LightPIR: Privacy-Preserving Route Discovery for Payment Channel Networks

Payment channel networks are a promising approach to improve the scalability of cryptocurrencies: they allow to perform transactions in a peer-to-peer fashion, along multi-hop routes in the network, without requiring consensus on the blockchain. However, during the discovery of cost-efficient routes for the transaction, critical information may be revealed about the transacting entities. This paper initiates the study of privacy-preserving route discovery mechanisms for payment channel networks. In particular, we present LightPIR, an approach which allows a source to efficiently discover a shortest path to its destination without revealing any information about the endpoints of the transaction. The two main observations which allow for an efficient solution in LightPIR are that: (1) surprisingly, hub labelling algorithms - which were developed to preprocess "street network like" graphs so one can later efficiently compute shortest paths - also work well for the graphs underlying payment channel networks, and that (2) hub labelling algorithms can be directly combined with private information retrieval. LightPIR relies on a simple hub labeling heuristic on top of existing hub labeling algorithms which leverages the specific topological features of cryptocurrency networks to further minimize storage and bandwidth overheads. In a case study considering the Lightning network, we show that our approach is an order of magnitude more efficient compared to a privacy-preserving baseline based on using private information retrieval on a database that stores all pairs shortest paths

HIDE & SEEK: Privacy-Preserving Rebalancing on Payment Channel Networks

Payment channels effectively move the transaction load off-chain thereby successfully addressing the inherent scalability problem most cryptocurrencies face. A major drawback of payment channels is the need to ``top up\u27\u27 funds on-chain when a channel is depleted. Rebalancing was proposed to alleviate this issue, where parties with depleting channels move their funds along a cycle to replenish their channels off-chain. Protocols for rebalancing so far either introduce local solutions or compromise privacy. In this work, we present an opt-in rebalancing protocol that is both private and globally optimal, meaning our protocol maximizes the total amount of rebalanced funds. We study rebalancing from the framework of linear programming. To obtain full privacy guarantees, we leverage multi-party computation in solving the linear program, which is executed by selected participants to maintain efficiency. Finally, we efficiently decompose the rebalancing solution into incentive-compatible cycles which conserve user balances when executed atomically

Activation of C–H Bonds in Pt^+ + x CH_4 Reactions, where x = 1–4: Identification of the Platinum Dimethyl Cation

Activation of C–H bonds in the sequential reactions of Pt^+ + x(CH_4/CD_4), where x = 1–4, have been investigated using infrared multiple photon dissociation (IRMPD) spectroscopy and theoretical calculations. Pt^+ cations are formed by laser ablation and exposed to controlled amounts of CH_4/CD_4 leading to [Pt,xC,(4x-2)H/D]^+ dehydrogenation products. Irradiation of these products in the 400–2100 cm^(–1) range leads to CH_4/CD_4 loss from the x = 3 and 4 products, whereas PtCH_2^+/PtCD_2^+ products do not decompose at all, and x = 2 products dissociate only when formed from a higher order product. The structures of these complexes were explored theoretically at several levels of theory with three different basis sets. Comparison of the experimental and theoretical results indicate that the species formed have a Pt(CH_3)_2^+(CH_4)_(x-2)/Pt(CD_3)_2^+(CD_4)_(x-2) binding motif for x = 2–4. Thus, reaction of Pt^+ with methane occurs by C–H bond activation to form PtCH_2^+, which reacts with an additional methane molecule by C–H bond activation to form the platinum dimethyl cation. This proposed reaction mechanism is consistent with theoretical explorations of the potential energy surface for reactions of Pt^+ with one and two methane molecules

Laparoscopic Isthmocele Repair: Efficacy and Benefits before and after Subsequent Cesarean Section.

OBJECTIVE: To evaluate the effect of laparoscopic isthmocele repair on isthmocele-related symptoms and/or fertility-related problems. The residual myometrial thickness before and after subsequent cesarean section was also evaluated. DESIGN: Retrospective, case series. SETTING: Public university hospital. POPULATION: Women with isthmocele (residual myometrium < 5 mm) complaining of abnormal uterine bleeding, chronic pelvic pain or secondary infertility not otherwise specified. METHODS: Women's complaints and the residual myometrium were assessed pre-operatively and at three to six months post-operatively. In patients who conceived after surgery, the latter was measured at least six months after delivery by cesarean section. MAIN OUTCOME MEASURES: Resolution of the main symptom three to six months after surgery and persistence of laparoscopic repair benefits after subsequent cesarean section were considered as primary outcome measures. RESULTS: Overall, 31 women underwent laparoscopic isthmocele repair. The success rates of the surgery as improvement of abnormal uterine bleeding, chronic pelvic pain and secondary infertility were 71.4% (10 of 14), 83.3% (10 of 12) and 83.3% (10 of 12), respectively. Mean residual myometrial thickness increased significantly from 1.77 mm pre-operatively to 6.67 mm, three to six months post-operatively. Mean myometrial thickness in patients who underwent subsequent cesarean section (N = 7) was 4.49 mm. In this sub-group, there was no significant difference between the mean myometrial thickness measured after the laparoscopic isthmocele repair and that measured after the subsequent cesarean section. None of these patients reported recurrence of their symptoms after delivery. CONCLUSION: Our findings suggest that the laparoscopic isthmocele excision and repair is an appropriate approach for the treatment of isthmocele-related symptoms when done by skilled laparoscopic surgeons. The benefit of this new surgical approach seems to persist even after a subsequent cesarean section. Further investigations and prospective studies are required to confirm this finding

