No-slip billiards with particles of variable mass distribution

Astute variations in the geometry of mathematical billiard tables have been and continue to be a source of understanding their wide range of dynamical behaviors, from regular to chaotic. Viewing standard specular billiards in the broader setting of no-slip (or rough) collisions, we show that an equally rich spectrum of dynamics can be called forth by varying the mass distribution of the colliding particle. We look at three two-parameter families of billiards varying both the geometry of the table and the particle, including as special cases examples of standard billiards demonstrating dynamics from integrable to chaotic, and show that markedly divergent dynamics may arise by changing only the mass distribution. Furthermore, for certain parameters, billiards emerge, which display unusual dynamics, including examples of full measure periodic billiards, conjectured to be nonexistent for the standard billiards in Euclidean domains.

Au nanoparticles decorated polypyrrole-carbon black/g-C3N4 nanocomposite as ultrafast and efficient visible light photocatalyst

Modification and bandgap engineering are proposed to be extremely significant in improving the photocatalytic activity of novel photocatalysts. The current research focused on the fabrication of ultrafast and efficient visible light-responsive ternary photocatalyst containing g-C₃N₄ nanostructures in conjugation with polypyrrole doped carbon black (PPy-C) and gold (Au) nanoparticles by highly effectual, simple, and straightforward methodology. Various analytical techniques like XRD, FESEM, TEM, XPS, FTIR, and UV-Vis spectroscopy were applied for characterization purposes. The XRD and XPS results confirmed the successful creation of a nanocomposite framework among Au, PPy-C and g-C₃N₄. The TEM images revealed that bare g-C₃N₄ holds sheets or layered graphitic structure with sizes ranging from 100 to 300 nm. The sponge-like PPy-C network intermingled perfectly with g-C₃N₄ sheets along with homogeneously distributed 5-15 nm Au nanoparticles. The band gap energy (E_g) for bare g-C₃N₄, PPy-C/g-C₃N₄ and Au@PPy-C/g-C₃N₄ nanocomposites were found to be 2.74, 2.68, and 2.60 eV, respectively. The photocatalytic activity for all newly designed photocatalysts have been assessed during the degradation of insecticide Imidacloprid and methylene blue (MB) dye, where Au@PPy-C/C₃N₄ was found to be extremely efficient with ultrafast removal of both imidacloprid and MB in just 25 min of visible light irradiation. It was revealed that the Au@PPy-C/g-C₃N₄ ternary photocatalyst removed 96.0% of target analyte imidacloprid, which is ⁓ 2.91 times more efficient than bare g-C₃N₄ in treating imidacloprid. This report provides a distinctly promising, highly effectual and straightforward route to destruct extremely toxic and notorious pollutants and opens a new gateway in the present challenging scenario of environmental concerns.

Development of Methanol Sensor Based on Sol-Gel Drop-Coating Co3O4·CdO·ZnO Nanoparticles Modified Gold-Coated µ-Chip by Electro-Oxidation Process

Herein, novel Co₃O₄·CdO·ZnO-based tri-metallic oxide nanoparticles (CCZ) were synthesized by a simple solution method in basic phase. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), Dynamic Light Scattering (DLS), Tunneling Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS) techniques to characterize the CCZ nanoparticles. XRD, TEM, DLS, and FESEM investigations have confirmed the tri-metallic nanoparticles’ structure, while XPS and EDS analyses have shown the elemental compositions of the CCZ nanoparticles. Later, a Au/μ-Chip was modified with the CCZ nanoparticles using a conducting binder, PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in a sol-gel system, and dried completely in air. Then, the CCZ/Au/μ-Chip sensor was used to detect methanol (MeOH) in phosphate buffer solution (PBS). Outstanding sensing performance was achieved for the CCZ/Au/μ-Chip sensor, such as excellent sensitivity (1.3842 µAµM⁻¹cm⁻²), a wide linear dynamic range of 1.0 nM–2.0 mM (R² = 0.9992), an ultra-low detection limit (32.8 ± 0.1 pM at S/N = 3), a fast response time (~11 s), and excellent reproducibility and repeatability. This CCZ/Au/μ-Chip sensor was further applied with appropriate quantification results in real environmental sample analyses.

