Subjects -> MEDICAL SCIENCES (Total: 8690 journals)
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MEDICAL SCIENCES (2415 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 3562 Journals sorted alphabetically
16 de Abril     Open Access   (Followers: 4)
3D Printing in Medicine     Open Access   (Followers: 5)
4 open     Open Access  
AADE in Practice     Hybrid Journal   (Followers: 6)
AAS Open Research     Open Access   (Followers: 2)
ABCS Health Sciences     Open Access   (Followers: 8)
Abia State University Medical Students' Association Journal     Full-text available via subscription   (Followers: 3)
AboutOpen     Open Access  
ACIMED     Open Access   (Followers: 1)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 48)
Acta Bio Medica     Full-text available via subscription   (Followers: 2)
Acta Bioethica     Open Access  
Acta Bioquimica Clinica Latinoamericana     Open Access   (Followers: 1)
Acta Científica Estudiantil     Open Access  
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Herediana     Open Access  
Acta Informatica Medica     Open Access   (Followers: 2)
Acta Medica (Hradec Králové)     Open Access  
Acta Medica Bulgarica     Open Access  
Acta Medica Colombiana     Open Access   (Followers: 1)
Acta Médica Costarricense     Open Access   (Followers: 2)
Acta Medica Indonesiana     Open Access  
Acta Medica International     Open Access  
Acta medica Lituanica     Open Access  
Acta Medica Marisiensis     Open Access   (Followers: 1)
Acta Medica Martiniana     Open Access  
Acta Medica Nagasakiensia     Open Access   (Followers: 1)
Acta Medica Peruana     Open Access   (Followers: 2)
Acta Médica Portuguesa     Open Access  
Acta Medica Saliniana     Open Access  
Acta Scientiarum. Health Sciences     Open Access   (Followers: 3)
Acupuncture & Electro-Therapeutics Research     Full-text available via subscription   (Followers: 9)
Acupuncture and Natural Medicine     Open Access  
Addiction Science & Clinical Practice     Open Access   (Followers: 9)
Addictive Behaviors Reports     Open Access   (Followers: 9)
Adıyaman Üniversitesi Sağlık Bilimleri Dergisi / Health Sciences Journal of Adıyaman University     Open Access   (Followers: 1)
Adnan Menderes Üniversitesi Sağlık Bilimleri Fakültesi Dergisi     Open Access   (Followers: 1)
Advanced Biomedical Research     Open Access  
Advanced Health Care Technologies     Open Access   (Followers: 10)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 9)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Bioscience and Clinical Medicine     Open Access   (Followers: 8)
Advances in Cell and Gene Therapy     Hybrid Journal   (Followers: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 27)
Advances in Clinical Radiology     Full-text available via subscription   (Followers: 2)
Advances in Life Course Research     Hybrid Journal   (Followers: 12)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Medical Education and Practice     Open Access   (Followers: 32)
Advances in Medical Ethics     Open Access   (Followers: 3)
Advances in Medical Research     Open Access   (Followers: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 9)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Medicine     Open Access   (Followers: 3)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 5)
Advances in Molecular Oncology     Open Access   (Followers: 2)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7)
Advances in Parkinson's Disease     Open Access   (Followers: 2)
Advances in Phytomedicine     Full-text available via subscription   (Followers: 1)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Regenerative Medicine     Open Access   (Followers: 4)
Advances in Skeletal Muscle Function Assessment     Open Access  
Advances in Therapy     Hybrid Journal   (Followers: 5)
Advances in Traditional Medicine     Hybrid Journal   (Followers: 7)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 15)
Advances in Virus Research     Full-text available via subscription   (Followers: 6)
Advances in Wound Care     Hybrid Journal   (Followers: 14)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 13)
African Health Sciences     Open Access   (Followers: 5)
African Journal of Biomedical Research     Open Access   (Followers: 1)
African Journal of Clinical and Experimental Microbiology     Open Access   (Followers: 4)
African Journal of Laboratory Medicine     Open Access   (Followers: 2)
African Journal of Medical and Health Sciences     Open Access   (Followers: 3)
African Journal of Thoracic and Critical Care Medicine     Open Access  
African Journal of Trauma     Open Access   (Followers: 1)
Afrimedic Journal     Open Access   (Followers: 3)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
AIDS Research and Human Retroviruses     Hybrid Journal   (Followers: 9)
AJOB Empirical Bioethics     Hybrid Journal   (Followers: 3)
AJSP: Reviews & Reports     Hybrid Journal   (Followers: 1)
Aktuelle Ernährungsmedizin     Hybrid Journal   (Followers: 6)
Al-Azhar Assiut Medical Journal     Open Access   (Followers: 2)
Al-Qadisiah Medical Journal     Open Access   (Followers: 1)
Alerta : Revista Científica del Instituto Nacional de Salud     Open Access  
Alexandria Journal of Medicine     Open Access   (Followers: 1)
Allgemeine Homöopathische Zeitung     Hybrid Journal   (Followers: 3)
Alpha Omegan     Full-text available via subscription  
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 2)
Althea Medical Journal     Open Access   (Followers: 2)
American Journal of Biomedical Engineering     Open Access   (Followers: 15)
American Journal of Biomedical Research     Open Access   (Followers: 2)
American Journal of Biomedicine     Full-text available via subscription   (Followers: 7)
American Journal of Chinese Medicine, The     Hybrid Journal   (Followers: 4)
American Journal of Clinical Medicine Research     Open Access   (Followers: 8)
American Journal of Family Therapy     Hybrid Journal   (Followers: 10)
American Journal of Law & Medicine     Full-text available via subscription   (Followers: 12)
American Journal of Lifestyle Medicine     Hybrid Journal   (Followers: 6)
American Journal of Managed Care     Full-text available via subscription   (Followers: 13)
American Journal of Medical Case Reports     Open Access   (Followers: 3)
American Journal of Medical Sciences and Medicine     Open Access   (Followers: 5)
American Journal of Medicine     Hybrid Journal   (Followers: 50)
American Journal of Medicine and Medical Sciences     Open Access   (Followers: 1)
