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1. Weak magnetic fields modulate superoxide to control planarian regeneration

   https://doi.org/10.3389/fphy.2022.1086809  

   Kinsey, Luke J. ; Van Huizen, Alanna V. ; Beane, Wendy S. ( January 2023 , Frontiers in Physics)

   Reactive oxygen species (ROS) signaling regulates cell behaviors and tissue growth in development, regeneration, and cancer. Commonly, ROS are modulated pharmacologically, which while effective comes with potential complications such as off-target effects and lack of drug tolerance. Thus, additional non-invasive therapeutic methods are necessary. Recent advances have highlighted the use of weak magnetic fields (WMFs, <1 mT) as one promising approach. We previously showed that 200 μT WMFs inhibit ROS formation and block planarian regeneration. However, WMF research in different model systems at various field strengths have produced a range of results that do not fit common dose response curves, making it unclear if WMF effects are predictable. Here, we test hypotheses based on spin state theory and the radical pair mechanism, which outlines how magnetic fields can alter the formation of radical pairs by changing electron spin states. This mechanism suggests that across a broad range of field strengths (0–900 μT) some WMF exposures should be able to inhibit while others promote ROS formation in a binary fashion. Our data reveal that WMFs can be used for directed manipulation of stem cell proliferation, differentiation, and tissue growth in predictable ways for both loss and gain of function during regenerative growth. Furthermore, wemore »examine two of the most common ROS signaling effectors, hydrogen peroxide and superoxide, to begin the identification and elucidation of the specific molecular targets by which WMFs affect tissue growth. Together, our data reveal that the cellular effects of WMF exposure are highly dependent on ROS, and we identify superoxide as a specific ROS being modulated. Altogether, these data highlight the possibilities of using WMF exposures to control ROS signaling in vivo and represent an exciting new area of research.« less
2. Weak magnetic fields alter stem cell–mediated growth

   https://doi.org/10.1126/sciadv.aau7201  

   Van Huizen, Alanna V. ; Morton, Jacob M. ; Kinsey, Luke J. ; Von Kannon, Donald G. ; Saad, Marwa A. ; Birkholz, Taylor R. ; Czajka, Jordan M. ; Cyrus, Julian ; Barnes, Frank S. ; Beane, Wendy S. ( January 2019 , Science Advances)

   Biological systems are constantly exposed to electromagnetic fields (EMFs) in the form of natural geomagnetic fields and EMFs emitted from technology. While strong magnetic fields are known to change chemical reaction rates and free radical concentrations, the debate remains about whether static weak magnetic fields (WMFs; <1 mT) also produce biological effects. Using the planarian regeneration model, we show that WMFs altered stem cell proliferation and subsequent differentiation via changes in reactive oxygen species (ROS) accumulation and downstream heat shock protein 70 (Hsp70) expression. These data reveal that on the basis of field strength, WMF exposure can increase or decrease new tissue formation in vivo, suggesting WMFs as a potential therapeutic tool to manipulate mitotic activity.
3. Reaction engineering implications of cellulose crystallinity and water-promoted recrystallization

   https://doi.org/10.1039/C9GC02466B  

   Tyufekchiev, Maksim ; Kolodziejczak, Alex ; Duan, Pu ; Foston, Marcus ; Schmidt-Rohr, Klaus ; Timko, Michael T. ( October 2019 , Green Chemistry)

