Significant Dip Research Articles

Type 1 diabetes incidence increased during the COVID-19 pandemic years 2020-2021 in Czechia: Results from a large population-based pediatric register.

BackgroundTo explore type 1 diabetes incidence patterns during the pandemic years 2020 and 2021 in Czechia, to compare them to the trends from the previous decade, and to test its association with indicators of containment measures and of pandemic severity (school closing and the all‐cause excess mortality).MethodsThe Czech Childhood Diabetes Register is a population‐based incidence register recording patients age 0–14.99 years at diabetes onset. Type 1 diabetes incidence in the pandemic period (April 2020–end of observation Dec 2021) was compared by Poisson regression models to the incidence patterns over the past decade 2010–2019.ResultsDuring the pandemic years 2020–2021, 956 children 0–14.99 years old manifested with type 1 diabetes in Czechia. The observed incidence (27.2/100,000/year) was significantly higher than what was expected from the trends over 2010–2019 (incidence rate ratio, IRR = 1.16, 95%CI 1.06–1.28, p = 0.0022). The incidence had a trough during the first lockdown (March–May 2020), then it rose above expected values with no usual summer decrease. The assessed pandemic indicators (school closing and all‐cause excess mortality) were not associated with the incidence levels.ConclusionsThe COVID‐19 pandemic was associated with a notable upward inflection of the type 1 diabetes incidence curve; the early months of the first lockdown were however hallmarked by a significant dip in new diabetes diagnoses. Long‐term observation will show whether the increased incidence originated only from accelerating an advanced preclinical Stage 2 to overt diabetes, or whether the pandemic triggered new cases of islet autoimmunity.

MO692: A Four-Year Analysis on Home Dialysis at the North Bristol NHS Trust—What to Do Next?

Abstract BACKGROUND AND AIMS Home dialysis, including peritoneal dialysis (PD) and home hemodialysis (HHD), has been associated with improved patient autonomy, quality of life and overall cost effectiveness (Weinhandl et al. Propensity matched mortality comparison of incident hemodialysis and peritoneal dialysis patients. J Am Soc Nephrol. 2010; 21: 499–506). The 2021 Get It Right First Time (GIRFT) Renal report revealed that home dialysis patients were at a lower risk of contracting and dying of coronavirus disease 2019 (COVID-19), compared to those who received in-center hemodialysis (ICHD) (2). Despite these advantages, uptake of home dialysis is still lower than that of ICHD. The aim of our study was to analyse the numbers and reasons for home dialysis withdrawal at the North Bristol NHS Trust between 2018 and 2021. METHOD All patients on PD and HHD between 2018 and 2021 were included. Analysis of the episodes that led to home dialysis cessation was carried out. As some patients required withdrawal more than once during the 4-year period, each episode of dropout was considered separately. The prevalence rate of patients on home dialysis was calculated. RESULTS The total number of patients on home dialysis increased from 74 in 2018 to 98 in 2021. The male: female ratio of patients was 3:2 with an average age of 58.3. The number of patients on PD increased from 58 at the end of 2018 to 82 in 2021. The number of patients on HHD remained stable over the years, with an average of 16. The prevalence rate of home dialysis was 17.1% at the end of 2021. Figure 1 shows the total number of patients who started and dropped out of home dialysis every year. The number of patients initiating PD was 58 in 2018, 55 in 2019, 37 in 2020 and 59 in 2021. The number of dropouts was 57 in 2018, 41 in 2019, 29 in 2020 and 43 in 2021. The dip in number of patients initiated on PD in 2020 can be attributed to the start of the COVID-19 pandemic, when elective procedures were temporarily withheld. On the other hand, a lower number dropped out during 2020. This may be explained by the emphasis given to self-isolation rules and persistence with home dialysis during the outbreak. The overall increase in PD uptake in 2021 may be explained by the establishment of a new specialist clinic that promotes the uptake of home dialysis. The initiation of a new peer support service group in 2021 may also have contributed. The number of patients initiating and withdrawing from HHD followed the same pattern, with a significant dip in 2020. Figure 2 demonstrates the reasons for withdrawal from PD over the study period. The most prevalent reasons were PD-related infections and transplantation. The observed figures for transplantation reflect the continuous efforts involved in the maintenance of a successful transplant programme. The figure also shows that termination of PD due to failure was highest in 2021. The authors postulate that this surge might be due to the previous year's low PD dropout rate. The leading reason for stopping HHD was transplantation. Other reasons included recovery of renal function and switching to conservative management. Death led to one dropout/year in 2018–20, but none in 2021. CONCLUSION Around 17% of the NBT’s total dialysis population is currently on home dialysis. The commonest reasons for termination of home dialysis were transplantation and PD-related infections. The GIRFT report recommends that all adult renal units in the UK should reach a minimum prevalence rate of 20% of their dialysis population on home dialysis by the end of 2024 (Lipkin et al. Renal medicine: Get It Right First Time (GIRFT) Programme National Specialty Report. March 2021. NHS England and NHS Improvement). Whereas our statistic falls slightly short of this, we aim to reach this target through various strategies. These include continued audit, home dialysis campaign, continued psychological services and a reduction in waiting time for PD catheter insertion.