American Journal of Medicine Studies     Open Access   (Followers: 3)
American Journal of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American Journal of the Medical Sciences     Hybrid Journal   (Followers: 12)
American Journal on Addictions     Hybrid Journal   (Followers: 11)
American medical news     Free   (Followers: 3)
American Medical Writers Association Journal     Full-text available via subscription   (Followers: 6)
Amyloid: The Journal of Protein Folding Disorders     Hybrid Journal   (Followers: 5)
Anales de la Facultad de Medicina     Open Access  
Anales de la Facultad de Medicina, Universidad de la República, Uruguay     Open Access  
Anales del Sistema Sanitario de Navarra     Open Access   (Followers: 1)
Analgesia & Resuscitation : Current Research     Hybrid Journal   (Followers: 6)
Anatolian Clinic the Journal of Medical Sciences     Open Access  
Anatomica Medical Journal     Open Access  
Anatomical Science International     Hybrid Journal   (Followers: 3)
Anatomical Sciences Education     Hybrid Journal   (Followers: 2)
Anatomy     Open Access   (Followers: 3)
Anatomy Research International     Open Access   (Followers: 4)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3)
Ankara Medical Journal     Open Access   (Followers: 2)
Ankara Üniversitesi Tıp Fakültesi Mecmuası     Open Access  
Annales de Pathologie     Full-text available via subscription  
Annales des Sciences de la Santé     Open Access  
Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
Annals of African Medicine     Open Access   (Followers: 2)
Annals of Anatomy - Anatomischer Anzeiger     Hybrid Journal   (Followers: 3)
Annals of Bioanthropology     Open Access   (Followers: 5)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 19)
Annals of Biomedical Sciences     Full-text available via subscription   (Followers: 4)
Annals of Clinical Hypertension     Open Access  
Annals of Clinical Microbiology and Antimicrobials     Open Access   (Followers: 15)
Annals of Family Medicine     Open Access   (Followers: 18)
Annals of Health Research     Open Access   (Followers: 1)
Annals of Ibadan Postgraduate Medicine     Open Access  
Annals of Medical and Health Sciences Research     Open Access   (Followers: 7)
Annals of Medicine     Hybrid Journal   (Followers: 12)
Annals of Medicine and Surgery     Open Access   (Followers: 7)
Annals of Medicine and Surgery Case Reports     Open Access   (Followers: 1)
Annals of Medicine and Surgery Protocols     Open Access   (Followers: 1)
Annals of Microbiology     Hybrid Journal   (Followers: 13)
Annals of Musculoskeletal Medicine     Open Access   (Followers: 2)
Annals of Nigerian Medicine     Open Access   (Followers: 1)
Annals of Rehabilitation Medicine     Open Access   (Followers: 1)
Annals of Saudi Medicine     Open Access  
Annals of the College of Medicine, Mosul     Open Access   (Followers: 1)
Annals of the New York Academy of Sciences     Hybrid Journal   (Followers: 5)
Annals of The Royal College of Surgeons of England     Full-text available via subscription   (Followers: 3)
Annals of the RussianAacademy of Medical Sciences     Open Access   (Followers: 1)
Annual Reports in Medicinal Chemistry     Full-text available via subscription   (Followers: 7)
Annual Reports on NMR Spectroscopy     Full-text available via subscription   (Followers: 5)
Annual Review of Medicine     Full-text available via subscription   (Followers: 18)
Anthropological Review     Open Access   (Followers: 25)
Anthropologie et santé     Open Access   (Followers: 5)
Antibiotics     Open Access   (Followers: 9)
Antibodies     Open Access   (Followers: 2)
Antibody Reports     Open Access   (Followers: 1)
Antibody Technology Journal     Open Access   (Followers: 1)
Antibody Therapeutics     Open Access   (Followers: 1)
Anuradhapura Medical Journal     Open Access  
Anwer Khan Modern Medical College Journal     Open Access   (Followers: 2)
Apmis     Hybrid Journal   (Followers: 2)
Apparence(s)     Open Access   (Followers: 1)
Applied Clinical Informatics     Hybrid Journal   (Followers: 4)
Applied Clinical Research, Clinical Trials and Regulatory Affairs     Hybrid Journal   (Followers: 2)
Applied Medical Informatics     Open Access   (Followers: 14)
Arab Journal of Nephrology and Transplantation     Open Access   (Followers: 1)
Arabian Journal of Scientific Research / المجلة العربية للبحث العلمي     Open Access   (Followers: 1)
Archive of Biomedical Science and Engineering     Open Access   (Followers: 1)
Archive of Clinical Medicine     Open Access   (Followers: 1)
Archive of Community Health     Open Access   (Followers: 1)
Archives Medical Review Journal / Arşiv Kaynak Tarama Dergisi     Open Access  
Archives of Asthma, Allergy and Immunology     Open Access  
Archives of Clinical Hypertension     Open Access   (Followers: 2)
Archives of Medical and Biomedical Research     Open Access   (Followers: 3)
Archives of Medical Laboratory Sciences     Open Access   (Followers: 1)
Archives of Medicine and Health Sciences     Open Access   (Followers: 5)
Archives of Medicine and Surgery     Open Access   (Followers: 1)
Archives of Organ Transplantation     Open Access   (Followers: 2)
Archives of Preventive Medicine     Open Access   (Followers: 3)
Archives of Pulmonology and Respiratory Care     Open Access   (Followers: 2)
Archives of Renal Diseases and Management     Open Access   (Followers: 2)
Archives of Trauma Research     Open Access   (Followers: 4)
Archivos de Medicina (Manizales)     Open Access   (Followers: 1)
ArgoSpine News & Journal     Hybrid Journal  
Arquivos Brasileiros de Oftalmologia     Open Access   (Followers: 1)
Arquivos de Ciências da Saúde     Open Access  
Arquivos de Medicina     Open Access   (Followers: 1)
Ars Medica : Revista de Ciencias Médicas     Open Access  
ARS Medica Tomitana     Open Access   (Followers: 1)
Art Therapy: Journal of the American Art Therapy Association     Hybrid Journal   (Followers: 19)
Arterial Hypertension     Open Access   (Followers: 1)
Artificial Intelligence in Medicine     Hybrid Journal   (Followers: 20)
Artificial Organs     Hybrid Journal   (Followers: 1)
ASHA Leader     Open Access   (Followers: 6)
Asia Pacific Family Medicine Journal     Open Access   (Followers: 4)
Asia Pacific Journal of Clinical Nutrition     Full-text available via subscription   (Followers: 13)
Asia Pacific Journal of Clinical Trials : Nervous System Diseases     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 7 8 | Last

