Subjects -> MEDICAL SCIENCES (Total: 8695 journals)
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    - CHIROPRACTIC, HOMEOPATHY, OSTEOPATHY (21 journals)
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    - GASTROENTEROLOGY AND HEPATOLOGY (190 journals)
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    - INTERNAL MEDICINE (179 journals)
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    - MEDICAL GENETICS (58 journals)
    - MEDICAL SCIENCES (2418 journals)
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    - SURGERY (405 journals)
    - UROLOGY, NEPHROLOGY AND ANDROLOGY (156 journals)

MEDICAL SCIENCES (2418 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: 50)
Acta Bio Medica     Open Access   (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   (Followers: 1)
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: 8)
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: 11)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 10)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Bioscience and Clinical Medicine     Open Access   (Followers: 7)
Advances in Cell and Gene Therapy     Hybrid Journal   (Followers: 1)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 27)
Advances in Clinical Radiology     Full-text available via subscription   (Followers: 4)
Advances in Life Course Research     Hybrid Journal   (Followers: 11)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Medical Education and Practice     Open Access   (Followers: 33)
Advances in Medical Ethics     Open Access   (Followers: 7)
Advances in Medical Research     Open Access   (Followers: 3)
Advances in Medical Sciences     Hybrid Journal   (Followers: 11)
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: 8)
Advances in Parkinson's Disease     Open Access   (Followers: 2)
Advances in Phytomedicine     Full-text available via subscription   (Followers: 2)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 21)
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: 8)
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: 15)
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: 4)
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: 14)
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: 7)
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: 6)
American Journal of Medicine     Hybrid Journal   (Followers: 51)
American Journal of Medicine and Medical Sciences     Open Access   (Followers: 2)
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: 7)
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)
Androgens : Clinical Research and Therapeutics     Open Access   (Followers: 3)
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: 3)
Annals of Ibadan Postgraduate Medicine     Open Access  
Annals of Medical and Health Sciences Research     Open Access   (Followers: 9)
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  
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: 27)
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: 5)
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: 6)
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: 20)
Arterial Hypertension     Open Access   (Followers: 1)
Artificial Intelligence in Medicine     Hybrid Journal   (Followers: 21)
Artificial Organs     Hybrid Journal   (Followers: 2)
ASHA Leader     Open Access   (Followers: 7)
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)

        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]
  • Accuracy of a Low-Cost Continuous Subcutaneous Insulin Infusion Pump
           Prototype: In Vitro Study Using Combined Methodologies
    • Abstract: Abstract Considering that infusion devices are safety-critical systems, the main goal of this paper is to evaluate the infusion accuracy and precision of a low-cost insulin infusion pump prototype, using two different methodologies. The first one used a microgravimetric method adapted from IEC60601-2-24, and the second estimated the displacement of the syringe plunger in response to programmed infusions. The low-cost prototype resulted in a compact and functional device with good accuracy. The prototype infused the programmed fluid doses with an average error of 2.2%. The percentage of infusions within ± 5% accuracy was 42.50 and of 84.17% for the ± 15% limit. The developed miniaturized mechanical system presented functionality, precision, and accuracy when coupled to the electronic system, responded well to repeatability tests. Additionally, the results from in vitro tests demonstrated that the performance of the device is satisfactory and comparable to commercial continuous insulin infusion pumps. This study presents a low-cost prototype as a candidate to be used by type 1 diabetic patients in Brazil and developing countries, especially in the context of public health.
      PubDate: 2021-01-25
       
