chains, and gases in one dimension, such as the Lieb-Liniger model describing cold atom gases and the Heisenberg quantum spin chain. We provide numerical evaluations in the Heisenberg XXZ spin chain, both for the spin diffusion constant, and for the diffusive effects during the melting of a small domain wall of spins, finding excellent agreement with time-dependent density matrix renormalization group numerical simulations.

Diffusion and Signatures of Localization in Stochastic Conformal Field Theory.

We define a simple model of conformal field theory in random space-time environments, which we refer to as stochastic conformal field theory. This model accounts for the effects of dilute random impurities in strongly interacting critical many-body systems. On one hand, surprisingly, although impurities are separated by macroscopic distances, we find that the infinite-time steady state is factorized on microscopic lengths, a signature of the emergence of localization. The stationary state also displays vanishing energy current and strong uncorrelated spatial fluctuations of local observables. On the other hand, at finite times, the transient shows a crossover from ballistic to diffusive energy propagation. In this regime and a Markovian limit, concentrating on current-generating initial states with a temperature imbalance, we show that the energy current and density satisfy simple dissipative hydrodynamic equations. We describe the space-time scales at which nonequilibrium currents exist. We show that a light-cone effect subsists in the presence of impurities although a momentum burst propagates transiently on a diffusive scale only.

Chronic Hepatitis E Viral Infection After Liver Transplantation: A Regression of Fibrosis After Antiviral Therapy.

Hepatitis E virus (HEV) infection is increasingly being reported in immunocompromised patients and particularly organ transplant recipients. In this context, HEV infection frequently evolves to chronic infection with a rapid progression of fibrosis to cirrhosis. Ribavirin monotherapy and a minimization of immunosuppression represent the treatment of choice, with a good response rate. However, no data are available on whether treatment can achieve a regression of liver fibrosis in chronic HEV patients. A 57-year-old male patient received a liver transplant for alcoholic cirrhosis and, 6 years later, developed biopsy-proven chronic HEV infection. The patient received different antiviral therapy regimens (pegylated interferon alpha 2b and ribavirin different dosages, and long-term treatment with ribavirin monotherapy still ongoing) but without achieving a sustained virological response. Liver function parameters normalized after 1 month of treatment but without the clearance of HEV. Hepatitis E virus RNA levels also remained detectable in the serum and stools throughout ribavirin monotherapy. No serious adverse events were reported. A gradual regression of liver fibrosis was reported (Metavir A0/F1 in 2015 versus A3/F4 in 2008). Long-term treatment with ribavirin is safe in liver transplant recipients, without achieving HEV sustained virological response, and may induce a biopsy-proven regression of liver fibrosis in a liver transplant recipient with cirrhosis after chronic HEV infection.

Positive end-expiratory pressure does not decrease cardiac output during laparoscopic liver surgery: A prospective observational evaluation.

BACKGROUND: Positive end-expiratory pressure (PEEP) has beneficial pulmonary effects but may worsen the hemodynamic repercussions induced by pneumoperitoneum (PNP) in patients undergoing laparoscopic liver resection. However, by increasing intraluminal vena cava (VC) pressures, PEEP may prevent PNP-induced VC collapse. The aim of this study was to test the validity of this hypothesis. METHODS: After IRB approval and written informed consent, 20 patients were evaluated prospectively. Measurements were performed before and after the application of 10 cmH2O PEEP on patients without PNP (Control group) and during a 12 cmH20 PNP. Results are provided as means [95%CI]. Comparison used paired-sample t test. RESULTS: PEEP induced a decrease in CI in Control subgroup (2.3 [2.0-2.6] and 2.1 [1.8-2.4] l min-1 m-2 before and after PEEP. P < 0.05). In contrast, PEEP on a pre-established PNP did not significantly modify cardiac index (CI). Transmural pressure on the abdominal vena cava decreased with PNP but was partly reversed by the addition of PEEP. CONCLUSION: The application of PEEP on a pre-established PNP during laparoscopic liver resection in normovolemic patients did not decrease CI. Analysis of transmural VC pressure variations confirms that the addition of PEEP may prevent the vena caval collapse induced by PNP.

In Situ Hypothermic Perfusion of the Liver for Complex Hepatic Resection: Surgical Refinements.

