Bayesian inference for a semi-parametric copula-based Markov chain

This paper presents a method to specify a strictly stationary univariate time series model with particular emphasis on the marginal characteristics (fat tailedness, skewness etc.). It is the first time in time series models with specified marginal distribution, a non-parametric specification is used. Through a Copula distribution, the marginal aspect are separated and the information contained within the order statistics allow to efficiently model a discretely-varied time series. The estimation is done through Bayesian method. The method is invariant to any copula family and for any level of heterogeneity in the random variable. Using count times series of weekly rearm homicides in Cape Town, South Africa, we show our method efficiently estimates the copula parameter representing the first-order Markov chain transition density

Recent Advances in Path Integral Control for Trajectory Optimization: An Overview in Theoretical and Algorithmic Perspectives

This paper presents a tutorial overview of path integral (PI) control approaches for stochastic optimal control and trajectory optimization. We concisely summarize the theoretical development of path integral control to compute a solution for stochastic optimal control and provide algorithmic descriptions of the cross-entropy (CE) method, an open-loop controller using the receding horizon scheme known as the model predictive path integral (MPPI), and a parameterized state feedback controller based on the path integral control theory. We discuss policy search methods based on path integral control, efficient and stable sampling strategies, extensions to multi-agent decision-making, and MPPI for the trajectory optimization on manifolds. For tutorial demonstrations, some PI-based controllers are implemented in MATLAB and ROS2/Gazebo simulations for trajectory optimization. The simulation frameworks and source codes are publicly available at https://github.com/INHA-Autonomous-Systems-Laboratory-ASL/An-Overview-on-Recent-Advances-in-Path-Integral-Control.Comment: 16 pages, 9 figure

Imaging characteristics and treatment of a penetrating brain injury caused by an oropharyngeal foreign body in a dog

A 4-year-old Border collie was presented with one episode of collapse, altered mentation, and a suspected pharyngeal stick injury. Magnetic resonance imaging (MRI) and computed tomography showed a linear foreign body penetrating the right oropharynx, through the foramen ovale and the brain parenchyma. The foreign body was surgically removed and medical treatment initiated. Complete resolution of clinical signs was noted at recheck 8 weeks later. Repeat MRI showed chronic secondary changes in the brain parenchyma. To the authors' knowledge, this is the first report of the advanced imaging findings and successful treatment of a penetrating oropharyngeal intracranial foreign body in a dog

Peripheral blood mononuclear cells of breast cancer patients can be reprogrammed to enhance anti-HER-2/neu reactivity and overcome myeloid-derived suppressor cells [poster abstract]

Barriers limiting the efficacy of adoptive cellular therapy (ACT) for breast cancer patients include immune suppression mediated by myeloid-derived suppressor cells (MDSC) and a low frequency of tumor-reactive memory T cells (Tm). Recently, we developed an ex vivo protocol to reprogram tumor-reactive murine splenocytes; these cells were found to be resistant to MDSC suppression and protected FVBN202 mice from tumor challenge. Here, we evaluated the clinical applicability of reprogramming tumor-sensitized PBMCs isolated from patients with early stage breast cancer by treatment with bryostatin 1 and ionomycin (B/I) combined with IL-2, IL-7 and IL-15. Our data demonstrate that reprogrammed cells are enriched with Tm cells (n=5; p=0.006), as well as activated CD56+(n=6; p=0.003) and CD161+ (n=4; p=0.02) NKT cells, and demonstrate expansion in total cell numbers (n=16; p=0.003) compared to baseline cells. Reprogrammed PBMCs displayed enhanced HER-2/neu-specific IFN-γ producing immune responses (n=6; p=0.04); non-reprogrammed control PBMC IFN-γ production was not significant (n=6; p=0.4). Furthermore, high-throughput sequencing analysis of the T cell receptor (TcR) Vβ in one patient demonstrated clonal expansion of specific TcR VJ recombination events resulting from cellular reprogramming, suggestive of an enriched frequency of specific tumor antigen-primed T cell clones. Interestingly, reprogrammed T cells were resistant to autologous CD33+ CD11b+ HLA-DRlo/- MDSCs, as determined by further enhanced HER-2/neu-specific IFN-γ secretion in the presence of MDSCs (n=6; p=0.03). Activated CD161+ NKT cells comprising 3% or greater of total reprogrammed cells rendered T cells resistant to MDSCs (n=3; p=0.02). Upregulation of NKG2D expression on CD161+(n=5; p=0.0006) and CD56+ (n=5; p=0.04) NKT cells resulted from cellular reprogramming. Therefore, NKG2D signaling was blocked using anti-NKG2D blocking antibody in our co-culture system, resulting in the abrogation of resistance to MDSCs as determined by blunted IFN-γ secretion (n=3; p=0.04). Finally, the phenotype of MDSCs after co-culture with reprogrammed PBMC was examined; we observed downregulation of CD11b expression (n=3; p=0.02) concomitant with HLA-DR upregulation on MDSCs (n=3; p=0.001); suggestive of induced maturation of MDSCs into Dendritic Cells (DC). The results of our study offer the following strategies to improve ACT of breast cancer: i) inclusion of activated NKT cells in ACT to overcome MDSC suppression by inducing MDSC maturation into DCs, and ii) PBMC reprogramming to enrich the frequency of tumor-reactive Tm cells