ERG and Behavioral CFF in Light-Damaged Albino Rats.

The full-field ERG is useful for index rod- or cone-mediated retinal function in rodent models of retinal degeneration. However, the relationship between the ERG response amplitudes and visually guided behavior, such as flicker detection, is not well understood. A comparison of ERG to behavioral responses in a light-damage model of retinal degeneration allows us to better understand the functional implications of electrophysiological changes. Flicker-ERG and behavioral responses to flicker were used to determine critical flicker frequency (CFF) under scotopic and photopic conditions before and up to 90 d after a 10-day period of low-intensity light damage. Dark- and light-adapted ERG flash responses were significantly reduced after light damage. The a-wave was permanently reduced, while the b-wave amplitude recovered over three weeks after light damage. There was a small, but significant dip in scotopic ERG CFF. Photopic behavioral CFF was slightly lower following light damage. The recovery of the b-wave amplitude and flicker sensitivity demonstrates the plasticity of retinal circuits following photopic injury.

Mitigating load burden on smart grid via EVs

World energy consumption is quickly rising as a result of population and economic expansion, particularly in big emerging economies, which will account for 90% of energy demand increase through 2035. Electric vehicles (EVs) are critical components of the electrification revolution aimed at reducing the carbon footprint. In this case study, a completely different side of EVs is explored where EVs can be used as an energy storage unit that has the potential to meet the demands of high energy needs in a variable electricity tariff setting. The study proposed in this work suggests that energy stored in EVs can also be used back in the smart grid at the time of high energy requirements which can significantly decrease the load shedding in both urban and rural areas. The simulation model presented on MATLAB shows a significant dip in energy demand after electricity stored in the Electric vehicles is used back in the smart grid. The study also proposed an ensemble model that is able to predict the overload in the Grid. The ensemble model achieving the R2 score of 0.87 and RMSE value of 0.06.

Air and water health: industrial footprints of COVID-19 imposed lockdown

Overall lockdown limitations toward the start of the year 2020 are credited to the annihilation and fatalities worldwide because of COVID-19. Most of the nations revealed rapid growth of COVID-19 cases and subsequently declared lockdown in several stages. Because of these lockdowns, industries had to stop producing goods other than the actual merchandise needed to survive. The air quality and natural water quality witnessed a noticeable improvement from limited human activity. This paper presents an investigation demonstrating this improvement under various lockdown periods, specifically for the Indian subcontinent. The rivers and atmosphere of Indian settings have been utilized here as a contextual analysis associated with industrial pollution. This work aims to study the associations and interrelationships between lockdowns during COVID-19 and their effect on air and water quality. The paper presents then and now an analysis of the Indian atmosphere based on various particulate matters and river health based on the biological oxygen demand, chemical oxygen demand, and dissolved oxygen. The study indicated a significant dip in air and water pollution levels and a significant improvement in the atmosphere and rivers’ quality during this period. Significant water bodies witnessed the pH level of 7.5 amidst lockdown, which is a good indicator of improved water health since the pH level of drinkable water is 7. The analysis carried out in this paper can also be mapped to other countries and landscapes of the world.

