551 research outputs found
Electromagnetic Pulse Driven Spin-dependent Currents in Semiconductor Quantum Rings
We investigate the non-equilibrium charge and spin-dependent currents in a
quantum ring with a Rashba spin orbit interaction (SOI) driven by two
asymmetric picosecond electromagnetic pulses. The equilibrium persistent charge
and persistent spin-dependent currents are investigated as well. It is shown
that the dynamical charge and the dynamical spin-dependent currents vary
smoothly with a static external magnetic flux and the SOI provides a SU(2)
effective flux that changes the phases of the dynamic charge and the dynamic
spin-dependent currents. The period of the oscillation of the total charge
current with the delay time between the pulses is larger in a quantum ring with
a larger radius. The parameters of the pulse fields control to a certain extent
the total charge and the total spin-dependent currents. The calculations are
applicable to nano-meter rings fabricated in heterojuctions of III-V and II-VI
semiconductors containing several hundreds electrons.Comment: 15pages, 5 figure
Evaluation of engineering properties of clayey sand bio-mediated with terrazyme enzyme
Soil stabilization is a practical approach for enhancing the suitability of problematic soil in construction projects. This study focusses on analyzing the impact of the bio-enzyme Terrazyme on the engineering properties of Mirpur soil, which exhibits inadequate performance as subgrade soil, particularly in moist conditions. The study investigates key engineering characteristics, including unconfined compressive strength (UCS), California Bearing Ratio (CBR), maximum dry density (MDD), Atterberg’s Limits, and compressibility index. Additionally, X-Ray Diffraction and SEM analysis were conducted to identify the mineral composition and particle structure of Mirpur soil. It is demonstrated that the incorporation of Terrazyme enhanced the engineering properties of the soil. The findings will contribute to a better understanding of the efficacy of bio-mediated soil stabilization techniques
The Green Synthesis of Silver Nanoparticles from Avena fatua Extract: Antifungal Activity against Fusarium oxysporum f.sp. lycopersici
Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies
TAT-peptide conjugated repurposing drug against SARS-CoV-2 main protease (3CLpro): potential therapeutic intervention to combat COVID-19
The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that originated in Chinese city of Wuhan has caused around 906,092 deaths and 28,040,853 confirmed cases worldwide (WHO, 11 September, 2020). In a life-threatening situation, where there is no specific and licensed anti-COVID-19 vaccine or medicine available; the repurposed drug might act as a silver bullet. Currently, more than 211 vaccines, 80 antibodies, 31 antiviral drugs, 35 cell-based, 6 RNA-based and 131 other drugs are in clinical trials. It is therefore utter need of the hour to develop an effective drug that can be used for the treatment of COVID-19 before a vaccine can be developed. One of the best-characterized and attractive drug targets among coronaviruses is the main protease (3CL^{pro}). Therefore, the current study focuses on the molecular docking analysis of TAT-peptide^{47–57} (GRKKRRQRRRP)-conjugated repurposed drugs (i.e., lopinavir, ritonavir, favipiravir, and hydroxychloroquine) with SARS-CoV-2 main protease (3CL^{pro} to discover potential efficacy of TAT-peptide (TP) - conjugated repurposing drugs against SARS-CoV-2. The molecular docking results validated that TP-conjugated ritonavir, lopinavir, favipiravir, and hydroxychloroquine have superior and significantly enhanced interactions with the target SARS-CoV-2 main protease. In-silico approach employed in this study suggests that the combination of the drug with TP is an excelling alternative to develop a novel drug for the treatment of SARS-CoV-2 infected patients. The development of TP based delivery of repurposing drugs might be an excellent approach to enhance the efficacy of the existing drugs for the treatment of COVID-19. The predictions from the results obtained provide invaluable information that can be utilized for the choice of candidate drugs for in vitro, in vivo and clinical trials. The outcome from this work prove crucial for exploring and developing novel cost-effective and biocompatible TP conjugated anti-SARS-CoV-2 therapeutic agents in immediate future
Ischaemic stroke and peripheral artery disease
Objective: To determine the frequency of atherosclerosis by ankle brachial index in patients with an ischaemic
stroke and to assess the association of carotid artery stenosis and ankle brachial index in ischaemic stroke.
Methods: This cross-sectional study was conducted at Abbasi Shaheed Hospital, Karachi, from July 2011 to May
2014, and comprised patients with ischaemic stroke. The patients were classified according to the Asian stroke
criteria for classification of brain infarction. Primary outcome measures included carotid artery stenosis and ankle
brachial index. The other independent variables were age, gender, body mass index and waist circumference. SPSS
20 was used for data analysis.
Results: A total of 327 patients were enrolled. The overall mean age was 57.612.8 years. Besides, 168(51.3%)
participants were males. Peripheral artery disease was found in 60(18.3%) patients. Mild carotid artery stenosis was
found in 182(55.6%) patients, moderate in 140(42.8%), severe in 3(0.9%) and complete occlusion in 2(0.6%) patients.
In patients having mild carotid artery stenosis, 32(17.5%) had peripheral artery disease, whereas in patients with
moderate carotid artery stenosis, 25(17.8%) had peripheral artery disease.
