bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of septic tank effluent using sequencing batch reactor along with the incorporation of rice husk and Bael pericarp as a natural adsorbent in reducing BOD and COD
Authors: Prasanna K , Annadurai R , Godson M D , Murali Aravind , Ashok Induja , Krishnan M V
Published: March 2021

The generation of liquid forms of waste has rapidly shown its hike in the presently expanding world. This quantification hugely includes the day today’s secretion of the human excreta into the septic tanks that are commonly found in every household. Proper treatment and disposal of faecal waste, once the septic tank is full, becomes challenging for every resident and local bodies. The primary contaminants found in the Septic Tank Effluents (STE) include many disease-causing pathogens, faecal coliform bacteria, detergents and toxic gases. The Sequencing Batch Reactor (SBR) takes its position when treating any waste, which contains a high amount of organic content. In this study, the characteristics, namely COD and BOD of STE samples collected from different locations of the semi-urban area at the outskirt of a town were analyzed. The STE samples treated using SBR mainly to reduce COD and BOD concentration found to be in higher concentration beyond the permissible limit. The same samples subjected to contact with adsorbents such as rice husk and powdered form of dried Bael (Aegle marmelos) outer shell. Results showed a good reaction with the adsorbents and found a significant reduction in COD and BOD concentration.
Comparative study of adsorptive removal of oxyanion (Cr2O4
-2) from aqueous media over unmodified and magnetically modified Melia azedarach
Authors: Nosheen M. , Khan A.A. , Salman M. , Shafqat S. S. , Sajid M. , Rizwan M. , Aslam M. , Ijaz F.
Published: March 2021

In the present study, unmodified Melia azedarach (UMA) and magnetically modified Melia azedarach (MMA) were used as a low cost biosorbent for the adsorptive removal of oxyanion (chromate ion Cr2O4
2-) from aqueous solution. The UMA and MMA were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning electron microscopy (SEM). Batch biosorption process was used to check the effect of well-known process parameters including biosorbent dose, contact time and pH of solution. Experimental results revealed that MMA has more adsorption capacity as compared to UMA. Maximum % age removal (60.49%) was observed under acidic condition (pH=2) using MMA. The obtained experimental data was evaluated using Langmuir and Freundlich isotherms as well as pseudo 1st and 2nd order reaction kinetic models. Results showed that equilibrium mechanism can satisfactorily be explained by Langmuir model as depicted by the correlation factor (close to unity) and follows 2nd order reaction kinetic models.
Reliable Smart Pet Feeding Machine Using Arduino Uno Starter Kit
Authors: Suffian M S Z M , Zaini A N H A , Jamali A , Mohamaddan S , Ashari M F
Published: March 2021

Pet feeding can be done manually by pet owners, or automatically with the help of the pet feeders. The main concerns here are to solve the issue of unavailability of pet owners and the hygiene aspect in pet feeding. The developed automated system enables pet owners to feed their pets while they are away. The main objective of operating this research is to develop an automated pet feeding device focusing on in house pets by utilizing Arduino Uno as its Central Processing Unit (CPU) or microcontroller which function to control a weight sensor (load cells) and a servo motor. Smart Pet Feeding Machine is an automated pet feeding device designed to run based on weight mechanism. It will automatically dispense pet foods when minimum amount of pet food weight is triggered and will automatically stop dispensing when it reaches maximum amount of weight. Its architectural design includes a vertical storage compartment to store pet foods, a square opening at the bottom of storage compartment as opening for dispensing, a motorized dispenser and an aluminium bowl to place dispensed pet foods. The motion of dispenser is operated by a servo motor attached to the dispenser.
Development of solar power system for Sarawak peat water continuous electrocoagulation treatment process
Authors: Rahman N Abdul , Linus A Albania , Philip A , Jihed E E , Gilan U J , Kumar N K M F , Yassin A
Published: March 2021

Sarawak state government has established Sarawak Alternative Rural Water Supply (SAWAS) programme in order to serve as a purpose of providing safe and clean water to the rural communities not connected to municipal clean water supply. In the rural areas of Sarawak, particularly on the coastal region where municipal water supply is not available, the villagers are normally resorted to utilize rainwater and peat water for daily usage. Some of these rural areas are even not connected to electricity grid. Subsequently, one of the proposed methods to eradicate these problems in supplying clean water without electricity supply grid is to implement stand-alone water treatment system with solar power system. As such, the main aim of the study is to design a solar power system to support Sarawak peat water electrocoagulation treatment process. The study is divided into two stages. In the first stage, the study designs a solar power system to support the treatment process of peat water for both batch and continuous electrocoagulation systems. This includes designing and fabrication of a small-scale solar power system. The second stage of the study involved experimental studies on both batch and continuous electrocoagulation systems in order to study the effectiveness of solar power system to supply electricity for the electrocoagulation systems. Overall, the study has developed a solar power system for both batch and continuous electrocoagulation of peat water system. From the experiments conducted, the developed systems are capable to reduce 18.8% and 46.15% of peat water turbidity for batch and continuous electrocoagulation systems respectively. However, in order to meet a more stringent drinking water standards, some improvements on the designed systems are indispensable.
Programmable electron density patterns induced by the interaction of an array laser and underdense plasma
Authors: ZHANG Xiaobo , QIAO Xin , ZHANG Aixia , XUE Jukui
Published: March 2021