   Mechanical decrystallization and water-promoted recrystallization of cellulose were studied to understand the effects of cellulose crystallinity on reaction engineering models of its acid-catalyzed hydrolysis. Microcrystalline cellulose was ball-milled for different periods of time, which decreased its crystallinity and increased the glucose yield obtained from acid hydrolysis treatment. Crystallinity increased after acid hydrolysis treatment, which has previously been explained in terms of rapid hydrolysis of amorphous cellulose, despite conflicting evidence of solvent promoted recrystallization. To elucidate the mechanism, decrystallized samples were subjected to various non-hydrolyzing treatments involving water exposure. Interestingly, all non-hydrolyzing hydrothermal treatments resulted in recovery of crystallinity, including a treatment consisting of heat-up and quenching that was selected as a way to estimate the crystallinity at the onset of hydrolysis. Therefore, the proposed mechanism involving rapid hydrolysis of amorphous cellulose must be incomplete, since the recrystallization rate of amorphous cellulose is greater than the hydrolysis rate. Several techniques (solid-state nuclear magnetic resonance, X-ray diffraction, and Raman spectroscopy) were used to establish that water contact promotes conversion of amorphous cellulose to a mixture of crystalline cellulose I and cellulose II. Crystallite size may also be reduced by the decrystallization-recrystallization treatment. Ethanolysis was used to confirm that the reactivity of themore »cellulose I/cellulose II mixture is distinct from that of truly amorphous cellulose. These results strongly point to a revised, more realistic model of hydrolysis of mechanically decrystallized cellulose, involving recrystallization and hydrolysis of the cellulose I/cellulose II mixture.« less
4. Frontline Science: Escherichia coli use LPS as decoy to impair neutrophil chemotaxis and defeat antimicrobial host defense

   https://doi.org/10.1002/JLB.4HI0319-109R  

   Kondo, Yutaka ; Ledderose, Carola ; Slubowski, Christian J. ; Fakhari, Mahtab ; Sumi, Yuka ; Sueyoshi, Koichiro ; Bezler, Ann-Katrin ; Aytan, Dilan ; Arbab, Mona ; Junger, Wolfgang G. ( August 2019 , Journal of Leukocyte Biology)

   Bacterial infections and sepsis are leading causes of morbidity and mortality in critically ill patients. Currently, there are no effective treatments available to improve clinical outcome in sepsis. Here, we elucidated a mechanism by which Escherichia coli (E. coli) bacteria impair neutrophil (PMN) chemotaxis and we studied whether this mechanism can be therapeutically targeted to improve chemotaxis and antimicrobial host defense. PMNs detect bacteria with formyl peptide receptors (FPR). FPR stimulation triggers mitochondrial ATP production and release. Autocrine stimulation of purinergic receptors exerts excitatory and inhibitory downstream signals that induce cell polarization and cell shape changes needed for chemotaxis. Here we show that the bacterial cell wall product LPS dose-dependently impairs PMN chemotaxis. Exposure of human PMNs to LPS triggered excessive mitochondrial ATP production and disorganized intracellular trafficking of mitochondria, resulting in global ATP release that disrupted purinergic signaling, cell polarization, and chemotaxis. In mice infected i.p. with E. coli, LPS treatment increased the spread of bacteria at the infection site and throughout the systemic circulation. Removal of excessive systemic ATP with apyrase improved chemotaxis of LPS-treated human PMNs in vitro and enhanced the clearance of E. coli in infected and LPS-treated mice. We conclude that systemic ATP accumulationmore »in response to LPS is a potential therapeutic target to restore PMN chemotaxis and to boost the antimicrobial host immune defense in sepsis.

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5. Development of Focused Transcranial Magnetic Stimulation for Rodents by Copper-Array Shields

   https://doi.org/DOI: 10.1109/TMAG.2018.2796098  

   Qinglei Meng, Mitchell Cherry ( February 2018 , IEEE transactions on magnetics)

   Transcranial magnetic stimulation (TMS) is one of the most widely used noninvasive brain stimulation methods. It has been utilized for both treatment and diagnosis of many neural diseases, such as neuropathic pain and loss of function caused by stroke. Existing TMS tools cannot deliver focused electric field to targeted penetration depth even though many important neurological disorders are originated from there. A breakthrough is needed to achieve noninvasive, focused brain stimulation. We demonstrated using magnetic shield to achieve magnetic focusing without sacrificing significant amount of throughput. The shield is composed of multiple layers of copper ring arrays, which utilize induced current to generate counter magnetic fields. We experimentally set up a two-pole stimulator system to verify device simulation. A transient magnetic field probe was used for field measurements. The focusing effect highly depends on the geometric design of shield. A tight focal spot with a diameter of smaller than 5 mm (plotted in MATLAB contour map) can be achieved by using copper ring arrays. With properly designed array structures and ring locations, the combined original and induced counter fields can produce a tightly focused field distribution with enhanced field strength at a depth of 7.5 mm beyond the shield plane,more »which is sufficient to reach many deep and critical parts of a mouse brain.« less