  • Size-Dependent Effective Diffusivity in Healthy Human and Porcine Joint
           Synovium
    • Abstract: Abstract Intra-articular drug delivery can be effective in targeting a diseased joint but is hampered by rapid clearance times from the diarthrodial joint. The synovium is a multi-layered tissue that surrounds the diarthrodial joint and governs molecular transport into and out of the joint. No models of drug clearance through synovium exist to quantify diffusivity across solutes, tissue type and disease pathology. We previously have developed a finite element model of synovium as a porous, permeable, fluid-filled tissue and used an inverse method to determine urea’s effective diffusivity (Deff) in de-vitalized synovium explants.22 Here we apply this method to determine Deff from unsteady diffusive transport of model solutes and confirm the role of molecular weight in solute transport. As molecular weight increased, Deff decreased in both human and porcine tissues, with similar behavior across the two species. Unsteady transport was well-described by a single exponential transient decay in concentration, yielding solute half-lives (t1/2) that compared favorably with the Deff determined from the finite element model fit. Determined values for Deff parallel prior observations of size-dependent in vivo drug clearance and provide an intrinsic parameter with greater ability to resolve size-dependence in vitro. Thus, this work forms the basis for understanding the influence of size on drug transport in synovium and can guide future studies to elucidate the role of charge and tissue pathology on the transport of therapeutics in healthy and pathological human synovium.
      PubDate: 2021-01-25
       
  • A 3-Layered Bioartificial Blood Vessel with Physiological Wall
           Architecture Generated by Mechanical Stimulation
    • Abstract: Abstract The generation of cellularized bioartificial blood vessels resembling all three layers of the natural vessel wall with physiological morphology and cell alignment is a long pursued goal in vascular tissue engineering. Simultaneous culture of all three layers under physiological mechanical conditions requires highly sophisticated perfusion techniques and still today remains a key challenge. Here, three-layered bioartificial vessels based on fibrin matrices were generated using a stepwise molding technique. Adipose-derived stem cells (ASC) were differentiated to smooth muscle cells (SMC) and integrated in a compacted tubular fibrin matrix to resemble the tunica media. The tunica adventitia-equivalent containing human umbilical vein endothelial cells (HUVEC) and ASC in a low concentration fibrin matrix was molded around it. Luminal seeding with HUVEC resembled the tunica intima. Subsequently, constructs were exposed to physiological mechanical stimulation in a pulsatile bioreactor for 72 h. Compared to statically incubated controls, mechanical stimulation induced physiological cell alignment in each layer: Luminal endothelial cells showed longitudinal alignment, cells in the media-layer were aligned circumferentially and expressed characteristic SMC marker proteins. HUVEC in the adventitia-layer formed longitudinally aligned microvascular tubes resembling vasa vasorum capillaries. Thus, physiologically organized three-layered bioartificial vessels were successfully manufactured by stepwise fibrin molding with subsequent mechanical stimulation.
      PubDate: 2021-01-22
       
  • Machine-Learning Provides Patient-Specific Prediction of Metastatic Risk
           Based on Innovative, Mechanobiology Assay
    • Abstract: Abstract Cancer mortality is mostly related to metastasis. Metastasis is currently prognosed via histopathology, disease-statistics, or genetics; those are potentially inaccurate, not rapidly available and require known markers. We had developed a rapid (~ 2 h) mechanobiology-based approach to provide early prognosis of the clinical likelihood for metastasis. Specifically, invasive cell-subsets seeded on impenetrable, physiological-stiffness polyacrylamide gels forcefully indent the gels, while non-invasive/benign cells do not. The number of indenting cells and their attained depths, the mechanical invasiveness, accurately define the metastatic risk of tumors and cell-lines. Utilizing our experimental database, we compare the capacity of several machine learning models to predict the metastatic risk. Models underwent supervised training on individual experiments using classification from literature and commercial-sources for established cell-lines and clinical histopathology reports for tumor samples. We evaluated 2-class models, separating invasive/non-invasive (e.g. benign) samples, and obtained sensitivity and specificity of 0.92 and 1, respectively; this surpasses other works. We also introduce a novel approach, using 5-class models (i.e. normal, benign, cancer-metastatic-non/low/high) that provided average sensitivity and specificity of 0.69 and 0.91. Combining our rapid, mechanical invasiveness assay with machine learning classification can provide accurate and early prognosis of metastatic risk, to support choice of treatments and disease management.
      PubDate: 2021-01-22
       
