Far-infrared absorption of water clusters by first-principles molecular dynamics

Far-infrared radiation alleviates steatohepatitis and fibrosis in metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a disease that causes an abnormal accumulation of fat in the liver, triggering inflammation and fibrosis, the mechanism of which is not fully understood and for which there is a lack of specific drug therapy. Far-infrared radiation (FIR) has demonstrated evident therapeutic efficacy across various diseases, and novel nanomaterial graphene patches can emit it through electric heating. This study aimed to investigate the potential protective effects of FIR against MAFLD. Mice were fed with a MCD diet to mimic MAFLD progression, and histopathology analysis, biochemical analysis, RT-qPCR, and Western blotting analysis were performed to assess the effect of FIR on MAFLD in vivo. The effect of FIR treatment on MAFLD in vitro was investigated by biochemical analysis and gene expression profiling of hepatocytes. Mice subjected to the MCD diet and treated with FIR exhibited reduced hepatic lipid deposition, inflammation, fibrosis and liver damage. The therapeutic effect exerted by FIR in mice may be caused by the enhancement of AMPK phosphorylation and inhibition of the TGFβ1-SMAD2/3 pathway. Besides, FIR intervention alleviated MAFLD in hepatocytes in vitro and the results were verified by gene expression profiling. Our results revealed a promising potential of FIR as a novel therapeutic approach for MAFLD.

Far-infrared radiation and its therapeutic parameters: A superior alternative for future regenerative medicine?

In future regenerative medicine, far-infrared radiation (FIR) may be an essential component of optical therapy. Many studies have confirmed or validated the efficacy and safety of FIR in various diseases, benefiting from new insights into FIR mechanisms and the excellent performance of many applications. However, the lack of consensus on the biological effects and therapeutic parameters of FIR limits its practical applications in the clinic. In this review, the definition, characteristics, and underlying principles of the FIR are systematically illustrated. We outline the therapeutic parameters of FIR, including the wavelength range, power density, irradiation time, and distance. In addition, the biological effects, potential molecular mechanisms, and preclinical and clinical applications of FIR are discussed. Furthermore, the future development and applications of FIR are described in this review. By applying optimal therapeutic parameters, FIR can influence various cells, animal models, and patients, eliciting diverse underlying mechanisms and offering therapeutic potential for many diseases. FIR could represent a superior alternative with broad prospects for application in future regenerative medicine.

Enhanced far infrared emissivity, UV protection and near-infrared shielding of polypropylene composites via incorporation of natural mineral for functional fabric development

Far infrared radiation in the range of 4-20 µm has been showed to have biological and health benefits to the human body. Therefore, incorporating far-infrared emissivity additives into polymers and/or fabrics hold promise for the development of functional textiles. In this study, we incorporated nine types of natural minerals into polypropylene (PP) film and examined their properties to identify potential candidates for functional textiles and apparels. The addition of 2% mineral powders into PP film increased the far-infrared emissivity (5-14 µm) by 7.65%-14.48%. The improvement in far-infrared emissivity within the range of 5-14 µm, which overlaps with the peak range of human skin radiation at 8-14 µm, results in increased absorption efficiency, and have the potential to enhance thermal and biological effects. Moreover, the incorporation of mineral powders in PP films exhibited favorable ultraviolet (UV) protection and near-infrared (NIR) shielding properties. Two films, specifically those containing red ochre and hematite, demonstrated excellent UV protection with a UPF rating of 50+ and blocked 99.92% and 98.73% of UV radiation, respectively. Additionally, they showed 95.2% and 93.2% NIR shielding properties, compared to 54.1% NIR shielding properties of PP blank films. The UV protection and NIR shielding properties offered additional advantages for the utilization of polymer composite with additives in the development of sportswear and other outdoor garments. The incorporation of minerals could absorb near-IR radiation and re-emit them at longer wavelength in the mid-IR region. Furthermore, the incorporation of minerals significantly improved the heat retention of PP films under same heat radiation treatment. Notably, films with red ochre and hematite exhibited a dramatic temperature increase, reaching 2.5 and 3.2 times the temperature increase of PP films under same heat radiation treatment, respectively (46.8 °C and 59.9 °C higher than the temperature increase of 20.9 °C in the PP film). Films with additives also demonstrated lower thermal effusivity than PP blank films, indicating superior heat insulation properties. Therefore, polypropylene films with mineral additives, particularly those containing red ochre and hematite, showed remarkable heat capacity, UV-protection, NIR-shielding properties and enhanced far infrared emissivity, making them promising candidates for the development of functional textiles.