The spatially modulated electron distribution of plasma is the basis for obtaining programmable electron density patterns. It has an important influence on plasma technology applications. We propose an efficient scheme to realize controllable electron density patterns in underdense plasma based on the array laser–plasma interaction. Theoretical evidence for the realization of programmable electron density patterns and the corresponding electrostatic field is provided analytically, which is confirmed by particle-in-cell simulations. Results show that the spatial distribution of electron density in the propagation and transverse directions of the laser can be highly modulated to obtain rich programmable electron density patterns by adjusting the array pattern code and pulse width of the array laser beam.
Charge transfer in plasma assisted dry reforming of methane using a nanosecond pulsed packed-bed reactor discharge
Authors: ZHANG Shuai , GAO Yuan , SUN Hao , FAN Zhe , SHAO Tao
Published: March 2021

This paper is aimed to investigate the effect of packing material on plasma characteristic from the viewpoint of charge transfer process. Both the charge accumulation and release processes in the dielectric barrier discharge reactor and packed-bed reactor were investigated by measuring voltage and current waveforms and taking ICCD images. The packing material was ZrO2 pellets and the reactors were driven by a parameterized nanosecond pulse source. The quantity of transferred charges in the dielectric barrier discharge reactor was enhanced when decreasing pulse rise time or increasing pulse width (within 150 ns), but reduced when the gas gap was packed with pellets. The quantity of accumulated charges in the primary discharge was larger than the quantity of released charges in the secondary discharges in the dielectric barrier discharge reactor, but they were almost equal in the packed-bed reactor. It indicates that the discharge behavior has been changed from the view of charge transfer process once the gas gap was packed with pellets, and the ICCD images confirmed it.
Numerical investigation of the pouring mechanism in the filling of epoxy resin in pressure casting processes
Authors: Pushpak Kumar , Chandy Abhilash J
Published: March 2021

Epoxy resins are one of the most widely used thermosetting materials, especially for transformer insulation in the electrical industry. One of the primary technologies used for manufacturing such products is based on pressure casting. Computational fluid dynamics (CFD) calculations of the mould filling stage in a pressure casting process for epoxy resin casting are carried out and presented in this paper. Two designs of a gating system are studied and their effects on the flow parameters in the mould are analyzed. The two designs being top pour and bottom pour inlet. A new solver is developed in an open source CFD framework, OpenFOAM, which incorporates the Navier–Stokes equations, energy equation including the viscous dissipation and a new isoAdvector approach for capturing the liquid-gas interface. The objective is to simulate the flow and heat transfer of epoxy resin, while being filled in the mould that is initially empty and heated to a specified temperature. Formulation was validated with experimental measurements of the classical dam breaking problem. For the resin filling problem, further verification was carried out using grid-dependent studies and temporal fill factor comparisons to experiments. In addition, instantaneous contours of volume fraction and temperature, and velocity vectors are studied to understand the flow patterns and heat transfer in the mould during the filling process. Among both the gating designs, the bottom pour was the more preferred one as it resulted in less turbulence, sloshing and it provides an easy passage for the voids to escape leading to higher fill factor. This analysis also helps in recognising the location of voids and thereby help in potentially identifying optimal process parameter settings for a more suitable mould design.
High-performance deterministic in situ electron-beam lithography enabled by cathodoluminescence spectroscopy
Authors: Rodt S , Reitzenstein S
Published: March 2021

The application of solid-state quantum emitters in real-world quantum information technologies requires precise nanofabrication platforms with high process yield. Self-assembled semiconductor quantum dots with excellent emission properties have proven to be among the best candidates to meet the needs of a number of novel quantum photonic devices. However, their spatial and spectral positions vary statistically on a scale that is far too large for their system integration via fixed lithography and inflexible processing schemes. We solve this severe problem by introducing a flexible and deterministic manufacturing scheme based on precise and convenient cathodoluminescence spectroscopy followed by high-resolution electron-beam lithography. The basics and application examples of this advanced in situ electron-beam lithography are described in this article. Although we focus here on quantum dots as photon emitters, this nanotechnology concept is very well suited for the fabrication of a variety of quantum nanophotonic devices based on quantum emitters that exhibit suitably strong cathodoluminescence signals.
Evaluation of a specialty hepatitis C virus telephone pharmacy service
Authors: Sabourin Ashley A , Fisher-Grant Kaleigh K , Saulles Adam R , Mohammad Rima A
Published: March 2021

Purpose

Direct-acting antivirals (DAAs) used to treat hepatitis C virus (HCV) infection are associated with significant drug-drug interactions (DDIs). Pharmacists are well positioned to identify and mitigate these DDIs. Data to guide assessment of the impact of HCV specialty pharmacy services on identifying and addressing DDIs with DAAs are lacking. The overall purpose of the study described here was to determine the incidence and severity of DDIs identified by specialty pharmacists among patients treated with DAAs prior to and 1 month into therapy.

