23,482 results match your criteria [value dynamic

Model-guided dynamic control of essential metabolic nodes boosts acetyl-coenzyme A-dependent bioproduction in rewired Pseudomonas putida.

Metab Eng 2021 Jul 31. Epub 2021 Jul 31.

The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark. Electronic address:

Pseudomonas putida is evolutionarily endowed with features relevant for bioproduction, especially under harsh operating conditions. The rich metabolic versatility of this species, however, comes at the price of limited formation of acetyl-coenzyme A (CoA) from sugar substrates. Since acetyl-CoA is a key metabolic precursor for a number of added-value products, in this work we deployed an in silico-guided rewiring program of central carbon metabolism for upgrading P. Read More

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How tissue T1-variability influences DCE-MRI perfusion parameters estimation of recurrent high-grade glioma after surgery followed by radiochemotherapy.

Acta Radiol 2021 Aug 3:2841851211035911. Epub 2021 Aug 3.

Neuroradiology Unit, Azienda Ospedaliero-Universitaria of Parma, Parma, Italy.

Background: Quantification of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) kinetic parameters (KPs) requires a determination of native tissue T1. Two approaches are adopted: (i) tissue T1-maps are acquired; and (ii) an a priori T1 value (fT1) is fixed for all patients (fT1-approach). Although it is more attractive, the fT1-approach might bias the results of KP calculations due to tissue T1 variability. Read More

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Can the delayed phase of quantitative contrast-enhanced mammography improve the diagnostic performance on breast masses?

Quant Imaging Med Surg 2021 Aug;11(8):3684-3697

Department of Ultrasonic Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.

Background: Contrast-enhanced mammography (CEM) is an imaging tool for breast cancer detection. Most quantitative analyses of CEM involve two phases, and it is unknown whether an added delayed phase can improve its diagnostic performance compared to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). This study aimed to evaluate whether the delayed phase improves the diagnostic performance of CEM in distinguishing malignant and benign masses. Read More

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Absolute calibration of the latent heat of transition using differential thermal analysis.

Rev Sci Instrum 2021 Jul;92(7):075106

Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Nadia 741246, West Bengal, India.

We describe a simple and accurate differential thermal analysis setup to measure the latent heat of solid state materials undergoing abrupt phase transitions in the temperature range from 77 K to above room temperature. We report a numerical technique for the absolute calibration of the latent heat of transition without the need for a reference sample. The technique is applied to three different samples-vanadium sesquioxide undergoing the Mott transition, bismuth barium ruthenate undergoing a magnetoelastic transition, and an intermetallic Heusler compound. Read More

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Lithium-salt-based deep eutectic solvents: Importance of glass formation and rotation-translation coupling for the ionic charge transport.

J Chem Phys 2021 Jul;155(4):044503

Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany.

Lithium-salt-based deep eutectic solvents, where the only cation is Li, are promising candidates as electrolytes in electrochemical energy-storage devices, such as batteries. We have performed broadband dielectric spectroscopy on three such systems, covering a broad temperature and dynamic range that extends from the low-viscosity liquid around room temperature down to the glassy state approaching the glass-transition temperature. We detect a relaxational process that can be ascribed to dipolar reorientational dynamics and exhibits the clear signatures of glassy freezing. Read More

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Deep low-Rank plus sparse network for dynamic MR imaging.

Med Image Anal 2021 Jul 24;73:102190. Epub 2021 Jul 24.

Research Center for Medical AI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; Pazhou Lab, Guangzhou, China. Electronic address:

In dynamic magnetic resonance (MR) imaging, low-rank plus sparse (L+S) decomposition, or robust principal component analysis (PCA), has achieved stunning performance. However, the selection of the parameters of L+S is empirical, and the acceleration rate is limited, which are common failings of iterative compressed sensing MR imaging (CS-MRI) reconstruction methods. Many deep learning approaches have been proposed to address these issues, but few of them use a low-rank prior. Read More

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Research on multiple bubbles in China's multi-level stock market.

PLoS One 2021 2;16(8):e0255476. Epub 2021 Aug 2.

School of Economics and Management, University of Science and Technology Beijing, Beijing, People's Republic of China.

Financial bubbles have always been a topic of long-term concern for economists. Understanding bubble phenomenon and dating the period of bubbles in real time can provide an early warning diagnosis for financial bubbles and help regulatory authorities to control it and maintain market order. The generalized sup ADF (GSADF) and backward sup ADF (BSADF) tests with flexible window width can effectively detect and date periodically collapsing bubbles in real time. Read More

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MR characteristics of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney: comparison with clear cell and papillary subtypes of renal cell carcinoma.

Abdom Radiol (NY) 2021 Aug 2. Epub 2021 Aug 2.

Department of Diagnostic Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.

Purpose: To describe MR features of mucinous tubular spindle cell carcinoma (MTSCC) of the kidney that may help differentiate from clear cell renal cell carcinoma (ccRCC) and papillary RCC (pRCC).

Methods: 15 MTSCCs were retrospectively evaluated by MR with T2-weighted image without fat suppression (n = 15) and dynamic contrast-enhanced (DCE), fat-suppressed T1-weighted GRE (n = 11). Size-matched ccRCC (n = 30) and pRCC (n = 30) were evaluated as control. Read More

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Maternal Epilepsy and Umbilical Cord Blood Oxidative Stress Level.

Fetal Pediatr Pathol 2021 Aug 2:1-10. Epub 2021 Aug 2.

Perinatology Department Ankara, Turkish Ministry of Health Ankara City Hospital, Turkey.

Introduction: We investigated the effect of epilepsy on cord blood oxidative stress status.

Material And Methods: Thirty (n = 30) pregnant women with epilepsy and thirty (n = 30) healthy controls enrolled in this case control study. Albumin and IMA values and dynamic thiol/disulfide parameters were measured. Read More

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In-silico study of peptide-protein interaction of antimicrobial peptides potentially targeting SARS and SARS-CoV-2 nucleocapsid protein.

In Silico Pharmacol 2021 27;9(1):46. Epub 2021 Jul 27.

Amity University, Noida, Uttar Pradesh India.

This study is an attempt to find a suitable therapy using antimicrobial peptides (AMPs) by identifying peptide-protein interaction of AMPs and nucleocapsid protein of SARS and SARS-CoV- 2. The AMPs were shortlisted from the APD3 database (Antimicrobial peptide database) based on various physicochemical parameters. The binding efficacy of AMPs was measured using the lowest energy score of the docked complexes with 10 selected AMPs. Read More

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Application of PET Imaging in the Brain Regions of the Emotional Control Loop in Patients with Generalized Anxiety Disorder.

J Healthc Eng 2021 22;2021:4505227. Epub 2021 Jul 22.

School of Economics and Management, China University of Geosciences (Wuhan), Wuhan 430000, China.

Objective: This study uses PET imaging to observe the uptake and metabolism of 18F-fluorodeoxyglucose (F-FDG) in the multibrain areas of the emotional control loop in patients with generalized anxiety disorder (GAD) and investigate the brain of GAD patient's functional abnormality mechanism.

Methods: The thesis clinically collected 20 GAD patients and 20 healthy subjects. Dynamic PET-CT scans were used. Read More

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Acute Cardiopulmonary and Muscle Oxygenation Responses to Normocapnic Hyperpnea Exercise in COPD.

Med Sci Sports Exerc 2021 Jul 30. Epub 2021 Jul 30.

Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada.

Purpose: To investigate cardiorespiratory responses and intercostal muscle oxygenation during normocapnic hyperpnea exercise in COPD.

Methods: Twenty-two patients with COPD performed a cardiopulmonary cycling exercise test to assess peak oxygen consumption (V˙O2peak) and minute ventilation (V˙Epeak). They also performed a normocapnic hyperpnea exercise alone, at 50-60% of V˙Epeak to exhaustion, using a respiratory device (Spirotiger) connected to a gas analyzer to monitor V˙O2, V˙E and end-tidal CO2 partial pressure (PETCO2). Read More

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Eco-efficiency in China's Loess Plateau Region and its influencing factors: a data envelopment analysis from both static and dynamic perspectives.

