Voltage-controlled two-dimensional Fresnel diffraction pattern in quantum dot molecules

This study explores the influence of inter-dot tunneling effects within a quantum dot molecule on the Fresnel diffraction phenomenon. Our findings indicate that the Fresnel diffraction of the output probe Gaussian field can be manipulated by adjusting the inter-dot tunneling parameter's strength and the characteristics of the coupling field. The inter-dot tunneling effect establishes a closed-loop system, setting conditions for the interference of the applied fields. We specifically examine a Laguerre-Gaussian (LG) coupling field, investigating how its properties-such as strength, value, and sign of the orbital angular momentum (OAM)-impact the Fresnel diffraction of the output probe field. Increasing the inter-dot tunneling parameter and the coupling LG field's strength allows for control over the spatial distribution of the Fresnel diffraction pattern. Notably, the inter-dot tunneling parameter can disturb the symmetry of the diffraction patterns. Additionally, considering a negative OAM for the coupling LG field transforms the diffraction pattern into its inverse shape. This suggests that, in the presence of the inter-dot tunneling effect, the Fresnel diffraction pattern is contingent on the direction of rotation of the helical phase front of the coupling LG field. Our results offer insights into quantum control of Fresnel diffraction patterns and the identification of OAM in LG beams, presenting potential applications in quantum technologies.

Microwave optical limiting via an acoustic field in a diamond mechanical resonator

We investigate the generation and control of the reverse saturable absorption (RSA) and optical limiting (OL) at microwave (mw) range in high-Q single-crystal diamond mechanical resonator (DMR) embedded with many nitrogen-vacancy (NV) centers. The strain-induced acoustic modes enable mechanical manipulation of NV centers. On the basis of strain-coupling mechanism, it is shown that the saturable absorption (SA) switches to the RSA by applying the acoustic field, leading to induce the OL in the diamond through the cross-Kerr effect. We demonstrate that the OL characteristics such as, threshold, efficiency, and dynamic range can be controlled by changing either the intensity or frequency of the acoustic field. Moreover, we show that this optical limiter can amplify noiselessly the low intensity of the mw field input to the sensors and also attenuate any gain-induced noise and increase in the intensity of the mw field if it exceeds the intensity threshold. In addition, it is shown that by increasing either the number of NV centers or length of the diamond, the optical limiter can be more efficient. The physical mechanism of the OL establishment is explained using the analytical expressions, which are in good agreement with the numerical results. Our proposed acoustic-induced optical limiter can be a scheme for protecting different optical and electronic devices in mw range, remote sensing, navigation, communications, microwave heating and thermo/laser therapy.

Clinical features and bleeding risk factors of angiodysplasia lesions in a Tunisian population

INTRODUCTION

Gastrointestinal angiodysplasia (GIAD) is the most common vascular anomaly in the gastrointestinal (GI) tract, yet little is known about the factors favoring their bleeding. Our study aim was to determine the characteristics of patients with GIAD lesions in a Tunisian population and identify the risk factors of bleeding.

PATIENTS AND METHODS

A retrospective study was carried out from January 2010 to February 2020 at a tertiary care medical center in Tunisia. Clinical and endoscopic data were collected from each patient's medical reports. We divided the patients into two groups: group A, patients with symptomatic GIAD; and group B, patients with incidental lesions. Group A was subsequently divided into two subgroups, according to the presence or absence of recurrent bleeding. The groups were compared by clinical, laboratory, and endoscopic features.

RESULTS

GIAD was diagnosed in 114 patients, with a mean age of 70 ± 13.3 years. GIAD lesions were mainly located in the colon (n = 72, 63%). Fifty-four patients (47%) presented with GIAD-related bleeding. The bleeding diagnosis was made during endoscopic procedures by visualizing active bleeding and the stigmata of recent hemorrhage in 10 (18.5%) and 12 (22.2%) cases, respectively. Most of the patients were treated by argon plasma coagulation (93%). Predictive factors of bleeding were age > 75 years, number of lesions >10, chronic kidney disease, diabetes mellitus, and coronary artery disease (p: 0.008; 0.002; 0.016; 0.048; and 0.039, respectively).

CONCLUSION

Knowledge of the predictive factors of bleeding aids endoscopists in the decision-making process in cases of angiodysplasia.

Bleeding disorder of unknown cause: Results from Iranian study

BACKGROUND

Definite diagnosis of patients with mild to moderate bleeding is challenging. Some studies reported that even more than 50% of their patients remained undiagnosed which is classified as a Bleeding disorder of unknown cause (BDUC). This study aims to document the clinical characteristics and proportion of patients with BDUC in the Iranian Comprehensive Hemophilia Care Center (ICHCC) one of the referral centers for diagnosis of congenital bleeding disorder in Iran.

METHODS

This study was conducted on 397 patients who were referred with a bleeding manifestation to ICHCC from 2019 to 2022. Demographic and laboratory data were documented for all patients. Bleeding questionnaires including ISTH-Bleeding Assessment tool (ISTH-BAT) and the Molecular and Clinical Markers for the Diagnosis and Management of Type 1 (MCMDM-1 (ISTH-BAT, MCMDM-1, and the Pictorial Bleeding Assessment Chart (PBLAC) were filled out for all patients. The data were analyzed by the statistical package for social science (SPSS version 22, SPSS, Chicago, Illinois, USA).

RESULTS

BDUC was diagnosed in 200 patients and 197 patients reached the final diagnosis. Hemophilia, von Willebrand disease (VWD), factor (F) VII deficiency, and platelet functional disorders (PFDs) were confirmed in 54, 49, 34, and 15 of the patients, respectively. No significant difference was found in bleeding scores between patients with BDUC and those with confirmed disease. In contrast, after setting cut-off (ISTH-BAT for males ≥ 4 and females ≥ 6 and MCMDM-1 for males ≥ 3 and females ≥ 5) clinically significant difference was found. There was no association between having a positive consanguineous marriage and setting a diagnosis; however, significant associations were seen for having a positive family history of bleeding. Age (OR =0.977, 95% CI.965-0.989), gender (BDUC female, 151/200; final diagnosis female, 95/197) (OR=3.3, 95% CI 2.16-5.06), family history (OR = 3.19, 95% CI 1.99-5.11), and consanguineous marriage (OR=1.59, 95% CI 1.03-2.45) were considered as a risk factor for categorizing the patients with BDUC or final diagnosis.