Methods

An observational, retrospective study was conducted to evaluate the impact of specialty pharmacy services in mitigating DDIs associated with use of DAAs. Adult patients with HCV infection (n = 200) who received DAAs and were enrolled with a specialty pharmacy service over a 1-year period were included. Endpoints included number, severity, and type of DDIs and DDIs per patient at baseline and 1 month into therapy, pharmacists’ interventions, and safety and clinical outcomes.

Results

Fifty-nine percent of patients had at least 1 DDI. A total of 170 DDIs were identified (137 at baseline and 33 at 1-month follow-up), and the mean number of DDIs per patient significantly decreased from baseline to 1-month follow-up (from 1.38 to 0.16, P < 0.0001). The rate of “potentially clinically significant” or “critical” interactions was significantly lower at 1-month follow-up vs baseline assessment (69.6% vs 81.7%, P < 0.0001). The most commonly identified DDIs involved acid suppressive medications (49.6% and 66.6% of DDIs at baseline and follow-up assessment, respectively) and cardiovascular medications (26.2% and 21.2%, respectively). Total number of DDI interventions was 131, with an acceptance rate of 85%. Most common intervention was patient education and monitoring.

Conclusion

Approximately 60% of patients had DDIs with DAAs. Implementing HCV specialty pharmacy services significantly decreased DDIs while maintaining SVR12.
Strange Games, Puppy Play and Exhaustive Intelligibility: A Response to Thi Nguyen’s Games: Agency as Art
Authors: Noë Alva
Published: March 2021

Thi Nguyen develops the view that games are, at least potentially, works of art that afford players the opportunity to experiment with agency and have aesthetically significant experiences. In this paper, I critically discuss this proposal. You can make art out of games, I argue, but only at the price of making bad games. I explore the significance of this rivalry between games and art.
Subconcussive brain vital signs changes predict head-impact exposure in ice hockey players
Authors: Fickling Shaun D , Smith Aynsley M , Stuart Michael J , Dodick David W , Farrell Kyle , Pender Sara C , D’Arcy Ryan C N
Published: March 2021

The brain vital signs framework is a portable, objective, neurophysiological evaluation of brain function at point-of-care. We investigated brain vital signs at pre- and post-season for age 14 or under (Bantam) and age 16–20 (Junior-A) male ice hockey players to (i) further investigate previously published brain vital sign results showing subconcussive cognitive deficits and (ii) validate these findings through comparison with head-impact data obtained from instrumented accelerometers. With a longitudinal study design, 23 male ice hockey players in Bantam (n = 13; age 13.63 ± 0.62) and Tier II Junior-A (n = 10; age 18.62 ± 0.86) divisions were assessed at pre- and post-season. None were diagnosed with a concussion during the season. Cognitive evoked potential measures of Auditory sensation (N100), Basic attention (P300) and Cognitive processing (N400) were analysed as changes in peak amplitudes and latencies (six standard scores total). A regression analysis examined the relationship between brain vital signs and the number of head impacts received during the study season. Significant pre/post differences in brain vital signs were detected for both groups. Bantam and Junior-A players also differed in number of head impacts (Bantam: 32.92 ± 17.68; Junior-A: 195.00 ± 61.08; P < 0.001). Importantly, the regression model demonstrated a significant linear relationship between changes in brain vital signs and total head impacts received (R = 0.799, P = 0.007), with clear differences between the Bantam and Junior-A groups. In the absence of a clinically diagnosed concussion, the brain vital sign changes appear to have demonstrated the compounding effects of repetitive subconcussive impacts. The findings underscored the importance of an objective physiological measure of brain function along the spectrum of concussive impacts.
Genetic kidney diseases as an underrecognized cause of chronic kidney disease: the key role of international registry reports
Authors: Torra Roser , Furlano Mónica , Ortiz Alberto , Ars Elisabet
Published: March 2021

Inherited kidney diseases (IKDs) are among the leading causes of early-onset chronic kidney disease (CKD) and are responsible for at least 10–15% of cases of kidney replacement therapy (KRT) in adults. Paediatric nephrologists are very aware of the high prevalence of IKDs among their patients, but this is not the case for adult nephrologists. Recent publications have demonstrated that monogenic diseases account for a significant percentage of adult cases of CKD. A substantial number of these patients have received a non-specific/incorrect diagnosis or a diagnosis of CKD of unknown aetiology, which precludes correct treatment, follow-up and genetic counselling. There are a number of reasons why genetic kidney diseases are difficult to diagnose in adulthood: (i) adult nephrologists, in general, are not knowledgeable about IKDs; (ii) existence of atypical phenotypes; (iii) genetic testing is not universally available; (iv) family history is not always available or may be negative; (v) lack of knowledge of various genotype–phenotype relationships and (vi) conflicting interpretation of the pathogenicity of many sequence variants. Registries can contribute to visualize the burden of IKDs by regularly grouping all IKDs in their annual reports, as is done for glomerulonephritis or interstitial diseases, rather than reporting only cystic disease and hiding other IKDs under labels such as ‘miscellaneous’ or ‘other’. Any effort to reduce the percentage of patients needing KRT with a diagnosis of ‘nephropathy of unknown etiology’ or an unspecific/incorrect diagnosis should be encouraged as a step towards precision nephrology. Genetic testing may be of value in this context but should not be used indiscriminately, but rather on the basis of a deep knowledge of IKDs.
Seed Predation of Interseeded Cover Crops and Resulting Impacts on Ground Beetles
Authors: Carabajal-Capitán Sara , Kniss Andrew R , Jabbour Randa
Published: March 2021