  • Is the 0.2%-Strain-Offset Approach Appropriate for Calculating the Yield
           Stress of Cortical Bone'
    • Abstract: Abstract The 0.2% strain offset approach is mostly used to calculate the yield stress and serves as an efficient method for cross-lab comparisons of measured material properties. However, it is difficult to accurately determine the yield of the bone. Especially when computational models require accurate material parameters, clarification of the yield point is needed. We tested 24 cortical specimens harvested from six bovine femora in three-point bending mode, and 11 bovine femoral cortical specimens in the tensile mode. The Young’s modulus and yield stress for each specimen derived from the specimen-specific finite element (FE) optimization method was regarded as the most ideal constitutive parameter. Then, the strain offset optimization method was used to find the strain offset closest to the ideal yield stress for the 24 specimens. The results showed that the 0 strain offsets underestimated (− 25%) the yield stress in bending and tensile tests, while the 0.2% strain offsets overestimated the yield stress (+ 65%) in three-point bending tests. Instead, the yield stress determined by 0.007 and 0.05% strain offset for bending and tensile loading respectively, can effectively characterize the biomechanical responses of the bone, thereby helping to build an accurate FE model.
      PubDate: 2021-01-21
       
  • Ranking and Rating Bicycle Helmet Safety Performance in Oblique Impacts
           Using Eight Different Brain Injury Models
    • Abstract: Abstract Bicycle helmets are shown to offer protection against head injuries. Rating methods and test standards are used to evaluate different helmet designs and safety performance. Both strain-based injury criteria obtained from finite element brain injury models and metrics derived from global kinematic responses can be used to evaluate helmet safety performance. Little is known about how different injury models or injury metrics would rank and rate different helmets. The objective of this study was to determine how eight brain models and eight metrics based on global kinematics rank and rate a large number of bicycle helmets (n=17) subjected to oblique impacts. The results showed that the ranking and rating are influenced by the choice of model and metric. Kendall’s tau varied between 0.50 and 0.95 when the ranking was based on maximum principal strain from brain models. One specific helmet was rated as 2-star when using one brain model but as 4-star by another model. This could cause confusion for consumers rather than inform them of the relative safety performance of a helmet. Therefore, we suggest that the biomechanics community should create a norm or recommendation for future ranking and rating methods.
      PubDate: 2021-01-21
       
  • Electric Field Stimulation for the Functional Assessment of Isolated
           Dorsal Root Ganglion Neuron Excitability
    • Abstract: Abstract Genetically encoded calcium indicators have proven useful for characterizing dorsal root ganglion neuron excitability in vivo. Challenges persist in achieving high spatial–temporal resolutions in vivo, however, due to deep tissue imaging and motion artifacts that may be limiting technical factors in obtaining measurements. Here we report an ex vivo imaging method, using a peripheral neuron-specific Advillin-GCaMP mouse line and electric field stimulation of dorsal root ganglion tissues, to assess the sensitivity of neurons en bloc. The described method rapidly characterizes Ca2+ activity in hundreds of dorsal root ganglion neurons (221 ± 64 per dorsal root ganglion) with minimal perturbation to the in situ soma environment. We further validate the method for use as a drug screening platform with the voltage-gated sodium channel inhibitor, tetrodotoxin. Drug treatment led to decreased evoked Ca2+ activity; half-maximal response voltage (EV50) increased from 13.4 V in untreated tissues to 21.2, 23.3, 51.5 (p < 0.05), and 60.6 V (p < 0.05) at 0.01, 0.1, 1, and 10 µM doses, respectively. This technique may help improve an understanding of neural signaling while retaining tissue structural organization and serves as a tool for the rapid ex vivo recording and assessment of neural activity.
      PubDate: 2021-01-21
       
  • Antifriction Mechanism of Longitudinal Vibration-Assisted Insertion in DBS
    • Abstract: Abstract Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease. The insertion of brain tissue is an important procedure that affects the whole operation and the sequela. During the insertion process, the friction between the tissue and the needle shaft is the main factor affecting the degree of tissue damage and the accuracy of target location. Vibration-assisted needle insertion has been shown to reduce friction during needle insertion into biological tissue. LuGre model is a friction model that includes coulomb friction and viscous friction between two contact surfaces and accurately describes the Stribeck effect. This paper studies the influence of longitudinal vibration on the friction force during needle insertion. Based on LuGre model, the influence of longitudinal vibration parameters on friction force is discussed. Through experiments on porcine brain tissue and gel phantom, the friction force during insertion and the positive pressure of tissue against the needle under different vibration parameters were investigated. The experiment showed that the vibration can change the friction force by affecting the equivalent friction coefficient and the positive pressure of tissue against the needle. The equivalent friction coefficient showed a specific trend with the change of vibration parameters, while the positive pressure does not change with the vibration parameters.
      PubDate: 2021-01-21
       
