keyword
MENU ▼
Read by QxMD icon Read
search

Mechanical force

keyword
https://www.readbyqxmd.com/read/28527429/coexistence-of-light-driven-na-and-h-transport-in-a-microbial-rhodopsin-from-nonlabens-dokdonensis
#1
Hongshen Zhao, Baofu Ma, Liangliang Ji, Longjie Li, Huanhuan Wang, Deliang Chen
Ion pumping microbial rhodopsins are photochemically active membrane proteins, converting light energy into ion-motive-force for ATP synthesis. Nonlabens dokdonensis rhodopsin 2 (NdR2), was recently identified as a light-driven Na(+) pump. However, few functional studies on NdR2 have been conducted to elucidate its mechanism of ion transport. By reconstituting NdR2 into liposomes, we proved that NdR2 functions as a light-driven Na(+)/H(+) pump. As Na(+) concentration increased, the dominant H(+) pump activity switched to the Na(+) pump activity at neutral pH...
May 10, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28526693/a-simple-laboratory-exercise-with-rat-isolated-esophagus-and-stomach-fundus-to-reveal-functional-differences-between-striated-and-smooth-muscle-cells
#2
Francisco José Batista-Lima, Kalinne Kelly Lima Gadelha, Daniel Maia Oliveira, Thiago Brasileiro Vasconcelos, Teresinha Silva Brito, Pedro Jorge Caldas Magalhães
This study describes an undergraduate student laboratory activity using isolated preparations from rat gastrointestinal tissues that possess contractile profiles typically exhibited by striated and smooth muscle cells. While students are introduced to an ex vivo methodology, they can compare differences in trace experiments, twitch aspects, phasic and tonic properties, force-frequency relationships, and pharmacological responsiveness of esophageal (striated) and fundic (smooth muscle) segments. Muscle strips were subjected to electrical field stimulation (EFS) applied by platinum electrodes immersed in the physiological solution...
June 1, 2017: Advances in Physiology Education
https://www.readbyqxmd.com/read/28526627/dynamic-fatigue-measurement-of-human-erythrocytes-using-dielectrophoresis
#3
Yuhao Qiang, Jia Liu, E Du
Erythrocytes must undergo severe deformation to pass through narrow capillaries and submicronic splenic slits for several hundred thousand times in their normal lifespan. Studies of erythrocyte biomechanics have been mainly focused on cell deformability and rheology measured from a single application of stress and mostly under a static or quasi-static state using classical biomechanical techniques, such as optical tweezers and micropipette aspiration. Dynamic behavior of erythrocytes in response to cyclic stresses that contributes to the membrane failure in blood circulation is not fully understood...
May 16, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28526500/pulmonary-function-tests-do-not-predict-mortality-in-patients-undergoing-continuous-flow-left-ventricular-assist-device-implantation
#4
Edo K S Bedzra, Todd F Dardas, Richard K Cheng, Jay D Pal, Claudius Mahr, Jason W Smith, Kent Shively, S Carolina Masri, Wayne C Levy, Nahush A Mokadam
OBJECTIVES: To investigate the effect of pulmonary function testing on outcomes after continuous flow left ventricular assist device implantation. METHODS: A total of 263 and 239 patients, respectively, had tests of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide preoperatively for left ventricular assist device implantations between July 2005 and September 2015. Kaplan-Meier analysis and multivariable Cox regressions were performed to evaluate mortality...
April 11, 2017: Journal of Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28526226/experimental-pain-in-the-groin-may-refer-into-the-lower-abdomen-implications-to-clinical-assessments
#5
M K Drew, T S Palsson, R P Hirata, M Izumi, G Lovell, M Welvaert, P Chiarelli, P G Osmotherly, T Graven-Nielsen
OBJECTIVES: To investigate the effects of experimental adductor pain on the pain referral pattern, mechanical sensitivity and muscle activity during common clinical tests. DESIGN: Repeated-measures design. METHODS: In two separate sessions, 15 healthy males received a hypertonic (painful) and isotonic (control) saline injection to either the adductor longus (AL) tendon to produce experimental groin pain or into the rectus femoris (RF) tendon as a painful control...