INTRODUCTION: While total vascular exclusion (TVE) with veno-venous bypass and hypothermia may be undertaken to increase liver tolerance for complex liver resection, these procedures are still associated with elevated rates of postoperative complications and mortality. In particular, one of the main issues of this strategy is the management of bleeding after declamping, which is enhanced by both hypothermic state and acidosis. To overcome this high risk of morbidity, several technical refinements might be undertaken and here described (with video). METHODS: All patients, requiring TVE >60 min and liver cooling during hepatectomy, were retrospectively included in this study. Technical key points as (a) patient selection, (b) anesthetic management, (c) two-surgeon's technique, (d) preparation for clamping, (e) veno-venous bypass, (f) cooling of the liver, and (g) parenchymal transection, rewarming, and declamping are described and detailed. RESULTS: From 2011 to 2013, we included 8 cases of liver resection with TVE, veno-venous bypass, and hypothermia for malignant disease. Due to the technical refinements, median observed overall blood loss of 550 ml (300-900) including 200 ml (50-300) at declamping and transfusion of packed red blood cell (PRBC) units was required in 5 patients with a mean of 1.25 PRBC/patient. CONCLUSION: The association of TVE, veno-venous bypass, and liver cooling can reduce the time of transection, and blue dye injection and liver rewarming before declamping can reduce blood loss and coagulopathy. Altogether, limited blood loss can be achieved for these complex procedures and may allow to decreasing morbidity.

From the left to the right: 13-year experience in laparoscopic living donor liver transplantation.

Living Donors are the best theoretical candidates to benefit from the advantages of laparoscopy, but development was slow because of concerns about graft integrity and donor safety. Herein our 13-year experience in laparoscopic Living Donor Liver Transplantation (LDLT) is presented. Laparoscopic Left Lateral Section (LLLS) was performed in children receiver, while Laparoscopic Left Hepatectomy (LLH)-including or not the middle hepatic vein-and Laparoscopic Right Hepatectomy (LRH) in adults. Two senior surgeons were always involved for each procedure. All donors were first-degree relatives. From 2001 to 2014, 71 procedures were performed: 63 LLLS (88.7%, 6 LLH (8.4%), and 2 LRH (2.8%). Surgical procedures required a mean of 271.1 ± 65.9, 318 ± 40.2, and 480 ± 0 min for LLLS, LLH, and LRH, respectively with a learning curve toward LLLH over the years (r = 0.09). Seven procedures (9.8%) required conversion. The mean hospital stay was 5.5 ± 3.4, 5.3 ± 0.6, and 8 ± 0 days for LLLS, LLH, and LRH, respectively. Complications occurred in 11 patients (17.3%) undergoing LLLS: 8 (12.7%) grade I and 3 (4.7%) grade II, according to the Modified Clavien-Dindo classification. Laparoscopic liver resection for LDLT requires an equivalent and parallel expertise in open LDLT and LLR. If LLLS for LDLT is now in an exploration phase in highly specialized centers, LLH and LRH for LDLT in adults lack evidence and cannot be recommended for wide introduction. For laparoscopic LDLT beginners, LLLS offers optimal conditions.

Pure laparoscopic left lateral sectionectomy in living donors: from innovation to development in France.

OBJECTIVE: In this study, we report the results obtained from 70 living donors in France. BACKGROUND: Left lateral sectionectomy for pediatric live donor liver transplantation is a well-standardized surgical procedure. Our team introduced the laparoscopic approach to live donation in 2002, and the reproducibility and safety of this method was discussed in 2006. METHODS: Between March 2001 and October 2012, a total of 70 donors underwent a liver procurement. Sixty-seven donors (95.7%) underwent a left lateral sectionectomy, and 3 underwent a left hepatectomy without middle hepatic vein procurement. All data were prospectively recorded in a database. RESULTS: Of the 70 donors, 66 (94%) liver grafts were procured by laparoscopy, whereas 4 (6%) patients required conversion into an open technique. Seventeen donors experienced complications, leading to an overall complication rate of 24.2%. Eleven donors (16%) had grade 1 complications, according to the Clavien system. Five donors (7.1%) presented grade 2 complications, and 1 donor (1.4%) had a grade 3 complication. No death occurred. Overall, patient and graft survival rates for pediatric recipients were 95% and 92% at 1 year, 95% and 88% at 3 years, and 95% and 84% at 5 years, respectively. CONCLUSIONS: The laparoscopic retrieval of the left lateral section for live donor liver transplantation is safe and reproducible and has transitioned from an innovative surgery to a development phase in France.

A Conceptual Technique for Laparoscopic Right Hepatectomy Based on Facts and Oncologic Principles: The Caudal Approach.