Interseeding cover crops into standing grains can promote both agronomic and environmental benefits within agroecosystems. Producers must decide which cover crops are the best fit for their goals, and whether diverse cover crop mixtures provide benefits that are worth the increased seed cost. Broadcast seeding is an accessible strategy to try interseeding but can lead to patchy establishment; it is unknown how much seed loss is due to seed predators. In a two-year study, six cover crop species—planted as either single species or mixtures—were interseeded into standing corn. We evaluated seed predation at the time of seeding, agronomic impact through cover crop, and weedy biomass at the end of the season, and conservation impact through activity-density of ground beetles (Coleoptera: Carabidae). Cover crop seeds were vulnerable to seed predation, primarily by vertebrate seed predators, and seed loss varied across cover crop species. Cover crop biomass did not differ according to cover crop diversity and weedy biomass was not affected by cover crop presence or species. Cover crop diversity effects on carabid activity-density were inconsistent: carabids were higher in diverse mixtures in 1 year of the study, but only predicted by vegetative cover, not by cover crop, in the second year. Interseeding cover crops into corn has potential benefits for ground beetles, although the value of mixtures must be further explored.
The Missing Expression Level–Evolutionary Rate Anticorrelation in Viruses Does Not Support Protein Function as a Main Constraint on Sequence Evolution
Authors: Wei Changshuo , Chen Yan-Ming , Chen Ying , Qian Wenfeng
Published: March 2021

One of the central goals in molecular evolutionary biology is to determine the sources of variation in the rate of sequence evolution among proteins. Gene expression level is widely accepted as the primary determinant of protein evolutionary rate, because it scales with the extent of selective constraints imposed on a protein, leading to the well-known negative correlation between expression level and protein evolutionary rate (the E–R anticorrelation). Selective constraints have been hypothesized to entail the maintenance of protein function, the avoidance of cytotoxicity caused by protein misfolding or nonspecific protein–protein interactions, or both. However, empirical tests evaluating the relative importance of these hypotheses remain scarce, likely due to the nontrivial difficulties in distinguishing the effect of a deleterious mutation on a protein’s function versus its cytotoxicity. We realized that examining the sequence evolution of viral proteins could overcome this hurdle. It is because purifying selection against mutations in a viral protein that result in cytotoxicity per se is likely relaxed, whereas purifying selection against mutations that impair viral protein function persists. Multiple analyses of SARS-CoV-2 and nine other virus species revealed a complete absence of any E–R anticorrelation. As a control, the E–R anticorrelation does exist in human endogenous retroviruses where purifying selection against cytotoxicity is present. Taken together, these observations do not support the maintenance of protein function as the main constraint on protein sequence evolution in cellular organisms.
Endometrial Receptivity Analysis (ERA) test: an unproven technology
Authors: Ben Rafael Zion
Published: March 2021

This article addresses the limitations of the endometrial receptivity array (ERA) methodology to increase implantation. Such limitations vary from the assumed inconsistency of the endometrial biopsy, the variable number of genes found to be dysregulated in endometrium samples without the embryonal-induced effect, the failure to account for the simultaneous serum progesterone level, and the expected low percentage of patients who may need this add-on procedure, to the difficulties in synchronising the endometrium with hormone replacements in successive cycles and the inherent perinatal risks associated with routine cryopreservation of embryos. Without a gold standard to compare, the claim that the window of implantation (WOI) might be off by ±12 h only requires a good argument for the advantage it provides to human procreation, knowing that embryos can linger for days before actual embedding starts and that the window is actually a few days. The intra-patient variations in the test need to be addressed. In summary, like all other add-ons, it is doubtful whether the ERA test use can significantly enhance implantation success rates.
Heuristic mean-variance optimization in Markov decision processes using state-dependent risk aversion
Authors: Schlosser Rainer
Published: March 2021

In dynamic decision problems, it is challenging to find the right balance between maximizing expected rewards and minimizing risks. In this paper, we consider NP-hard mean-variance (MV) optimization problems in Markov decision processes with a finite time horizon. We present a heuristic approach to solve MV problems, which is based on state-dependent risk aversion and efficient dynamic programming techniques. Our approach can also be applied to mean-semivariance (MSV) problems, which particularly focus on the downside risk. We demonstrate the applicability and the effectiveness of our heuristic for dynamic pricing applications. Using reproducible examples, we show that our approach outperforms existing state-of-the-art benchmark models for MV and MSV problems while also providing competitive runtimes. Further, compared to models based on constant risk levels, we find that state-dependent risk aversion allows to more effectively intervene in case sales processes deviate from their planned paths. Our concepts are domain independent, easy to implement and of low computational complexity.
Yield dissection models to improve yield: a case study in tomato
Authors: Tsutsumi-Morita Yutaka , Heuvelink Ep , Khaleghi Sedighehsadat , Bustos-Korts Daniela , Marcelis Leo F M , Vermeer Kim M C A , van Dijk Hannelore , Millenaar Frank F , Van Voorn George A K , Van Eeuwijk Fred A
Published: March 2021

