دانلود و نمایش مقالات مرتبط با molecules::صفحه 1
دانلود بهترین مقالات isi همراه با ترجمه فارسی 2

با سلام خدمت کاربران در صورتی که با خطای سیستم پرداخت بانکی مواجه شدید از طریق کارت به کارت (6037997535328901 بانک ملی ناصر خنجری ) مقاله خود را دریافت کنید (تا مشکل رفع گردد). 

نتیجه جستجو - molecules

تعداد مقالات یافته شده: 57
ردیف عنوان نوع
1 استخراج مایع-مایع ذرات ویروسی با مایعات یونی
سال انتشار: 2021 - تعداد صفحات فایل pdf انگلیسی: 8 - تعداد صفحات فایل doc فارسی: 23
درحالیکه مایعات یونی (IL ها) قبلاً برای استخراج انواع مولکول‌های زیستی از سیستم‌های آبپوش استفاده می‌شدند، تاکنون استفاده از آنها بریا استخراج ذرات ویروسی به ندرت مورد بررسی قرار گرفته است. از آنجاکه روش‌های کنونی برای استخراج ذرات ویروسی بسیار زمانبر، طاقت‌فرسا و نیازمند تجهیزات خاص هستند یا بازیابی بسیار اندکی دارند، هدف این پژوهش اثبات مفهومی، بررسی IL ها به عنوان راه‌حل احتمالی برای استخراج کل ذرات ویروسی است. در این مقاله تعداد 11 IL با روش پلاک و qPCR مورد ارزیابی قرار گرفتند تا مشخص شود آیا آنها ویژگی‌های استخراجی کافی را دارند یا خیر. از غربالگری نخست توانستیم حداقل 4 مایع با ویژگی‌های مناسب استخراج در حد 2 تا 4 لگاریتم واحد را شناسایی نماییم. امیدوارکننده‌ترین مایع یعنی [C4C1Pyr][NTf2] به کاهش بیش از 4 لگاریتم واحدی ویروس P100 و بیش از 3 لگاریتم واحدی برای PRD1 ختم شد. این IL با بررسی پایداری استخراج برای گستره‌های مختلف pH و غلظت نمک و در حضور آلاینده‌های طبیعی، با جزئیات بیشتر ارزیابی شد. این بررسی‌ها وابستگی به pH و عوامل متغیر بازدهی استخراج را نشان داد، در نتیجه بهترین نتایج در pH طبیعی برابر با 7.5 به دست آمد. علاوه بر مقدار ژنوم ویروسی در فاز آبپوش، وجود ویروس‌های عفونی نیز مشخص شد. در نتیجه، این پژوهش اثبات مفهومی، برخی IL های دارای مشخصه‌های مناسب استخراج ویروس را شناسایی کرد و یک گام ارزشمند در تیمار آماده‌سازی نمونه‌های آبی ارائه نمود.
کلیدواژه ها: مایعات یونی | ذرات ویروسی | ویروس | نمونه‌های آبپوش | استخراج مایع-مایع
مقاله ترجمه شده
2 To Hop or not to Hop: Exceptions in the FCS Diffusion Law
به هاپ آری یا نه : استثنائات در قانون پخش FCS-2020
Diffusion obstacles in membranes have not been directly visualized because of fast membrane dynamics and the occurrence of subresolution molecular complexes. To understand the obstacle characteristics, mobility-based methods are often used as an indirect way of assessing the membrane structure. Molecular movement in biological plasma membranes is often characterized by anomalous diffusion, but the exact underlying mechanisms are still elusive. Imaging total internal reflection fluorescence correlation spectroscopy (ITIR-FCS) is a well-established mobility-based method that provides spatially resolved diffusion coefficient maps and is combined with FCS diffusion law analysis to examine subresolution membrane organization. In recent years, although FCS diffusion law analysis has been instrumental in providing new insights into the membrane structure below the optical diffraction limit, there are certain exceptions and anomalies that require further clarification. To this end, we correlate the membrane structural features imaged by atomic force microscopy (AFM) with the dynamics measured using ITIR-FCS. We perform ITIR-FCS measurements on supported lipid bilayers (SLBs) of various lipid compositions to characterize the anomalous diffusion of lipid molecules in distinct obstacle configurations, along with the high-resolution imaging of the membrane structures with AFM. Furthermore, we validate our experimental results by performing simulations on image grids with experimentally determined obstacle configurations. This study demonstrates that FCS diffusion law analysis is a powerful tool to determine membrane heterogeneities implied from dynamics measurements. Our results corroborate the commonly accepted interpretations of imaging FCS diffusion law analysis, and we show that exceptions happen when domains reach the percolation threshold in a biphasic membrane and a network of domains behaves rather like a meshwork, resulting in hop diffusion.
مقاله انگلیسی
3 Synaptic Specificity, Recognition Molecules, and Assembly of Neural Circuits
ویژگی سیناپسی ، مولکولهای تشخیص و مونتاژ مدارهای عصبی-2020
Developing neurons connect in specific and stereotyped ways to form the complex circuits that underlie brain function. By comparison to earlier steps in neural development, progress has been slow in identifying the cell surface recognition molecules that mediate these synaptic choices, but new high-throughput imaging, genetic, and molecular methods are accelerating progress. Over the past decade, numerous large and small gene families have been implicated in target recognition, including members of the immunoglobulin, cadherin, and leucine-rich repeat superfamilies. We review these advances and propose ways in which combinatorial use of multifunctional recognition molecules enables the complex neuron-neuron interactions that underlie synaptic specificity.
مقاله انگلیسی
4 Light trapping induced flexible wrinkled nanocone SERS substrate for highly sensitive explosive detection
بستر SERS nanocone چین خورده انعطاف پذیر ناشی از به دام انداختن نور برای تشخیص مواد منفجره بسیار حساس-2020
We reported an ultrasensitive TNT detection method via a novel light trapping induced wrinkled nanocone flexible SERS substrate, which was fabricated by colloidal lithography and oxygen plasma etching on transparent PET film. Especially, a set of nanowrinkles with 50−60 nm was found on the sidewall of nanocone after etching. By coating 30 nm gold film, this flexible SERS substrate provided uniform hot spots, which demonstrated high reproducibility and sensitivity. 4-ATP molecules based Meisenheimer complex, which is a well-known chargetransfer interaction between electron-poor TNT and electron-rich amino group, was taken to detect ultra-low concentration of TNT explosive. The Raman signal of TNT was significantly enhanced by charge-transfer, light trapping effect and coupled electromagnetic field. The detection sensitivity of TNT molecules was as low as 10−13mol/L, and show a good linear response in the range from 10−8 to 10−13mol/L. Consequently, by brushing this flexible SERS substrate onto a cloth bag, trace amount of TNT residues with concentration as low as 10-10mol/L can be easily analyzed. It is believed that the proposed highly sensitive and uniform flexible substrate provides a significant solution for trace analysis of TNT residue in criminal forensic, military and security check.
Keywords: Nanocone | Nanowrinkle | Flexible materials | Light trapping | SERS
مقاله انگلیسی
5 Vascularized neural constructs for ex-vivo reconstitution of blood-brain barrier function
سازه های عصبی عروقی برای بازسازی قبلی در داخل بدن و عملکرد سد خونی مغز-2020
Ex-vivo blood-brain barrier (BBB) model is of great value for studying brain function and drug development, but it is still challenging to engineer macroscale three-dimensional (3D) tissue constructs to recapitulate physiological and functional aspects of BBB. Here, we describe a delicate 3D vascularized neural constructs for ex-vivo reconstitution of BBB function. The tissue-engineered tissue construct is based on a multicomponent 3D coculture of four types of cells, which typically exist in the BBB and were spatially defined and organized to mimic the in vivo BBB structure and function. A porous polycaprolactone/poly (D,L-lactide-co-glycolide) (PCL/PLGA) microfluidic perfusion system works as the vasculature network, which was made by freeze-coating a 3D-printed sacrificial template. Endothelial cells were seeded inside the channels of the network to form 3D interconnected blood vessels; while other types of cells, including pericytes, astrocytes, and neurons, were co-cultured in a collagen matrix wrapping the vasculature network to derive a vascularized neural construct that recapitulates in vivo BBB function with great complexity and delicacy. Using this model, we successfully reconstituted BBB function with parameters that are similar to the in vivo condition, and demonstrated the identification of BBBpenetrating therapeutics by examining the molecular delivery to neuronal cells when relevant biologic molecules were applied to the vasculature circulation system of the neural construct.