Seismic evidence of two cryptic sutures in Northwestern Australia: Implications for the style of subduction during the Paleoproterozoic assembly of Columbia

Plate tectonics, including rifting, subduction, and collision processes, was likely to have been different in the past due to the secular cooling of the Earth. The northeastern part of the West Australian Craton (WAC) has a complex Archean and Paleoproterozoic tectonic history; therefore, it provides an opportunity to study how subduction and collision processes evolved during the emergence of plate tectonics, particularly regarding the assembly of Earth's first supercontinent, Columbia. Because the northeastern boundary of the WAC and the southwestern boundary of the North Australian Craton (NAC) are covered by the Phanerozoic Canning Basin, the regional tectonic evolution has remained enigmatic, including how many tectonic elements were assembled and what may have driven rifting and subsequent collision events. Here, we use new passive-source seismic modeling to identify a seismically distinct segment of the lithosphere, the Percival Lakes Province, which lies east of the Pilbara Craton and is separated by two previously unknown southeast-trending lithosphere scale Paleoproterozoic sutures. We interpret that the northeastern suture, separates the Percival Lakes Province from the NAC, records the amalgamation of the WAC with the NAC. The southwestern suture separates the PLP from the reworked northeastern margin of the Pilbara Craton, including the East Pilbara Terrane and the Rudall Province. A significant upper mantle dipping structure was identified in the southwestern suture, and we interpret it to be a relic of subduction that records a previously unknown Paleoproterozoic collision that pre-dated the amalgamation of the WAC and NAC. By comparing our findings with previously documented dipping features, we show that the Paleoproterozoic collisions are seismically distinguishable from their Phanerozoic counterparts.

Geometry-dependent rupture process of the 2015 Gorkha, Nepal, earthquake determined using a dip-varying inversion approach with teleseismic, high-rate GPS, static GPS and InSAR data

SUMMARYFault geometry is widely recognized as one of the most important factors that affect the rupture process and damages of earthquakes. However, there have been few earthquake cases in which the close relation between the fault geometry and rupture process is resolved from inversions of seismic and geodetic observations. In this study, we develop an approach to simultaneously estimate the rupture process and dip-angle variation on the fault. The effectiveness of our new approach was validated through inverse numerical tests. We apply the new approach to the 2015 Mw7.8 Gorkha earthquake and obtain a dip-varying rupture model by jointly inverting the teleseismic, near-fault high-rate GPS, static co-seismic GPS and InSAR data. Our results show a ramp–flat décollement-ramp fault geometry of the earthquake. The shallow ramp may have prevented the rupture from breaking through to the surface. The variation of dip angle changing with depth leads to significantly different rupture velocities and rupture lengths at shallow and deep fault portions. Particularly, the northeastern downdip ramp behaves as a geometric barrier and rapidly slows down the rupture propagation in 35–45 s after the rupture initiation. In contrast, the rupture duration and fault length in the updip portion are relatively long since there is no significant lateral dip change. Furthermore, the approach can improve our understanding of the relationship between rupture behaviour and fault geometry for other thrust low-dip-angle (dip < 45°) earthquakes.

Solid-Density Ion Temperature from Redshifted and Double-Peaked Stark Line Shapes.

Heβ spectral line shapes are important for diagnosing temperature and density in many dense plasmas. This work presents Heβ line shapes measured with high spectral resolution from solid-density plasmas with minimized gradients. The line shapes show hallmark features of Stark broadening, including quantifiable redshifts and double-peaked structure with a significant dip between the peaks; these features are compared to models through a Markov chain MonteCarlo framework. Line shape theory using the dipole approximation can fit the width and peak separation of measured line shapes, but it cannot resolve an ambiguity between electron density n_{e} and ion temperature T_{i}, since both parameters influence the strength of quasistatic ion microfields. Here a line shape model employing a full Coulomb interaction for the electron broadening computes self-consistent line widths and redshifts through the monopole term; redshifts have different dependence on plasma parameters and thus resolve the n_{e}-T_{i} ambiguity. The measured line shapes indicate densities that are 80-100% of solid, identifying a regime of highly ionized but well-tamped plasma. This analysis also provides the first strong evidence that dense ions and electrons are not in thermal equilibrium, despite equilibration times much shorter than the duration of x-ray emission; cooler ions may arise from nonclassical thermalization rates or anomalous energy transport. The experimental platform and diagnostic technique constitute a promising new approach for studying ion-electron equilibration in dense plasmas.