Yield as a complex trait may either be genetically improved directly, by identifying QTLs contributing to yield, or indirectly via improvement of underlying components, where parents contribute complementary alleles to different components. We investigated the utility of two yield dissection models in tomato for identifying promising yield components and corresponding QTLs. In a harvest dissection, marketable yield was the product of number of fruits and individual fruit fresh weight. In a biomass dissection, total yield was the product of fruit fresh-dry weight ratio and total fruit dry weight. Data came from a greenhouse experiment with a population of hybrids formed from four-way RILs. Trade-offs were observed between the component traits in both dissections. Genetic improvements were possible by increasing the number of fruits and the total fruit dry weight to offset losses in fruit fresh weight and fruit fresh-dry weight ratio. Most yield QTLs colocalized with component QTLs, offering options for the construction of high-yielding genotypes. An analysis of QTL allelic effects in relation to parental origin emphasized the complementary role of the parents in the construction of desired genotypes. Multi-QTL models were used for the comparison of yield predictions from yield QTLs and predictions from the products of components following multi-QTL models for those components. Component QTLs underlying dissection models were able to predict yield with the same accuracy as yield QTLs in direct predictions. Harvest and biomass yield dissection models may serve as useful tools for yield improvement in tomato by either or both of combining individual component QTLs and multi-QTL component predictions.
Concentrations of para-Fluorofuranylfentanyl in Paired Central and Peripheral Blood Collected during Postmortem Death Investigations
Authors: Rodriguez Salas Judith , Krotulski Alex J , Newman Reta , Thogmartin Jon R , Mohr Amanda L A , Logan Barry K
Published: March 2021

The opioid epidemic in the USA has been associated with an increasing mortality rate in large part due to the emergence and proliferation of synthetic opioids over the last 15 years. Fentanyl and its analogs have played a large part in these statistics due to their potency and toxicity. Fluorofuranylfentanyl (FFF) is a fentanyl analog that emerged in the USA in 2018 and was associated with numerous adverse events and deaths. During this study, a liquid chromatography tandem mass spectrometry workflow was developed to accurately identify the isomer of FFF present (ortho- vs. meta- vs. para-) in medicolegal death investigation cases from Pinellas County, Florida. FFF was quantified in central and peripheral blood samples collected at autopsy. In addition, the metabolism of FFF was studied using liquid chromatography quadrupole time-of-flight mass spectrometry. para-FFF was quantitatively confirmed in 29 postmortem cases; no other isomer of FFF was detected. Central blood concentrations ranged between 0.66 and 73 ng/mL (mean = 11 ± 14 ng/mL, median = 10 ng/mL) and peripheral blood concentrations ranged between 0.53 and 23 ng/mL (mean = 5.7 ± 6.4 ng/mL, median = 2.7 ng/mL). A comparison of central to peripheral blood concentrations was evaluated to determine the possibility of postmortem redistribution. The metabolism of ortho-FFF was studied and found to undergo metabolic processes similar to fentanyl, producing ortho-fluorofuranyl-norfentanyl, fluoro-4-anilino-N-phenethylpiperidine, and hydroxylated species. The results of this study demonstrate the toxicity of FFF and its implication in medicolegal death investigations. Laboratories must remain aware of new or re-emerging fentanyl analogs, as they pose significant risks to public health and public safety.
A3 THE LOSS OF THE CIRCADIAN CLOCK GENE BMAL1 INCREASES TUMOUR INITIATION IN APCMIN MICE
Authors: Nunes M , Trombley C , Flôres D E , Wu G , Curran C , Taleb Z , Hogenesch J B , Karpowicz P
Published: March 2021

Background

Circadian rhythms are autonomously running 24h cycles in bodily processes. In animals these rhythms are driven by a molecular time keeper known as the circadian clock. The clock is a transcription-translation feedback loop composed of the transcription factors Bmal1 and Clock as well as their repressors Per and Cry. The circadian clock regulates over 40% of the genome rhythmically. Chronic circadian disruption, in the case of shift work, can lead to pathologies including cancer. Colorectal cancer is most frequently initiated through a mutation in the Wnt pathway regulator, Apc. Several studies have attempted to provide a mechanistic link between cancer and circadian clock disruption but the use of mice on mixed genetic backgrounds and poor circadian models have made this link unclear.

Aims

We aim to determine if the circadian clock plays a role in intestinal tumourigenesis.

Methods

We crossed the Apcmin mouse strain, a common intestinal tumour model, with Bmal1 mutant mice, which lack a functioning circadian clock. After creating an isogenic strain, we examined the number of tumours in control (Bmal1+/+) and clock dead (Bmal1-/-) animals. We derived organoids, a 3D cell culture method, from Apc+/+; Bmal1+/+ (healthy, clock-live), Apc+/+, Bmal1-/-(healthy, clock-dead), Apcmin; Bmal1+/+(adenoma, clock-live), Apcmin; Bmal1-/- (adenoma, clock-live) mouse ileum and collected every 2h from 24-48h after synchronizing their circadian clock. Collected samples were sent for RNA sequencing and assessed for circadian regulated transcripts. This experiment was followed up by in vitro organoid assays.