Correlation of signal averaged electrocardiography findings with fibrosis on cardiac magnetic resonance imaging

Background

Signal averaged electrocardiogram (SAECG) is a non invasive test to record delayed depolarization of myocardium with slow conduction that can potentially be the substrate for monomorphic ventricular tachycardia in high risk patients. Cardiac magnetic resonance imaging (cMRI) techniques for fibrosis imaging using late gadolinium enhancement (LGE) and T1 mapping remain the gold standard for characterization of myocardial tissue and triaging patients for risk of ventricular arrhythmias. However, cMRI remains unavailable in some areas, is time consuming, expensive and impossible for some patients to obtain due to claustrophobia, renal impairment or implanted hardware. To date, data is lacking with regards to correlation of findings between these two modalities.

Purpose

To investigate whether late potentials identified by SAECG correlate with the presence of fibrosis seen with cMRI. If correlation is established, SAECG could potentially be used as a non-invasive, cheaper, more convenient and readily available tool for risk stratification in patients at high risk for ventricular arrhythmias.

Methods

SAECGs were obtained in 25 consecutive patients undergoing cMRI. Patients with wide QRS (>120 ms) on ECG were excluded. Positive SAECG was defined as at least 1/3 abnormal criteria. Standard criteria were used. Results of the 2 modalities were compared. Sensitivity and specificity of SAECG for diagnosing fibrosis on cMRI were calculated.

Results

The mean age of the patients was 50.3±5.8 years and the mean ejection fraction was 48.9±5.8% as determined by cMRI. Forty-eight percent of the patients had fibrosis on cMRI by either LGE, T1 mapping or both. The sensitivity and specificity of SAECG were 75% and 100%, respectively. Seven patients had history of ventricular tachycardia and 6 patients had dilated cardiomyopathy.

Conclusion

SAECG is extremely specific in identifying patients with myocardial fibrosis on cMRI. A positive test may confer a lesser indication to pursue cMRI solely for purposes of risk stratification, and may correlate with risk of ventricular arrhythmia.

Funding Acknowledgement

Type of funding sources: None.

124 The Microsurgical Learning Curve: Can We Make the First Steps Faster and Safer; A Cadaveric Study with A Novel Principle of Learning

Aim

Learning anew surgical technique can be a daunting experience for both the teacher and learner. Raising free flaps is a complex process, and our aim is to find out whether using Hi-fidelity simulation on cadavers can make the learning faster and safer.

Method

We used fresh frozen cadavers according to our local protocols. In the first stage of the study, we used 4 upper limbs in the first instance using different dye techniques. We use these in an international course and obtain feedback from the trainees.

Results

To a novel learner, we found that using a bright green dye was the important factor in making the first steps of learning easier and faster. This is perhaps due to the confounding information when raising the flap. We found that it made understanding the concept of free flap raising much faster when clarified with colour. It also made anticipating the steps easier when identifying the perforators. To an experienced trainee/consultant: We found teaching the concept of perforators easier, the ease of finding the perforators would raise confidence of the novel trainees. They will be able to conceptualize the principles of flap raising much faster. They believed it would also make them quicker at anticipating steps of the procedure.

Conclusions

Learning is an incredible process that we still have to better control and understand. Using simple tricks such as colour changes can make initial learning faster, which means cheaper and safer

Using ethnographic film in tackling podoconiosis

Background

Ethiopia has one of the worst podoconiosis rates in the world, affecting >1.5 million patients. We present our ethnographic film ‘Tigist, the story of a girl with podoconiosis’ and its potential use in tackling podoconiosis.

Methods

We conducted visual ethnography, consisting of video-recorded participant observations and interviews with seven patients, three healthcare workers and two podoconiosis experts.