CONCLUSION

The findings are mainly in line with previous studies about BDUC patients. The large number of patients with BDUC underlines the incompleteness of available routine laboratory tests and shows the necessity of progress in the development of reliable diagnostic tools to identify underlying bleeding disorders.

Natural killer cells and their exosomes in viral infections and related therapeutic approaches: where are we?

Innate immunity is the first line of the host immune system to fight against infections. Natural killer cells are the innate immunity lymphocytes responsible for fighting against virus-infected and cancerous cells. They have various mechanisms to suppress viral infections. On the other hand, viruses have evolved to utilize different ways to evade NK cell-mediated responses. Viruses can balance the response by regulating the cytokine release pattern and changing the proportion of activating and inhibitory receptors on the surface of NK cells. Exosomes are a subtype of extracellular vesicles that are involved in intercellular communication. Most cell populations can release these nano-sized vesicles, and it was shown that these vesicles produce identical outcomes to the originating cell from which they are released. In recent years, the role of NK cell-derived exosomes in various diseases including viral infections has been highlighted, drawing attention to utilizing the therapeutic potential of these nanoparticles. In this article, the role of NK cells in various viral infections and the mechanisms used by viruses to evade these important immune system cells are initially examined. Subsequently, the role of NK cell exosomes in controlling various viral infections is discussed. Finally, the current position of these cells in the treatment of viral infections and the therapeutic potential of their exosomes are reviewed. Video Abstract.

Validity and reliability of the Persian version of the Cornell Scale for Depression in Dementia

The current study aimed to evaluate the validity and reliability of the Persian version of the Cornell Scale for Depression in Dementia (CSDD) in 100 patients aged ≥60 with dementia in Tehran, Iran. Test-retest reliability and internal consistency were analyzed through intraclass correlation coefficient and Cronbach's alpha tests, respectively. The validity was assessed in the areas of face, content and structural validity. The Geriatric Depression Scale (GDS) and The Montgomery-Åsberg Depression Rating Scale (MADRS) were also used to determine the convergent validity. The intraclass correlation coefficient (ICC) was equal to or more than 0.8 between the results of determining depression twice via the CSDD. The internal consistency (Cronbach's α = 0.90) was excellent. The factor analysis, identified five main factors (mood-related signs, behavioral disturbance, physical signs, cyclic functions and ideational disturbance), aside from depression, demonstrated the variance to be 37.88%. Evaluating convergent validity showed satisfactory results (p < 0001). Using the MADRS as standard. the best cut-points for the CSDD via the use of the Youden index were scores of 5.5, 10.5 and 16.5 for mild, moderate and severe depression, respectively. The Persian version of the CSDD is sufficient in terms of validity and reliability for screening depression in the elderly with dementia in Iran.

Natural killer cells in COVID-19: from infection, to vaccination and therapy

Natural killer (NK) cells are among the most important innate immunity members, which are the first cells that fight against infected cells. The function of these cells is impaired in patients with COVID-19 and they are not able to prevent the spread of the disease or destroy the infected cells. Few studies have evaluated the effects of COVID-19 vaccines on NK cells, though it has been demonstrated that DNA vaccines and BNT162b2 can affect NK cell response. In the present paper, the effects of SARS-CoV-2 on the NK cells during infection, the effect of vaccination on NK cells, and the NK cell-based therapies were reviewed.

Optical limiting via spontaneously generated coherence

We investigate the reverse saturable absorption (RSA) and optical limiting (OL) in a three-level V-type quantum system considering the effect of the spontaneously generated coherence (SGC). It is shown that in the absence of the SGC effect, the saturable absorption (SA) is dominant in the system. By taking into account the SGC effect, we prove that the SA dramatically switches to the RSA. Moreover, it is demonstrated that the OL threshold and OL efficiency can be controlled by the SGC effect. In addition, we show that the applied field properties such as detuning can modify the SGC-induced optical limiter efficiency. It is also shown an increase in the atomic density and length of the medium makes the optical limiter more efficient. The analytical calculation shows that the Kerr nonlinearity caused by the SGC effect is the main mechanism of the system evolution. Finally, the theoretical Z-scan experiment is presented to confirm the obtained results. Our proposed scheme can be useful to design controllable atomic optical limiters for optical devices with different sensitivities.

The Role of NK Cells and Their Exosomes in Graft Versus Host Disease and Graft Versus Leukemia

Natural killer (NK) cells are one of the innate immune cells that play an important role in preventing and controlling tumors and viral diseases, but their role in hematopoietic stem cell transplantation (HCT) is not yet fully understood. However, according to some research, these cells can prevent infections and tumor relapse without causing graft versus host disease (GVHD). In addition to NK cells, several studies are about the anti-leukemia effects of NK cell-derived exosomes that can highlight their roles in graft-versus-leukemia (GVL). In this paper, we intend to investigate the results of various articles on the role of NK cells in allogeneic hematopoietic cell transplantation and also their exosomes in GVL. Also, we have discussed the antiviral effects of these cells in post-HCT cytomegalovirus infection.

Comparison of clinicodemographic characteristics and pattern of vascular involvement in 126 patients with Takayasu arteritis: a report from Iran and Turkey

Takayasu arteritis (TA) is an extremely uncommon vasculitis that primarily affects the aorta and its branches. Due to the genetic and ethnicity effect, a diverse array of TA clinical manifestations has been reported worldwide. The purpose of the present study was to compare the clinicodemographic characteristics and pattern of vascular involvement of Iranian and Turkish TA patients. This study was a retrospective, cross-sectional investigation of 126 TA patients in Iran and Turkey. All of the variables analyzed were extracted from historical medical records. In 126 TA patients, the ratio of females to males was 8.6:1, and the average age at onset of disease was 30.5±11.1 years. Fatigue (49.2%) and a weak or absent pulse (79.4%) were the most prevalent symptoms and signs, respectively. The most prevalent angiographic classifications were types V and I in Iranian patients (41.09%) and type I in the Turkish population (47.7%) The left subclavian artery was the vessel most frequently affected by TA (66.6%). Our findings indicated that there were no significant differences between the two countries in terms of clinicodemographic characteristics or vascular involvement. Some clinical manifestations, such as claudication, were more prevalent in the Turkish population due to a higher incidence of occlusive lesions in the right subclavian artery.