  • An Evolving Clinical Need: Discordant Oxygenation Measurements of
           Intubated COVID-19 Patients
    • Abstract: Abstract Since the first appearance of the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) earlier this year, clinicians and researchers alike have been faced with dynamic, daily challenges of recognizing, understanding, and treating the coronavirus disease 2019 (COVID-19) due to SARS-CoV-2. Those who are moderately to severely ill with COVID-19 are likely to develop acute hypoxemic respiratory failure and require administration of supplemental oxygen. Assessing the need to initiate or titrate oxygen therapy is largely dependent on evaluating the patient’s existing blood oxygenation status, either by direct arterial blood sampling or by transcutaneous arterial oxygen saturation monitoring, also referred to as pulse oximetry. While the sampling of arterial blood for measurement of dissolved gases provides a direct measurement, it is technically challenging to obtain, is painful to the patient, and can be time and resource intensive. Pulse oximetry allows for non-invasive, real-time, continuous monitoring of the percent of hemoglobin molecules that are saturated with oxygen, and usually closely predicts the arterial oxygen content. As such, it was particularly concerning when patients with severe COVID-19 requiring endotracheal intubation and mechanical ventilation within one of our intensive care units were observed to have significant discordance between their predicted arterial oxygen content via pulse oximetry and their actual measured oxygen content. We offer these preliminary observations along with our speculative causes as a timely, urgent clinical need. In the setting of a COVID-19 intensive care unit, entering a patient room to obtain a fresh arterial blood gas sample not only takes exponentially longer to do given the time required for donning and doffing of personal protective equipment (PPE), it involves the consumption of already sparce PPE, and it increases the risk of viral exposure to the nurse, physician, or respiratory therapist entering the room to obtain the sample. As such, technology similar to pulse oximetry which can be applied to a patients finger, and then continuously monitored from outside the room is essential in preventing a particularly dangerous situation of unrealized hypoxia in this critically-ill patient population. Additionally, it would appear that conventional two-wavelength pulse oximetry may not accurately predict the arterial oxygen content of blood in these patients. This discordance of oxygenation measurements poses a critical concern in the evaluation and management of the acute hypoxemic respiratory failure seen in patients with COVID-19.
      PubDate: 2021-01-19
       
  • Two Magnetic Sensor Based Real-Time Tracking of Magnetically Inflated
           Swallowable Intragastric Balloon
    • Abstract: Abstract This paper presents a two magnetic sensor based tracking method for a magnetically inflated intragastric balloon capsule (MIBC) which is used for obesity treatment. After the MIBC is swallowed, it is designed to be inflated inside the stomach by approaching a permanent magnet (PM) externally near the abdomen. However, if the balloon inflation is accidentally triggered while the MIBC is still in the esophagus, the esophagus will be damaged. Therefore, to safely inflate the MIBC, we aim to track the MIBC’s position along the esophagus and confirm the MIBC passes through. Typically, magnetic sensor based tracking systems tend to be bulky and costly since they involve computationally intensive optimization with many magnetic sensors. To solve those problems, we develop an algorithm that estimates the position of the PM inside the MIBC by using the grid search combined with the dynamically confined search range and search threshold modulation. Our tracking method achieved an average 1D position error of 3.48 mm which is comparable to the up to 4 mm average error for the other magnetic sensor based tracking systems that require more sensors and computational power compared to our system.
      PubDate: 2021-01-15
       