April 21, 2017: Journal of Science and Medicine in Sport
https://www.readbyqxmd.com/read/28526090/reduced-hdac2-in-skeletal-muscle-of-copd-patients
#6
Masako To, Elisabeth B Swallow, Kenich Akashi, Kosuke Haruki, S Amanda Natanek, Michael I Polkey, Kazuhiro Ito, Peter J Barnes
BACKGROUND: Skeletal muscle weakness in chronic obstructive pulmonary disease (COPD) is an important predictor of poor prognosis, but the molecular mechanisms of muscle weakness in COPD have not been fully elucidated. The aim of this study was to investigate the role of histone deacetylases(HDAC) in skeletal muscle weakness in COPD. METHODS AND RESULTS: Twelve COPD patients, 8 smokers without COPD (SM) and 4 healthy non-smokers (NS) were recruited to the study. HDAC2 protein expression in quadriceps muscle biopsies of COPD patients (HDAC2/β-actin: 0...
May 19, 2017: Respiratory Research
https://www.readbyqxmd.com/read/28525957/determining-dominant-driving-forces-affecting-controlled-protein-release-from-polymeric-nanoparticles
#7
Josh Smith, Kayla G Sprenger, Rick Liao, Andrea Joseph, Elizabeth Nance, Jim Pfaendtner
Enzymes play a critical role in many applications in biology and medicine as potential therapeutics. One specific area of interest is enzyme encapsulation in polymer nanostructures, which have applications in drug delivery and catalysis. A detailed understanding of the mechanisms governing protein/polymer interactions is crucial for optimizing the performance of these complex systems for different applications. Using a combined computational and experimental approach, this study aims to quantify the relative importance of molecular and mesoscale driving forces to protein release from polymeric nanoparticles...
May 19, 2017: Biointerphases
https://www.readbyqxmd.com/read/28525820/sensing-inhomogeneous-mechanical-properties-of-human-corneal-descemet-s-membrane-with-afm-nano-indentation
#8
Rosa Di Mundo, Giuseppina Recchia, Mohit Parekh, Alessandro Ruzza, Stefano Ferrari, Giuseppe Carbone
The paper describes a highly space-resolved characterization of the surface mechanical properties of the posterior human corneal layer (Descemet's membrane). This has been accomplished with Atomic Force Microscopy (AFM) nano-indentation by using a probe with a sharp tip geometry. Results indicate that the contact with this biological tissue in liquid occurs with no (or very low) adhesion. More importantly, under the same operating conditions, a broad distribution of penetration depth can be measured on different x-y positions of the tissue surface, indicating a high inhomogeneity of surface stiffness, not yet clearly reported in the literature...
May 10, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28525774/development-and-validation-of-a-physical-model-to-investigate-the-biomechanics-of-infant-head-impact
#9
M Jones, D Darwall, G Khalid, R Prabhu, A Kemp, O Arthurs, P Theobald
Head injury in childhood is the single most common cause of death or permanent disability from injury. However, despite its frequency and significance, there is little understanding of the response of a child's head to injurious loading. This is a significant limitation when making early diagnoses, informing clinical and/or forensic management or injury prevention strategies. With respect to impact vulnerability, current understanding is predominantly based on a few post-mortem-human-surrogate (PMHS) experiments...
April 13, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28525572/crosstalk-between-vertical-and-horizontal-gene-transfer-plasmid-replication-control-by-a-conjugative-relaxase
#10
Fabián Lorenzo-Díaz, Cris Fernández-López, Rudi Lurz, Alicia Bravo, Manuel Espinosa
Horizontal gene transfer is a key process in the evolution of bacteria and also represents a source of genetic variation in eukaryotes. Among elements participating in gene transfer, thousands of small (<10 kb) mobile bacterial plasmids that replicate by the rolling circle mechanism represent a driving force in the spread of antibiotic resistances. In general, these plasmids are built as genetic modules that encode a replicase, an antibiotic-resistance determinant, and a relaxase that participates in their conjugative mobilization...