Predictive factors of difficult biliary cannulation: An experience of a tunisian tertiary center

Introduction

Selective biliary cannulation is a prerequisite for a successful endoscopic retrograde cholangiopancreatography (ERCP). However, conventional biliary access can be difficult. The aims of our study were to determine the prevalence of difficult biliary cannulation (DBC) and its associated factors and to describe the efficiency and safety of used standard and advanced cannulation techniques.

Methods

We conducted a single-center retrospective study including all patients with naïve papilla who had an ERCP procedure in Gastroenterology department of Mohamed Taher Maamouri Hospital from June 2019 to December 2021. Efficiency was defined as successful selective deep biliary cannulation. DBC was defined based on the presence of one or more of the European Society of Gastrointestinal Endoscopy (ESGE) criteria (5-5-1): more than five cannulation attempts, more than 5 min before cannulation and more than one accidental passage in the wirsung. Prevalence was measured using ESGE 5-5-1 cutoffs and chinese set cutoffs 15-10-2. Predictors of DBC were sought by univariate and multivariate analysis (SPSS software, p significant if < 0.05).

Results

We included 664 patients (mean age 62 years and sex ratio M/W = 0.8). Main indication for ERCP was choledocholithiasis (67%, n = 442) followed by malignant biliary stenosis (21%, n = 138). Based on ESGE criteria, prevalence of DBC was 42.62% (n = 283). Prevalence was 21.15% when 15-10-2 cutoffs are applied in trainee-involved procedure. Cumulative biliary success rate was 96.46%. Standard cannulation method achieved access in 98.2% while advanced methods permitted success in 92.2% in fistulotomy, 94.1% in papillotomy and 77.3% in transpancreatic sphincterotomy. Independent predictive factors of DBC in multivariate analysis were: Trainee presence OR 1.80 [1.24-2.65], SOD OR 4.71 [1.11-19.88], biliary stenosis found on imaging examinations (OR 2.53 [1.63-3.92], small papilla OR 4.09 [1.82-9.17] and difficult orientation of the papilla OR 14.90 [3.28-67.62].

Conclusion

DBC is a frequent endoscopic situation. Predictors of DBC can be related to trainee involvement in the procedure, anatomical and clinical factors. A thorough understanding of these factors can actively contribute to ERCP management plans.

A UK retrospective analysis of recurrent cardiovascular events following acute myocardial infarction in patients with multivessel disease and additional risk factors

Background

Patients with multivessel disease (MVD) are at increased risk of recurrent cardiovascular (CV) events in the early period after acute myocardial infarction (AMI) compared to patients without MVD, possibly due to increased atherosclerotic burden. Moreover, many have additional risk factors such as older age, peripheral artery disease (PAD), prior AMI or diabetes that could further increase risk of recurrent events. Real-world evidence regarding the impact of additional CV risk factors on outcomes in patients with MVD remains sparse.

Purpose

To assess clinical outcomes in the early period after AMI in a UK cohort of patients with MVD and additional risk factors.

Methods

A retrospective analysis (January 1, 2008–December 31, 2018, inclusive) was conducted using the Clinical Practice Research Datalink database linked to Hospital Episode Statistics and Office of National Statistics databases to identify patients with a confirmed diagnosis of MVD within the study period and at least one non-fatal myocardial infarction (MI) diagnosis code on or after their first recorded MVD diagnosis. The effect of diabetes on clinical outcomes was assessed by comparing patients diagnosed with diabetes on or prior to their index AMI with those with no concurrent diabetes diagnosis (MVD+DM and MVD-DM cohorts, respectively). Clinical outcomes were also assessed in AMI patients without diabetes but with at least two additional risk factors including: age &gt;65 years, PAD diagnosis or prior MI diagnosis (MVD2RF+ cohort), and those with a single or none of the aforementioned risk factors (MVD2RF- cohort). Major adverse CV events (MACE) was defined as a composite of non-fatal AMI, non-fatal stroke or CV death.

Results

Of the 78,128 patients with MVD identified, 19,768 and 52,197 were eligible for inclusion in the MVD+DM and MVD-DM cohorts respectively. Occurrence of MACE was similar between the MVD+DM and MVD-DM cohorts at both 90 days (15% vs. 14%) and 1 year (19% vs. 17%) post-AMI; however, all-cause and CV mortality were significantly higher in the MVD+DM cohort over the study period (p&lt;0.001). In the subset of patients without diabetes, 7,531 and 44,666 patients met the criteria for the MVD2RF+ and MVD2RF- cohorts, respectively. A substantially higher proportion of patients in the MVD2RF+ cohort experienced a MACE within 90 days or 1 year post-MI compared with the MVD2RF- cohort (90 days: 45% vs. 9%; 1 year: 56% vs. 11%), with non-fatal MI accounting for the majority of recurrent events. Kaplan-Meier survival analysis revealed that both all-cause and CV mortality were significantly higher in the MVD2RF+ than the MVD2RF- cohort (p&lt;0.001).

Conclusions

Having multiple risk factors including older age, PAD and a history of AMI substantially increases the risk of recurrent events in patients with MVD, particularly in the early period after AMI. Strategies to reduce the systemic atherosclerotic burden and risk of recurrent events in these patients are needed.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): CSL Behring

Influence of different irrigation regimes and planting times on the quality and quantity of calyx, seed oil content and water use efficiency of roselle (Hibiscus sabdariffa L.)

This study was carried out to examine the physiological traits, quality of calyx extract and seed oil content of roselle (Hibiscus sabdariffa L.) as affected by irrigation regimes and planting dates. The growth period from seed sowing to calyx harvesting was shortened as planting time was delayed. Stem diameter and plant height were decreased by drought stress or late planting, but calyx yield, total phenolic content, total anthocyanin content, vitamin C, and calyx water use efficiency increased under mild drought condition. In addition, antioxidant activity and calyx water use efficiency were significantly increased by late planting. It was suggested that an increase in calyx harvest index in delay in planting would be due to better photosynthesis activity and higher assimilate use efficiency because of the increase in sink capacity. Seed oil content decreased considerably due to drought stress and delay in planting date. These findings suggest that mild drought stress improves the quality and quantity of calyx and water use efficiency.

Immune cells-derived exosomes function as a double-edged sword: role in disease progression and their therapeutic applications

Exosomes, ranging in size from 30 to 150 nm as identified initially via electron microscopy in 1946, are one of the extracellular vesicles (EVs) produced by many cells and have been the subject of many studies; initially, they were considered as cell wastes with the belief that cells produced exosomes to maintain homeostasis. Nowadays, it has been found that EVs secreted by different cells play a vital role in cellular communication and are usually secreted in both physiological and pathological conditions. Due to the presence of different markers and ligands on the surface of exosomes, they have paracrine, endocrine and autocrine effects in some cases. Immune cells, like other cells, can secrete exosomes that interact with surrounding cells via these vesicles. Immune system cells-derived exosomes (IEXs) induce different responses, such as increasing and decreasing the transcription of various genes and regulating cytokine production. This review deliberate the function of innate and acquired immune cells derived exosomes, their role in the pathogenesis of immune diseases, and their therapeutic appliances.

DEVELOPMENT OF FUNCTIONAL HYBRID SCAFFOLDS FOR WOUND HEALING APPLICATIONS

Hybrid hydrogels composed of chitosan (CS) and hyaluronic acid (HA) and collagen (Coll) were prepared by polyelectrolyte complex self-assembly. These scaffolds displayed a good intermingling of the polymeric chains, with porosities above 80% and good interconnected structures with pore sizes lying between 30–115 μm. The ionic interactions between CS and HA make the scaffolds have larger storage modulus and longer LVR regions than their pure counterparts. Both quantities progressively decrease as the HA and Coll concentrations in the formulation rise. These hybrid hydrogels showed good swelling extents from ca. 420 to ca. 690% and suitable resistance to enzymatic degradation, which was slightly lower for scaffolds containing CS to larger extents or Coll in the formulation. All scaffolds were largely cytocompatible and allowed the proliferation of both mouse fibroblast and human keratinocytes with their infiltration inside, thus becoming optimal matrices for intended tissue engineering applications as well as transdermal drug delivery depots.

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Hybrid scaffolds were obtained by polyelectrolyte ionic self-assembly

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Scaffolds were largely porous with suitable pore sizes for cell proliferation

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Scaffolds showed exceptional swelling and good resistance to enzymatic attack

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They were nontoxic and enabled cell proliferation and infiltration inside the scaffold

The controversial association of gut and urinary microbiota with kidney stone formation

Nephrolithiasis (kidney stones) is one of the most common chronic kidney diseases that are typically more common among adult men comparing to adult women. The prevalence of this disease is increasing which is influenced by genetic and environmental factors. Kidney stones are mainly composed of calcium oxalate and urinary oxalate which is considered a dangerous factor in their formation. Besides diverse leading reasons in the progression of nephrolithiasis, the gut and urinary microbiome has been recognized as a major player in the development or prevention of it. These microbes produce metabolites that have diverse effects on host biological functions. Therefore, Changes in the composition and structure of the microbiome (dysbiosis) have been implicated in various diseases. The present review focuses on the roles of gut and urinary in kidney stone formation.

Ventricular arrhythmias in patients with immune checkpoint inhibitor myocarditis

Background

Immune checkpoint inhibitor (ICI)-associated myocarditis is associated with a markedly increased risk of morbidity and mortality. The occurrence of ventricular arrhythmias (VA) in patients with ICI-associated myocarditis has not been well characterized.

Purpose

The aim of this study was to determine the characteristics and risk factors for severe VA in patients with ICI myocarditis.

Methods

The cohort consisted of 202 patients with ICI myocarditis. Ventricular arrhythmias were defined as a composite of sustained ventricular tachycardia and ventricular fibrillation. We used a multivariable logistic regression model to test the association between clinical variables and the development of VA.

Results

From a cohort of 202 patients with ICI myocarditis (67±13 years, 35% female, 60% hypertension, 23% diabetes mellitus), 41 (20.3%) developed VA, of which, 33 had VT and 8 had VF. The median time from admission to VF was 144 hours and to VT was 72 hours. A VA occurred in 17.5% of patients with a normal LVEF, and 25% of patients with reduced LVEF. On univariate analysis, a QRS duration &gt;110ms (OR 2.88, 95% CI 1.40 to 6.16, P=0.005) and a QTc duration &gt;470ms were associated with an increased probability of VA (OR 2.58, 95% CI 1.23, 5.41, P=0.012). The association remained significant after adjustment for age and gender. Additionally, a longer time from admission to initiation of corticosteroids was associated with a higher probability of VA (OR 1.06, 95% CI 1.01 to 1.13, P=0.027). The association between the time from admission to administration of corticosteroids and probability of VA remained significant after adjustment for age, gender, and LVEF on admission (OR, 1.06, 95% CI 1.00, 1.13, P=0.037) where each 6-hour delay in the initiation of corticosteroids was associated with a 4% increase in the risk for VA.

Conclusions

Ventricular arrhythmias are common in the setting of ICI myocarditis and are observed in patients presenting with both a preserved and a reduced LVEF. Wider QRS and longer QT at presentation and longer time from admission to initiation of corticosteroids were associated with an increased risk of VA.

Funding Acknowledgement

Type of funding sources: None.

Superluminal light propagation in a normal dispersive medium

The propagation of a Laguerre-Gaussian (LG) beam through a dispersive medium is investigated. The effect of the doughnut-like intensity profile of the probe LG beam on the group velocity is studied. We find an analytical expression for the group velocity out of the optical axis and compare with its projection onto the propagation axis. It is turned out that the group velocity vector is along the optical axis at the waist of the beam and the Rayleigh range. We numerically and analytically investigate the effect of the helical phase front of the coupling LG field on the group velocity of the probe LG field in a four-level double V-type quantum system. Our analysis predicts a strange behavior for the group velocity of the probe LG beam inside a normal dispersive medium in the gain region so that it can exceed the speed of light in free space, leads to the gain-assisted superluminal light propagation in normal dispersion. Such an unusual propagation of the LG beam results from the distortion of its helical phase front via the classical interference of the planar and LG fields. The obtained results may find some potential applications in increasing the velocity of the information transmission in optical communications.