Keywords: Tissue engineering | 3D printing | Organ on a chip | Blood-brain barrier | Vasculature network | Neuro-engineering | Drug screening
مقاله انگلیسی
6 Serotonin induces Arcadlin in hippocampal neurons
سروتونین آرکادلین را در سلول های عصبی هیپوکامپ القا می کند-2020
The monoamine hypothesis does not fully explain the delayed onset of recovery after antidepressant treatment or the mechanisms of recovery after electroconvulsive therapy (ECT). The common mechanism that operates both in ECT and monoaminergic treatment presumably involves molecules induced in both of these conditions. A spine density modulator, Arcadlin (Acad), the rat orthologue of human Protocadherin-8 (PCDH8) and of Xenopus and zebrafish Paraxial protocadherin (PAPC), is induced by both electroconvulsive seizure (ECS) and antidepressants; however, its cellular mechanism remains elusive. Here we confirm induction of Arcadlin upon stimulation of an N-methyl-D-aspartate (NMDA) receptor in cultured hippocampal neurons. Stimulation of an NMDA receptor also induced acute (20 min) and delayed (2 h) phosphorylation of the p38 mitogen-activated protein (MAP) kinase; the delayed phosphorylation was not obvious in Acad–/– neurons, suggesting that it depends on Arcadlin induction. Exposure of highly mature cultured hippocampal neurons to 1–10 μM serotonin for 4 h resulted in Arcadlin induction and p38 MAP kinase phosphorylation. Co-application of the NMDA receptor antagonist D-(-)-2-amino-5-phosphonopentanoic acid (APV) completely blocked Arcadlin induction and p38 MAP kinase phosphorylation. Finally, administration of antidepressant fluoxetine in mice for 16 days induced Arcadlin expression in the hippocampus. Our data indicate that the Arcadlin-p38 MAP kinase pathway is a candidate neural network modulator that is activated in hippocampal neurons under the dual regulation of serotonin and glutamate and, hence, may play a role in antidepressant therapies.
Keywords: Serotonin | Protocadherin | Adhesion | Synaptic plasticity | Antidepressant | Mitogen-activated protein kinase
مقاله انگلیسی
7 Refinement of cerebellar network organization by extracellular signaling during development
پالایش سازمان شبکه مخچه با سیگنالینگ خارج سلولی در حین توسعه-2020
The cerebellum forms regular neural network structures consisting of a few major types of neurons, such as Purkinje cells, granule cells, and molecular layer interneurons, and receives two major inputs from climbing fibers and mossy fibers. Its regular structures consist of three well-defined layers, with each type of neuron designated to a specific location and forming specific synaptic connections. During the first few weeks of postnatal development in rodents, the cerebellum goes through dynamic changes via proliferation, migration, differentiation, synaptogenesis, and maturation, to create such a network structure. The development of this organized network structure presumably relies on the communication between developing elements in the network, including not only individual neurons, but also their dendrites, axons, and synapses. Therefore, it is reasonable that extracellular signaling via synaptic transmission, secreted molecules, and cell adhesion molecules, plays important roles in cerebellar network development. Although it is not yet clear as to how overall cerebellar development is orchestrated, there is indeed accumulating lines of evidence that extracellular signaling acts toward the development of individual elements in the cerebellar networks. In this article, we introduce what we have learned from many studies regarding the extracellular signaling required for cerebellar network development, including our recent study suggesting the importance of unbiased synaptic inputs from parallel fibers
Keywords : synaptic inputs | extracellular signaling | Purkinje cells | cerebellar granule cells | molecular layer interneurons | climbing fibers
مقاله انگلیسی
8 Correlation and prediction of surface tension of highly non-ideal hydrous binary mixtures using artificial neural network
همبستگی و پیش بینی تنش سطحی مخلوطهای باینری هیدروژن غیر ایده آل با استفاده از شبکه عصبی مصنوعی-2020