Physical properties and biological effects of ceramic materials emitting infrared radiation for pain, muscular activity, and musculoskeletal conditions

BACKGROUND

Up to 33% of the general population worldwide suffer musculoskeletal conditions, with low back pain being the single leading cause of disability globally. Multimodal therapeutic options are available to relieve the pain associated with muscular disorders, including physical, complementary, and pharmacological therapies. However, existing interventions are not disease modifying and have several limitations.

METHOD

Literature review.

RESULTS

In this context, the use of nonthermal infrared light delivered via patches, fabrics, and garments containing infrared-emitting bioceramic minerals have been investigated. Positive effects on muscular cells, muscular recovery, and reduced inflammation and pain have been reported both in preclinical and clinical studies. There are several hypotheses on how infrared may contribute to musculoskeletal pain relief, however, the full mechanism of action remains unclear. This article provides an overview of the physical characteristics of infrared radiation and its biological effects, focusing on those that could potentially explain the mechanism of action responsible for the relief of musculoskeletal pain.

CONCLUSIONS

Based on the current evidence, the following pathways have been considered: upregulation of endothelial nitric oxide synthase, increase in nitric oxide bioavailability, anti-inflammatory effects, and reduction in oxidative stress.

A pilot study on the effects of far-infrared-emitting fabric on neuromuscular performance of knee extensor and male fertility

The aim of this study was to evaluate the time course of the effects of far-infrared emitting fabric (FIR) on neuromuscular performance of knee extensor over 120 h and to investigate whether the use of FIR affects semen. This is a crossover, randomized, double-blind, and placebo-controlled trial split into neuromuscular and fertility assessments. Four (28.8 ± 4.7 years old) and six (29 ± 3.9 years old) healthy, resistance-trained males completed all neuromuscular and fertility assessments, respectively. In neuromuscular assessments, for five consecutive days, the participants underwent neuromuscular tests in an isokinetic dynamometer (maximal isometric voluntary contraction (MVC) and fatigue test) every 24 h in both conditions (FIR and Placebo). In fertility assessments, participants performed three semen collections: Baseline, FIR, and Placebo. FIR and Placebo collections were performed after five consecutive days of use of the pants. Conventional parameters and sperm DNA fragmentation were evaluated. In the FIR condition, the participants showed significant differences in total work at 96 h (p < 0.001; Cohen’s d = 3.73), 120 h (p = 0.01; Cohen’s d = 2.65), and pre-MVC at 120 h (p = 0.02; Cohen’s d = 2.15) when compared to Placebo. FIR did not significantly (p > 0.05) affect the conventional semen parameters or sperm DNA fragmentation compared to Baseline or Placebo. FIR improved the knee extensor neuromuscular performance of healthy resistance-trained individuals, with 112.4 ± 7.8 h accumulated, and did not affect their seminal parameters (conventional or sperm DNA fragmentation), with 113.1 ± 10.2 h accumulated.

Infrared Radiation in the Management of Musculoskeletal Conditions and Chronic Pain: A Systematic Review

Infrared radiation (IR) is a promising complementary treatment for musculoskeletal conditions and chronic pain. By means of a systematic review, we evaluated the contribution of IR to the management of these ailments. PubMed-MEDLINE, Scopus, and Cochrane Library–Cochrane Central Register of Controlled Trials were systematically searched until 20 December 2021. The literature search yielded 233 relevant records. Following the screening of titles and abstracts, 42 full-texts were evaluated. As per inclusion/exclusion criteria, 13 publications were entered into the qualitative assessment. These studies described the effects of IR in humans: three studies focused on osteoarthritis, four studies on fibromyalgia, and six encompassed a wider range of diseases (ankylosing spondylitis, recovery from sports injuries, myofascial pain syndrome). Based on the findings of our systematic review, we noted a decrease in pain levels, as evaluated by the visual analog scale (VAS), in patients suffering from musculoskeletal disorders treated with IR. In addition, IR use led to a decrease in Fibromyalgia Impact Questionnaire (FiQ) scores in subjects diagnosed with fibromyalgia. Nevertheless, IR has failed to facilitate muscle recovery following athletic injuries.