Application of recurrence plot analysis to characterise whole chamber propagation of atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Oxford Biomedical Research Centre

Introduction

Non-contact charge density mapping allows visualisation of whole chamber propagation during atrial fibrillation (AF). The identification of regions with repetitive or, conversely, more complex patterns of wavefront propagation may provide clues to mechanisms responsible for AF maintenance and lead to improved outcomes from catheter ablation. Our novel mapping approach based on signal recurrence plots has never been applied to whole chamber, bi-atrial recording of atrial fibrillation.

Purpose

To apply recurrence analysis to characterise whole chamber bi-atrial AF propagation.

Methods

Non-contact dipole signals from left and right atrial maps were obtained during simultaneous bi-atrial charge density mapping of AF. Signals were converted to phase and mean phase coherence calculated for the generation of recurrence distance matrices for the whole chamber and each anatomical region (6x LA and 4x RA) over the 30-second recording duration, where a value of 1 (purple, see figure panel A) represents uniform repetitive conduction, and 0 (red), irregular, non-repetitive activity. Whole chamber and regional mean recurrence values were calculated and correlated with the frequency of wavefronts of localised irregular activation patterns.

Results

Maps were obtained prior to ablation in 21 patients (5 paroxysmal (pAF), 16 persistent AF (persAF)) undergoing de-novo catheter ablation procedures. Whole chamber recurrence was higher in patients with pAF (0.40 ± 0.08) than persAF (0.34 ± 0.05), p &lt; 0.0005. There was an inverse correlation between regional recurrence values and the number of localised irregular activations detected (-0.7021, p &lt; 0.0005, figure panel B) with the lateral LA and anterior RA demonstrating the highest recurrence values in each chamber (figure panel C).

Conclusion

Use of recurrence distance matrices characterises global AF propagation phenotypes. Regional values are inversely correlated with the frequency of localised irregular activation patterns identified demonstrating an anatomic dependence in the level of AF propagation complexity, greatest in the anterior LA and septal RA. Comparison of strategies targeting regions with maximal vs. minimal values during catheter ablation may define an optimal approach to treatment of persistent AF. Abstract Figure. Recurrence abstract figure

Tunneling-induced Talbot effect

We investigate the reforming of a plane wave into a periodic waveform in its propagation through a structural asymmetry four-level quantum dot molecule (QDM) system that is induced by an inter-dot tunneling process and present the resulting tunneling-induced Talbot effect. The tunneling process between two neighborhood dots is provided with the aid of a gate voltage. Using a periodic coupling field the response of the medium to the propagating plane probe beam becomes periodic. The needed periodic coupling field is generated with the interference of two coherent plane waves having a small angle and propagating almost parallel to the probe beam direction. In the presence of the tunneling effect of an electron between two adjacent QDs, for the probe beam propagating through the QDM system, the medium becomes transparent where the coupling fields interfere constructively. As a result, the spatial periodicity of the coupling field modulates the passing plane probe beam. We determine the minimum length of the QDM system to generate a periodic intensity profile with a visibility value equal to 1 for the probe field at the exit plane of the medium. It is also shown that by increasing the propagation length of the probe beam through the QDM medium, the profile of the maximum intensity areas becomes sharper. This feature is quantified by considering a sharpness factor for the intensity profile of the probe beam at the transverse plane. Finally, we investigate free space propagation of the induced periodic field and present the Talbot images of the tunneling-induced periodic patterns at different propagation distances for different values of the QDM medium lengths. The presented dynamically designing method of the periodic coherent intensity patterns might find applications in science and technology. For instance, in optical lithography, the need to use micro/nanofabricated physical transmission diffraction gratings, in which preparation of them is expensive and time-consuming, can be eliminated.

Laguerre-Gaussian modes generated vector beam via nonlinear magneto-optical rotation

Laguerre-Gaussian (LG) beams contain a helical phase front with a doughnut-like intensity profile. We use the LG beam to introduce a rather simple method for generation of a vector beam (VB), a beam with spatially-dependent polarization in the beam cross section, via the nonlinear magneto-optical rotation (NMOR). We consider the NMOR of the polarization of a linearly polarized probe field passing through an inverted Y-type four-level quantum system interacting with a LG control field and a static magnetic field. It is shown that the polarization of the transmitted field is spatially distributed by the orbital angular momentum (OAM) of the LG control field, leading to generation of the VB with azimuthally symmetric polarization distribution. We show that the polarization and intensity distributions of the VB spatially vary by changing the OAMs of the LG control field. Moreover, the radial index of the LG control field has a major role in more spatially polarization distributing of the VB. It is shown that the intensity of the generated VBs in different points of the beam cross section can be controlled by the OAM as well as the radial index of the LG control field. However, the VB with highly spatially distributed can be generated for higher values of the radial index of LG control field. The analytical calculations determine the contribution of the different nonlinear (cross-Kerr effect) phenomena on the generation of the VB. We show that the VB is mainly generated via birefringence induced by the applied fields. Finally, we use asymmetric LG (aLG) beams for making the VBs with asymmetric polarization distribution. It is shown that by applying aLG beams, the azimuthal symmetry of the polarization distribution breaks and the asymmetric polarization distribution can be controlled by OAM and radial index of the aLG control field. The obtained results may find more interesting applications in fiber/free space optical communication to enhance the capacity of the information transmission.