Prediction of surface tension of highly non-ideal binary aqueous–organic mixtures is crucial for interpreting the interaction between the molecules. In this regard, a multi-layer perceptron (MLP) artificial neural network (ANN) model is developed to predict the binary aqueous–organic surface tension as a function of mixture composition and temperature while the organic compounds are very dissimilar in size and type. To correlate the binary surface tension, gathered experimental surface tension data consisted of 30 binary mixtures containing 2271 data points in the wide temperature range of 273–471.15 K are randomly divided into three different subsets namely training (70 % of total data), validation (15 % of total data) and testing (15 % of total data) subsets. Different input variables are examined and the number of hidden neurons is optimized. The obtained results revealed that it is possible to correlate the binary surface tension with the best MLP network with 27 neurons in the hidden layer and inputs variables of temperature, mole fraction, molecular weight and critical pressure of non-water component with the average absolute relative deviation (AARD %) of lower than 1.43 %. Comparison of accuracy of the MLP model with several common models such as Jouyban-Acree model, Wilson equation, Paquette and Rasmussen areas and several equations of state including SRK, PR and CPA revealed more accuracy of the proposed MLP based model.
Keywords: Surface tension | Modeling | Binary mixture | Non-ideal | ANN
مقاله انگلیسی
9 A self-assembled layer-by-layer surface modification to fabricate the neuron-rich model from neural stem/precursor cells
اصلاح سطح لایه به لایه خود مونتاژ برای ساخت مدل غنی از نورون از سلولهای بنیادی / پیش ساز عصبی-2020
Background/Purpose: In vitro neural cell-based models have been widely used to mimic the in vivo neural tissue environments and quantitatively understand the effects of pharmaceutical molecules on neural diseases. Recently, several biomimetic neural tissue models have been widely developed by using biomaterials or surface modification. However, the complex protocols of material synthesis or surface modification lack an easy execution to fabricate the neuron favorite environment. Methods: In this study, we utilized a layer-by-layer technique as a surface modification method for regulating the behaviors of neural stem/precursor cells (NSPCs) on material surfaces. Polyelectrolyte multilayers (PEMs) via alternate deposition of poly (allylamine hydrochloride) (PAH) and poly (sodium-4-styrenesulfonate) (PSS) were used to culture NSPCs. After incubation for 7 days, the neuronal differentiation of NSPCs and synapse function of differentiated neurons were identified by immunocytochemistry for lineage specific markers. Results: Compared with the only PAH film, the PSS-ending film (neuron-rich model) was shown to significantly promote differentiation of NSPCs into neurons (more than 50%), form a neuronal network structure; and differentiated neurons exhibiting functional synaptic activity.
KEYWORDS : Polyelectrolyte multilayer (PEM) | Neural stem/ precursor cells | (NSPCs) | Neuronal | differentiation | Neurite outgrowth
مقاله انگلیسی
10 Visualizing Mitochondrial Form and Function within the Cell
تجسم فرم و عملکرد میتوکندری در سلول-2020
The specific cellular role of mitochondria is influenced by the surrounding environment because effective mitochondrial function requires the delivery of inputs (e.g., oxygen) and export of products (e.g., signaling molecules) to and from other cellular components, respectively. Recent technological developments in mitochondrial imaging have led to a more precise and comprehensive understanding of the spatial relationships governing the function of this complex organelle, opening a new era of mitochondrial research. Here, I highlight current imaging approaches for visualizing mitochondrial form and function within complex cellular environments. Increasing clarity of mitochondrial behavior within cells will continue to lend mechanistic insights into the role of mitochondria under normal and pathological conditions and point to spatially regulated processes that can be targeted to improve cellular function
مقاله انگلیسی
rss مقالات ترجمه شده rss مقالات انگلیسی rss کتاب های انگلیسی rss مقالات آموزشی
logo-samandehi
بازدید امروز: 2632 :::::::: بازدید دیروز: 3084 :::::::: بازدید کل: 5716 :::::::: افراد آنلاین: 53