  • Review of Wearable and Portable Sensors for Monitoring Personal Solar UV
           Exposure
    • Abstract: Abstract Sunlight is one of the main environmental resources that keeps all the organisms alive on earth. The ultraviolet (UV) radiation from the sun is essential for vitamin D synthesis in the human body, which is crucial for bone and muscle health. In addition, sun exposure also helps to reduce the risk of some cardiovascular diseases and cancers. However, excessive UV exposure can lead to adverse effects, including some eye diseases, premature aging, sunburn and skin cancers. The solar UV irradiance itself depends on many environmental factors. In fact, the UV index reported in weather forecasts is an estimation under cloudless conditions. Personal UV exposure also depends on one’s outdoor activities and habits. Furthermore, the UV intake depends on the skin sensitivity. Therefore, there is a need for research into monitoring the optimal daily UV exposure for health benefits, without developing potential health risks. To facilitate the monitoring of solar UV intensity and cumulative dose, a variety of UV sensors have been developed in the past few decades and many are commercially available. Examples of sensors being marketed are: portable UV dosimeter, wearable UV radiometer, personal UV monitor, and handheld Solarmeter®. Some of the UV sensors can be worn as personal health monitors, which promote solar exposure protection. The paper provides a comprehensive review of the wearable and portable UV sensors for monitoring personal UV exposure, including a discussion of their unique advantages and limitations. Proposals are also presented for possible future research into reliable and practical UV sensors for personal UV exposure monitoring.
      PubDate: 2021-01-11
       
  • Forces Involved with Labor and Delivery—A Biomechanical Perspective
    • Abstract: Abstract Childbirth is a primarily biomechanical process of physiology, and one that engineers have recently begun to address in a broader fashion. Computational models are being developed to address the biomechanical effects of parturition on both maternal and fetal tissues. Experimental research is being conducted to understand how maternal tissues adapt to intrauterine forces near the onset of labor. All of this research requires an understanding of the forces that are developed through maternal efforts—both uterine contractions and semi-voluntary pushing—and that can be applied by the clinician to assist with the delivery. This work reviews the current state of knowledge regarding forces of labor and delivery, with a focus on macro-level biomechanics.
      PubDate: 2021-01-11
       
  • Bioengineering Approaches for Placental Research
    • Abstract: Abstract Research into the human placenta’s complex functioning is complicated by a lack of suitable physiological in vivo models. Two complementary approaches have emerged recently to address these gaps in understanding, computational in silico techniques, including multi-scale modeling of placental blood flow and oxygen transport, and cellular in vitro approaches, including organoids, tissue engineering, and organ-on-a-chip models. Following a brief introduction to the placenta’s structure and function and its influence on the substantial clinical problem of preterm birth, these different bioengineering approaches are reviewed. The cellular techniques allow for investigation of early first-trimester implantation and placental development, including critical biological processes such as trophoblast invasion and trophoblast fusion, that are otherwise very difficult to study. Similarly, computational models of the placenta and the pregnant pelvis at later-term gestation allow for investigations relevant to complications that occur when the placenta has fully developed. To fully understand clinical conditions associated with the placenta, including those with roots in early processes but that only manifest clinically at full-term, a holistic approach to the study of this fascinating, temporary but critical organ is required.
      PubDate: 2021-01-08
       
  • Is Experience in Hemodialysis Cannulation Related to Expertise' A
           Metrics-based Investigation for Skills Assessment
    • Abstract: Abstract Cannulation is not only one of the most common medical procedures but also fraught with complications. The skill of the clinician performing cannulation directly impacts cannulation outcomes. However, current methods of teaching this skill are deficient, relying on subjective demonstrations and unrealistic manikins that have limited utility for skills training. Furthermore, of the factors that hinders effective continuing medical education is the assumption that clinical experience results in expertise. In this work, we examine if objective metrics acquired from a novel cannulation simulator are able to distinguish between experienced clinicians and established experts, enabling the measurement of true expertise. Twenty-two healthcare professionals, who practiced cannulation with varying experience, performed a simulated arteriovenous fistula cannulation task on the simulator. Four clinicians were peer-identified as experts while the others were designated to the experienced group. The simulator tracked the motion of the needle (via an electromagnetic sensor), rendered blood flashback function (via an infrared light sensor), and recorded pinch forces exerted on the needle (via force sensing elements). Metrics were computed based on motion, force, and other sensor data. Results indicated that, with near 80% of accuracy using both logistic regression and linear discriminant analysis, the objective metrics differentiated between experts and the experienced, including identifying needle motion and finger force as two prominent features that distinguished between the groups. Furthermore, results indicated that expertise was not correlated with years of experience, validating the central hypothesis of the study. These insights contribute to structured and standardized medical skills training by enabling a meaningful definition of expertise and could potentially lead to more effective skills training methods.
      PubDate: 2021-01-08
       