MicroRNAs in the interaction between host-bacterial pathogens: A new perspective

Gene expression regulation plays a critical role in host-pathogen interactions, and RNAs function is essential in this process. miRNAs are small noncoding, endogenous RNA fragments that affect stability and/or translation of mRNAs, act as major posttranscriptional regulators of gene expression. miRNA is involved in regulating many biological or pathological processes through targeting specific mRNAs, including development, differentiation, apoptosis, cell cycle, cytoskeleton organization, and autophagy. Deregulated microRNA expression is associated with many types of diseases, including cancers, immune disturbances, and infection. miRNAs are a vital section of the host immune response to bacterial-made infection. Bacterial pathogens suppress host miRNA expression for their benefit, promoting survival, replication, and persistence. The role played through miRNAs in interaction with host-bacterial pathogen has been extensively studied in the past 10 years, and knowledge about these staggering molecules' function can clarify the complicated and ambiguous interactions of the host-bacterial pathogen. Here, we review how pathogens prevent the host miRNA expression. We briefly discuss emerging themes in this field, including their role as biomarkers in identifying bacterial infections, as part of the gut microbiota, on host miRNA expression.

Effect of Two Educational Interventions Regarding the Management of Traumatic Dental Injuries on Mothers of 8-Year-Old Children

Objectives: This study evaluated the effect of two educational interventions on knowledge and self-reported practice of mothers of 8-year-old children regarding emergency management of traumatic dental injuries (TDIs). Materials and Methods: Six public elementary schools (girls and boys) in Tehran were randomly selected. The mothers of 8-year-old students at each school were randomly assigned to three groups: intervention by poster, intervention by pamphlet, and control. An anonymous valid and reliable questionnaire, including demographics, previous experience on TDIs, mothers’ knowledge, and self-reported practice about emergency management of TDIs was provided to the mothers. After collecting the questionnaires, educational interventions by poster and pamphlet with similar contents regarding step-by-step emergency management of TDIs were performed for the target groups. Three months after the interventions, the same questionnaire was completed by the mothers. The results of pre-test and post-test were compared. Results: Totally, 201 mothers participated in this study. The mean knowledge score significantly increased in the pamphlet group after the intervention, while this change was not significant in the poster and control groups (P>0.05). The mean knowledge score was significantly higher in the pamphlet group than the poster group (P=0.009). The mean self-reported practice score significantly increased after the intervention in both intervention groups (P<0.05) but not in the control group. There was no significant difference in the mean self-reported practice score between the two intervention groups (P>0.05). Conclusion: Both pamphlet and poster were equally effective in improving the self-reported practice of mothers regarding TDIs, which highlights the significance of educating mothers. 

Pollen viability of Euro-Mediterranean orchids under different storage conditions: The possible effects of climate change

The future impact of climate change and a warmer world is a matter of great concern. We therefore aimed to evaluate the effects of temperature on pollen viability and fruit set of Mediterranean orchids. The in vitro and controlled pollination experiments were performed to evaluate the ability of pollinia stored at lower and higher temperatures to germinate and produce fruits and seeds containing viable embryos. In all of the examined orchids, pollen stored at -20 °C remained fully viable for up to 3 years, reducing its percentage germination from year 4 onwards. Pollinia stored at higher temperatures had a drastic reduction in vitality after 2 days at 41-44 °C, while pollinia stored at 47-50 °C did not show any pollen tube growth. The different levels of pollen viability duration among the examined orchids can be related to their peculiar reproductive biology and pollination ecology. The germinability of pollinia stored at lower temperatures for long periods suggests that orchid pollinia can be conserved ex situ. In contrast, higher temperatures can have harmful effects on the vitality of pollen and consequently on reproductive success of the plants. To our knowledge, this is the first report demonstrating the effects of global change on orchid pollen, and on pollen ability to tolerate, or not, higher air temperatures. Although vegetative reproduction allows orchids to survive a few consecutive warm years, higher temperatures for several consecutive years can have dramatic effects on reproductive success of orchids.

Tunneling-induced optical limiting in quantum dot molecules

We present a convenient way to obtain an optical power limiting behavior in a quantum dot molecule system, induced by an interdot tunneling. Also, the effect of system parameters on the limiting performance is investigated; interestingly, the tunneling rate can affect the limiting performance of the system so that the threshold of the limiting behavior can be a function of the input voltage, allowing the optimization of the limiting action. Furthermore, by investigating the absorption of the probe field, it is demonstrated that the optical limiting is due to a reverse saturable absorption mechanism; indeed, analytical results show that this mechanism is based on a cross-Kerr optical nonlinearity induced by the tunneling. Additionally, the limiting properties of the system are studied by using a Z-scan technique.

Improving the function of neutrophils from chronic granulomatous disease patients using mesenchymal stem cells' exosomes

In chronic granulomatous disease (CGD) patients, reactive oxygen species (ROS) production by neutrophils is impaired. So, they are susceptible to infections. Studies showed that, mesenchymal stem cells (MSCs) have protective effects on the function of neutrophils and an approach that MSCs use to apply their effects, is secreting soluble factors and exosomes. So, we investigated the effects of MSC-exosomes and MSC-conditioned media (MSC-CM) on the function and apoptosis of neutrophils in CGD patients. In this study, neutrophils were isolated from healthy donors and CGD patients and then incubated with exosomes or CM that were prepared from MSCs. Then, neutrophil respiratory burst, apoptosis and phagocytosis capacity were evaluated by NBT assay, Annexin V-PI method and Giemsa staining. It was demonstrated that both MSC-exosomes and CM could improve the phagocytosis capacity and ROS production of neutrophils in CGD patients and healthy donors. In contrast to the healthy group, in CGD patients, exosomes significantly reduced the percentage of viable neutrophils. This report indicated that MSC exosomes and CM could increase the function of the neutrophils isolated from CGD patients. But decreasing the number of the living cells is one of the limitations of them. However, it is hoped that this intervention will be developed in future studies to minimize its limitations.

Predictors of Favorable Outcome after Endovascular Thrombectomy in MRI: Selected Patients with Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

Clinical outcomes after endovascular treatment for acute basilar artery occlusions need further investigation. Our aim was to analyze predictors of a 90-day good functional outcome defined as mRS 0-2 after endovascular treatment in MR imaging-selected patients with acute basilar artery occlusions.

MATERIALS AND METHODS

We analyzed consecutive MR imaging-selected patients with acute basilar artery occlusions endovascularly treated within the first 24 hours after symptom onset. Successful and complete reperfusion was defined as modified TICI scores 2b-3 and 3, respectively. Outcome at 90 days was analyzed in univariate and multivariate analysis regarding baseline patient treatment characteristics and periprocedural outcomes.

RESULTS

One hundred ten patients were included. In 10 patients, endovascular treatment was aborted for failed proximal/distal access. Overall, successful reperfusion was achieved in 81.8% of cases (n = 90; 95% CI, 73.3%-88.6%). At 90 days, favorable outcome was 31.8%, with a mortality rate of 40.9%; the prevalence of symptomatic intracranial hemorrhage within 24 hours was 2.7%. The median time from symptom onset to groin puncture was 410 minutes (interquartile range, 280-540 minutes). In multivariable analysis, complete reperfusion (OR = 6.59; 95% CI, 2.17-20.03), lower pretreatment NIHSS (OR = 0.77; 95% CI, 0.64-0.94), the presence of posterior communicating artery collateral flow (OR = 2.87; 95% CI, 1.05-7.84), the absence of atrial fibrillation (OR = 0.18; 95% CI, 0.03-0.99), and intravenous thrombolysis administration (OR = 2.75; 95% CI, 1.04-7.04) were associated with 90-day favorable outcome.

CONCLUSIONS

In our series of MR imaging-selected patients with acute basilar artery occlusions, complete reperfusion was the strongest predictor of a good outcome. Lower pretreatment NIHSS, the presence of posterior communicating artery collateral flow, the absence of atrial fibrillation, and intravenous thrombolysis administration were associated with favorable outcome.

Wharton's Jelly Mesenchymal Stem Cells Exosomes and Conditioned Media Increased Neutrophil Lifespan and Phagocytosis Capacity

Neutrophils are the first cells involved in inflammation and pathogen elimination, but they have a short lifespan. So, strategies for enhancing neutrophil lifespan and activities can be useful in many situations such as patients with immunodeficiencies. Previous researches demonstrated that mesenchymal stem cell (MSC) has anti-apoptotic effects on neutrophils. These multipotent cells have immunomodulatory properties and can be isolated from different tissues. MSCs isolated from Wharton's jelly (WJ-MSCs), a mucosal connective tissue of the umbilical cord, may be better candidates than MSCs obtained from bone marrow or adipose tissue, because WJ-MSCs are younger and protected from damages that are resulted from aging, environmental toxins, and diseases. In addition, they have high proliferative capacity, easier accessibility, and more abundance. It was shown that following in vitro expansion, they are more effective than other sources of MSCs. Cell to cell contact or secretion of soluble factors and exosomes are the main approaches of MSCs in applying their effects. Exosomes and conditioned media (CM) were prepared from WJ-MSCs. Then, neutrophils were isolated and cultured with medium, CM, or exosomes. Then, neutrophil respiratory burst, apoptosis, and phagocytosis capacity were assessed by NBT assay, Annexin V-PI method, and Giemsa staining, respectively. Both treatments improved neutrophil lifespan and phagocytosis. Only MSC-CM could enhance neutrophil respiratory burst. This research demonstrated that MSC-exosomes and CM have protective effects on neutrophil function and lifespan. It can be concluded that MSC mediators can be responsible factors for protective functions of MSCs on neutrophils.

P1389Periodicity and Spatial Stability of Complex Propagation Patterns in Atrial Fibrillation

Introduction

Non-contact charge density mapping identifies complex wavefront propagation including localised rotational activation (LRA), localised irregular activation (LIA) and focal firing (FF). However, the duration of mapping required to reveal underlying patterns and their temporal stability is unknown.

Purpose

We sought to evaluate the variability in propagation patterns over increasing durations of recordings up to 30 seconds and examine the stability of these patterns between 2 separate maps with the aim of identifying the minimum duration required to reveal underlying patterns and how they represent the stable arrhythmia substrate.

Methods

Patients undergoing first time AcQMap guided catheter ablation were studied. 30s recordings of left atrial propagation were analysed. LIA, LRA, and FF were quantified for frequency, percentage time present and percentage surface area affected (for FF only frequency was assessed) at increasing durations up to 30s in 1s increments. At each incremental recording duration the percentage change in each variable was calculated. For occurrence frequency the results for every possible combination of maps of increasing duration within the 30s recording were compared whilst for occurrence time and surface area a 5s moving average at 1s increments was calculated. The point at which variability was seen to plateau represents the minimum optimal mapping duration. Spatial stability was assessed by correlating the frequency of patterns at each vertex of the anatomy over 2 separate 30s recordings. Stability of regions with the most repetitive patterns were compared using Cohen’s kappa statistic.

Results

15 patients were analysed (age 63 ± 9, 10 male, BMI 30 ± 5, CHA2DS2Vasc 1 ± 1.3, ejection fraction 54 ± 12%, left atrial diameter 46 ± 7mm, paroxysmal 1, persistent 14) with 11 included in the spatial stability analysis due to availability of recordings of sufficient duration. LRA demonstrated most variability followed by LIA and FF. Variability in LIA, LRA and FF decrease at increasing durations. LIA and FF variability plateau by 13 and 17s respectively. LRA plateaus at 23s. Variability of &lt;10% is reached in all parameters at 18s.

LIA demonstrated the greatest stability with average R2 of 0.76 ± 0.14 (figure). Average R2 for LRA and FF were 0.45 ± 0.16 and 0.47 ± 0.12.  Low frequency focal firings were widely distributed across the atrial surface. For FF occurring at a frequency ≥10 over the 30s, average R2 value was 0.65 ± 0.14. Cohen kappa statistic was 0.70 for LIA and 0.45 for LRA.

Conclusion

Mapping durations of ≥23s are required to identify all temporally variable propagation patterns although shorter durations will identify less variable LIA and FF. 

LIA demonstrates high spatiotemporal stability and may best reflect disrupted conduction caused by the underlying atrial substrate and tissue architecture. Regions of high frequency FF are temporally stable and may represent important targets for ablation.

