23 research outputs found

    Quasiperiodic criticality and spin-triplet superconductivity in superconductor-antiferromagnet moire patterns

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    Quasiperiodicity has long been known to be a potential platform to explore exotic phenomena, realizing an intricate middle point between ordered solids and disordered matter. In particular, quasiperiodic structures are promising playgrounds to engineer critical wavefunctions, a powerful starting point to engineer exotic correlated states. Here we show that systems hosting a quasiperiodic modulation of antiferromagnetism and spin-singlet superconductivity, as realized by atomic chains in twisted van der Waals materials, host a localization-delocalization transition as a function of the coupling strength. Associated with this transition, we demonstrate the emergence of a robust quasiperiodic critical point for arbitrary incommensurate potentials, that appears for generic relative weights of the spin-singlet superconductivity and antiferromagnetism. We show that the inclusion of residual electronic interactions leads to an emergent spin-triplet superconducting state, that gets dramatically enhanced at the vicinity of the quasiperiodic critical point. Our results put forward quasiperiodicity as a powerful knob to engineer robust superconducting states, providing an alternative pathway towards artificially designed unconventional superconductors.Comment: 11 pages, 5 figure

    Hamiltonian learning with real-space impurity tomography in topological moire superconductors

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    Extracting Hamiltonian parameters from available experimental data is a challenge in quantum materials. In particular, real-space spectroscopy methods such as scanning tunneling spectroscopy allow probing electronic states with atomic resolution, yet even in those instances extracting effective Hamiltonian is an open challenge. Here we show that impurity states in modulated systems provide a promising approach to extracting non-trivial Hamiltonian parameters of a quantum material. We show that by combining the real-space spectroscopy of different impurity locations in a moire topological superconductor, modulations of exchange and superconducting parameters can be inferred via machine learning. We demonstrate our strategy with a physically-inspired harmonic expansion combined with a fully-connected neural network that we benchmark against a conventional convolutional architecture. We show that while both approaches allow extracting exchange modulations, only the former approach allows inferring the features of the superconducting order. Our results demonstrate the potential of machine learning methods to extract Hamiltonian parameters by real-space impurity spectroscopy as local probes of a topological state.Comment: 11 pages, 8 figure

    Lung cancer risk and the inhibitors of angiotensin converting enzyme; an updated review on recent evidence

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    The renin-angiotensin-aldosterone system (RAAS) has a significant act in the pathology of blood pressure and cancer. One of the dominant sections of angiotensin II (Ang II) and angiotensin-converting enzyme (ACE) expression generation in the human body is the capillary veins in the lung. Changes in the expression of RAAS were revealed to be included in several lung diseases. There are several studies on the anticancer effect of ACE inhibitors; however, Hicks and colleagues reported an augmented risk of 14% for advancing lung cancer for patients consuming ACE inhibitors against angiotensin receptor blockers (ARBs) administration. Several lines of evidence indicated that ARB users have a lower risk of tumor progression and metastasis and progression of lung cancer. This review has surveyed some studies about the study by Hicks et al with conflicting results. Some Hicks’s study limitations are summarized here such as genetic effects, comparative study, residual confounding factors such as smoking, detection bias owing to cough, and socio-economic status. It is suggested some natural alternatives to ACE Inhibitors in here.publishedVersio

    Selegiline induced differentiation of rat bone marrow mesenchymal stem cells to dopaminergic neurons in vitro

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    Today, the use of mesenchymal stem cells (MSCs) for treating human diseases has attracted wide attention. The aim of this study is the expression of dopaminergic genes such as Nestin, patched Tumor Suppressor (PTCH), Sonic Hedgehog (SHH), Tyrosine Hydroxylase (TH) and Nuclear receptor-related factor 1 (NURR1) in MSCs after induction with selegiline. Rat bone marrow mesenchymal stem cells (rBMSCs) were extracted from femur and tibia bones and incubated with alpha Minimum Essential Medium (α-MEM) and 10% Fetal bovine serum (FBS). The stemness of cells at passage 4 was determined by the positive response to CD71 and CD90 markers and their differentiation into adipocytes and osteoblasts. The expression of SHH, PTCH, TH, NURR1 and Nestin genes in the cells after induction by 10-8 M selegiline for 48 hours was investigated by Reverse transcription polymerase chain reaction (RT-PCR) and Real Time-PCR methods. Isolated rBMSCs expressed CD71 and CD90 markers in culture conditions and could differentiate into adipocytes and osteoblasts. Induced cells showed neuronal morphology, positive response to Nestin and TH immunostaining. There was a significant increase of dopaminergic genes TH and NURR1 compared to the untreated cells. The results showed that selegiline with a dose of 10-8 M for 48 hours can lead to dopaminergic differentiation in rBMSCs

    Lung cancer and kidney injury: An updated review

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    Lung cancer is the leading cause of cancer deaths worldwide, accounting for an estimated 1.8 million deaths. Lung cancer is also the most common primary cancer leading to soft tissue (ST) metastasis. Renal disease may occur as a direct or indirect consequence of the cancer itself (e.g., post-renal obstruction, compression, or infiltration), its treatment (e.g., radiotherapy or chemotherapy), or its related complications (e.g., opportunistic infection). Existing evidence shows that the most frequent primary solid tumor responsible for renal metastasis is pulmonary carcinoma, followed by gastric, breast, soft tissue, and thyroid carcinomas. Chronic kidney disease is a potential risk factor in the survival of patients with lung cancer. In this review, we will discuss causes of kidney injury in relation to lung cancer, potential mechanisms of kidney injury, and treatment options

    Strive for kidney health for everyone during COVID-19; the possible theme for the world kidney day 2021