Results

The circadian clock controls 41 genes in the intestinal epithelium, including genes like Tead4 which are known to be important in intestinal biology. There are twofold more tumours in Bmal1-/- mice than their Bmal1+/+ littermates, and Bmal1-/- tumours upregulate Tead4 and Hippo pathway targets and downregulate Wnt pathway targets. Bmal1-/- adenoma organoids show increased self-renewal when compared to Bmal1+/+ adenoma organoids. However, this increase in self-renewal is lost when organoids are treated with inhibitors of the hippo pathway.

Conclusions

The circadian clock is important in maintaining the health of an organism, and disruption of the clock can lead to many health consequences including cancer. We show for the first time that the circadian clock controls the hippo signaling mediator Tead4. Additionally, we show that the loss of the clock leads to an increase in the number of tumours present in the epithelium which are characterized by an increase in hippo signaling. This research shows the important of considering time of day when studying stem cells during homeostasis and in cancer.

Funding Agencies

CIHRNSERC
A6 THE ROLE OF TUFT CELLS IN INTESTINAL HOMEOSTASIS
Authors: Zhang A , Pang Y , Menzies S , Sly L M
Published: March 2021

Background

Intestinal epithelial cells may actively regulate homeostasis by recognizing and responding to extracellular signals. One of these cell types, tuft cells, has been proposed to have a role in secretion, absorption, and reception. However, their role in the intestine has not been fully characterized. We have found that tuft cells express the SH2 domain-containing inositol 5’-phosphatase (SHIP), which was formerly thought to be restricted to hematopoietic cells. SHIP negatively regulates PI3K-mediated cell growth, proliferation, and activation. Tuft cells secrete IL-25, which activates group 2 innate lymphoid cells (ILC2s), leading to type 2 immune responses. Tuft cells may contribute to inflammation in the intestine by increasing ILC2 numbers and/or activation, leading to type II inflammation.

Aims

My hypothesis is that SHIP inhibits tuft cell responses to innate immune stimuli by limiting PI3K activation. Moreover, SHIP deficiency will increase tuft cell responses to commensal microbes, causing ILC2-mediated type II inflammation. To investigate the role of SHIP in tuft cell responses in vivo, I will use a tuft cell-specific SHIP deficient mouse in the dextran sodium sulfate (DSS)-induced colitis model.

Methods

We created a mouse deficient in SHIP only in intestinal tuft cells (Fabpcre x SHIPfl/fl) to investigate the impact of SHIP deficiency in tuft cells on responses to luminal microbes. Tuft cell-specific SHIP deficient mice (8-week-old) and their wild type littermates were subjected to DSS-induced colitis for 7 days. Clinical disease activity was monitored daily and gross pathology, including total colon length, was examined at the experimental endpoint. The concentrations of pro-inflammatory type I and type II cytokines were assessed in colonic tissue homogenates via ELISA.

Results

During DSS-induced colitis, mice with SHIP deficient tuft cells had increased disease activity compared to their wild type littermates, particularly evident in their weight loss. Mice with SHIP deficient tuft cells also had significantly shorter colons than their wild type littermates. IL-25 concentrations (produced by tuft cells) were increased in full thickness colon homogenates from mice with SHIP deficient tuft cells. In contrast, pro-inflammatory cytokines IL-1β, IL-6, and TNF did not differ between genotypes. Thus, increased tuft cell activity due to SHIP deficiency correlated with increased disease severity during DSS-induced colitis.

Conclusions

SHIP deficiency in intestinal tuft cells leads to increased tuft cell activity and exacerbated colitis during DSS treatment. Tuft cells may contribute to inflammation via IL-25 production, leading to increased type II inflammation by ILC2s. In future studies, we will target IL-25 in this model to determine whether increased tuft cell IL-25 production plays a causal role in disease exacerbation.

Funding Agencies

NSERC
A10 FOOD ANTIGEN-STRESS INTERACTION LEADS TO INCREASE PAIN SIGNALING IN ILEUM AND COLON VIA STAT6 IN AN IBS MODEL
Authors: Lopez Lopez C , Jaramillo Polanco J , Yu Y , Tsang Q K , Vanner S , Reed D E
Published: March 2021

Background

Abdominal pain can be triggered by food ingestion in IBS patients. Previously we have shown that a food antigen induces local release of immune mediators in the colon that increase dorsal root ganglion (DRG) neuron excitability when there is previous antigen exposure in the presence of psychological stress. However, it is unknown if this effect is limited to the colon. Furthermore, the involvement of histamine in the neuronal hyperexcitability suggests that the stress-food antigen interaction evokes a Th2 immune response. Thus, we sought to investigate the role of STAT6, a transcription factor downstream of Th2 cytokines and important for IgE production.

Aims

1) Determine if stress-food antigen interaction leads to release of mediators within the small intestine that increase DRG neuron excitability. 2) Determine the involvement of STAT6 on neuronal hyperexcitability induced by the stress-food antigen interaction.