Results

We acquired video recordings of social moments, the state of podoconiosis patients’ bodies and minds, their emotions and the impact of poverty.

Conclusions

Our film allows for an intensified understanding of patients’ daily experiences with podoconiosis, potentially impacting care, awareness and medical teaching programs.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

The predictive value of CHA2DS2-VASc score on adverse in-hospital outcomes among patients with the acute coronary syndrome and atrial fibrillation who undergo PCI

Background

Patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) and having concomitant atrial fibrillation (AF) have a greater risk of adverse short- and long-term outcomes and death compared with patients in the same setting but without AF. On the other hand, the predictive value of CHA2DS2-VASc score in terms of in-hospital mortality and periprocedural adverse events following PCI among patients with ACS and AF is unknown.

Purpose

We retrospectively analyzed data of patients with the main admission diagnosis of ACS that underwent PCI and had AF during the 2004–2014 period from the large nationwide US National Inpatient Sample (NIS) database.

Methods

A CHA2DS2-VASc score was calculated for each patient and incorporated into a multivariable-adjusted logistic regression to determine its independent impact on in-hospital outcomes consisting of death, acute kidney injury (AKI), bleeding, vascular injury, and stroke/transient ischemic attack (TIA).

Results

A total of 283,890 patients with AF who underwent PCI following ACS were included in the analysis. The average reported prevalence of the AF in the whole cohort was 10.0% with a significant trend (p<0.001) of increase during the observed 10-year period. The average age of the cohort was 72.1±11 years, 63.4% were male while the median CHA2DS2-VASc score was 3 (IQR 2–4). Crude rates of adverse in-hospital outcomes were significantly higher among patient groups with higher CHA2DS2-VASc score (Table 1). Following adjustment for baseline covariates, incremental increase in CHA2DS2-VASc score was independently associated with an increased odds of in-hospital death (OR 1.20, CI 95% 1.18–1.22), periprocedural vascular injury (OR 1.18, 95% CI 1.17–1.20), bleeding (OR 1.17, 95% CI 1.16–1.18), stroke/TIA (OR 1.17, 95% CI 1.15–1.19), and AKI (OR 1.05, 95% CI 1.04–1.06) (Figure 1).

Conclusions

The CHA2DS2-VASc score provides important prognostic information in ACS patients with AF undergoing PCI and is independently associated with in-hospital death and periprocedural adverse events. Therefore, CHA2DS2-VASc score could be used as a practical and inexpensive tool for risk stratification in this population.

Figure 1

Funding Acknowledgement

Type of funding source: None

The Rhipicephalus appendiculatus tick vector of Theileria parva is absent from cape buffalo (Syncerus caffer) populations and associated ecosystems in northern Uganda

Rhipicephalus appendiculatus is the major tick vector of Theileria parva, an apicomplexan protozoan parasite that causes the most economically important and lethal disease of cattle in East and central Africa. The African cape buffalo (Syncerus caffer) is the major wildlife host of T. parva from southern Uganda and Kenya to southern Africa. We show herein that R. appendiculatus appears to be absent from the two largest national parks in northern Uganda. Syncerus caffer is common in both of these national parks, specifically Murchison falls (MFNP) and Kidepo Valley (KVNP). We re-confirmed the previously reported absence of T. parva in buffalo sampled in the two northern parks based on RLB data using a nested PCR based on the T. parva p104 gene. By contrast, T. parva-infected R. appendiculatus ticks and parasite-infected buffalo were present in Lake Mburo (LMNP) in South central Uganda. This suggests that the distribution of R. appendiculatus, which is predicted to include the higher rainfall regions of northern Uganda, may be limited by additional, as yet unknown factors.