  • From Transcript to Tissue: Multiscale Modeling from Cell Signaling to
           Matrix Remodeling
    • Abstract: Abstract Tissue-level biomechanical properties and function derive from underlying cell signaling, which regulates mass deposition, organization, and removal. Here, we couple two existing modeling frameworks to capture associated multiscale interactions—one for vessel-level growth and remodeling and one for cell-level signaling—and illustrate utility by simulating aortic remodeling. At the vessel level, we employ a constrained mixture model describing turnover of individual wall constituents (elastin, intramural cells, and collagen), which has proven useful in predicting diverse adaptations as well as disease progression using phenomenological constitutive relations. Nevertheless, we now seek an improved mechanistic understanding of these processes; we replace phenomenological relations in the mixture model with a logic-based signaling model, which yields a system of ordinary differential equations predicting changes in collagen synthesis, matrix metalloproteinases, and cell proliferation in response to altered intramural stress, wall shear stress, and exogenous angiotensin II. This coupled approach promises improved understanding of the role of cell signaling in achieving tissue homeostasis and allows us to model feedback between vessel mechanics and cell signaling. We verify our model predictions against data from the hypertensive murine infrarenal abdominal aorta as well as results from validated phenomenological models, and consider effects of noisy signaling and heterogeneous cell populations.
      PubDate: 2021-01-07
       
  • Liquid Poly-N-acetyl Glucosamine (sNAG) Improves Achilles Tendon Healing
           in a Rat Model
    • Abstract: Abstract The Achilles tendon, while the strongest and largest tendon in the body, is frequently injured. Even after surgical repair, patients risk re-rupture and long-term deficits in function. Poly-N-acetyl glucosamine (sNAG) polymer has been shown to increase the rate of healing of venous leg ulcers, and use of this material improved tendon-to-bone healing in a rat model of rotator cuff injury. Therefore, the purpose of this study was to investigate the healing properties of liquid sNAG polymer suspension in a rat partial Achilles tear model. We hypothesized that repeated sNAG injections throughout healing would improve Achilles tendon healing as measured by improved mechanical properties and cellular morphology compared to controls. Results demonstrate that sNAG has a positive effect on rat Achilles tendon healing at three weeks after a full thickness, partial width injury. sNAG treatment led to increased quasistatic tendon stiffness, and increased tangent and secant stiffness throughout fatigue cycling protocols. Increased dynamic modulus also suggests improved viscoelastic properties with sNAG treatment. No differences were identified in histological properties. Importantly, use of this material did not have any negative effects on any measured parameter. These results support further study of this material as a minimally invasive treatment modality for tendon healing.
      PubDate: 2021-01-06
       
  • Low-Profile Electromagnetic Field Sensors in the Measurement and Modelling
           of Three-Dimensional Jaw Kinematics and Occlusal Loading
    • Abstract: Abstract Dynamic occlusal loading during mastication is clinically relevant in the design and functional assessment of dental restorations and removable dentures, and in evaluating temporomandibular joint dysfunction. The aim of this study was to develop a modelling framework to evaluate subject-specific dynamic occlusal loading during chewing and biting over the entire dental arch. Measurements of jaw motion were performed on one healthy male adult using low-profile electromagnetic field sensors attached to the teeth, and occlusal anatomy quantified using an intra-oral scanner. During testing, the subject chewed and maximally compressed a piece of rubber between both second molars, first molars, premolars and their central incisors. The occlusal anatomy, rubber geometry and experimentally measured rubber material properties were combined in a finite element model. The measured mandibular motion was used to kinematically drive model simulations of chewing and biting of the rubber sample. Three-dimensional dynamic bite forces and contact pressures across the occlusal surfaces were then calculated. Both chewing and biting on the first molars produced the highest bite forces across the dental arch, and a large amount of anterior shear force was produced at the incisors and the second molars. During chewing, the initial tooth-rubber contact evolved from the buccal sides of the molars to the lingual sides at full mouth closure. Low-profile electromagnetic field sensors were shown to provide a clinically relevant measure of jaw kinematics with sufficient accuracy to drive finite element models of occlusal loading during chewing and biting. The modelling framework presented provides a basis for calculation of physiological, dynamic occlusal loading across the dental arch.
      PubDate: 2021-01-06
       