Methods

BALB/c mice were exposed to water avoidance stress (WAS) or sham stress (SHAM) for 1 hr daily for 10 days. On day 2–10, mice were exposed to ovalbumin (OVA) or saline (SAL). Seven days later, mice were re-exposed to either OVA or SAL every 2 days for 2 weeks yielding 3 groups: WAS/OVA+OVA, WAS/SAL+OVA, and SHAM/OVA+OVA. STAT6 deficient mice were also exposed to WAS/OVA+OVA protocol. Ileum or colonic supernatants were obtained 4 hours after tissue collection. DRG neurons were incubated overnight with supernatants prior to perforated patch clamp recordings. Neuronal excitability was evaluated by measuring the rheobase (minimum current to elicit an action potential, decreased rheobase indicates increased excitability). Mechanosensitivity of extrinsic afferent nerves innervating distal ileum was examined using ex vivo extracellular afferent nerve recordings. Data was analyzed by one or two-way ANOVA with Bonferroni post-hoc test.

Results

Ileum supernatants from WAS/OVA+OVA mice increased DRG neuron excitability compared to WAS/SAL+OVA and SHAM/OVA+OVA mice (63.3 ± 6.2 pA vs 83.2 ± 5.4 pA, 86.7 ± 4.5 pA, p<0.05). Ileum afferent nerve response to distention was significantly augmented in WAS/OVA+OVA mice compared to WAS/SAL+OVA and SHAM/OVA+OVA (P<0.05, n=4–7). DRG neurons incubated with WAS/OVA+OVA supernatant from STAT6 deficient mice were less excitable compared to neurons incubated with colonic supernatants from wild type mice (86.5 ± 4.1 pA vs 67.6 ± 4.8 pA, p<0.05).

Conclusions

Stress-food antigen interaction releases mediators in both the small intestine and colon to increase nociceptive signaling, an important finding as IBS can involve both areas. The release of excitatory mediators within the gut appears to involve STAT6. Thus, a stress-food antigen interaction evoking a Th2 immune response in the gut may be a mechanism underlying food induced symptoms in IBS.

Funding Agencies

Queen’s University, Department of Medicine
A19 HEALTH CARE UTILIZATION DIFFERENCES BETWEEN FIRST NATIONS AND THE GENERAL POPULATION WITH INFLAMMATORY BOWEL DISEASE IN SASKATCHEWAN
Authors: Marques Santos J , Fowler S , Jennings D , Brass C , Porter L , Porter R , Sanderson R , Peña-Sánchez J
Published: March 2021

Background

Indigenous patients with inflammatory bowel disease (IBD) have expressed concerns about barriers to access IBD care. The limited evidence of IBD among Indigenous people highlights the need for studies evaluating access to IBD care in this population.

Aims

We aimed to compare health care utilization between First Nations (FNs) and individuals from the general population (GP) diagnosed with IBD in Saskatchewan (SK).

Methods

A population-based retrospective cohort study was conducted using administrative health databases of SK from 1998 to 2017 fiscal years. As a patient-oriented research initiative, outcomes of interest were chosen in collaboration with Indigenous patients and family advocates. A validated algorithm requiring multiple health care contacts was applied to identify incident IBD cases. The self-declared FN status variable was used to divide IBD cases between FNs and the general population (GP). To balance the groups, 1:5 age and sex matching was applied. Cox-proportional models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95%CI). Stratified analysis was completed for those diagnosed before and after 2008 (pre- and post-biologic eras).

Results

A matched cohort with 696 IBD incident cases was created (FN=116, GP=580). Comparing health care utilization of FNs and individuals from the GP with IBD, there were no statistically significant differences in outpatient gastroenterology visits (FNs=81.0%, GP=83.6%), colonoscopies (FNs=91.4%, GP=86.9%), and surgeries for IBD (FNs=31.0%, GP=33.5%). We observed differences in prescription claims for any medication for IBD (FNs=79.3%, GP=89.3%) and 5-aminosalicylic acid (5-ASA) claims (FNs=75.9%, GP=81.4%). The HRs adjusted by rural/urban residence and diagnostic type showed differences in prescription claims for any IBD medication (HR=0.52, 95%CI 0.41–0.65) and 5-ASA (HR=0.57, 95%CI 0.45–0.72). In the pre-biologic era, FNs had a lower risk of having a prescription claim for any IBD medication (HR=0.32, 95%CI 0.23–0.45) and 5-ASA (HR=0.33, 95%CI 0.24–0.47), respectively. These differences were not significant in the post-biologic era.

Conclusions

Our study identified an inverse association between FN status and having prescription medication claims for IBD in SK. We considered multiple confounding variables when evaluating this association but could not control by disease severity. Thus, this association might reflect a barrier to access IBD medications or that FNs with IBD might present a milder disease. Further studies should continue evaluating access to IBD care, medication use, and disease severity among FNs living with IBD.

Funding Agencies

Saskatchewan Centre for Patient-Oriented Research (SCPOR), Saskatchewan Health Research Foundation (SHRF), and College of Medicine, University of Saskatchewan.
A20 DIAGNOSTIC ACCURACY OF A LOW COST, WIDELY AVAILABLE TEST STRIP FOR PREDICTING A POSITIVE FECAL CALPROTECTIN TEST
Authors: Trasolini R , Wong S , Salh B
Published: March 2021

Background

Fecal calprotectin is a non-invasive test of colonic inflammation used for monitoring inflammatory bowel disease activity and for risk stratifying non-specific colonic symptoms. Calprotectin is a leukocyte specific enzyme. A similar test, leukocyte esterase is used to detect leukocytes in urine and is widely available as a low-cost point-of-care test strip. We hypothesize that an unmodified version of the urine test strip would be highly accurate in predicting a positive fecal calprotectin test in a real world sample of patients.