Conclusion: Abnormally low ankle brachial index suggesting subclinical peripheral artery disease was 18%.
Keywords: Ischaemic stroke, Peripheral artery disease, Ankle brachial index, Carotid artery stenosis. (JPMA 67: 1138; 2017)sch_pod67pub4830pub
Copy number architectures define treatment-mediated selection of lethal prostate cancer clones
Despite initial responses to hormone treatment, metastatic prostate cancer invariably evolves to a lethal state. To characterize the intra-patient evolutionary relationships of metastases that evade treatment, we perform genome-wide copy number profiling and bespoke approaches targeting the androgen receptor (AR) on 167 metastatic regions from 11 organs harvested post-mortem from 10 men who died from prostate cancer. We identify diverse and patient-unique alterations clustering around the AR in metastases from every patient with evidence of independent acquisition of related genomic changes within an individual and, in some patients, the co-existence of AR-neutral clones. Using the genomic boundaries of pan-autosome copy number changes, we confirm a common clone of origin across metastases and diagnostic biopsies, and identified in individual patients, clusters of metastases occupied by dominant clones with diverged autosomal copy number alterations. These autosome-defined clusters are characterized by cluster-specific AR gene architectures, and in two index cases are topologically more congruent than by chance (p-values 3.07 × 10-8 and 6.4 × 10-4). Integration with anatomical sites suggests patterns of spread and points of genomic divergence. Here, we show that copy number boundaries identify treatment-selected clones with putatively distinct lethal trajectories
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Seizure Clusters, Seizure Severity Markers, and SUDEP Risk.
Rationale: Seizure clusters may be related to Sudden Unexpected Death in Epilepsy (SUDEP). Two or more generalized convulsive seizures (GCS) were captured during video electroencephalography in 7/11 (64%) patients with monitored SUDEP in the MORTEMUS study. It follows that seizure clusters may be associated with epilepsy severity and possibly with SUDEP risk. We aimed to determine if electroclinical seizure features worsen from seizure to seizure within a cluster and possible associations between GCS clusters, markers of seizure severity, and SUDEP risk. Methods: Patients were consecutive, prospectively consented participants with drug-resistant epilepsy from a multi-center study. Seizure clusters were defined as two or more GCS in a 24-h period during the recording of prolonged video-electroencephalography in the Epilepsy monitoring unit (EMU). We measured heart rate variability (HRV), pulse oximetry, plethysmography, postictal generalized electroencephalographic suppression (PGES), and electroencephalography (EEG) recovery duration. A linear mixed effects model was used to study the difference between the first and subsequent seizures, with a level of significance set at p < 0.05. Results: We identified 112 GCS clusters in 105 patients with 285 seizures. GCS lasted on average 48.7 ± 19 s (mean 49, range 2-137). PGES emerged in 184 (64.6%) seizures and postconvulsive central apnea (PCCA) was present in 38 (13.3%) seizures. Changes in seizure features from seizure to seizure such as seizure and convulsive phase durations appeared random. In grouped analysis, some seizure features underwent significant deterioration, whereas others improved. Clonic phase and postconvulsive central apnea (PCCA) were significantly shorter in the fourth seizure compared to the first. By contrast, duration of decerebrate posturing and ictal central apnea were longer. Four SUDEP cases in the cluster cohort were reported on follow-up. Conclusion: Seizure clusters show variable changes from seizure to seizure. Although clusters may reflect epilepsy severity, they alone may be unrelated to SUDEP risk. We suggest a stochastic nature to SUDEP occurrence, where seizure clusters may be more likely to contribute to SUDEP if an underlying progressive tendency toward SUDEP has matured toward a critical SUDEP threshold
Pharmacological Evaluation and Synthesis of New Sulfonamides Derivatives Based on 1,4-Benzodioxane
We report here the synthesis of a series of N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide and its N-substituted derivatives with benzyl chloride and ethyl iodide. Initially, 2,3-dihydrobenzo[1,4]dioxine-6-sulfonyl chloride (1) was subjected to react with various aryl amines (2a-e) to afford parent compounds N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide (3a-e). At second step, these parent compounds were reacted with benzyl chloride (4) and ethyl iodide (5) as to synthesize N-benzyl-N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide (6a-e) and N-ethyl-N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide (7a-e) in the presence of lithium hydride and N,Nꞌ-dimethylformamide respectively. FT-IR, Nuclear Magnetic Resonance (1H-NMR) and Mass Spectrometry (MS) techniques were used to investigate the structures of these synthesized compounds. A fingerprinted study was conducted against some enzymes like butyrylcholin-esterase (BChE), acetylcholinesterase (AChE) and lipoxygenase (LOX). This study revealed that most of them demonstrated a moderate activity against butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) however promisingly a good activity against lipoxygenase enzyme was observed. Finally, an antimicrobial and hemolytic activities of these sulfonamides were probed which confirmed that the parent sulfonamides 3b have the proficient antimicrobial activities, while the derivatives 6a, 7a, 7b and 7c explored a good activity against the selected panel of bacterial and fungal species. All the compounds were further computationally docked against (LOX), (BChE) and (AChE) enzymes and these interaction highlighted the importance of sulfonamides in the inhibition of the target enzymes
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