Far-infrared-emitting fabric improves neuromuscular performance of knee extensor

The aim of this study was to verify if exposure to the far-IR emitted by fabric (FIR) is able to improve the neuromuscular performance of the knee extensors of resistance-trained males regardless of changes of the temperature. It is a crossover, randomized, double-blind, and placebo-controlled trial. Fourteen resistance-trained males (age: 24.3 ± 4 years; body mass: 82.8 ± 11.3 kg; height: 176.3 ± 4.2 cm) were randomly assigned to one of initial conditions: FIR (n = 7) or placebo (n = 7). After 4 days, the participants were submitted to neuromuscular tests in an isokinetic dynamometer (maximal isometric voluntary contraction (MVC) and fatigue test). After a week of washout, participants performed the other condition. We measured peak torque (Nm), total work (J), fatigue index (%), root mean square (mV), median frequency (Hz), and temperature (°C) of thigh. The FIR was worn for 82 ± 19 h before the experimental session, totaling 317 ± 74 kJ of energy irradiation. There was a significant increase (p < 0.05) for pre-MVC (318.5 ± 68.7 Nm) and post-MVC (284.1 ± 58.2 Nm), and a trend (p = 0.055) for significant increase for total work (4,122.2 ± 699.8 J) on FIR condition regardless of none change on temperature and electromyographic (EMG) signals. FIR improved the neuromuscular performance of knee extensors in resistance-trained males regardless of changes on temperature and EMG. The present results suggest that the FIR could optimize the neuromuscular performance with 82 ± 19 h of wear.

Effects of far infrared light on Alzheimer's disease-transgenic mice

Far infrared light has been used in many medical procedures. However, the detailed biological mechanisms of infrared light's effects have not yet been elucidated. Many researchers have pointed out the thermal effects of treatments such as infrared saunas, which are known to increase blood flow. Alzheimer's disease (AD) is associated with gradual decreases in brain blood flow and resulting dementia. In this study, we attempted to clarify the beneficial effects of far infrared light using the 5xFAD mouse, a transgenic model of AD. We exposed 5xFAD mice to far infrared light for 5 months. Among the far infrared-exposed AD mice, body weights were significantly decreased, and the levels of nerve growth factor and brain-derived neurotrophic factor protein were significantly increased in selected brain areas (compared to those in non-irradiated AD mice). However, cognition and motor function (as assessed by Morris water maze and Rota Rod tests, respectively) did not differ significantly between the irradiated and non-irradiated AD mouse groups. These results indicated that exposure to far infrared light may have beneficial biological effects in AD mice. However, the experimental schedule and methods may need to be modified to obtain clearer results.

Temperature Dependence of Intramolecular Vibrational Bands in Small Water Clusters

Cyclic water clusters are pivotal for understanding atmospheric reactions as well as liquid water, yet the temperature (T) dependence of their dynamics and spectroscopy is poorly studied. The development of highly accurate water potentials, such as MB-pol, partly rectifies this. It remains to account for the quantum nuclear effects (NQE), because quantum nuclear dynamics become increasingly inaccurate at low temperatures. From a practical point of view, we find that NQE can be accounted for simply by subtracting a constant from the frequencies obtained from the velocity autocorrelation functions (VACF) of classical nuclear dynamics, resulting in unprecedented agreement with experiment, mostly within 5 cm^-1. We have performed classical simulations of (H₂O)_n clusters (n = 2-5) from 20 K and up to their melting temperature, calculating both all-atom and partial VACF, thus generating the temperature dependence of the vibrational frequencies (IR and Raman bands). Focusing on the hydrogen-bonded (HBed) OH stretch and HOH bend, we find opposing T dependencies. The HBed OH modes blue shift linearly with T, attributed to ring expansion rather than any specific conformational change. The lowest-frequency Raman concerted mode is predicted to show the largest such shift. In contrast, the HOH bend undergoes a red-shift, with the highest frequency concerted band undergoing the largest red-shift. These results can be explained by a coupled-oscillator model for n hydrogen atoms on a ring, constrained to move either tangentially (stretch) or perpendicularly (bend) to the ring. With increasing temperature and weakening of HBs, the intrinsic force constant increases (stretch) or remains constant (bend), while the nearest-neighbor coupling constant decreases, and this results in the interesting behavior revealed herein. T-dependent Raman studies are required for testing some of these predictions.

Cation solvation with quantum chemical effects modeled by a size-consistent multi-partitioning quantum mechanics/molecular mechanics method

In the condensed phase, quantum chemical properties such as many-body effects and intermolecular charge fluctuations are critical determinants of the solvation structure and dynamics.

An adaptive quantum mechanics/molecular mechanics method for the infrared spectrum of water: incorporation of the quantum effect between solute and solvent

Quantum effects in solute–solvent interactions, such as the many-body effect and the dipole-induced dipole, are known to be critical factors influencing the infrared spectra of species in the liquid phase.

Far infrared radiation (FIR): its biological effects and medical applications

Far infrared (FIR) radiation (λ = 3-100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3- 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects.