On random object allocation

In this thesis, we study a linkage between object allocation problems and twosided matching markets. Our main purpose is to analyse the desirable properties such as efficiency, respect for rank and no-discrimination, and associate them with well-known stability concept. We show that any rank respecting allocation could be interpreted a stable allocation of a specific matching market. Under certain circumstances, the allocation also exhibits no-discrimination. Also, we associate our two-sided matching market derived from an object allocation problem with aggregate efficiency concept. Moreover, we provide a process that yields the PS allocatio

Mitigating Off-Policy Bias in Actor-Critic Methods with One-Step Q-learning: A Novel Correction Approach

Compared to on-policy counterparts, off-policy model-free deep reinforcement learning can improve data efficiency by repeatedly using the previously gathered data. However, off-policy learning becomes challenging when the discrepancy between the underlying distributions of the agent's policy and collected data increases. Although the well-studied importance sampling and off-policy policy gradient techniques were proposed to compensate for this discrepancy, they usually require a collection of long trajectories and induce additional problems such as vanishing/exploding gradients or discarding many useful experiences, which eventually increases the computational complexity. Moreover, their generalization to either continuous action domains or policies approximated by deterministic deep neural networks is strictly limited. To overcome these limitations, we introduce a novel policy similarity measure to mitigate the effects of such discrepancy in continuous control. Our method offers an adequate single-step off-policy correction that is applicable to deterministic policy networks. Theoretical and empirical studies demonstrate that it can achieve a "safe" off-policy learning and substantially improve the state-of-the-art by attaining higher returns in fewer steps than the competing methods through an effective schedule of the learning rate in Q-learning and policy optimization

Integrin-Blocking Antibodies Delay Keratinocyte Re-Epithelialization in a Human Three-Dimensional Wound Healing Model

The α6β4 integrin plays a significant role in tumor growth, angiogenesis and metastasis through modulation of growth factor signaling, and is a potentially important therapeutic target. However, α6β4-mediated cell-matrix adhesion is critical in normal keratinocyte attachment, signaling and anchorage to the basement membrane through its interaction with laminin-5, raising potential risks for targeted therapy. Bioengineered Human Skin Equivalent (HSE), which have been shown to mimic their normal and wounded counterparts, have been used here to investigate the consequences of targeting β4 to establish toxic effects on normal tissue homeostasis and epithelial wound repair. We tested two antibodies directed to different β4 epitopes, one adhesion-blocking (ASC-8) and one non-adhesion blocking (ASC-3), and determined that these antibodies were appropriately localized to the basal surface of keratinocytes at the basement membrane interface where β4 is expressed. While normal tissue architecture was not altered, ASC-8 induced a sub-basal split at the basement membrane in non-wounded tissue. In addition, wound closure was significantly inhibited by ASC-8, but not by ASC-3, as the epithelial tongue only covered 40 percent of the wound area at 120 hours post-wounding. These results demonstrate β4 adhesion-blocking antibodies may have adverse effects on normal tissue, whereas antibodies directed to other epitopes may provide safer alternatives for therapy. Taken together, we conclude that these three-dimensional tissue models provide a biologically relevant platform to identify toxic effects induced by candidate therapeutics, which will allow generation of findings that are more predictive of in vivo responses early in the drug development process

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Root Resorption in Orthodontics

WOS: 000439324700004PubMed ID: 30112483Root resorption has been the subject of many studies, and it can be caused by many factors such as the mechanics used during orthodontic treatment, factors related to the type and magnitude of the force, and other factors related to treatment such as the type of tooth movement and malocclusion. The clinical importance of root resorption is directly related to its detectability. Therefore, orthodontic and biological factors that may cause root resorption were evaluated using various imaging methods in present use. In this review, root resorption in orthodontics was considered from different viewpoints

Visual perception of faces with unilateral and bilateral cleft lip and palate: An Eye-Tracking Study

WOS: 000397052400006PubMed ID: 28102012Objectives: To test the hypotheses that there are differences between orthodontists, individuals with cleft lip and palate (CLP) and laypersons in the visual perception of faces with unilateral (UCLP) and bilateral cleft lip and palate (BCLP), the faces with UCLP and BCLP are visually perceived differently and the hierarchy of visual attention changes when viewing individuals with CLP. Setting and Sample Population: Department of Orthodontics and Experimental Psychology at Ege University, Izmir. Sixty images ( faces with a social smile and at rest) of 30 volunteers (unaffected controls, UCLP, BCLP) were viewed by 80 participants: orthodontists, individuals with CLP and laypersons. Materials and Methods: Eye fixations on four areas of interest were quantified: eyes, nose, upper lip and lower lip-chin. Time to first fixation, fixation before, fixation count and fixation duration parameters were analysed. Results: Orthodontists fixated on the upper-lip area more often than laypersons or individuals with CLP (F-2.144= 8.47, P=. 00,. eta(2) =. 19 in faces at rest). The upper-lip area received more fixations (F2.144=21.93, P=. 00,. eta(2) =. 23) and longer fixation durations ( F2.144= 28.86, P=. 00,. eta(2) =. 27) from all participants who gazed on faces with UCLP and a social smile. Conclusion: The hypotheses of the study were supported. Orthodontists and laypersons focused more attention on the upper lip and eyes in the resting position, respectively. The upper-lip area of the BCLP images captured more attention at rest

Fuzzy association rule mining approach to identify e-commerce product association considering sales amount

Online stores assist customers in buying the desired products online. Great competition in the e-commerce sector necessitates technology development. Many e-commerce systems not only present products but also offer similar products to increase online customer interest. Due to high product variety, analyzing products sold together similar to a recommendation system is a must. This study methodologically improves the traditional association rule mining (ARM) method by adding fuzzy set theory. Besides, it extends the ARM by considering not only items sold but also sales amounts. Fuzzy association rule mining (FARM) with the Apriori algorithm can catch the customers' choice from historical transaction data. It discovers fuzzy association rules from an e-commerce company to display similar products to customers according to their needs in amount. The experimental result shows that the proposed FARM approach produces much information about e-commerce sales for decision-makers. Furthermore, the FARM method eliminates some traditional rules considering their sales amount and can produce some rules different from ARM.TUBITAK (The Scientific and Technological Research Council of Turkey) [3180641]This work has been financially supported by TUBITAK (The Scientific and Technological Research Council of Turkey), Project Number: 3180641