Similar Journals
Journal Cover
Annals of Biomedical Engineering
Journal Prestige (SJR): 1.042
Citation Impact (citeScore): 3
Number of Followers: 19  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1573-9686 - ISSN (Online) 0090-6964
Published by Springer-Verlag Homepage  [2626 journals]
  • Muscular Thin Films for Label-Free Mapping of Excitation Propagation in
           Cardiac Tissue
    • Abstract: Abstract Muscular thin films (MTFs), have already found a variety of applications in cardiac tissue engineering and in building of lab-on-a-chip systems. Here we present a novel approach to label-free mapping of excitation waves in the cardiomyocyte cell cultures with the use of MTFs. Neonatal rat ventricular cardiomyocytes were cultured on polydimethylsiloxane (PDMS) thin films and observed by means of off-axis illumination. Inflexions of the membrane created by the contraction of cardiomyocytes led to formation of patterns of bright and dark areas on the surface of the membrane. These patterns were recorded and analyzed for the monitoring of the contraction propagation. The method was compared with a standard optical mapping technique based on the use of a Ca2+-sensitive fluorescent dye. A good consistency of the results obtained by these two methods was demonstrated. The proposed method is non-toxic and might be of particular interest for the purpose of continuous monitoring in test systems based on human induced pluripotent stem cells.
      PubDate: 2020-10-01
       
  • Scalable Signature-Based Molecular Diagnostics Through On-chip Biomarker
           Profiling Coupled with Machine Learning
    • Abstract: Abstract Molecular diagnostics have traditionally relied on discrete biological substances as diagnostic markers. In recent years however, advances in on-chip biomarker screening technologies and data analytics have enabled signature-based diagnostics. Such diagnostics aim to utilize unique combinations of multiple biomarkers or diagnostic ‘fingerprints’ rather than discrete analyte measurements. This approach has shown to improve both diagnostic accuracy and diagnostic specificity. In this review, signature-based diagnostics enabled by microfluidic and micro-/nano- technologies will be reviewed with a focus on device design and data analysis pipelines and methodologies. With increasing amounts of data available from microfluidic biomarker screening, isolation, and detection platforms, advanced data handling and analytics approaches can be employed. Thus, current data analysis approaches including machine learning and recent advances with image processing, along with potential future directions will be explored. Lastly, the needs and gaps in current literature will be elucidated to inform future efforts towards development of molecular diagnostics and biomarker screening technologies.
      PubDate: 2020-10-01
       
  • Influence of Patient-Specific Characteristics on Transcatheter Heart Valve
           Neo-Sinus Flow: An In Silico Study
    • Abstract: Abstract Thrombosis in post-transcatheter aortic valve replacement (TAVR) patients has been correlated with flow stasis in the neo-sinus. This study investigated the effect of the post-TAVR geometry on flow stasis. Computed tomography angiography of 155 patients who underwent TAVR using a SAPIEN 3 were used to identify patients with and without thrombosis, and quantify thrombus volumes. Six patients with 23-mm SAPIEN 3 valves were then selected from the cohort and used to create patient-specific post-TAVR computational fluid dynamic models. Regions of flow stasis (%Volstasis, velocities below 0.05 m/s) were identified. The results showed that all post-TAVR anatomical measurements were significantly different in patients with and without thrombus, but only sinus diameter had a linear correlation with thrombus volume (r = 0.471, p = 0.008). A linear correlation was observed between %Volstasis and thrombus volume (r = 0.821, p = 0.007). The combination of anatomy and valve deployment created a unique geometry in each patient, which when combined with patient-specific cardiac output, resulted in distinct flow patterns. While parametric studies have shown individual anatomical or deployment metrics may relate to flow stasis, the combined effects of these metrics potentially contributes to the biomechanical environment promoting thrombosis, therefore hemodynamic studies of TAVR should account for these patient-specific factors.
      PubDate: 2020-10-01
       
  • An Image Registration-Based Morphing Technique for Generating
           Subject-Specific Brain Finite Element Models
    • Abstract: Abstract Finite element (FE) models of the brain are crucial for investigating the mechanisms of traumatic brain injury (TBI). However, FE brain models are often limited to a single neuroanatomy because the manual development of subject-specific models is time consuming. The objective of this study was to develop a pipeline to automatically generate subject-specific FE brain models using previously developed nonlinear image registration techniques, preserving both external and internal neuroanatomical characteristics. To verify the morphing-induced mesh distortions did not influence the brain deformation response, strain distributions predicted using the morphed model were compared to those from manually created voxel models of the same subject. Morphed and voxel models were generated for 44 subjects ranging in age, and simulated using head kinematics from a football concussion case. For each subject, brain strain distributions predicted by each model type were consistent, and differences in strain prediction was less than 4% between model type. This automated technique, taking approximately 2 h to generate a subject-specific model, will facilitate interdisciplinary research between the biomechanics and neuroimaging fields and could enable future use of biomechanical models in the clinical setting as a tool for improving diagnosis.
      PubDate: 2020-10-01
       
  • A COVID-19 Airway Management Innovation with Pragmatic Efficacy
           Evaluation: The Patient Particle Containment Chamber
    • Abstract: Abstract The unique resource constraints, urgency, and virulence of the coronavirus disease 2019 pandemic has sparked immense innovation in the development of barrier devices to protect healthcare providers from infectious airborne particles generated by patients during airway management interventions. Of the existing devices, all have shortcomings which render them ineffective and impractical in out-of-hospital environments. Therefore, we propose a new design for such a device, along with a pragmatic evaluation of its efficacy. Must-have criteria for the device included: reduction of aerosol transmission by at least 90% as measured by pragmatic testing; construction from readily available, inexpensive materials; easy to clean; and compatibility with common EMS stretchers. The Patient Particle Containment Chamber (PPCC) consists of a standard shower liner draped over a modified octagonal PVC pipe frame and secured with binder clips. 3D printed sleeve portals were used to secure plastic sleeves to the shower liner wall. A weighted tube sealed the exterior base of the chamber with the contours of the patient’s body and stretcher. Upon testing, the PPCC contained 99% of spray-paint particles sprayed over a 90s period. Overall, the PPCC provides a compact, affordable option that can be used in both the in-hospital and out-of-hospital environments.
      PubDate: 2020-10-01
       
  • Computational Tools for the Reliability Assessment and the Engineering
           Design of Procedures and Devices in Bariatric Surgery
    • Abstract: Abstract Obesity is one of the main health concerns worldwide. Bariatric Surgery (BS) is the gold standard treatment for severe obesity. Nevertheless, unsatisfactory weight loss and complications can occur. The efficacy of BS is mainly defined on experiential bases; therefore, a more rational approach is required. The here reported activities aim to show the strength of experimental and computational biomechanics in evaluating stomach functionality depending on bariatric procedure. The experimental activities consisted in insufflation tests on samples of swine stomach to assess the pressure-volume behaviour both in pre- and post-surgical configurations. The investigation pertained to two main bariatric procedures: adjustable gastric banding (AGB) and laparoscopic sleeve gastrectomy (LSG). Subsequently, a computational model of the stomach was exploited to validate and to integrate results from experimental activities, as well as to broad the investigation to a wider scenario of surgical procedures and techniques. Furthermore, the computational approach allowed analysing stress and strain fields within stomach tissues because of food ingestion. Such fields elicit mechanical stimulation of gastric receptors, contributing to release satiety signals. Pressure-volume curves assessed stomach capacity and stiffness according to the surgical procedure. Both AGB and LSG proved to reduce stomach capacity and to increase stiffness, with markedly greater effect for LSG. At an internal pressure of 5 kPa, outcomes showed that in pre-surgical configuration the inflated volume was about 1000 mL, after AGB the inflated volume was slightly lower, while after LSG it fell significantly, reaching 100 mL. Computational modelling techniques showed the influence of bariatric intervention on mechanical stimulation of gastric receptors due to food ingestion. AGB markedly enhanced the mechanical stimulation within the fundus region, while LSG significantly reduced stress and strain intensities. Further computational investigations revealed the potentialities of hybrid endoscopic procedures to induce both reduction of stomach capacity and enhancement of gastric receptors mechanical stimulation. In conclusion, biomechanics proved to be useful for the investigation of BS effects. Future exploitations of the biomechanical methods may largely improve BS reliability, efficacy and penetration rate.
      PubDate: 2020-10-01
       
  • Efficiently Simulating an Endograft Deployment: A Methodology for Detailed
           CFD Analyses
    • Abstract: Abstract Numerical models of endografts for the simulation of endovascular aneurysm repair are increasingly important in the improvement of device designs and patient outcomes. Nevertheless, current finite element analysis (FEA) models of complete endograft devices come at a high computational cost, requiring days of runtime, therefore restricting their applicability. In the current study, an efficient FEA model of the Anaconda™ endograft (Terumo Aortic, UK) was developed, able to yield results in just over 4 h, an order of magnitude less than similar models found in the literature. The model was used to replicate a physical device that was deployed in a 3D printed aorta and comparison of the two shapes illustrated a less than 5 mm placement error of the model in the regions of interest, consistent with other more computationally intensive models in the literature. Furthermore, the final goal of the study was to utilize the deployed fabric model in a hemodynamic analysis that would incorporate realistic fabric folds, a feature that is almost always omitted in similar simulations. By successfully exporting the deployed graft geometry into a flow analysis, it was illustrated that the inclusion of fabric wrinkles enabled clinically significant flow patterns such as flow stagnation and recirculation to be detected, paving the way for this modelling methodology to be used in future for stent design optimisation.
      PubDate: 2020-10-01
       
  • In Vitro Assessment of Flow Variability in an Intracranial Aneurysm Model
           Using 4D Flow MRI and Tomographic PIV
    • Abstract: Abstract Aneurysm rupture has been suggested to be related to aneurysm geometry, morphology, and complex flow activity; therefore, understanding aneurysm-specific hemodynamics is crucial. 4D Flow MRI has been shown to be a feasible tool for assessing hemodynamics in intracranial aneurysms with high spatial resolution. However, it requires averaging over multiple heartbeats and cannot account for cycle-to-cycle hemodynamics variations. This study aimed to assess cycle-to-cycle flow dynamics variations in a patient-specific intracranial aneurysm model using tomographic particle image velocimetry (tomo-PIV) at a high image rate under pulsatile flow conditions. Time-resolved and time-averaged velocity flow fields within the aneurysm sac and estimations of wall shear stress (WSS) were compared with those from 4D Flow MRI. A one-way ANOVA showed a significant difference between cardiac cycles (p value < 0.0001); however, differences were not significant after PIV temporal and spatial resolution was matched to that of MRI (p value 0.9727). This comparison showed the spatial resolution to be the main contributor to assess cycle-to-cycle variability. Furthermore, the comparison with 4D Flow MRI between velocity components, streamlines, and estimated WSS showed good qualitative and quantitative agreement. This study showed the feasibility of patient-specific in-vitro experiments using tomo-PIV to assess 4D Flow MRI with high repeatability in the measurements.
      PubDate: 2020-10-01
       
  • A Novel Multiplex Based Platform for Osteoarthritis Drug Candidate
           Evaluation
    • Abstract: Abstract Osteoarthritis (OA) is characterized by irreversible cartilage degradation with very limited therapeutic interventions. Drug candidates targeted at prototypic players had limited success until now and systems based approaches might be necessary. Consequently, drug evaluation platforms should consider the biological complexity looking beyond well-known contributors of OA. In this study an ex vivo model of cartilage degradation, combined with measuring releases of 27 proteins, was utilized to study 9 drug candidates. After an initial single drug evaluation step the 3 most promising compounds were selected and employed in an exhaustive combinatorial experiment. The resulting most and least promising treatment candidates were selected and validated in an independent study. This included estimation of mechanical properties via finite element modelling (FEM) and quantification of cartilage degradation as glycosaminoglycan (GAG) release. The most promising candidate showed increase of Young’s modulus, decrease of hydraulic permeability and decrease of GAG release. The least promising candidate exhibited the opposite behaviour. The study shows the potential of a novel drug evaluation platform in identifying treatments that might reduce cartilage degradation. It also demonstrates the promise of exhaustive combination experiments and a connection between chondrocyte responses at the molecular level with changes of biomechanical properties at the tissue level.
      PubDate: 2020-10-01
       
  • Sprouting Angiogenesis: A Numerical Approach with Experimental Validation
    • Abstract: Abstract A functional vascular network is essential to the correct wound healing. In sprouting angiogenesis, vascular endothelial growth factor (VEGF) regulates the formation of new capillaries from pre-existing vessels. This is a very complex process and mathematical formulation permits to study angiogenesis using less time-consuming, reproducible and cheaper methodologies. This study aimed to mimic the chemoattractant effect of VEGF in stimulating sprouting angiogenesis. We developed a numerical model in which endothelial cells migrate according to a diffusion-reaction equation for VEGF. A chick chorioallantoic membrane (CAM) bioassay was used to obtain some important parameters to implement in the model and also to validate the numerical results. We verified that endothelial cells migrate following the highest VEGF concentration. We compared the parameters—total branching number, total vessel length and branching angle—that were obtained in the in silico and the in vivo methodologies and similar results were achieved (p-value smaller than 0.5; n = 6). For the difference between the total capillary volume fractions assessed using both methodologies values smaller than 15% were obtained. In this study we simulated, for the first time, the capillary network obtained during the CAM assay with a realistic morphology and structure.
      PubDate: 2020-09-24
       
  • Transcorneal Electrical Stimulation Reduces Neurodegenerative Process in a
           Mouse Model of Glaucoma
    • Abstract: Abstract Glaucoma is a neurodegenerative disease in which the retinal ganglion cell axons of the optic nerve degenerate concomitant with synaptic changes in the retina, leading finally to death of the retinal ganglion cells (RGCs). Electrical stimulation has been used to improve neural regeneration in a variety of systems, including in diseases of the retina. Therefore, the focus of this study was to investigate whether transcorneal electrical stimulation (TES) in the DBA2/J mouse model of glaucoma could improve retinal or optic nerve pathology and serve as a minimally invasive treatment option. Mice (10 months-old) received 21 sessions of TES over 8 weeks, after which we evaluated RGC number, axon number, and anterograde axonal transport using histology and immunohistochemistry. To gain insight into the mechanism of proposed protection, we also evaluated inflammation by quantifying CD3+ T-cells and Iba1+ microglia; perturbations in metabolism were shown via the ratio pAMPK to AMPK, and changes in trophic support were tested using protein capillary electrophoresis. We found that TES resulted in RGC axon protection, a reduction in inflammatory cells and their activation, improved energy homeostasis, and a reduction of the cell death-associated p75NTR. Collectively, the data indicated that TES maintained axons, decreased inflammation, and increased trophic factor support, in the form of receptor presence and energy homeostasis, suggesting that electrical stimulation impacts several facets of the neurodegenerative process in glaucoma.
      PubDate: 2020-09-24
       
  • Laboratory Reconstructions of Bicycle Helmet Damage: Investigation of
           Cyclist Head Impacts Using Oblique Impacts and Computed Tomography
    • Abstract: Abstract Although head injuries are common in cycling, exact conditions associated with cyclist head impacts are difficult to determine. Previous studies have attempted to reverse engineer cyclist head impacts by reconstructing bicycle helmet residual damage, but they have been limited by simplified damage assessment and testing. The present study seeks to enhance knowledge of cyclist head impact conditions by reconstructing helmet damage using advanced impact testing and damage quantification techniques. Damage to 18 helmets from cyclists treated in emergency departments was quantified using computed tomography and reconstructed using oblique impacts. Damage metrics were related to normal and tangential velocities from impact tests as well as peak linear accelerations (PLA) and peak rotational velocities (PRV) using case-specific regression models. Models then allowed original impact conditions and kinematics to be estimated for each case. Helmets were most frequently damaged at the front and sides, often near the rim. Concussion was the most common, non-superficial head injury. Normal velocity and PLA distributions were similar to previous studies, with median values of 3.4 m/s and 102.5 g. Associated tangential velocity and PRV medians were 3.8 m/s and 22.3 rad/s. Results can inform future oblique impact testing conditions, enabling improved helmet evaluation and design.
      PubDate: 2020-09-24
       
  • Surface Contact Features, Impact Obliquity, and Preimpact Rotational
           Motion in Concussive Helmet-to-Ground Impacts: Assessment via a New Impact
           Test Device
    • Abstract: Abstract This paper reports the development of a test device for replicating unique features of concussion-causing helmet-to-ground impacts. Helmet-to-ground impacts are characterized by an oblique impact velocity vector, preimpact rotational motion of the helmeted head, and an impact into a compliant frictional surface of unknown effective mass. No helmet assessment testing program replicates these impact characteristics, yet they influence brain injury risk and therefore may influence helmet design priorities. To replicate these mechanics, the carriage of a drop tower was modified by the addition of a curvilinear bearing track and a hinged torso-neck fixture to which a helmeted head of a Hybrid III anthropomorphic test device was mounted. Preimpact rotational motion of the head was imparted by forcing a link arm to follow the curvilinear path as the carriage fell under gravity. At impact, the rotating helmeted head struck a vertically mounted surface. The ground impact features of head kinematics are illustrated by comparing rear impacts into a rigid, low-friction surface against those into a compliant frictional surface simulating turf. With the rigid, low-friction surface, the head experienced a change in rotational rate of approximately 40 rad/s, which corresponded to a peak rotational acceleration of approximately αy = − 4000 rad/s2. In contrast, peak rotational acceleration with the compliant frictional surface was approximately αy = − 1000 rad/s2 while the helmet was in contact with the surface. Neck loads were significantly greater with the compliant frictional surface. Translational head acceleration was less sensitive to the surface characteristics, with the peak of the anterior-posterior component essentially unchanged.
      PubDate: 2020-09-22
       