Aims

To explore a low cost, rapid alternative to the fecal calprotectin test

Methods

All inpatient and outpatient stool samples tested for calprotectin by the Vancouver General Hospital laboratory from February 2020 to November 2020 were included prospectively. Samples were simultaneously tested for fecal leukocyte esterase using an unmodified Roche Cobas Chemstrip urinalysis test strip by central lab personnel. An identical aliquot was sent to LifeLabs for calprotectin as per standard protocol. All samples were suspended in buffer using established laboratory protocols prior to testing. Fecal leukocyte esterase results were reported as 0–4+ based on visual interpretation, calprotectin results were reported as mcg/g of stool. REB review and approval was obtained prior to data collection. Sensitivity, Specificity and AUROC were calculated using Microsoft Excel and JROCFIT.

Results

26 samples were collected. Using a fecal calprotectin greater than 120 mcg/g as a gold standard an AUROC of 0.89 (SE= .06) was calculated. A leukocyte esterase reading of 2+ or greater had the best test characteristics based on ROC curve analysis. Using this cutoff, 21/26 samples were concordant, giving an accuracy of 80.8%, sensitivity of 90.9% and specificity of 73.3%. Positive likelihood ratio was 8.07 and negative likelihood ratio was 0.29. Assuming an AUROC of 0.8, the sample size N=26 is 90% powered (β=0.9) to predict the true AUROC within 0.1 with a type I error rate of .05 (α<.05).

Conclusions

This study suggests application of a prepared stool sample to a urinalysis test strip gives a result highly predictive of a positive fecal calprotectin test. Further results are being collected prospectively to improve the robustness of these preliminary data. Secondary outcomes including comparison to endoscopy and biopsy results where available are planned if an adequate sample size can be accrued. Future studies justifying independent clinical use of leukocyte esterase would require a common gold standard comparator such as endoscopy. Fecal calprotectin testing is not universally insured and is not available as a rapid test strip. Use of fecal leukocyte esterase may reduce costs and shorten time to results if proven to be independently reliable.

Funding Agencies

None
A31 COMPLEX ROLE OF DIETARY FIBERS IN IBD: MICROBES MEDIATE FIBER-INDUCED INFLAMMATION
Authors: Armstrong H , Valcheva R , Santer D , Zhang Z , Rieger A , Dijk S I , Dickner R , Jerasi J , Mander I K , Moreau F , Gorman H , Lafleur D , Jovel J , Petrova A , Chadee K , Carroll M W , Huynh H Q , Madsen K , Dieleman L A , Wine E
Published: March 2021

Background

Dietary fibers pass through the bowel undigested and are fermented within the intestine by microbes, typically promoting gut health. However, many IBD patients describe experiencing sensitivity to fibers. β-glucan, found on the surface of fungal cells during fungal infection, has been shown to bind to fiber receptors, such as Dectin-1, on host immune cells, resulting in a pro-inflammatory response. These fungal fibres share properties with dietary fibers.

Aims

As an altered gut microbial composition has been associated with IBD, we hypothesized that the loss of fiber-fermenting microbes populating the gut in IBD could lead to dietary fibers not being efficiently broken down into their beneficial biproducts (e.g. short chain fatty acids; SCFA), resulting in binding of intact fibers to pro-inflammatory host cell receptors.

Methods

Immune and epithelial cell lines and colonic biopsies cultured ex vivo were incubated with oligofructose or inulin (5g/L), or pre-fermented fibers (24hr anaerobic fermentation). Immune responses were measured by cytokine secretion (ELISA), and expression (qPCR). Barrier integrity was measured by transepithelial resistance (TEER). Food frequency questionnaire (FFQ) data of patient fiber consumption were correlated with gut microbes (shotgun sequencing) and immune responses to fiber in patient biopsies.

Results

Unfermented oligofructose induced IL-1β secretion in leukocytes (macrophage, T cell, neutrophil) and in colon biopsies from pediatric Crohn disease (CD; n=38) and ulcerative colitis (UC; n=20) patients cultured ex vivo, but not in non-IBD patients (n=21). IL-1β secretion was greater in patients with more severe disease. Pre-fermentation of oligofructose by whole-microbe intestinal washes from non-IBD patients or remission patients reduced secretion of IL-1β, while whole microbe intestinal washes from severe IBD patients were unable to ferment oligofructose or reduce cytokine secretion. Fiber effects on IL-1β secretion in biopsies positively correlated with effects on barrier integrity in T84 cells. Fiber-associated immune responses in patient biopsies cultured ex vivo (ELISA) correlated with fiber avoidance (FFQ) and gut microbiome (sequencing) in matching patient samples.

Conclusions

Our findings demonstrate that intolerance and avoidance of prebiotic fibers in select IBD patients is associated with the inability to ferment these fibers, leading to pro-inflammatory immune responses and intestinal barrier disruption. This highlights select disease state scenarios, in which administration of fermentable fibers should be avoided and tailored dietary interventions should be considered in IBD patients.

Funding Agencies

CIHRWeston Foundation