No abstract available.
Biophysics* ; Metabolism*

As an important intracellular genetic and regulatory center, the nucleus is not only a terminal effector of intracellular biochemical signals, but also has a significant impact on cell function and phenotype through direct or indirect regulation of nuclear mechanistic cues after the cell senses and responds to mechanical stimuli. The nucleus relies on chromatin-nuclear membrane-cytoskeleton infrastructure to couple signal transduction, and responds to these mechanical stimuli in the intracellular and extracellular physical microenvironments. Changes in the morphological structure of the nucleus are the most intuitive manifestation of this mechanical response cascades and are the basis for the direct response of the nucleus to mechanical stimuli. Based on such relationships of the nucleus with cell behavior and phenotype, abnormal nuclear morphological changes are widely used in clinical practice as disease diagnostic tools. This review article highlights the latest advances in how nuclear morphology responds and adapts to mechanical stimuli. Additionally, this article will shed light on the factors that mechanically regulate nuclear morphology as well as the tumor physio-pathological processes involved in nuclear morphology and the underlying mechanobiological mechanisms. It provides new insights into the mechanisms that nuclear mechanics regulates disease development and its use as a potential target for diagnosis and treatment.
Cell Nucleus ; Biophysics ; Cytoskeleton ; Phenotype ; Signal Transduction

We studied the intradiscal pressure in order to understand the biophysics of the lumbar intervertebral disk. We evaluated the relationship between disk morphology and intradiscal pressure in 90 lumbar intervertebral disks of 64 patients. The intrinsic intradiscal pressure in the ruptured disks was much lower than that in the normal or bulging disk, but intrinsic intradiscal pressure alone did not correlate in a statistically significant way to the absence, or presence and/or type of disk herniation. The elastance of normal disks was statistically significantly higher than that of the protruded disk(p<0.05) ; however, the elastance of lumbar disk was not affected by type of disk protrusion. Factors affecting disk elastance were the degeneration and the integrity of the annulus fibrosus and the posterior longitudinal ligament. The authors experienced no complication during the procedure. The measurement of the intradiscal pressure to evaluated the biophysical function of lumbar intervertebral disks is only a simple and risk-free procedure. Also it is suggested that patients with bulging disks of high elastance may be treated by reducing intradiscal pressure with percutaneous procedures such as chemonucleolysis, and automated discectomy using Nucleotome.
Biophysics ; Diskectomy ; Humans ; Intervertebral Disc Chemolysis ; Intervertebral Disc* ; Longitudinal Ligaments

In recent years, investigation focusing on biophysical characteristics of moxibustion results in advancement. The investigations aiming at elucidating the mechanism of maoxibustion from the angle of biophysics show that the effectiveness of moxibustion results not only from thermal effect, but also from the combine effects of spectral radiation, bio-thermal effect and non-thermal-bio effect. Currently, multi-discipline techniques are applied in research about biophysical characteristics of moxibustion which received broad attention. These researches show a good way and method to elucidating the mechanism of moxibustion; furthermore, they provid experimental evidence for the advancement in clinical practices and the research and design of imitating moxibustion instruments. This paper states the researches focusing on the effect of moxibustion on local body temperature, the infrared spectrum characteristics of moxibustion, bio-thermal effect and energy conversion of moxibustion, bio-heat transfer of moxibustion and microcirculation.
Animals ; Biophysics ; Body Temperature ; Energy Transfer ; Humans ; Microcirculation ; Moxibustion

Biomedical Research ; trends ; Biophysics ; trends ; Magnetics ; trends ; Science ; trends

The cryoballoon was invented to achieve circumferential pulmonary vein isolation more efficiently to compliment the shortcomings of point-by-point ablation by radiofrequency ablation (RFA). Its efficacy and safety were shown to be comparable to those of RFA, and the clinical outcomes have improved with the second-generation cryoballoon. The basic biophysics, implemental techniques, procedural recommendations, clinical outcomes, and complications of the cryoballoon are presented in this practical and systematic review.
Atrial Fibrillation ; Biophysics ; Catheter Ablation ; Cryosurgery ; Pulmonary Veins