Effects of whole body vibration on human contrast sensitivity function

Introduction: Vibration is a known aeromedical stressor in rotary-winged aircraft and is known to affect visual acuity (VA). In aerospace operational conditions, contrast sensitivity (CS) takes the upper hand over VA for optimal visual performance. Examination of the effects of low frequencies whole body vibration of short duration on CS was the desired objective of the study. Material and Methods: Thirty healthy volunteers were exposed to low frequency whole body vibration using Multi-axial Vibration Simulator. Vibration frequency along the Z-axis varied from 4 to 20 Hz over a period of 30 min. CS was recorded in no vibration, under vibration and 30 min following exposure to vibration using CSV-1000 equipment at spatial frequencies of 3, 6, 12, and 18 cycles per degree (cpd). Results: CS, after an initial degradation, gradually improved with the increase in frequencies of vibration for the lower spatial frequencies (3, 6 cpd). The increasing trend was also noticed for higher spatial frequencies (12, 18 cpd) till 16 Hz; thereafter, a significant dip (P = 0.048) was observed at 20 Hz of vibration. No significant difference was observed following 30 min of post exposure. Conclusion: In contrast to the popular belief, an improvement in CS with increasing frequencies of vibration could be concluded from the results of the study. However, the sudden decrement in CS at higher CPD at higher frequencies of vibration could adversely affect visual performance of an aircrew.

Hip fractures: mortality and correlation with preoperative comorbidities in Indian elderly population

<p class="abstract"><strong>Background:</strong> Hip fractures are an emerging health care problem due to increase in the elderly population all over the world and the associated complications, morbidity and mortality. The objective of this study is to find out the mortality rates in Indian elderly population with hip fractures and to establish an association between various related complications pre and post operatively for a better risk stratification.</p><p class="abstract"><strong>Methods: </strong>A prospective observational cohort study, was carried out at a high-volume orthopaedic centre from 2009 to 2018. And all patients managed for hip fractures were followed up till death or 05 years.</p><p class="abstract"><strong>Results: </strong>The age adjusted first-year mortality was found to be 33% with statistically significant increase in the mortality in individuals with three or more pre-op comorbidities. The significantly associated co-morbidities were chronic renal failure (Hazard ratio 2.32 with CI 1.65- 3.24) and diabetes mellitus (Hazard ratio 1.66 with CI 1.25 – 2.21). There has been a significant dip in the cumulative survival rates of these individuals irrespective of age, sex, preop anaemia.</p><p class="abstract"><strong>Conclusions: </strong>A knowledge about the comorbidities/ risk factors and the extent to which they influence the long-term survival in the geriatric hip fracture patients can help treating physician to effectively prioritise and plan management in coordination with allied specialities. </p>

Early detection of exacerbation of the severe acute respiratory syndrome coronavirus 2 infection using Fitbit (DEXTERITY pilot study)

Abstract Some patients with coronavirus disease 2019 (COVID-19) experienced sudden death because of sudden symptom deterioration. Thus, an alarm system that could detect early signs of COVID-19 exacerbation beforehand, to prevent serious illness or death of patients while receiving outpatient treatment at home or in hotels is necessary. Here, we tested whether estimated oxygen variations (EOV), a relative physiological scale that represents users' blood oxygen saturation level during sleep measured by Fitbit, predicted COVID-19 symptom exacerbation. Study period was from August to November 2020. We enrolled 23 COVID-19 patients diagnosed by SARS-CoV-2 polymerase chain reaction-positive (mean age ± standard deviation, 50.9±20 years; 70% female), let each patient wore the Fitbit for 30 days; COVID-19 symptoms were exacerbated in 6 (26%). High EOV signal (a patient's oxygen level exhibits significant dip and recovery within the index period) had 80% sensitivity before symptom exacerbations, whereas resting heart rate signal only had 50% sensitivity. Coincidental obstructive sleep apnea syndrome confirmed by polysomnography was detected in a patient by consistently high EOV signals. This pilot study successfully detected early COVID-19 symptoms exacerbation by measuring EOV and may help to identify early signs of COVID-19 exacerbation. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): The investigational device used in this study, Fitbit Charge 3, was provided by Fitbit Japan. Summary of high EOV signals and eventsThe clinical course of COVID-19

Early Detection of Symptom Exacerbation in Patients With SARS-CoV-2 Infection Using the Fitbit Charge 3 (DEXTERITY): Pilot Evaluation.

