\n<\/p>\n
I\u2019m grateful for the warnings threaded through Stephanie Pappas\u2019s \u201cThe Truth about Testosterone\u201d and would like to elaborate from personal experience. As a transgender man, I adore the effects of testosterone. But I discovered some unwelcome ones when my levels climbed. My higher dosage was accidental; I assumed my doctor wanted me to increase it each week until she said, \u201cHalt!\u201d<\/p>\n
It sounds like one man\u2019s accident is another man\u2019s aim, however, given that cisgender men with testosterone in the normal range of 300 to 1,000 nanograms per deciliter (ng\/dl) can easily get prescriptions for the hormone. Above 1,000 ng\/dl, I grew impatient, irritable and disturbingly apathetic. Once an eager listener at volunteer meetings, I felt like I was the only person in the room. All these other humans with their human opinions! They exasperated me.<\/p>\n
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n
STEVE HUITING NEVADA CITY, CALIF.<\/p>\n
In \u201cPerfect Slice\u201d [Advances], Max Springer describes a slicing problem involving convex shapes as equivalent to \u201casking whether an avocado of a given size, no matter the exact shape, can always be split into two halves with each side revealing at least some sizable slice,\u201d in the case of three-dimensional objects.<\/p>\n
Does \u201ctwo halves\u201d mean two true halves or two pieces? And does \u201csome sizable slice\u201d mean that the area of the cut is not zero\u2014that the two \u201chalves\u201d are not connected by just a thread?<\/p>\n
DAWN JACOBS VIA E-MAIL<\/p>\n
SPRINGER REPLIES: \u201cTwo halves\u201d in this problem means two disconnected pieces. Moving your knife completely through a fruit at any angle will always give you two pieces but not necessarily two halves. The description of \u201csome sizable slice\u201d is capturing a deeper mathematical boundary on how large the area of each of the two cross sections will be. As described in my article, the recently proved result of the problem says we can always cut an object into two pieces so that each has a cross section of at least a given size. This may seem intuitive for fruits but gets more complex in higher dimensions.<\/p>\n
\u201cCan Sunlight Cure Disease?,\u201d by Rowan Jacobsen [June], leaves us with a sense of mystery as to the mechanism of action for the health benefits of sunshine. Yet in the same issue, a clue is offered by Martin Picard in \u201cThe Social Lives of Mitochondria.\u201d The benefits of sunshine might arise from its effect at the mitochondrial level, as demonstrated in a July Scientific Reports paper by Glen Jeffery of University College London and his colleagues. Picard does recommend diet, socialization and exercise to optimize mitochondrial function, including in a brief reference to his work with Nirosha Murugan of Wilfrid Laurier University in Ontario. But he doesn\u2019t refer to the health benefits of exposure to the outdoors.<\/p>\n
HAROLD PUPKO TORONTO<\/p>\n
Picard says that, so far, the best hypothesis for how mitochondrial DNA\u2019s inner membrane folds, called cristae, line up appears to involve \u201celectromagnetic fields induced by the flow of electrical charge across\u201d those folds. He then goes on to describe how mitochondria communicate with mitochondria in other cells chemically. Perhaps mitochondria are the field sensors and generators, or possibly the \u201cconcentrators,\u201d of biology.<\/p>\n
DONALD WELLER HILLSBORO, ORE.<\/p>\n
PICARD AND MURUGAN REPLY: Pupko is right that the health benefits of sunshine may act, in part, through mitochondria. To exert biological effects, light must be absorbed by a chromophore. Mitochondria have such chromophores, including cytochrome c oxidase (an electron shuttle in the electron-transport chain), which absorbs red and near-infrared photons, abundant in natural light. These wavelengths enhance the electrochemical potential across the inner mitochondrial membrane, energizing mitochondria and increasing adenosine triphosphate synthesis.<\/p>\n
For example, photobiomodulation with near-infrared light can rescue retinal function in vivo and reduce Alzheimer\u2019s pathology in mice. In humans, transcranial photobiomodulation can improve working memory. In a 2024 human study, just 15 minutes of exposure to 670-nanometer red light reduced postprandial glucose spikes by nearly 30 percent.<\/p>\n
Mechanistic studies, including simulations and photoacoustic imaging, reveal how different wavelengths of light interact with chromophores. A study using solar simulators that matched the intensity of summer sunlight demonstrated that mitochondrial responses to light are cell-type-specific: epidermal keratinocytes showed mitochondrial damage under intense sunlight, whereas dermal fibroblasts were more resilient. Sunlight can therefore be broadly beneficial, but its effects depend strongly on wavelength, intensity and exposure time, with ultraviolet light carrying well-known risks.<\/p>\n
Mitochondria\u2019s broader light sensitivity may also help explain why time spent in nature feels restorative. Plants reflect much of the near-infrared spectrum, saturating green spaces with low-energy, tissue-penetrating wavelengths.<\/p>\n
In response to Weller: Across biology, mitochondria produce some of the strongest electric fields. As food-derived electrons flow toward oxygen, the electron transport chain generates an electrochemical gradient across the inner mitochondrial membrane. The voltage potential spans a distance of only about five nanometers, producing an electric field on the order of 30 million volts per meter.<\/p>\n
These immense electric fields rise and fall with metabolic demands and energy flow. Such fluctuations in electric fields are expected to generate low-frequency electromagnetic signals. Although it is beyond the reach of today\u2019s instruments, detecting such signals from individual mitochondria appears to be an essential step toward fully understanding them as a social, energetic collective that transforms and regulates energy across living systems. And the composition of mitochondria suggests they may not only generate but also respond to electromagnetic fields.<\/p>\n
Perhaps the best direct evidence of biologically relevant fields at the scale of mitochondria is the transmitochondrial cristae alignment. This occurs at intermitochondrial junctions, electron-dense contacts between two mitochondria.<\/p>\n
\u201cResearch in Reverse,\u201d by Charles C. Mann [September], should have referred to the Canadian National Breast Screening Study of cancer.<\/p>\n
\u201cPeople Watching,\u201d by Clarissa Brincat [Advances; October], should have quoted Laura Lewis as saying that humans\u2019 and chimpanzees\u2019 shared primate ancestor lived around five million years ago.<\/p>\n
In \u201cPrevention Intervention,\u201d by Jyoti Madhusoodanan [Innovations in Alzheimer\u2019s; October], OHSU\u2019s name should be Oregon Health & Science University.<\/p>\n","protected":false},"excerpt":{"rendered":"
HIGH TESTOSTERONE I\u2019m grateful for the warnings threaded through Stephanie Pappas\u2019s \u201cThe Truth about Testosterone\u201d and would like to elaborate from personal experience. As a transgender man, I adore the effects of testosterone. But I discovered some unwelcome ones when my levels climbed. My higher dosage was accidental; I assumed my doctor wanted me to<\/p>\n","protected":false},"author":1,"featured_media":34288,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[58],"tags":[580,19525,862,3684],"class_list":{"0":"post-34287","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-issue","9":"tag-julyaugust","10":"tag-readers","11":"tag-respond"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/34287","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=34287"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/34287\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/34288"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=34287"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=34287"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=34287"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}