The extracellular matrix (ECM) is a heterogeneous, connective network composed of fibrous glycoproteins that coordinate in vivo to provide the physical scaffolding, mechanical stability, and biochemical cues necessary for tissue morphogenesis and homeostasis. This review highlights some of the recently raised aspects of the roles of the ECM as related to the fields of biophysics and biomedical engineering. Fundamental aspects of focus include the role of the ECM as a basic cellular structure, for novel spontaneous network formation, as an ideal scaffold in tissue engineering, and its essential contribution to cell sheet technology. As these technologies move from the laboratory to clinical practice, they are bound to shape the vast field of tissue engineering for medical transplantations.
Biomedical Engineering ; Biophysics ; Cellular Structures ; Collagen ; Cues ; Elastin ; Extracellular Matrix* ; Fibronectins ; Glycoproteins ; Homeostasis ; Morphogenesis ; Tissue Engineering*

OBJECTIVETo study on basic Volt-ampere (V-A) characteristics of human acupoints and the changes with physiologic and pathologic changes, and probe their biophysical basis.

METHODSThe research works of this research group about V-A characteristics of acupoints in recent 10 years were systematized and analyzed.

RESULTSV-A characteristic curve of human acupoints is of the both characteristics of non-linear and inertia. Compared with controlled point, the lower electric resistance characteristic of acupoints is not popular and the lower inertia is popular. V-A area of acupoints has no obvious circadian rhythms and the inertia area of a large part of acupoints has obvious circadian rhythms, with the phase of peak value corresponding to the phase of valley value of body temperature rhythms. V-A characteristics of acupoints in the patients of heart disease or stomach diseases changes obviously, and these changes have a certain specificities of acupoints. After remission of the lesion, the V-A characteristics of acupoints restore normal. The V-A area and the inertia area of acupoints in the corpse are obviously smaller than the normal person, with disappearance of the characteristics of both the non-linear and inertia of the normal person.

CONCLUSIONHuman acupoints have characteristics of non-linear and inertia, and the non-linear characteristic reflects complexity of physiology and behavior, while the inertia characteristic is related with energy metabolism of acupoints. The inertia area can more sensitively reflect human physiologic and pathological changes as compared with the V-A area, so it is an important index for the studies on electric characteristics of acupoints in the future.

T cell activation and function require physical contact with antigen presenting cells at a specialized junctional structure known as the immunological synapse. Once formed, the immunological synapse leads to sustained T cell receptor-mediated signalling and stabilized adhesion. High resolution microscopy indeed had a great impact in understanding the function and dynamic structure of immunological synapse. Trends of recent research are now moving towards understanding the mechanical part of immune system, expanding our knowledge in mechanosensitivity, force generation, and biophysics of cell-cell interaction. Actin cytoskeleton plays inevitable role in adaptive immune system, allowing it to bear dynamic and precise characteristics at the same time. The regulation of mechanical engine seems very complicated and overlapping, but it enables cells to be very sensitive to external signals such as surface rigidity. In this review, we focus on actin regulators and how immune cells regulate dynamic actin rearrangement process to drive the formation of immunological synapse.
Actin Cytoskeleton ; Actins ; Antigen-Presenting Cells ; Biophysics ; Immune System ; Immunological Synapses ; Microscopy ; T-Lymphocytes ; Ursidae

Heart rate variability (HRV) is governed by the autonomic nervous system (ANS) and is routinely used to estimate the state of body and mind. At the same time, recorded HRV features can vary substantially between people. A model for HRV that (1) correctly simulates observed HRV, (2) reliably functions for multiple scenarios, and (3) can be personalised using a manageable set of parameters, would be a significant step forward toward understanding individual responses to external influences, such as physical and physiological stress. Current HRV models attempt to reproduce HRV characteristics by mimicking the statistical properties of measured HRV signals. The model presented here for the simulation of HRV follows a radically different approach, as it is based on an approximation of the physiology behind the triggering of a heart beat and the biophysics mechanisms of how the triggering process—and thereby the HRV—is governed by the ANS. The model takes into account the metabolisation rates of neurotransmitters and the change in membrane potential depending on transmitter and ion concentrations. It produces an HRV time series that not only exhibits the features observed in real data, but also explains a reduction of low frequency band-power for physically or psychologically high intensity scenarios. Furthermore, the proposed model enables the personalisation of input parameters to the physiology of different people, a unique feature not present in existing methods. All these aspects are crucial for the understanding and application of future wearable health.
Autonomic Nervous System ; Biophysics ; Heart Rate ; Heart ; Membrane Potentials ; Neurotransmitter Agents ; Physiology ; Stress, Physiological ; Vital Signs