BackgroundSome patients with COVID-19 experienced sudden death due to rapid symptom deterioration. Thus, it is important to predict COVID-19 symptom exacerbation at an early stage prior to increasing severity in patients. Patients with COVID-19 could experience a unique “silent hypoxia” at an early stage of the infection when they are apparently asymptomatic, but with rather low SpO2 (oxygen saturation) levels. In order to continuously monitor SpO2 in daily life, a high-performance wearable device, such as the Apple Watch or Fitbit, has become commercially available to monitor several biometric data including steps, resting heart rate (RHR), physical activity, sleep quality, and estimated oxygen variation (EOV).ObjectiveThis study aimed to test whether EOV measured by the wearable device Fitbit can predict COVID-19 symptom exacerbation.MethodsWe recruited patients with COVID-19 from August to November 2020. Patients were asked to wear the Fitbit for 30 days, and biometric data including EOV and RHR were extracted. EOV is a relative physiological measure that reflects users’ SpO2 levels during sleep. We defined a high EOV signal as a patient’s oxygen level exhibiting a significant dip and recovery within the index period, and a high RHR signal as daily RHR exceeding 5 beats per day compared with the minimum RHR of each patient in the study period. We defined successful prediction as the appearance of those signals within 2 days before the onset of the primary outcome. The primary outcome was the composite of deaths of all causes, use of extracorporeal membrane oxygenation, use of mechanical ventilation, oxygenation, and exacerbation of COVID-19 symptoms, irrespective of readmission. We also assessed each outcome individually as secondary outcomes. We made weekly phone calls to discharged patients to check on their symptoms.ResultsWe enrolled 23 patients with COVID-19 diagnosed by a positive SARS-CoV-2 polymerase chain reaction test. The patients had a mean age of 50.9 (SD 20) years, and 70% (n=16) were female. Each patient wore the Fitbit for 30 days. COVID-19 symptom exacerbation occurred in 6 (26%) patients. We were successful in predicting exacerbation using EOV signals in 4 out of 5 cases (sensitivity=80%, specificity=90%), whereas the sensitivity and specificity of high RHR signals were 50% and 80%, respectively, both lower than those of high EOV signals. Coincidental obstructive sleep apnea syndrome confirmed by polysomnography was detected in 1 patient via consistently high EOV signals.ConclusionsThis pilot study successfully detected early COVID-19 symptom exacerbation by measuring EOV, which may help to identify the early signs of COVID-19 exacerbation.Trial RegistrationUniversity Hospital Medical Information Network Clinical Trials Registry UMIN000041421; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000047290

Investigation of the steady and unsteady forces acting on a pair of circular cylinders in crossflow up to ultra-high Reynolds numbers

Measurements of the steady and unsteady forces acting on a pair of circular cylinders in crossflow are performed from subcritical up to ultra-high Reynolds numbers. The two cylinders with equal diameters d are arranged inline at two centre-to-centre distances: S/d = 2.8 and 4. The trend of the drag curve for the upstream cylinder Cd_{1}(Re) at both distances is similar to that for a single circular cylinder. The development of the drag curves Cd_{2}(Re, S/d = 2.8, 4) of the downstream cylinder is inverse to that of the upstream cylinder. For both cylinder spacing values, the drag on the downstream cylinder is negative for subcritical Reynolds numbers, increases abruptly to positive values at the beginning of the supercritical regime, and shows a significant dip at transcritical Reynolds numbers. This drag inversion indicates that the critical distance Sc decreases sharply in the supercritical Reynolds number range. For S/d = 2.8 at Rerightarrow 10^{7}, the downstream cylinder experiences once more a thrust force. The curve of the Strouhal number St(Re) of the downstream cylinder for S/d = 4 is very close to that of a single cylinder. For Reynolds numbers of Reapprox 1times10^{6} - 7times10^{6}, the Strouhal numbers have nearly equal values of Stapprox 0.22 - 0.24 for both distances. This is followed by a branching. For Rerightarrow 10^{7} and the case S/d = 2.8, the Strouhal numbers dip at St = 0.17. However, for S/d = 4, they increase up to St = 0.27. In the supercritical range, two peaks occur in the power spectra for the large distance S/d = 4. Based on a wavelet analysis, we can conclude that the low-frequency mode, which does not occur for a single cylinder, is an interference effect.Graphic abstract

Crystal Growth, Tetrahertz Generation, and Optical Characterization of EHPSI-4NBS

Nonlinear optical (NLO) organic crystals such as DAST, OH1, HMQ-TMS, and BNA have shown value as highly efficient terahertz (THz) generators, compared to their inorganic crystal counterparts. This is due to their higher peak electric fields and THz pulses with broader bandwidths generated with simple optical rectification setups. However, organic crystals exhibit phonon absorptions that reduce the THz output at specific frequencies. This is clearly appreciated in the state-of-the-art DAST crystal, which shows a significant generation dip at 1.1 THz. To solve this problem, new NLO organic crystals capable of producing THz radiation with unique spectra are under constant development, and the discovery of improved THz sources can help accelerate a host of condensed matter studies that are enabled with high-field THz science. In this article, we introduce the crystal growth and optical characterization of EHPSI-4NBS, and a comprehensive comparison of THz generation with benchmark organic crystals, showing that this novel crystal features higher generated electric fields. EHPSI-4NBS covers the electromagnetic spectrum from 0.1 to 3.8 THz without significant generation dips. These advantages make EHPSI-4NBS a promising crystalline material for THz generation applications.

A fluidized-bed reactor for enhanced mass transfer and increased performance in thermally regenerative batteries for low-grade waste heat recovery

A thermally regenerative battery with a fluidized-bed reactor design (TRB-FB) is developed to enhance mass transfer and promote battery performance. The results demonstrate that the fluidized-bed design induces highly efficient mass transfer and improves the battery performance considerably. Comparative tests show that the highest power density (11.6 W m−2), total charge (274.6 C), and energy density based on the anolyte volume (834.2 Wh m−3) are obtained with the TRB-FB. Moreover, reversibility testing over successive cycles reveals that the TRB-FB generates a relatively stable power output over 15 batch cycles. Although a decreased particle diameter induces better fluidization, highly efficient mass transfer, and improved performance, an exceedingly small particle diameter results in decreased fluidization and a significant dip in battery performance. The optimal particle diameter is determined to be 187.5 μm. In addition, increasing the stirring rate within a certain range further enhances mass transfer and promotes battery performance.

Effect of TiC particles on ductility dip cracking susceptibility of Ni-base superalloy

Ni-base superalloy FM-52M is mainly used in welded structures of key equipment of nuclear power plants, such as pressure vessels and heat dissipation evaporators. It is prone to form coarse columnar microstructures during welding and has significant ductility dip cracking (DDC) susceptibility. This work attempted to introduce micrometre-sized TiC particles into FM-52M welds to refine the microstructure and alleviate sensitivity to DDC. A Ni–TiC coating with good dispersion and uniformity of TiC particles was first prepared on the substrate by composite electroplating. The TiC particles were then directly introduced into the molten pool during tungsten–inert gas welding. Scanning electron microscopy and electron backscatter diffraction were used to analyse the microstructure of the weld and strain-to-fracture testing was performed to evaluate its DDC sensitivity. The experimental results showed that solidification grains of the weld were obviously refined and its high-temperature mechanical properties were reinforced. The minimum critical strain for DDC increased to approximately 3.5%, and the crack morphology was small and tortuous. Compared with the original material, the microstructure and DDC resistance of the weld were improved by introducing TiC particles.

On the impact of absorbed dose specification, tissue heterogeneities, and applicator heterogeneities on Monte Carlo-based dosimetry of Ir-192, Se-75, and Yb-169 in conventional and intensity-modulated brachytherapy for the treatment of cervical cancer.

The purpose of this study was to evaluate the impact of dose reporting schemes and tissue/applicator heterogeneities for 192 Ir-, 75 Se-, and 169 Yb-based MRI-guided conventional and intensity-modulated brachytherapy. Treatment plans using a variety of dose reporting and tissue/applicator segmentation schemes were generated for a cohort (n=10) of cervical cancer patients treated with 192 Ir-based Venezia brachytherapy. Dose calculations were performed using RapidBrachyMCTPS, a Geant4-based research Monte Carlo treatment planning system. Ultimately, five dose calculation scenarios were evaluated: (a) dose to water in water (Dw,w ); (b) Dw,w taking the applicator material into consideration (Dw,wApp ); (c) dose to water in medium (Dw,m ); (d and e) dose to medium in medium with mass densities assigned either nominally per structure (Dm,m (Nom) ) or voxel-by-voxel (Dm,m ). Ignoring the plastic Venezia applicator (Dw,wApp ) overestimates Dm,m by up to 1% (average) with high energy source (192 Ir and 75 Se) and up to 2% with 169 Yb. Scoring dose to water (Dw,wApp or Dw,m ) generally overestimates dose and this effect increases with decreasing photon energy. Reporting dose other than Dm,m (or Dm,m Nom ) for 169 Yb-based conventional and intensity-modulated brachytherapy leads to a simultaneous overestimation (up to 4%) of CTVHR D90 and underestimation (up to 2%) of bladder D2cc due to a significant dip in the mass-energy absorption ratios at the depths of nearby targets and OARs. Using a nominal mass-density assignment per structure, rather than a CT-derived voxel-by-voxel assignment for MRI-guided brachytherapy, amounts to a dose error up to 1% for all radionuclides considered. The effects of the considered dose reporting schemes trend correspondingly between conventional and intensity-modulated brachytherapy. In the absence of CT-derived mass densities, MRI-only-based dosimetry can adequately approximate Dm,m by assigning nominal mass densities to structures. Tissue and applicator heterogeneities do not significantly impact dosimetry for 192 Ir and 75 Se, but do for 169 Yb; dose reporting must be explicitly defined since Dw,m and Dw,w may overstate the dosimetric benefits.

Association of central blood pressure profile, ambulatory blood pressure parameters with 2D echocardiographic diastolic dysfunction and carotid intima-media thickness in patients with coronary artery disease

Introduction: Blood Pressure (BP) and its diurnal variability are linked to endothelial dysfunction and arterial stiffness, promoting atherosclerosis which can be observed as intimal thickening in carotid arteries and atherosclerotic lesions in coronary angiograms. Objectives: To evaluate the association of Diastolic Dysfunction (DD) in patients with Coronary Artery Disease (CAD) with central and Ambulatory Blood Pressure Monitoring (ABPM) indices and to assess Carotid Intima Media Thickness (CIMT) in different CAD score groups and then to compare the results with individuals having normal coronaries. Methodology: A descriptive cross-sectional study was conducted at Cardiology Unit Kandy in 2017/18. Patients undergoing elective coronary angiography were categorized in to low, intermediate and high SYNTAX score group. Invasive BP was recorded and Pulsatility Index (PI) was derived. Carotid ultrasound was used to assess CIMT and diastolic function was assessed by 2D echocardiogram. Patients had their 24-hour ABPM recorded. Results were compared with individuals having normal coronary arteries on angiogram. Results: There were a total of 60 subjects out of which 40 (Mean age=59.77±8.73years) had angiographically proven CAD and 20 subjects had no CAD on angiogram. Amongst the CAD group the calculated PI was 0.82±0.36. The ratio of early diastolic mitral inflow velocity to annular velocity (E/e’) which denotes diastolic dysfunction, had strong positive correlation with PI (r=0.942, p=0.002). The mean CIMT for right and left carotid arteries were 0.62±0.11mm and 0.65±0.13mm respectively. A higher but statistically insignificant (p=0.087) CIMT value was noted among patients with SYNTAX score ≥ 23 (7.55±3.01) than in SYNTAX score ≤ 22 (6.87±1.93). Low SYNTAX score group had 45%, (n=18) abnormal dipping pattern in ABPM whereas only 12.5%, (n=05) in the intermediate to high score group showed this pattern, which was statistically highly significant (X2=30.7, p=0.004). Between the CAD group and subjects having normal coronary arteries, the following parameters did not show statistically significant difference. Invasively derived PI (0.76±0.17 and 0.78±0.15, p=0.318), ABPM-derived atherogenic index (r=0.005, p=0.658 and r=0.003, p=0.554), CIMT value (0.63±0.10 mm and 0.52±0.19 mm, p=0.196) and the mitral annular E/e’ velocity (9.56±5.40 and 10.81±3.22, p=0.372). Conclusion: Diastolic dysfunction which is reflected by E/e’ positively correlated with invasively derived PI which indicate incipient arterial stiffness. Therefore E/e’ could be used as a non-invasive tool to assess arterial stiffness indirectly. In ABPM, statistically significant abnormal dipping pattern was observed in low SYNTAX group compared to high group which demonstrates the difference in BP variability and haemodynamic diversity amongst CAD patients with different atherosclerotic disease burden. These findings reflect the usefulness of non-invasive parameters such as E/e’ and CIMT to predict the extent of coronary artery disease and the need for further detailed studies in this field using large patient population in order to find out the best non-invasive parameter which independently predict the CAD burden.