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    Increasing awareness regarding CKD and self-care during COVID-19 pandemic has become the most important aspect for the nephrologists. Hence it is appropriate that the theme of the forthcoming World Kidney Day on 11 March 2021 should be “Strive for kidney health for everyone during COVID-19

    Association of body mass index and physical activity with fatigue, depression, and anxiety among Iranian patients with multiple sclerosis

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    IntroductionDepression, fatigue, and anxiety are three common clinical comorbidities of multiple sclerosis (MS). We investigated the role of physical activity (PA) level and body mass index (BMI) as modifiable lifestyle factors in these three comorbidities.MethodsA cross-sectional study was conducted in the MS specialist clinic of Sina Hospital, Tehran, Iran. Demographic and clinical data were collected. BMI was categorized in accordance with the WHO’s standard classification. Physical activity (PA) level and sitting time per day were obtained using the short form of the International Physical Activity Questionnaire (IPAQ-SF). Fatigue, anxiety, and depression scores were measured using the Persian version of the Fatigue Severity Scale (FSS), Beck Anxiety Inventory (BAI), and Beck’s Depression Inventory II (BDI-II) questionnaires, respectively. The correlation between the metabolic equivalent of tasks (MET), BMI, and daily sitting hours with depression, anxiety, and fatigue were checked using the linear regression test. The normal BMI group was considered a reference, and the difference in quantitative variables between the reference and the other groups was assessed using an independent sample t-test. Physical activity was classified with tertiles, and the difference in depression, anxiety, and fatigue between the PA groups was evaluated by a one-way ANOVA test.ResultsIn total, 85 MS patients were recruited for the study. The mean ± SD age of the participants was 39.07 ± 8.84 years, and 72.9% (n: 62) of them were female. The fatigue score was directly correlated with BMI (P: 0.03; r: 0.23) and sitting hours per day (P: 0.01; r: 0.26) and indirectly correlated with PA level (P < 0.01; r: −0.33). Higher depression scores were significantly correlated with elevated daily sitting hours (P: 0.01; r: 0.27). However, the correlation between depression with PA and BMI was not meaningful (p > 0.05). Higher anxiety scores were correlated with BMI (P: 0.01; r: 0.27) and lower PA (P: 0.01; r: −0.26). The correlation between anxiety and sitting hours per day was not significant (p > 0.05). Patients in the type I obesity group had significantly higher depression scores than the normal weight group (23.67 ± 2.30 vs. 14.05 ± 9.12; P: 0.001). Fatigue (32.61 ± 14.18 vs. 52.40 ± 12.42; P: <0.01) and anxiety (14.66 ± 9.68 vs. 27.80 ± 15.48; P: 0.01) scores were significantly greater among participants in the type II obesity group in comparison with the normal weight group. Fatigue (P: 0.01) and anxiety (P: 0.03) scores were significantly different in the three levels of PA, but no significant difference was found in the depression score (P: 0.17).ConclusionOur data suggest that a physically active lifestyle and being in the normal weight category are possible factors that lead to lower depression, fatigue, and anxiety in patients with MS

    Impurity-induced excitations in a topological two-dimensional ferromagnet/superconductor van der Waals moiré heterostructure

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    The emergence of a topological superconducting state in van der Waals heterostructures provides a new platform for exploring novel strategies to control topological superconductors. In particular, impurities in van der Waals heterostructures, generically featuring a moiré pattern, can potentially lead to the unique interplay between atomic and moiré length scales, a feature absent in generic topological superconductors. Here we address the impact of nonmagnetic impurities on a topological moiré superconductor, both in the weak and strong regime, considering both periodic arrays and single impurities in otherwise pristine infinite moiré systems. We demonstrate a fine interplay between impurity-induced modes and the moiré length, leading to radically different spectral and topological properties depending on the relative impurity location and moiré lengths. Our results highlight the key role of impurities in van der Waals heterostructures featuring moiré patterns, revealing the key interplay between length and energy scales in artificial moiré systems.Peer reviewe

    Analysis of the Spatio-temporal variations of thermal patterns of Shiraz city by satellite images and GIS processing

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    In recent years, climate change has caused an increase in the air temperature and consequently the temperature of the earth's surface. The temperature of the earth's surface has had various effects on urban life and has caused the formation of thermal islands in cities. Thermal islands are one of the important criteria in regional planning. The city of Shiraz is considered to be a large population center in the southwest of Iran on the one hand and one of the important tourism centers of Iran on the other hand, so the purpose of this research is to monitor the spatial form of thermal islands in this city. The satellite images of Shiraz city were first collected and extracted in the hot periods of the year from 1985-to 2020 using the data of Landsat’s 4 and 5 (TM), 7 (ETM+), and 8 (OLI/TIRS). After required preprocessing, the Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), Normalized Difference Built-up Index (NDBI), and the urban heat dispersion index were determined by the Urban Thermal Field Variance Index (UTFVI). The regions with UHI, the variation of the temperature in the city, and the relationship between the LST and surface vegetation were evaluated based on the results of image processing to determine the UHIs of Shiraz. The temporal variations of the temperature pattern of Shiraz city indicated that about 12.76 km2 was added to the area of the fourth temperature class from 1985 to 2020. Results of NDVI evaluation in the studied period showed a decline in the vegetation from 22.28 km2 in 1985 to 17.54 km2 in 2020 due to alteration of the land use which can explain the formation and increase of the UHIs in the mentioned regions. At the beginning of the investigated period (1985), the temperature of the earth's surface was 17°Celsius and reached 21°Celsius at the end of the period (2020). The monitoring of the spatial form of the surface temperature of the earth shows that heat islands are moving from the outskirts of the city towards the city center. UTFVI also revealed that the awful regions (very hot temperatures) are mainly concentrated in the west and north-west to the south west of Shiraz (including some parts of districts 9 and 10), south east of district 7, and north of district 1
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