Abstract Figure 1

Hypothesis for the management and treatment of the COVID-19-induced acute respiratory distress syndrome and lung injury using mesenchymal stem cell-derived exosomes

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of the coronaviridae that causes respiratory disorders. After infection, large amounts of inflammatory cytokines are secreted, known as the cytokine storm. These cytokines can cause pulmonary damage induced by inflammation resulting in acute respiratory distress syndrome (ARDS), and even death.

One of the therapeutic approaches for treatment of ARDS is a mesenchymal stem cell (MSC). MSCs suppress inflammation and reduce lung injury through their immunomodulatory properties. MSCs also have the potential to prevent apoptosis of the lung cells and regenerate them. But our suggestion is using MSCs-derived exosomes. Because these exosomes apply the same immunomodulatory and tissue repair effects of MSCs and they don’t have problems associated to cell maintenance and injections.

For investigation the hypothesis, MSCs should be isolated from tissues and characterized. Then, the exosomes should be isolated from the supernatants and characterized. These exosomes should be injected into a transgenic animal for COVID-19. In the final section, lung function assessment, histological examination, micro-CT, differential leukocyte, viral load analysis, cytokine assay, and CRP level analysis can be investigated.

COVID-19 treatment is currently focused on supportive therapies and no vaccine has been developed for it. So, numerous researches are needed to find potential therapies. Since the pathogenesis of this disease was identified in previous studies and can cause lung injury with ARDS, investigation of the therapeutic approaches that can suppress inflammation, cytokine storm and ARDS can be helpful in finding a novel therapeutic approach for this disease.

Acoustic field induced nonlinear magneto-optical rotation in a diamond mechanical resonator

We study the nonlinear magneto-optical rotation (MOR) of a linearly polarized microwave probe field passing through many nitrogen-vacancy (NV) centers embedded in a high-Q single-crystal diamond mechanical resonator. On the basis of the strain-mediated coupling mechanism, we establish a three-level closed-loop system in the ground states of the NV center in the presence of a static magnetic field. It is shown that by applying an acoustic field, the birefringence is induced in the system through the cross-Kerr effect, so that the probe field is transmitted with a high intensity and rotated polarization plane by 90 degrees. In addition, we demonstrate that the acoustic field has a major role in enhancing the MOR angle to 90 degrees. Moreover, it is shown that the MOR angle of the polarization plane after passing through the presented system is sensitive to the relative phase of the applied fields. The physical mechanism of the MOR enhancement is explained using the analytical expressions which are in good agreement with the numerical results. The presented scheme can be used as a polarization converter for efficient switching TE/TM modes in optical communication, the depolarization backscattering lidar, polarization spectroscopy and precision measurements.

The clinical value of the delta finger to palm distance in systemic sclerosis

Systemic sclerosis (SSc) is a collagen-vascular disorder characterized by fibrosis and vasculopathy. Delta finger to palm distance (delta FTP) is an index measuring the distance between the tip of the third finger to the distal palmar crease in the flexed and extended position. The present study aimed to evaluate the clinical value of delta FTP and to assess the correlation of delta FTP with modified Rodnan skin score (mRSS) and forced vital capacity (FVC) over the 12-month follow-up. This prospective longitudinal study began with 50 participants who were followed for twelve months. Lowess smoothing and linear regression were applied to detect and assess the relationship between delta FTP and mRSS. p-values were adjusted by the Benjamini-Hochberg method (BHM) as a control for false discovery rate. Delta FTP was lower among patients with higher disease duration (p-valueadj: 0.008), diffuse cutaneous SSc (p-valueadj: 0.006), digital ulcers (p-valueadj: 0.003), telangiectasia (p-valueadj: 0.006) and dysphagia (p-valueadj: 0.036). The mRSS has a significant negative linear effect on the delta FTP at the baseline and the end of the follow-up (r: -0.31 and -0.40, respectively). Moreover, changes of mRSS and delta FTP showed a negative linear association over time (r: -0.22). These linear effects remained significant after regrouping the patients based on their SSc subtype. Delta FTP and FVC were not correlated either at the baseline or at the end. It seems that the delta FTP can be a valuable clinical index, supported by its correlated changes with mRSS and other SSc clinical manifestations over the one-year follow-up.

Coherent control of Optical limiting in atomic systems

Generation and control of the reverse saturable absorption (RSA) and optical limiting (OL) are investigated in a four-level Y-type quantum system. It is demonstrated that the applied laser fields induce the RSA and it can be coherently controlled by either intensity or frequency of the applied laser fields. The effect of the static magnetic field on the induced RSA is studied and we obtain that it has a constructive role in determining the intensity range in which the OL is established in the system. In addition, we find that the transmission of the suggested optical limiter can be decreased either by increasing the length of the medium or by getting the atomic system denser. Finally, the Z-scan technique is presented to confirm our theoretical results. The proposed scheme can be used in designing the coherent optical limiters with controllable threshold and intensity range of the OL.

Rapid and direct molecular detection of Streptococcus pneumoniae and Haemophilus influenzae isolated in oropharynx and nasal cavity of children

There is a direct correlation between asymptomatic oropharyngeal colonization by pathogenic bacteria and the prevalence of paediatric respiratory infections. Streptococcus pneumoniae and Haemophilus influenzae are common cause of serious bacterial infections such as meningitis in children. This study aimed to monitor healthy children to detect asymptomatic carriers of S. pneumoniae and H. influenzae. In the present cross-sectional study, real-time PCR assay was developed and evaluated in comparison with culture for direct detection of S. pneumoniae and H. influenzae in 123 oropharynx and nasal cavity specimens from healthy children in Ilam, Iran. In addition, virulence factor (ply and hpd) and iron uptake (tbpA and piuA) genes were evaluated by PCR. Our results demonstrated that among all isolates only 14 S. pneumoniae and eight H. influenzae were identified by phenotypic methods, whereas 37 and 21 S. pneumoniae and H. influenzae were identified, respectively, by real-time PCR assay. All S. pneumoniae and H. influenzae isolates possessed tbpA and piuA genes. Also, 81% (30/37) of S. pneumoniae isolates were positive for ply gene, which encoded pneumolysin, as well as 90% (19/21) of H. influenzae isolates were positive for hpd gene. Simultaneous colonization of S. pneumoniae and H. influenzae could indicate the importance of monitoring of healthy children to identification of carriers.