Electrocatalytic Oxidation of 4-Aminophenol Molecules at the Surface of an FeS2 /Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium

FeS₂ /carbon nanotube (CNT) nanocomposites were synthesized and immobilized on the surface of a glassy carbon electrode (GCE) in order to investigate the electrocatalytic conversion of 4-aminophenol (4-AP) into p-quinone in an aqueous medium. The reformed electronic properties (in terms of lowering of band-gap energy and charge-transfer resistance), as well as improved surface area, result in an enhanced redox reaction of 4-AP in the presence of FeS₂ -CNT NCs compared to that with FeS₂ alone. The 4-AP molecules undergo coupled two-proton and two-electron transfer quasi-reversible redox reactions with a symmetry factor of 0.55 and standard rate constant (k°) of 0.8 cm s^-1 . Here, quinone imine is generated as an intermediate which is later converted into quinone in an irreversible hydrolysis reaction. The best catalytic performance can be obtained at the pH value of 7.0.

Fabrication of a hydrazine chemical sensor based on facile synthesis of doped NZO nanostructure materials

In this approach, nickel-doped zinc oxide (NZO) nanostructure materials were synthesized by the solution method in the basic phase.

P1732The additive value of pre- and post-reperfusion cardiac troponin T levels in risk stratification of patients with ST-segment elevation myocardial infarction

Background

Despite therapeutic advances, mortality rates following ST-segment elevation myocardial infarction (STEMI) are still alarmingly high. There is conflicting evidence regarding the prognostic role of high-sensitivity cardiac troponin T (hs-cTnT) measurements before and after primary percutaneous coronary intervention (PPCI) over traditional predictors of mortality in STEMI patients.

Purpose

To determine the additive prognostic value of pre- and 12h post-PPCI hs-cTnT levels in STEMI patients

Methods

Retrospective longitudinal study including 3,113 consecutive STEMI patients treated with PPCI at a university hospital covering a population of 1.6 million in the North East of England. Clinical, procedural, and laboratory data were prospectively collected during patient hospitalization while hs-cTnT measurements were performed at admission to the catheterization laboratory and at 12h post-PPCI. Median follow-up was 53 months. The study endpoints were in-hospital and overall mortality. Mortality data were obtained from the UK Office of National Statistics.

Results

Admission hs-cTnT >515ng/L (4th quartile) was independently associated with in-hospital mortality [HR=2.39 per highest to lower quartiles; 95% CI: 1.44 to 3.97; p=0.001] after multivariate adjustment for a core clinical model of in-hospital mortality prediction. Likewise, admission hs-cTnT >515ng/L independently predicted overall mortality (HR=1.25 per highest to lower quartiles; 95% CI: 1.00 to 1.57; p=0.044) after adjustment for covariates significantly associated with this endpoint. Admission hs-cTnT correctly reclassified risk for in-hospital death [net reclassification index (NRI)=44.1%, p<0.001) and overall mortality (NRI=60.4%, p<0.001). Conversely, 12h hs-cTnT was not independently associated with mortality.

Conclusion

Admission, but not 12h post-reperfusion, hs-cTnT predicts mortality and improves risk stratification in the PPCI era. These results support the role of hs-cTnT in risk stratification of post-STEMI patients and challenge the cost-effectiveness of routine 12h hs-cTnT measurements.

Assessment of the prevalence of Theileria lestoquardi in sheep from the Sudan using serological and molecular methods

Malignant theileriosis of sheep and goats caused by Theileria lestoquardi is considered to be among the most important tick borne diseases in the Sudan. Information on the prevalence of the disease in different parts of the Sudan is limited. The purpose of this study was to estimate the prevalence of the disease in five states of the Sudan using molecular and serological assays. A total of 393 blood and serum samples from clinically asymptomatic sheep were analysed using nested reverse line blot (nRLB) and loop mediated isothermal amplification (LAMP), as well as an enzyme-linked immunosorbent assay (ELISA). The results indicated a sero-prevalence of 33.8% while RLB and LAMP assays revealed molecular prevalences of 29.5 and 22.6% respectively. The prevalence of Theileria lestoquardi varied significantly according to the geographical origin of the infected animals, whereas age and gender did not have a significant effect. RLB data indicated that T. lestoquardi usually occurred as a co-infection with the non-pathogenic Theileria ovis. Using RLB as a gold standard, a sensitivity of 68.1% and a specificity of 96.4% were recorded for LAMP and a sensitivity of 75.9% and a specificity of 83.8% for ELISA. The Kappa coefficient between nRLB and LAMP indicated a significant level of agreement (0.692), but only moderate concordance (0.572) between nRLB and ELISA. The results of the present study confirm and extend earlier findings regarding the widespread of T. lestoquardi infections in sheep in the Sudan. The data provide evidence that should enable the veterinary authorities to deploy appropriate control measures.

European consensus on the standardization of robotic total mesorectal excision for rectal cancer

AIM

Surgery for rectal cancer is challenging for both technical and anatomical reasons. The European Academy of Robotic Colorectal Surgery (EARCS) provides a competency-based training programme through a standardized approach. However, there is no consensus on technical standards for robotic surgery when used during surgery for rectal cancer. The aim of this consensus study was to establish operative standards for anterior resection incorporating total mesorectal excision (TME) using robotic techniques, based on recommendations of expert European colorectal surgeons.

METHOD

A Delphi questionnaire with a 72-item statement was sent through an electronic survey tool to 24 EARCS faculty members from 10 different countries who were selected based on expertise in robotic colorectal surgery. The task was divided into theatre setup, colonic mobilization and rectal dissection, and each task area was further divided into several subtasks. The levels of agreement (A* > 95% agreement, A > 90%, B > 80% and C > 70%) were considered adequate while agreement of < 70% was considered inadequate. Once consensus was reached, a draft document was compiled and sent out for final approval.

RESULTS

The average length of experience of robotic colorectal surgery for participants in this study was 6 years. Initial agreement was 87%; in nine items, it was < 70%. After suggested modifications, the average level of agreement for all items reached 94% in the second round (range 0.75-1).

CONCLUSION

This is the first European consensus on the standardization of robotic TME. It provides a baseline for technical standards and structured training in robotic rectal surgery.

Findings from aetiological investigation of Auditory Neuropathy Spectrum Disorder in children referred to cochlear implant programs

OBJECTIVES

Auditory neuropathy spectrum disorder (ANSD) is an audiological diagnosis characterised by hearing dysfunction in the presence of intact outer hair cell function in the cochlea. ANSD is thought to account for 7-10% of all childhood permanent hearing impairment, and can result from a range of pathological processes. This paper describes the rationale, methods and findings from the aetiological investigation of ANSD.

METHODS

Retrospective audit of four cochlear implant programmes.

RESULTS

97 patients were identified. 79% of patients were identified before the age of one. Prematurity and jaundice were the most frequently identified aetiological factors. 33 patients had cochlear nerve deficiency on imaging. Genetic diagnoses identified included otoferlin, SX010 gene, connexin 26 and A1FM1 gene mutations. ANSD was seen in conjunction with syndromes including Kallman syndrome, CHARGE syndrome, X-linked deafness, SOTOS syndrome, Brown Vieletto Van Laere syndrome, and CAPOS syndrome.

DISCUSSION

We present a two-level system of aetiological investigation that is clinically practical. Patients with ANSD sufficiently severe to consider cochlear implantation are generally identified at an early age. Aetiological investigation is important to guide prognosis and identify comorbidity.

CONCLUSION

Prematurity and jaundice are the most commonly identified aetiological factors in ANSD. Imaging findings identify crucial factors in a significant minority. An important minority may have genetic and syndromic diagnoses that require further management.

Selective bilirubin sensor fabrication based on doped IAO nanorods for environmental remediation

In this approach, low-dimensional facile IAO nanorods were prepared by using the hydrothermal technique, which is efficiently applied to develop a non-enzymatic sensor coated with GCE probe by electrochemical reduction method.