Review of ionospheric irregularities and ionospheric electrodynamic coupling in the middle latitude region

This paper briefly reviews ionospheric irregularities that occur in the E and F regions at mid-latitudes. Sporadic E (ES) is a common ionospheric irregularity phenomenon that is first noticed in the E layer. ES mainly appears during daytime in summer hemispheres, and is formed primarily from neutral wind shear in the mesosphere and lower thermosphere (MLT) region. Field-aligned irregularity (FAI) in the E region is also observed by Very High Frequency (VHF) radar in mid-latitude regions. FAI frequently occurs after sunset in summer hemispheres, and spectrum features of E region FAI echoes suggest that type-2 irregularity is dominant in the nighttime ionosphere. A close relationship between ES and E region FAI implies that ES may be a possible source of E region FAI in the nighttime ionosphere. Strong neutral wind shear, steep ES plasma density gradient, and a polarized electric field are the significant factors affecting the formation of E region FAI. At mid-latitudes, joint observational experiments including ionosonde, VHF radar, Global Positioning System (GPS) stations, and all-sky optical images have revealed strong connections across different scales of ionospheric irregularities in the nighttime F region, such as spread F (SF), medium-scale traveling ionospheric disturbances (MSTID), and F region FAI. Observations suggest that different scales of ionospheric irregularities are generally attributed to the Perkins instability and subsequently excited gradient drift instability. Nighttime MSTID can further evolve into small-scale structures through a nonlinear cascade process when a steep plasma density gradient exists at the bottom of the F region. In addition, the effect of ionospheric electrodynamic coupling processes, including ionospheric E-F coupling and inter-hemispheric coupling on the generation of ionospheric irregularities, becomes more prominent due to the significant dip angle and equipotentiality of magnetic field lines in the mid-latitude ionosphere. Polarized electric fields can map to different ionospheric regions and excite plasma instabilities which form ionospheric irregularities. Nevertheless, the mapping efficiency of a polarized electric field depends on the ionospheric background and spatial scale of the field.

Chloroquine nasal drops in asymptomatic & mild COVID-19: An exploratory randomized clinical trial.

Background & objectives:Chloroquine (CQN) administered as nasal drops has the potential to achieve much greater local tissue levels than with oral/systemic administration. This trial was undertaken to study the efficacy and safety profile of topical nasal administration of CQN drops in reducing viral load and preventing clinical progression in early COVID-19 infection.Methods:This randomized clinical trial was done with a sample size of 60. Reverse transcription-polymerase chain reaction (RT-PCR) confirmed asymptomatic patients or those with mild COVID-19 illness [National Early Warning Score (NEWS) ≤4] were included. Patients were randomized in a 1:1 manner. Control arm (standard supportive treatment, n=30) was compared with intervention arm (n=30) of standard treatment plus CQN eye drops (0.03%) repurposed as nasal drops administered six times daily (0.5 ml/dose) for 10 days. Outcome measures were adverse events and adherence; clinical progression and outcomes were measured by NEWS; sequential RT-PCR cycle threshold (Ct) values were also noted on days 0, 3, 7 and 10.Results:Nasal CQN was associated with local irritation in seven and non-compliance in one of 30 patients. Eleven patients were excluded due to enrolment error (2 – recovered; 9 – false-positive referral), and 49 patients were analyzed as per modified intention-to-treat analysis. Clinical recovery was noted as similar with 100 per cent asymptomatic by day seven in both arms. Virological outcomes also indicated similarly improving Ct values in both arms, and similar proportion of patients transitioning to non-infectivity by day 10 (controls - 19/25; nasal CQN - 15/24). Nine false-positive patients with enrolment error and day 0 RT-PCR negative were initially uninfected but had continuing COVID-19 exposure and treatment as per randomization. Patients receiving nasal CQN (n=5) demonstrated stable Ct values from day 0 to 10, while patients with no nasal CQN (n=4) demonstrated significant dip in Ct value indicating to infection (Ct<35) and infectivity (Ct<33).Interpretation & conclusions:The present study suggests to the potential of topical nasal CQN in the prevention of COVID-19 infection if administered before the infection is established. No significant differences in clinical or virological outcome were however, demonstrated in patients with mild but established illness.