Environ Sci Pollut Res Int 2021 Jul 31. Epub 2021 Jul 31.

Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, 710027, Shaanxi Province, China.

China's Loess Plateau Region (LPR) plays a significant role in national ecological security and development. Due to the advantage that relates environment with economy, eco-efficiency has become an important indicator of sustainable analysis. Using cross-level panel data for the period 2006-2017, this paper studied LPR's static eco-efficiency and dynamic performance through a combined application of DEA super-efficient slack-based measure and Malmquist Productivity Index at multi-scales. Read More

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Predictive performance of dynamic arterial elastance for arterial pressure response to fluid expansion in mechanically ventilated hypotensive adults: a systematic review and meta-analysis of observational studies.

Ann Intensive Care 2021 Jul 31;11(1):119. Epub 2021 Jul 31.

Department of Intensive Care Medicine, HwaMei Hospital, University of Chinese Academy of Sciences, Ningbo, 315000, Zhejiang, China.

Background: Dynamic arterial elastance (Ea) has been extensively considered as a functional parameter of arterial load. However, conflicting evidence has been obtained on the ability of Ea to predict mean arterial pressure (MAP) changes after fluid expansion. This meta-analysis sought to assess the predictive performance of Ea for the MAP response to fluid expansion in mechanically ventilated hypotensive patients. Read More

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Do chronic heart failure symptoms interact with burden of treatment? Qualitative literature systematic review.

BMJ Open 2021 07 30;11(7):e047060. Epub 2021 Jul 30.

Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK.

Objective: Explore the interaction between patient experienced symptoms and burden of treatment (BoT) theory in chronic heart failure (CHF). BoT explains how dynamic patient workload (self-care) and their capacity (elements influencing capability), impacts on patients' experience of illness.

Design: Review of qualitative research studies. Read More

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Characterizing ammonia emissions from water bodies using dynamic floating chambers.

Sci Total Environ 2021 Jul 10;796:148978. Epub 2021 Jul 10.

Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266200, Shandong, China; Sino-French Research Institute for Ecology and Environment (ISFREE), Shandong University, Qingdao 266200, Shandong, China. Electronic address:

Ammonia (NH) is the most important alkaline gas in the atmosphere and plays a central role in atmospheric pollution and the global N cycle. Water bodies receive increasing nitrogen inputs from effluents and atmospheric deposition due to anthropogenic activities and are regarded as the major natural NH and NH sinks. In this work, floating dynamic flux chambers were deployed at four types of freshwater (rivers, large reservoirs, medium-sized reservoirs and ponds) systems and a coastal seawater system to estimate the water-air NH emission fluxes. Read More

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Tuning the dynamic fragility of acrylic polymers by small molecules: the interplay of molecular structures.

Soft Matter 2021 Jul 30. Epub 2021 Jul 30.

Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science & Engineering, East China University of Science & Technology, Shanghai 200237, China.

This report studied changes in the dynamic fragility (m) of poly(butyl methacrylate) (PBMA) by introducing guest hindered phenols capable of forming two or three intermolecular hydrogen bonds (inter-HBs) per molecule with the host polymer. The small molecules effectively decrease the m value, even if they apparently increase the glass transition temperature (Tg) of mixtures. The reduction in m was confirmed by enthalpy relaxation in two aspects: adding the guest molecule leads to a stronger cooling rate dependence of the limiting fictive temperature together with an apparent increase in aging rate of PBMA hybrids at low concentrations. Read More

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Routine histopathology of septal myectomy for hypertrophic obstructive cardiomyopathy in a greek cohort.

Histol Histopathol 2021 Jul 30:18369. Epub 2021 Jul 30.

Laboratory of Histology and Embryology, Department of Medicine, School of Life Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.

Hypertrophic cardiomyopathy (HCM) is a diverse inherited disease affecting 1 in 500 individuals irrespective of gender and ethnicity. A fraction of HCM patients will eventually develop drug refractory dynamic obstruction of the left ventricular outflow tract. For such patients, septal myectomy is the procedure of choice to alleviate their symptoms and improve their quality of life. Read More

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Prognostic value of DCE-CT-derived blood volume and flow compared to core biopsy microvessel density in patients with metastatic renal cell carcinoma.

Eur Radiol Exp 2021 Jul 30;5(1):32. Epub 2021 Jul 30.

Department of Oncology, Aarhus University Hospital (AUH), Palle Juul-Jensens Blvd. 99, 8200, Aarhus N, Denmark.

Background: Angiogenesis is prominent in metastatic renal cell carcinoma (mRCC). We compared two angiogenesis assessment methods: dynamic contrast-enhanced computed tomography (DCE-CT)-derived blood volume (BV) and blood flow (BF) and core biopsy microvessel density (MVD).

Methods: As planned in DaRenCa Study-1 study, DCE-CT and core biopsy were performed from the same tumour/metastasis at baseline. Read More

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A diffusive virus model with a fixed intracellular delay and combined drug treatments.

J Math Biol 2021 Jul 29;83(2):19. Epub 2021 Jul 29.

Department of Applied Mathematics, National Pingtung University, Pingtung, 90003, R.O.C., Taiwan.

The method of administration of an effective drug treatment to eradicate viruses within a host is an important issue in studying viral dynamics. Overuse of a drug can lead to deleterious side effects, and overestimating the efficacy of a drug can result in failure to treat infection. In this study, we proposed a reaction-diffusion within-host virus model which incorporated information regarding spatial heterogeneity, drug treatment, and the intracellular delay to produce productively infected cells and viruses. Read More

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Infer HIV transmission dynamics from gene sequences among young men who have sex with men in China.

Infect Dis Model 2021 10;6:832-838. Epub 2021 Jul 10.

Department of Mathematics, Shanghai University, 99 Shangda Road, Shanghai, 200444, PR China.

To investigate the transmission dynamics and temporal and spatial migration characteristics of HIV spread among men who have sex with men (MSM) in China, a total of 1012 HIV-1 partial pol sequences, including five subtypes, were studied. Bayesian analysis were applied for each subtype to infer its dynamic characters including the effective reproductive number ( ) and migration process. The mean curve of each was almost always greater than 1 (even the 95% highest posterior density (HPD) lower value) along with time, which supports the necessity for a comprehensive study about risk behaviors among young MSM group in China. Read More

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C-Pittsburgh compound B and F-THK 5351 positron emission tomography brain imaging in cognitively normal individuals.

World J Nucl Med 2021 Apr-Jun;20(2):133-138. Epub 2020 Jun 27.

National Cyclotron and PET Centre, Chulabhorn Hospital, Chulabhorn Royal Academy, Bangkok, Thailand.

Abnormal beta-amyloid plaques and tau protein accumulation are the core pathologic features of Alzheimer's disease. However, the accumulation of these proteins is also common in cognitively normal elderly people. Therefore, this study is aimed to evaluate the amyloid and tau accumulation in the cognitively normal population. Read More

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Effective cesium removal from Cs-containing water using chemically activated opaline mudstone mainly composed of opal-cristobalite/tridymite (opal-CT).

Sci Rep 2021 Jul 28;11(1):15362. Epub 2021 Jul 28.

Department of Earth and Environmental Sciences, Chonnam National University, 77, Yongbong-ro, Buk-gu, Gwangju, 61186, Republic of Korea.

Opaline mudstone (OM) composed of opal-CT (SiO·nHO) has high potential use as a cesium (Cs) adsorbent, due to its high specific surface area (SSA). The objective of this study was to investigate the Cs adsorption capacity of chemically activated OM and the adsorption mechanism based on its physico-chemical properties. We used acid- and base-activation methods for the surface modification of OM. Read More

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Physician leaders' cross-boundary use of social media: what are the implications in the current COVID-19 environment?

Leadersh Health Serv (Bradf Engl) 2021 07;ahead-of-print(ahead-of-print)

School of Information Management, Dalhousie University Faculty of Management, Halifax, Canada.

Purpose: The purpose of this study is to better understand social media (SM) factors that physician leaders need to consider, as they adapt their cross-boundary practices to engage with colleagues and patients. Firstly, this study explores why SM is being used by physicians to cross horizontal (physician to physician) and stakeholder (physician to patient) boundaries prior to COVID-19. Secondly, based on the studies reviewed, this study provides insights on the practical SM implications for physician leaders working in the COVID-19 environment to actively enhance their practices, reduce public confusion and improve patient care, thus informing health-care practices. Read More

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Comparison of Changes in PPV Using a Tidal Volume Challenge with a Passive Leg Raising Test to Predict Fluid Responsiveness in Patients Ventilated Using Low Tidal Volume.

Indian J Crit Care Med 2021 Jun;25(6):685-690

Critical Care Medicine Department, Cairo University, Cairo, Egypt.

Background: Tidal volume challenge pulse pressure variation (TVC-PPV) is considered one of the recent reliable dynamic indices of fluid responsiveness (FR); also, passive leg raising (PLR)-induced changes in cardiac output (CO) detected by echocardiography are considered a reliable reversible self-fluid challenge test; many patients share eligibility for both tests.

Objectives: The study aimed to compare the sensitivity and specificity of both tests for the prediction of FR in mechanically ventilated patients with hemodynamic instability.

Methods: We studied 46 patients. Read More

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Multiparametric Magnetic Resonance Imaging in Evaluation of Clinically Significant Prostate Cancer.

Indian J Radiol Imaging 2021 Jan 23;31(1):65-77. Epub 2021 May 23.

Department of Imaging Sciences and Pathology, Saifee Hospital, Mumbai, Maharashtra, India.

 In this prospective study, we evaluate the role of multiparametric magnetic resonance imaging (mp-MRI) in the assessment of clinically significant prostate cancer at 1.5 T without endorectal coil (ERC).  Forty-five men with clinical suspicion of prostate cancer (prostate-specific antigen [PSA] level > 4 ng/mL, hard prostate on digital rectal examination, and suspicious area at transrectal ultrasound [TRUS]) were evaluated using the mp-MRI protocol over a period of 24 months. Read More

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January 2021

Assessment of Blood-Brain Barrier Integrity in Tuberculous Meningitis Using Dynamic Contrast-Enhanced MR Perfusion.

Indian J Radiol Imaging 2021 Jan 1;31(1):30-36. Epub 2021 Jun 1.

Department of Pediatric Neurology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.

Tuberculous meningitis (TBM) is the most common form of central nervous system tuberculosis. The aim of the study was to quantitatively evaluate blood-brain barrier (BBB) perfusion changes in TBM patients using dynamic contrast-enhanced (DCE) MR perfusion. Thirty untreated patients of TBM and 10 healthy controls were prospectively evaluated by conventional imaging and DCE MR perfusion. Read More

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January 2021

Remdesivir analogs against SARS-CoV-2 RNA-dependent RNA polymerase.

J Biomol Struct Dyn 2021 Jul 27:1-14. Epub 2021 Jul 27.

Division of Computer Aided Drug Design, The Red-Green Research Centre, BICCB, Tejgaon, Dhaka, Bangladesh.

The COVID-19 pandemic has already taken many lives but is still continuing its spread and exerting jeopardizing effects. This study is aimed to find the most potent ligands from 703 analogs of remdesivir against RNA-dependent RNA polymerase (RdRp) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus . RdRp is a major part of a multi-subunit transcription complex of the virus, which is essential for viral replication. Read More

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First-principles Investigations on a Two-dimensional SN/Black Phosphorene van der Waals Heterostructure: Mechanical, Carrier Transport and Thermoelectric Anisotropy.

J Phys Condens Matter 2021 Jul 27. Epub 2021 Jul 27.

Central South University, Central South University, Changsha, 410083, CHINA.

Isolated monolayer two-dimensional (2D) materials have attracted great attentions due to their unique optical, electrical, mechanical, thermoelectric properties and potential applications in nanoelectronic, optoelectronic and thermoelectric devices. However, it more and more difficult to find high performance and multifunctional monolayer 2D materials. The 2D van der Waals (vdW) heterostructure, which holds two different 2D materials together by vdW interactions, has opened up a new horizon in modulation of the energy band structure, the anisotropy of electrons and phonons, and the improvement of their thermoelectric properties for monolayer 2D materials. Read More

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