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| Here is your customized Science X Newsletter for week 34:  | Among 54 adults with mild cognitive impairment and sleep disturbances, self-reported vitamin D intake ≥5,000 IU/day was associated with >13% higher Montreal Cognitive Assessment scores than no supplementation. Lower doses showed no association, and cognitive scores did not differ between vitamin D2 and D3. | | |  | Maternal age effects in rotifers can reverse within one generation, arguing against cumulative DNA damage or mutations as the primary cause. Epigenetic histone modifications and maternally inherited mitochondrial DNA are candidate mechanisms, with genetic variation potentially altering whether effects are harmful or beneficial. | | |  | Urolithin A activated PKG1α and improved relaxation, reduced fibrosis, and limited cardiomyocyte enlargement in experimental HFpEF models. Heart-function measures improved by up to 80% in animals, and engineered human cardiac tissue showed improved relaxation. Clinical efficacy in people remains untested. | | |  | A ~1-km-high escarpment likely formed during Rodinia’s breakup about 800 million years ago and extended across western North America. Its long-term retreat may have eroded 5–10 km of rock, exposing Grand Canyon basement and contributing to the Great Unconformity. | | |  | Cmpd17b, a formylpeptide receptor agonist, lowered mean arterial pressure by 6 mmHg in hypertensive mice without affecting normotensive mice. It reduced kidney, aortic and left-ventricular fibrosis and improved aortic flexibility, but did not improve cardiac pumping or small-vessel function. | | |  | Male Neanderthal pelvises resemble modern female pelvises more than modern male pelvises, suggesting an ancestral configuration retained in both. Forward-positioned hip joints in modern males may form an energy-storing, shock-absorbing walking mechanism, while childbirth-related constraints may limit similar changes in females. | | |  | In two phase III trials of 1,399 adolescents and adults with severe alopecia areata, daily upadacitinib produced ≥80% scalp-hair regrowth at 24 weeks in nearly half receiving 15 mg and >54% receiving 30 mg, versus ~2% with placebo. Eyebrow and eyelash regrowth also improved; common adverse events were acne and respiratory infections. | | |  | CD4 cytotoxic T lymphocytes increased with age in blood samples, reaching a median 17.6% in people aged ≥110 years. Their expansion was driven by dominant clones, some with receptor sequences matching clones reported in cancers. These observations do not establish cancer protection or a causal role in longevity. | | |  | Neanderthal pelvises were wider overall from infancy, yet female birth-canal dimensions resembled those of modern humans, supporting similar childbirth mechanics. Pelvic features linked to locomotion differed without indicating reduced walking efficiency from wider hips. These patterns favor a trade-off between childbirth and pelvic-floor stability over one between childbirth and bipedal locomotion. | | |  | Neutral-atom quantum simulators directly measured excitation spectra predicted by Ising and tricritical Ising conformal field theories. Many-body modulation spectroscopy resolved universal, size-rescaled energy levels and symmetry-dependent spectra in chains of up to 35 atoms, confirming predicted critical behavior. | | |  | Vitamin C does not prevent colds in the general population or help when started after symptoms begin. Regular supplementation may modestly reduce severe symptom duration and severity, with greater effects in athletes and military personnel. High doses can cause gastrointestinal effects, kidney-stone risk, increased iron absorption, and drug interactions. | | |  | Over 35 years, nymphal blacklegged tick abundance tracked mouse populations, rising about 40% after strong mouse years, while deer abundance showed no long-term association. Large acorn crops predicted elevated nymph abundance two years later. Infection prevalence depended on the broader host community, and field ticks survived extreme temperatures, although warmer years predicted fewer nymphs. | | |  | Meta-analysis of 28 experiments across seven bird species indicates that fresh nest plants can improve nestling morphological condition, including body mass and size. Evidence did not support reduced parasites or pathogens, nor clearly favor courtship, nest protection, or medicinal mechanisms; effects may involve nest physical properties or microclimate. | | |  | Hesperetin improved age-related liver damage in old mice, restoring mitochondrial and endoplasmic-reticulum function and reducing steatosis, inflammation, fibrosis, and liver-injury markers. It reversed ~24% of age-associated gene-expression changes through an Hmgcs2–PPARα–Cisd2 pathway; liver-specific Cisd2 loss markedly reduced these effects. Human liver genes showed age-related declines, but clinical benefit remains untested. | | |  | TOFA increased energy expenditure and fat oxidation in obese mice, improving weight, insulin sensitivity, glucose control, triglycerides, and fatty liver features without significant lean-mass loss. Combined with GLP-1 drugs, it produced greater metabolic benefits; human safety and efficacy remain untested. | | |  | A hybrid microresonator–fiber loop generated a stable microcomb and converted it into multiple precisely spaced millimeter-wave signals. Individual comb frequencies could be tuned while preserving precision in the microwave output, supporting potential high-capacity communications, sensing, and precision timing applications. | | |  | In tree shrews, indoor illumination enriched with 419–446 nm indigo light prevented experimentally induced myopia, whereas shorter violet wavelengths were blocked by the ocular lens. The findings implicate light-sensitive pathways in refractive development, but effectiveness and safety in children require clinical testing. | | |  | Gut bacteria convert dietary nitrate and nonheme iron into dinitrosyl iron complexes, which accumulate mainly in liver and kidneys; germ-free mice lacked these compounds. In animal disease models, increased complexes improved vascular function, blood pressure, glucose control, and liver fat. Human effects remain unconfirmed. | | |  | Adult hippocampal neurogenesis was stalled in major depressive disorder, alongside molecular disruptions across hippocampal circuits involved in synaptic function, energy metabolism, inflammation, and cellular stress. These changes may contribute to impaired memory pattern separation and identify molecular targets for depression subtypes and therapies. | | |  | A proposed quantum-gravity framework introduces uncertainty between the universe’s size and expansion rate, modifying cosmic expansion equations. This effect could produce accelerated expansion without an additional dark-energy field and may replace the Big Bang singularity with a bounce from a contracting phase. Upcoming cosmological surveys could test these predictions. |
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