OBJECTIVE: To evaluate a new conceptual technique of laparoscopic right hepatectomy. BACKGROUND: Despite significant improvements in surgical care in the last decades, morbidity is still high after major hepatectomy. Blood loss and transfusions are known to significantly increase the risk of postoperative complications and cancer recurrence after liver resection. A laparoscopic approach may improve perioperative outcomes in these cases, but data in literature are limited and the surgical technique is not yet standardized. METHODS: A new conceptual technique of right hepatectomy was designed using evidence-based facts and oncologic rules: laparoscopy with pneumoperitoneum, low central venous pressure, intermittent pedicle clamping, anterior approach without mobilization, and parenchymal section with ultrasonic dissector. Thirty patients were prospectively enrolled between October 2011 and September 2013. Primary endpoint was intraoperative blood loss. RESULTS: Eighty percent of patients underwent surgery for malignant disease and cirrhosis was present in 11 patients. Benign lesions accounted for 13% of indications, whereas living liver donation was performed in 2 cases. Median blood loss was 100 mL (50-700) and transfusion rate was 7%. Five patients (16.6%) required conversion to laparotomy, including 2 using hybrid technique. The median operative time was 360 minutes (210-510). R0 resection rate was 87% (21/24). Postoperative morbidity rate was 23% (7/30) with 8 complications including 6 Clavien III-IV. No respiratory complication occurred. The median hospital stay was 8 days. No patient died. CONCLUSIONS: This study showed that several evidence-based facts could be combined to define a new conceptual technique of laparoscopic right hepatectomy allowing for low blood loss and morbidity.

Preliminary report of major surgery in liver transplant recipients receiving m-TOR inhibitors without therapeutic discontinuation.

INTRODUCTION: Mammalian target rapamycin inhibitors (m-TORi) are increasingly used in patients undergoing liver transplantation (LT). Yet, there is rising concern that they also could impair wound healing and favor the development of several surgical complications. This report was designed to evaluate both feasibility and safety of major surgery in liver transplant recipients receiving m-TORi-based immunosuppression without therapeutic discontinuation. METHODS: From 2007 to 2012, six liver transplant recipients underwent nine major abdominal or thoracic surgical procedures without m-TORi discontinuation or specific dosage adjustment. Their characteristics and postoperative outcomes were retrospectively analyzed. RESULTS: Indications for m-TORi were de novo or recurrent malignant disease in five patients and calcineurin inhibitors related neurologic toxicity in one patient. Abdominal procedures, thoracic procedures, and combined thoracic and abdominal procedures were performed in six, two, and one cases respectively. Emergency surgery was performed in one case and elective procedures were performed in eight cases, including five for malignant disease and three for late surgical complications following LT. No patient died postoperatively. One major complication was observed, but no patient required reoperation. No evisceration, incisional surgical site infection, or lymphocele occurred. CONCLUSIONS: Major surgery in liver transplant recipients receiving m-TOR inhibitors appears both feasible and safe without therapeutic discontinuation or specific dosage adjustment.

Laparoscopic division of a portosystemic shunt for recurrent life-threatening rectal variceal bleeding: report of a case.

In patients with severe portal hypertension related to liver cirrhosis, recanalization of umbilical veins may lead to both development and rupture of massive anorectal varices. In this setting, while transjugular intrahepatic portosystemic shunt (TIPS) is considered as the treatment of choice, the management of these patients remains unclear in case of contraindications to TIPS. Laparoscopic division of massive portosystemic shunts has been reported to yield beneficial effects in patients with isolated hepatic encephalopathy but has never been attempted in a context of life-threatening lower gastrointestinal bleeding. In the present case report, we both describe the operative technique of laparoscopic division of recanalized umbilical veins to treat recurrent massive haemorrhage following rupture of giant rectal varices in a 68-year-old Child C cirrhotic patient contraindicated to TIPS and report the postoperative course of the patient.

Split liver transplantation using extended right grafts: the natural history of segment 4 and its impact on early postoperative outcomes.

Split liver transplantation (SLT) using extended right grafts is associated with complications related to ischemia of hepatic segment 4 (S4), and these complications are associated with poor outcomes. We retrospectively analyzed 36 SLT recipients so that we could assess the association of radiological, biological, and clinical features with S4 ischemia. The overall survival rates were 84.2%, 84.2%, and 77.7% at 1, 3, and 5 years, respectively. The recipients were mostly male (24/36 or 67%) and had a median age of 52 years (range = 13-63 years), a median body mass index of 22.9 kg/m(2) (range = 17.3-29.8 kg/m(2) ), and a median graft-to-recipient weight ratio of 1.3% (range = 0.9%-1.9%). S4-related complications were diagnosed in 22% of the patients (8/36) with a median delay of 22 days (range = 10-30 days). Secondary arterial complications were seen in 3 of these patients and led to significantly decreased graft survival in comparison with the graft survival of patients without complications (50.0% versus 85.6%, P = 0.017). Patients developing S4-related complications had significantly elevated aspartate aminotransferase (AST) levels (>1000 IU/L) on postoperative day (POD) 1 and elevated gamma-glutamyl transpeptidase (GGT) levels (>300 IU/L) on PODs 7 and 10 (P < 0.05). These AST and GGT elevations conferred a significantly high risk of developing these complications (odds ratio = 42, 95% confidence interval = 4-475, P < 0.05). The ischemic volume of S4 was extremely variable (0%-95%) and did not correlate with S4-related complications. In conclusion, our results suggest that S4-related complications are risk factors for worse graft survival, and the development of these complications can be anticipated by the early identification of a specific biological profile and a routine radiological examination.