Changes in plasma free fatty acids in obese patients before and after bariatric surgery highlight alterations in lipid metabolism

This work was supported by the British Heart Foundation (grant ref: FS/20/3/34956).Obesity is a complex disease that increases an individual’s risk of developing other diseases and health-related problems. A common feature is dyslipidemia characterized by increased levels of plasma lipids, which include non-esterified fatty acids (NEFAs). The role of NEFAs in obesity-related morbidity is interesting as NEFAs constitute a reservoir of metabolic energy, are principal components of cell membranes and are precursors for signalling molecules. Bariatric surgery promotes sustained weight loss in severely obese patients, reducing the incidence and severity of co-morbidities. In this study we measure changes in circulating NEFA species in plasma samples taken from 25 obese individuals before and 9 months after Roux-en-Y gastric bypass surgery. The mean weight of the cohort reduced by 29.2% from 149.0±25.1 kg pre-surgery to 105.5±19.8 kg post-surgery and the BMI by 28.2% from 51.8±6.3 kg/m2 pre-surgery to 37.2±5.4 kg/m2. Mean glycated haemoglobin (HbA1c) reduced from 6.5±1.3% to 5.5±0.5%, consistent with the intervention leading to improved glycaemic control, particularly in those who were dysglycemic prior to surgery. Total and LDL cholesterol concentrations were markedly reduced following surgery. Concentrations of seven NEFAs were found to decrease 9 months after surgery compared to pre-surgery levels: myristate, palmitoleate, palmitate, linoleate, oleate, stearate and arachidonate. Bariatric surgery led to increased lipogenesis and elongase activity and decreased stearoyl-CoA desaturase 1 activity. This study thus highlights metabolic changes that take place following gastric bypass surgery in severely obese patients.Publisher PDFPeer reviewe

FOLFIRINOX for advanced pancreatic cancer:The Princess Margaret Cancer Centre experience

BACKGROUND: FOLFIRINOX has been shown to significantly increase both overall survival (OS) and progression-free survival (PFS) in metastatic pancreas cancer. There is limited data regarding the treatment of locally advanced pancreatic cancer. We present a retrospective study of patients with both locally advanced and metastatic pancreas cancer using FOLFIRINOX as first-line therapy in our centre. METHODS: This is a retrospective review of patients treated with FOLFIRINOX for pancreatic cancer at Princess Margaret Cancer Centre, between December 2011 and July 2014. The primary objective was to evaluate the efficacy and safety of FOLFIRINOX when used with dose modifications. RESULTS: One hundred two patients were identified; 66 metastatic and 36 locally advanced. Sixty-eight per cent of patients initiated treatment with a dose reduction. The median (95% CI) OS in the metastatic group was 13.1 (6.3–16.1) months with full dose and 12.9 (10.3–30.1) months with modified dose. The median (95% CI) OS in the locally advanced group was 11.1 (6.1–not reached) months with full dose and 23 (not reached–not reached) months with modified dose. The median (95% CI) PFS in the metastatic group was 6.2 (4.9–15.2) months with full dose and 8.7 (5.7–12.9) months with modified dose. The median (95% CI) PFS in the locally advanced group was 11.1 (3.1–not reached) months with full dose and 10.4 (6.8–not reached) months with modified dose. Grade 3/4 haematologic adverse events were observed in 43% of patients. Grade 3/4 non-haematologic adverse events were observed in 28% of patients. Patient well-being significantly improved from baseline to cycle 4 (P=0.002). CONCLUSIONS: Efficacy was achievable with dose-modified FOLFIRINOX in daily setting. The safety of FOLFIRINOX remains a concern with a high rate of grades 3 and 4 neutropaenia despite dose reduction

Vitamin E δ-tocotrienol Sensitizes Human Pancreatic Cancer Cells to TRAIL-induced Apoptosis Through Proteasome-Mediated Down-Regulation of c-FLIP

Background: Vitamin E δ-tocotrienol (VEDT), a vitamin E compound isolated from sources such as palm fruit and annatto beans, has been reported to have cancer chemopreventive and therapeutic effects. Methods: We report a novel function of VEDT in augmenting tumor necrosis factor-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis in pancreatic cancer cells. The effects of VEDT were shown by its ability to trigger caspase-8-dependent apoptosis in pancreatic cancer cells. Results: When combined with TRAIL, VEDT significantly augmented TRAIL-induced apoptosis of pancreatic cancer cells. VEDT decreased cellular FLICE inhibitory protein (c-FLIP) levels without consistently modulating the expression of decoy death receptors 1, 2, 3 or death receptors 4 and 5. Enforced expression of c-FLIP substantially attenuated VEDT/TRAIL-induced apoptosis. Thus, c-FLIP reduction plays an important part in mediating VEDT/TRAIL-induced apoptosis. Moreover, VEDT increased c-FLIP ubiquitination and degradation but did not affect its transcription, suggesting that VEDT decreases c-FLIP levels through promoting its degradation. Of note, degradation of c-FLIP and enhanced TRAIL-induced apoptosis in pancreatic cancer cells were observed only with the anticancer bioactive vitamin E compounds δ-, γ-, and β-tocotrienol but not with the anticancer inactive vitamin E compounds α-tocotrienol and α-, β-, γ-, and δ-tocopherol. Conclusions: c-FLIP degradation is a key event for death receptor-induced apoptosis by anticancer bioactive vitamin E compounds in pancreatic cancer cells. Moreover, VEDT augmented TRAIL inhibition of pancreatic tumor growth and induction of apoptosis in vivo. Combination therapy with TRAIL agonists and bioactive vitamin E compounds may offer a novel strategy for pancreatic cancer intervention

On the sui generis value capture of new digital technologies: the case of AI

Digital technologies are emerging at a fast rate, with applications ranging from farming to recruitment. Much of the research on these technologies has concerned optimization and applications, with less focus on the regulation and governance of these systems and how they might bring about foundational and theoretical shifts. Indeed, much of the literature is concerned with forwarding technical approaches, and the potential opportunities and harms, without offering theoretical or philosophical perspectives; few have asked what a digital thing is, what the ontological nature and state of phenomena produced and expressed by digital things are, and if there are distinctions between the conceptions of digital and non-digital technologies. We forward this discussion by investigating the question of what value is being expressed by an algorithm, which we conceptualize in terms of a digital asset, which we define as a valued digital thing that is derived from a particular digital technology

Patterns of tobacco use in the United Arab Emirates healthy future (UAEHFS) pilot study

© 2018 Al-Houqani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Introduction Self-reported tobacco use in the United Arab Emirates is among the highest in the region. Use of tobacco products other than cigarettes is widespread, but little is known about specific behavior use patterns. There have been no studies that have biochemically verified smoking status. Methods The UAE Healthy Future Study (UAEHFS) seeks to understand the causes of non-communicable diseases through a 20,000-person cohort study. During the study pilot, 517 Emirati nationals were recruited to complete a questionnaire, provide clinical measurements and biological samples. Complete smoking data were available for 428 participants. Validation of smoking status via cotinine testing was conducted based on complete questionnaire data and matching urine samples for 399 participants, using a cut-off of 200ng/ml to indicate active smoking status. Results Self-reported tobacco use was 36% among men and 3% among women in the sample. However, biochemical verification of smoking status revealed that 42% men and 9% of women were positive for cotinine indicating possible recent tobacco use. Dual and poly-use of tobacco products was fairly common with 32% and 6% of the sample reporting respectively. Conclusions This is the first study in the region to biochemically verify tobacco use self-report data. Tobacco use in this study population was found to be higher than previously thought, especially among women. Misclassification of smoking status was more common than expected. Poly-tobacco use was also very common. Additional studies are needed to understand tobacco use behaviors and the extent to which people may be exposed to passive tobacco smoke. Implications This study is the first in the region to biochemically verify self-reported smoking status