May 19, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28524676/matter-wave-tractor-beams
#11
Alexey A Gorlach, Maxim A Gorlach, Andrei V Lavrinenko, Andrey Novitsky
Optical and acoustic tractor beams are currently the focus of intense research due to their counterintuitive property of exerting a pulling force on small scattering objects. In this Letter we propose a matter-wave tractor beam and utilize the de Broglie waves of nonrelativistic matter particles in analogy to "classical" tractor beams. We reveal the presence of the quantum-mechanical pulling force for the variety of quantum mechanical potentials observing the resonant enhancement of the pulling effect under the conditions of the suppressed scattering known as the Ramsauer-Townsend effect...
May 5, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28524270/interaction-studies-of-copper-complex-containing-food-additive-carmoisine-dye-with-human-serum-albumin-hsa-spectroscopic-investigations
#12
Nahid Shahabadi, Alireza Akbari, Mina Jamshidbeigi, Soraya Moradi Fili
In this study, the interaction between human serum albumin (HSA) and a copper complex of carmoisine dye; [Cu(carmoisine)2 (H2 O)2 ], was studied in vitro using multi-spectroscopic methods. It was found that the intrinsic fluorescence of HSA was quenched by the addition of the [Cu(carmoisine)2 (H2 O)2 ] complex and the quenching mechanism was considered as static quenching by formation of a [Cu(carmoisine)2 (H2 O)2 ]-HSA complex. The binding constant was about 10(4)  M(-1) at room temperature. The values of the calculated thermodynamic parameters (ΔH < 0 and ΔS > 0) suggested that both hydrogen bonds and the hydrophobic interactions were involved in the binding process...
May 19, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28524265/a-highly-sensitive-resonance-rayleigh-scattering-and-colorimetric-assay-for-the-recognition-of-propranolol-in-%C3%AE-adrenergic-blocker
#13
Xuanping Tan, Jidong Yang, Qiong Yang, Qin Li
In this work, a highly sensitive, citrate anion-capped gold nanoparticles (AuNPs)-based assay for the determination of propranolol in real samples with resonance Rayleigh scattering (RRS) and colorimetry was developed. When AuNPs were prepared by the sodium citrate reduction method, citrate anions self-assembled on the surface of AuNPs to form supramolecular complex anions. In BR 4.6 buffer solution, propranolol was positively charged and could bind with AuNPs to form larger aggregates through electrostatic force and hydrophobic effects...
May 19, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28524074/neurotrauma-the-crosstalk-between-neurotrophins-and-inflammation-in-the-acutely-injured-brain
#14
REVIEW
Lindolfo da Silva Meirelles, Daniel Simon, Andrea Regner
Traumatic brain injury (TBI) is a major cause of morbidity and mortality among young individuals worldwide. Understanding the pathophysiology of neurotrauma is crucial for the development of more effective therapeutic strategies. After the trauma occurs, immediate neurologic damage is produced by the traumatic forces; this primary injury triggers a secondary wave of biochemical cascades together with metabolic and cellular changes, called secondary neural injury. In the scenario of the acutely injured brain, the ongoing secondary injury results in ischemia and edema culminating in an uncontrollable increase in intracranial pressure...
May 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28523865/the-interstitial-carbon-of-the-nitrogenase-femo-cofactor-is-far-better-stabilized-than-previously-assumed
#15
Jörg Grunenberg
The first quantum-mechanical calculations of all relevant potential constants in both the iron-molybdenum cofactor and the iron-vanadium cofactor of nitrogenase suggest that the carbide is bound to the center of the enzyme much more strongly than hitherto assumed. Previous studies seemed to indicate a dummy function of the interstitial carbon, with a weak force constant (ca. 0.32 N cm(-1) ). Our new investigations confirm a different picture: the central carbon atom binds the iron-sulfur cluster through six covalent C-Fe bonds...
May 19, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28523304/optical-coherence-tomography-applications-in-tooth-wear-diagnosis
#16
Veronica MercuŢ, Sanda Mihaela Popescu, Monica Scrieciu, Marina Olimpia Amărăscu, Mihaela Vătu, Oana Andreea Diaconu, Eugen Osiac, Ştefan Mugurel Ghelase
Dental wear represents an irreversible loss of dental hard tissue under the action of physical, chemical and mechanical factors, excluding dental caries and acute trauma. Four clinical forms of dental wear are described: erosion, attrition, abfraction, and abrasion. Most experts agree that in each clinical form multiple etiological factors are involved, one being predominant. Optical coherence tomography (OCT) is a non-invasive optical method characterized by a micronic resolution. The applications of this type of investigation are multiple in the medical field in recent years, and OCT is gaining a growing importance in dentistry...
2017: Romanian Journal of Morphology and Embryology, Revue Roumaine de Morphologie et Embryologie
https://www.readbyqxmd.com/read/28523242/effects-of-bracket-slot-size-during-en-masse-retraction-of-the-six-maxillary-anterior-teeth-using-an-induction-heating-typodont-simulation-system
#17
Ji-Yong Kim, Won-Jae Yu, Prasad N K Koteswaracc, Hee-Moon Kyung
OBJECTIVE: To investigate how bracket slot size affects the direction of maxillary anterior tooth movement when en-masse retraction is performed in sliding mechanics using an induction-heating typodont simulation system. METHODS: An induction-heating typodont simulation system was designed based on the Calorific Machine system. The typodont included metal anterior and resin posterior teeth embedded in a sticky wax arch. Three bracket slot groups (0.018, 0.020, and 0...
May 2017: Korean Journal of Orthodontics
https://www.readbyqxmd.com/read/28522235/a-review-of-terrestrial-aerial-and-aquatic-keratins-the-structure-and-mechanical-properties-of-pangolin-scales-feather-shafts-and-baleen-plates
#18
Bin Wang, Tarah N Sullivan
Keratinous materials, omnipresent as the hard and durable epidermal appendages of animals, are one of the toughest biological materials. They exhibit diverse morphologies and structures that serve a variety of amazing and inspiring mechanical functions. In this work, we provide a review of representative terrestrial, aerial and aquatic keratinous materials, pangolin scales, feather shafts and baleen plates, and correlate their hierarchical structures to respective functions of dermal armor, flight material and undersea filter...
May 8, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28521914/the-face-of-conflict-significant-sharp-force-trauma-to-the-mid-facial-skeleton-in-an-individual-of-probable-16th-17th-century-date-excavated-from-byczyna-poland
#19
Agata Izabela Cieślik, Paweł Dąbrowski, Magdalena Anita Przysiężna-Pizarska
A variety of injuries have always been associated with violence, consequences of which people had to deal with. In this paper we present a complex of craniofacial and dental injuries resulted from sharp force trauma. The basis of our study was historical skeletal material excavated from archeological site in Byczyna (11th-17th century), Poland. An individual whose skeleton was exhumed from the grave No. 610 exhibited healed, oblique trauma of the left maxilla, damage to the crowns of right central and lateral incisors and concomitant luxation of the right maxillary central incisor...
June 2017: International Journal of Paleopathology
https://www.readbyqxmd.com/read/28521203/3d-full-field-quantification-of-cell-induced-large-deformations-in-fibrillar-biomaterials-by-combining-non-rigid-image-registration-with-label-free-second-harmonic-generation
#20
Alvaro Jorge-Peñas, Hannelore Bové, Kathleen Sanen, Marie-Mo Vaeyens, Christian Steuwe, Maarten Roeffaers, Marcel Ameloot, Hans Van Oosterwyck
To advance our current understanding of cell-matrix mechanics and its importance for biomaterials development, advanced three-dimensional (3D) measurement techniques are necessary. Cell-induced deformations of the surrounding matrix are commonly derived from the displacement of embedded fiducial markers, as part of traction force microscopy (TFM) procedures. However, these fluorescent markers may alter the mechanical properties of the matrix or can be taken up by the embedded cells, and therefore influence cellular behavior and fate...
May 10, 2017: Biomaterials
keyword
keyword
33364
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"