  • Ultrasound Features of Skeletal Muscle Can Predict Kinematics of Upcoming
           Lower-Limb Motion
    • Abstract: Abstract Seamless integration of lower-limb assistive devices with the human body requires an intuitive human-machine interface, which would benefit from predicting the intent of individuals in advance of the upcoming motion. Ultrasound imaging was recently introduced as an intuitive sensing interface. The objective of the present study was to investigate the predictability of joint kinematics using ultrasound features of the rectus femoris muscle during a non-weight-bearing knee extension/flexion. Motion prediction accuracy was evaluated in 67 ms increments, up to 600 ms in time. Statistical analysis was used to evaluate the feasibility of motion prediction, and the linear mixed-effects model was used to determine a prediction time window where the joint angle prediction error is barely perceivable by the sample population, hence clinically reliable. Surprisingly, statistical tests revealed that the prediction accuracy of the joint angle was more sensitive to temporal shifts than the accuracy of the joint angular velocity prediction. Overall, predictability of the upcoming joint kinematics using ultrasound features of skeletal muscle was confirmed, and a time window for a statistically and clinically reliable prediction was found between 133 and 142 ms. A reliable prediction of user intent may provide the time needed for processing, control planning, and actuation of the assistive devices at critical points during ambulation, contributing to the intuitive behavior of lower-limb assistive devices.
      PubDate: 2020-09-21
       
  • Chondrocyte Deformations Under Mild Dynamic Loading Conditions
    • Abstract: Abstract Dynamic deformation of chondrocytes are associated with cell mechanotransduction and thus may offer a new understanding of the mechanobiology of articular cartilage. Despite extensive research on chondrocyte deformations for static conditions, work for dynamic conditions remains rare. However, it is these dynamic conditions that articular cartilage in joints are exposed to everyday, and that seem to promote biological signaling in chondrocytes. Therefore, the objective of this study was to develop an experimental technique to determine the in situ deformations of chondrocytes when the cartilage is dynamically compressed. We hypothesized that dynamic deformations of chondrocytes vastly differ from those observed under steady-state static strain conditions. Real-time chondrocyte geometry was reconstructed at 10, 15, and 20% compression during ramp compressions with 20% ultimate strain, applied at a strain rate of 0.2% s−1, followed by stress relaxation. Dynamic compressive chondrocyte deformations were non-linear as a function of nominal strain, with large deformations in the early and small deformations in the late part of compression. Early compression (up to about 10%) was associated with chondrocyte volume loss, while late compression (> ~ 10%) was associated with cell deformation but minimal volume loss. Force continued to decrease for 5 min in the stress-relaxation phase, while chondrocyte shape/volume remained unaltered after the first minute of stress-relaxation.
      PubDate: 2020-09-21
       
  • Breath Hold Facilitates Targeted Deposition of Aerosolized Droplets in a
           3D Printed Bifurcating Airway Tree
    • Abstract: Abstract The lungs have long been considered a desired route for drug delivery but, there is still a lack of strategies to rationally target delivery sites especially in the presence of heterogeneous airway disease. Furthermore, no standardized system has been proposed to rapidly test different ventilation strategies and how they alter the overall and regional deposition pattern in the airways. In this study, a 3D printed symmetric bifurcating tree model mimicking part of the human airway tree was developed that can be used to quantify the regional deposition patterns of different delivery methodologies. The model is constructed in a novel way that allows for repeated measurements of regional deposition using reusable parts. During ventilation, nebulized ~3-micron-sized fluid droplets were delivered into the model. Regional delivery, quantified by precision weighing individual airways, was highly reproducible. A successful strategy to control regional deposition was achieved by combining an inspiratory wave form with a “breath hold” pause after each inspiration. Specifically, the second generation of the tree was successfully targeted, and deposition was increased by up to four times in generation 2 when compared to a ventilation without the breath hold (p < 0.0001). Breath hold was also demonstrated to facilitate deposition into blocked regions of the model, which mimic airway closure during an asthma that receive no flow during inhalation. Additionally, visualization experiments demonstrated that in the absence of fluid flow, the deposition of 3-micron water droplets is dominated by gravity, which, to our knowledge, has not been confirmed under standard laboratory conditions.
      PubDate: 2020-09-21
       
  • In Vivo Pressurization of the Zebrafish Embryonic Heart as a Tool to
           Characterize Tissue Properties During Development
    • Abstract: Abstract Cardiac morphogenesis requires an intricate orchestration of mechanical stress to sculpt the heart as it transitions from a straight tube to a multichambered adult heart. Mechanical properties are fundamental to this process, involved in a complex interplay with function, morphology, and mechanotransduction. In the current work, we propose a pressurization technique applied to the zebrafish atrium to quantify mechanical properties of the myocardium under passive tension. By further measuring deformation, we obtain a pressure-stretch relationship that is used to identify constitutive models of the zebrafish embryonic cardiac tissue. Two-dimensional results are compared with a three-dimensional finite element analysis based on reconstructed embryonic heart geometry. Through these steps, we found that the myocardium of zebrafish results in a stiffness on the order of 10 kPa immediately after the looping stage of development. This work enables the ability to determine how these properties change under normal and pathological heart development.
      PubDate: 2020-09-21
       
  • Neurovascular Coupling in Special Operations Forces Combat Soldiers
    • Abstract: Abstract The purpose of this study was to investigate how concussion history affects neurovascular coupling in Special Operations Forces (SOF) combat Soldiers. We studied 100 SOF combat Soldiers [age = 33.5 ± 4.3 years; height = 180.4 ± 6.0 cm; 55 (55.0%) with self-reported concussion history]. We employed transcranial Doppler (TCD) ultrasound to assess neurovascular coupling (NVC) via changes in posterior cerebral artery (PCA) velocity in response to a reading and a visual search task. Baseline TCD data were collected for 2 min. NVC was quantified by the percent change in overall PCA response curves. We employed linear mixed effect models using a linear spline with one knot to assess group differences in percent change observed in the PCA velocity response curves between SOF combat Soldiers with and without a concussion history. Baseline PCA velocity did not significantly differ (t98 = 1.28, p = 0.20) between those with and without concussion history. Relative PCA velocity response curves did not differ between those with and without a concussion history during the reading task (F1,98 = 0.80, p = 0.37) or the visual search task (F1,98 = 0.52, p = 0.47). When assessing only SOF combat Soldiers with a concussion history, differential response to task was significantly greater in those with 3 or more concussions (F1,4341 = 27.24, p < 0.0001) relative to those with 1–2 concussions. Despite no main effect of concussion history on neurovascular coupling response in SOF combat Soldiers, we observed a dose-response based on lifetime concussion incidence. While long-term neurophysiological effects associated with head impact and blast-related injury are currently unknown, assessing NVC response may provide further insight into cerebrovascular function and overall physiological health.
      PubDate: 2020-09-17
       
  • Occupant Restraint in Far-Side Impacts: Cadaveric and WorldSID Responses
           to a Far-Side Airbag
    • Abstract: Abstract Previous studies indicate that seatbelts may require supplementary restraints to increase their effectiveness in far-side impacts. This study aimed to evaluate the effectiveness of a novel, far-side-specific airbag in restraining and preventing injuries in far-side impacts, and to evaluate the WorldSID’s response to the presence of a far-side airbag. A series of tests with three Post-Mortem Human Subjects and the WorldSID was conducted in a vehicle-based sled environment equipped with a far-side airbag. Results of these tests were evaluated and compared to a previous test series conducted without the airbag. All of the PMHS retained the shoulder belt on the shoulder. The airbag significantly reduced PMHS injury severity and maximum lateral head excursion. While the WorldSID exhibited a similar decrease in lateral excursion, it was unable to represent PMHS thoracic deflection or injury probability, and it consistently slipped out of the shoulder belt. This indicates that the WorldSID is limited both in its ability to evaluate the effect of changes in the seatbelt system and in its ability to predict thoracic injury risk and assess airbag-related injury mitigation countermeasures.
      PubDate: 2020-09-17
       
  • Perivascular Secretome Influences Hematopoietic Stem Cell Maintenance in a
           Gelatin Hydrogel
    • Abstract: Abstract Adult hematopoietic stem cells (HSCs) produce the body’s full complement of blood and immune cells. They reside in specialized microenvironments, or niches, within the bone marrow. The perivascular niche near blood vessels is believed to help maintain primitive HSCs in an undifferentiated state but demonstration of this effect is difficult. In vivo studies make it challenging to determine the direct effect of the endosteal and perivascular niches as they can be in close proximity, and two-dimensional in vitro cultures often lack an instructive extracellular matrix environment. We describe a tissue engineering approach to develop and characterize a three-dimensional perivascular tissue model to investigate the influence of the perivascular secretome on HSC behavior. We generate 3D endothelial networks in methacrylamide-functionalized gelatin hydrogels using human umbilical vein endothelial cells (HUVECs) and mesenchymal stromal cells (MSCs). We identify a subset of secreted factors important for HSC function, and examine the response of primary murine HSCs in hydrogels to the perivascular secretome. Within 4 days of culture, perivascular conditioned media promoted maintenance of a greater fraction of hematopoietic stem and progenitor cells. This work represents an important first-generation perivascular model to investigate the role of niche secreted factors on the maintenance of primary HSCs.
      PubDate: 2020-09-16
       
 
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