  • A Millifluidic Perfusion Cassette for Studying the Pathogenesis of Enteric
           Infections Using Ex-Vivo Organoids
    • Abstract: Abstract To generate physiologically-relevant experimental models, the study of enteric diarrheal diseases is turning increasingly to advanced in vitro models that combine ex vivo, stem cell-derived “organoid” cell lines with bioengineered culture environments that expose them to mechanical stimuli, such as fluid flow. However, such approaches require considerable technical expertise with both microfabrication and organoid culture, and are, therefore, inaccessible to many researchers. For this reason, we have developed a perfusion system that is simple to fabricate, operate, and maintain. Its dimensions approximate the volume and cell culture area of traditional 96-well plates and allow the incorporation of fastidious primary, stem cell-derived cell lines with only minimal adaptation of their established culture techniques. We show that infections with enteroaggregative E. coli and norovirus, common causes of infectious diarrhea, in the system display important differences from static models, and in some ways better recreate the pathophysiology of in vivo infections. Furthermore, commensal strains of bacteria can be added alongside the pathogens to simulate the effects of a host microbiome on the infectious process. For these reasons, we believe that this perfusion system is a powerful, yet easily accessible tool for studying host-pathogen interactions in the human intestine.
      PubDate: 2021-01-06
       
  • Characterization of Chitosan-Based Scaffolds Seeded with Sheep Nasal
           Chondrocytes for Cartilage Tissue Engineering
    • Abstract: Abstract The treatment of cartilage defect remains a challenging issue in clinical practice. Chitosan-based materials have been recognized as a suitable microenvironment for chondrocyte adhesion, proliferation and differentiation forming articular cartilage. The use of nasal chondrocytes to culture articular cartilage on an appropriate scaffold emerged as a promising novel strategy for cartilage regeneration. Beside excellent properties, chitosan lacks in biological activity, such as RGD-sequences. In this work, we have prepared pure and protein-modified chitosan scaffolds of different deacetylation degree and molecular weight as platforms for the culture of sheep nasal chondrocytes. Fibronectin (FN) was chosen as an adhesive protein for the improvement of chitosan bioactivity. Prepared scaffolds were characterised in terms of microstructure, physical and biodegradation properties, while FN interactions with different chitosans were investigated through adsorption–desorption studies. The results indicated faster enzymatic degradation of chitosan scaffolds with lower deacetylation degree, while better FN interactions with material were achieved on chitosan with higher number of amine groups. Histological and immunohistochemical analysis of in vitro engineered cartilage grafts showed presence of hyaline cartilage produced by nasal chondrocytes.
      PubDate: 2021-01-06
       
  • Comparison of in Vascular Bioreactors and In Vivo Models of Degradation
           and Cellular Response of Mg–Zn–Mn Stents
    • Abstract: Abstract Traditional in vitro evaluation criteria of magnesium (Mg)-based stents cannot reflect the degradation process in vivo, due to the interdependence and interference between biodegradable properties and bioenvironment. The current direct and indirect evaluation approaches of in vitro biocompatibility do not have a hydrodynamic environment and vascular biological structure existing in vivo. Herein, we designed a vascular bioreactor to provide an ex vivo culture environment for vessels, which reveals the degradation behavior of Mg–Zn–Mn stent and the effect of its degradation on cells. We reported that rabbit carotid arteries could maintain native morphology and viability in the bioreactor under the best condition within a flow rate of 5.4 mL min−1 and a culture time of one week. With this culture condition, Mg–Zn–Mn stents were implanted into the arteries in the bioreactors and compared with in vivo rabbit models. The arteries maintained cell survival in the bioreactor, but the cell attachment was absent on the stent struts, associated with a fast degradation. Conversely, the stents achieved a rapid and complete endothelialization in vivo for two weeks. This study could provide a correlation and difference of the degradation behavior and cellular response to the degradation of Mg-based stent between ex vivo and in vivo approaches.
      PubDate: 2021-01-06
       
 
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