The effect of stopping visiting hours during the COVID-19 pandemic on loneliness and mood in patients at an intermediate care hospital

BACKGROUND: To study how mood and feelings of loneliness in our in-patients differed before and after the re-introduction of social visits during COVID-19 restrictions.METHODS: The University of California, Los Angeles [UCLA] loneliness scale, the Hospital Anxiety and Depression Scale [HADS] and the Cornell scale were applied to all in-patients in an intermediate care hospital who fulfilled the inclusion criteria during two separate periods between May and September 2020, prior and after the re-introduction of limited visiting hours.RESULTS: 45 patients were included in the 1st phase and 30 patients during the 2nd phase. 66.7% were female and 33.3 % male. There was a significant difference in all the test results between the 1st and 2nd phase of the study (HADS-A p=0.0191; HADS-D p=0.0447; Cornell p=0.0037; UCLA p=0.0376).CONCLUSION: Social visits, even when limited in nature can still have a positive effect on patient’s mood and level of loneliness.peer-reviewe

Anterior cruciate ligament reconstruction with concomitant meniscal repair: Is graft choice predictive of meniscal repair success?

Background: When meniscal repair is performed during anterior cruciate ligament (ACL) reconstruction (ACLR), the effect of ACL graft type on meniscal repair outcomes is unclear. Hypothesis: The authors hypothesized that meniscal repairs would fail at the lowest rate when concomitant ACLR was performed with bone--patellar tendon--bone (BTB) autograft. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent meniscal repair at primary ACLR were identified from a longitudinal, prospective cohort. Meniscal repair failures, defined as any subsequent surgical procedure addressing the meniscus, were identified. A logistic regression model was built to assess the association of graft type, patient-specific factors, baseline Marx activity rating score, and meniscal repair location (medial or lateral) with repair failure at 6-year follow-up. Results: A total of 646 patients were included. Grafts used included BTB autograft (55.7%), soft tissue autograft (33.9%), and various allografts (10.4%). We identified 101 patients (15.6%) with a documented meniscal repair failure. Failure occurred in 74 of 420 (17.6%) isolated medial meniscal repairs, 15 of 187 (8%) isolated lateral meniscal repairs, and 12 of 39 (30.7%) of combined medial and lateral meniscal repairs. Meniscal repair failure occurred in 13.9% of patients with BTB autografts, 17.4% of patients with soft tissue autografts, and 19.4% of patients with allografts. The odds of failure within 6 years of index surgery were increased more than 2-fold with allograft versus BTB autograft (odds ratio = 2.34 [95% confidence interval, 1.12-4.92]; Conclusion: Meniscal repair location (medial vs lateral) and baseline activity level were the main drivers of meniscal repair outcomes. Graft type was ranked third, demonstrating that meniscal repairs performed with allograft were 2.3 times more likely to fail compared with BTB autograft. There was no significant difference in failure rates between BTB versus soft tissue autografts. Registration: NCT00463099 (ClinicalTrials.gov identifier)

Scalable psychological interventions for Syrian refugees in Europe and the Middle East: STRENGTHS study protocol for a prospective individual participant data meta-analysis

Introduction: The World Health Organization's (WHO) scalable psychological interventions, such as Problem Management Plus (PM+) and Step-by-Step (SbS) are designed to be cost-effective non-specialist delivered interventions to reduce symptoms of common mental disorders, such as anxiety, depression and post-traumatic stress disorder (PTSD). The STRENGTHS consortium aims to evaluate the effectiveness, cost-effectiveness and implementation of the individual format of PM+ and its group version (gPM+), as well as of the digital SbS intervention among Syrian refugees in seven countries in Europe and the Middle East. This is a study protocol for a prospective individual participant data (IPD) meta-analysis to evaluate (1) overall effectiveness and cost-effectiveness and (2) treatment moderators of PM+, gPM+ and SbS with Syrian refugees. Methods and analysis: Five pilot randomised controlled trials (RCTs) and seven fully powered RCTs conducted within STRENGTHS will be combined into one IPD meta-analytic dataset. The RCTs include Syrian refugees of 18 years and above with elevated psychological distress (Kessler Psychological Distress Scale (K10>15)) and impaired daily functioning (WHO Disability Assessment Schedule 2.0 (WHODAS 2.0>16)). Participants are randomised into the intervention or care as usual control group, and complete follow-up assessments at 1-week, 3-month and 12-month follow-up. Primary outcomes are symptoms of depression and anxiety (25-item Hopkins Symptom Checklist). Secondary outcomes include daily functioning (WHODAS 2.0), PTSD symptoms (PTSD Checklist for DSM-5) and self-identified problems (PSYCHLOPS). We will conduct a one-stage IPD meta-analysis using linear mixed models. Quality of evidence will be assessed using the GRADE approach, and the economic evaluation approach will be assessed using the CHEC-list. Ethics and dissemination: Local ethical approval has been obtained for each RCT. This IPD meta-analysis does not require ethical approval. The results of this study will be published in international peer-reviewed journals

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London