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Neil Shubin wants NAS to stay relevant

New president of the beleaguered National Academy of Sciences discusses its future and the precarious state of U.S. science under Trump

BAM-BepA complexes in outer membrane protein quality control

Abstract Correct folding of outer membrane proteins (OMPs) by the β-barrel assembly machinery (BAM) is essential for maintaining the outer membrane (OM) barrier function of diderm bacteria. When OMP biogenesis is perturbed, the β-barrel assembly enhancing protease A (BepA) binds to BAM to mediate quality control, but how BepA interacts with BAM and degrades substrate OMPs remains unclear. Here, cryoEM structures of BAM-bound BepA reveals that BepA induces large conformational changes in the BAM complex enabling the enzyme to poise its active site within the periplasmic ring of BAM, beneath the BamA barrel. The lid of BepA is dynamic, embedding two of its water-soluble helices deep into the membrane bilayer when BAM-bound, which readies BepA for proteolysis of misfolding OMPs. Movement of BepA’s plug is triggered by OMP binding rather than interaction with BAM, activating the enzyme for cleavage. We reveal BepA preferentially recognises Aromatic-X-Aromatic (Ar-X-Ar) motifs which are enriched in OMP sequences. The results reveal a mechanism for proteolytic degradation by BepA in OMP quality control which requires interaction with BAM, the membrane, and its OMP substrates.

Trends and Prevalence of Chronic Kidney Disease in the United States

TL–LASSO-Net: a hybrid transfer learning and LASSO-based framework for robust colon cancer histopathology classification on LC25000 and GlaS datasets

Roots navigate around decay regions by sensing local pH gradients

Plant tropisms enable roots to navigate complex soils by responding to directional environmental cues. Biological decay, although central to nutrient cycling, also creates microbially active and potentially hostile niches. In this work, we identified “saprotropism,” a previously unrecognized growth response that enables roots to actively bend away from decaying plant-derived matter. Fungal-driven microbial decomposition released organic acids and formed stable pH gradients in surrounding soil, allowing roots to pinpoint decay without direct contact. Root epidermal cells sensed this acidic gradient through the root meristem growth factor peptide-receptor module, converting external pH asymmetry into asymmetric abscisic acid (ABA) distribution. ABA asymmetry drove microtubule reorganization, which was decoded into decay-avoidant root bending. Together, these findings establish microbial decay–derived chemical gradients as an instructive signal for root navigation and expand the framework of microbe-soil-plant communication.

One Pivotal Trial for FDA Approval — Ending the Two-Trial Dogma

Step-graded AlGaN barrier engineering in AlGaN/GaN HEMTs for high-linearity low-noise RF amplifiers

Abstract Compositionally graded AlGaN barrier GaN-HEMTs present a promising path to enhance device linearity, which is essential for low-noise radio-frequency (RF) amplifiers. In this work, a step-graded (SG) AlGaN/GaN HEMT is proposed and systematically investigated to explore the advantage of graded barrier compared to conventional HEMTs. The effect of Al-composition on DC/RF performance of the conventional HEMT (CHEMT), is initially analyzed, where 25% Al composition delivered optimal performance. Further, a step-graded (SG) barrier (Al composition varying from 25% to 15%) is introduced, forming an SGHEMT. The outcomes show that, graded barrier allows for a modified 2DEG confinement resulting in more distributed carrier profile, offering improved and broader transconductance (g m ), and suppressed higher-order nonlinearities, thereby enhancing device linearity. Additionally, the impact of drain bias is also studied, where the SGHEMT achieves maximum performance at V DS = 5 V, due to enhanced electric field and improved carrier transport. Moreover, thickness of SG-AlGaN barrier is scaled from 22 nm to 11 nm to achieve better electrical performance. The optimized SGHEMT with 11 nm barrier is found to have g m of 420.4 mS/mm, maximum I D of 1.83 A/mm, higher I d−sat of 2.82 A/mm, & enhanced f T of 154.3 GHz due to better channel electrostatics, enhanced carrier confinement, improved drive current capability. paving the way for better linearity performances. These results emphasize exceptional DC/RF performance traits of proposed SGHEMT, rendering it a strong candidate for low-noise RF amplifiers that demand high linearity operation.

Adaptation across an extreme elevational gradient in Andean leaf-eared mice, the world’s highest-dwelling mammal

Andean leaf-eared mice ( Phyllotis vaccarum ) live at the highest elevations of any mammal, and they also have the broadest elevational range, from sea level to mountain summits of >6700 meters. Highland populations have evolved an enhanced thermogenic capacity in hypoxia relative to lowland conspecifics, and this improved physiological performance is associated with an increased mitochondrial respiratory capacity in skeletal muscle. Population genomic analyses identified mechanisms of hypoxia adaptation and revealed an unanticipated dimension of environmental adaptation in P. vaccarum because selection on biotransformation pathways suggests an evolved capacity to metabolize plant-derived dietary toxins. The world’s highest-dwelling mammal has adapted to habitats at both the low- and high-elevation limits of its range, and much of the elevation-related selection relates to previously unappreciated aspects of feeding ecology.

For Those Left Behind

The effect of seaweed extract application under salinity stress on growth characteristics and antioxidant response of ornamental pansy (Viola × wittrockiana)

Leaping out of the water: Aerial-aquatic locomotion with flapping wings

Wing-propelled diving birds flap their wings to move through air and water, yet the wing morphology and kinematics that enable this behavior remain poorly understood because of the difficulty of collecting in situ data. The impact of flapping frequency, wing size, and stiffness on locomotion in—and transition between—the two media are still unknown. We compared data from diving birds against experiments using a flapping-wing robot capable of flying, swimming, plunge diving, and exiting the water. We show that frequency adaptation, flexible wings, and powerful actuation enable seamless transitions without folding wings or legs, that large wings enhance flight without substantially reducing underwater efficiency, and that tail-body distance and egress angle affect water exit. These results clarify how birds (and robots) balance multifluid locomotion constraints.

Measles Inclusion-Body Encephalitis after Allogeneic Stem-Cell Transplantation

Prediction of mechanical properties of Austempered Flake Graphite Iron and compacted graphite iron using response surface methodology

Neural circuits for valence updating in social memory

Social animals recognize familiar conspecifics and selectively avoid harmful ones. As social relationships shift, continuous updating of social valence is essential, yet the underlying neural mechanisms remain unclear. Here, by artificially transforming a previously neutral conspecific into an aggressive one, we show that valence updating depends on enhanced synaptic connectivity and physiological changes within the hippocampal ventral CA1 (vCA1)–basolateral amygdala (BLA)–nucleus accumbens (NAc) circuit. Following defeat, social memory engram neurons in the vCA1 strengthened their connections with BLA neurons carrying negative valence. The vCA1–BLA–NAc neural circuit flexibly regulates adaptive social behaviors.

Setmelanotide for the Treatment of Acquired Hypothalamic Obesity

Determination of the surface properties and isomer pair separation powers of benzoin gums using inverse gas chromatography

A single freeze cycle redirects iron mineral transformation

Polycrystalline ice formation concentrates mineral nanoparticles into liquid boundaries between growing ice crystals. Here we show that minutes of freezing dictate iron mineral fate over subsequent months of aqueous aging. A single freeze–thaw cycle irreversibly aggregates ferrihydrite through converging physical and chemical mechanisms. Freeze concentration collapses electrostatic barriers while cryosuction strips hydration layers and compresses nanoparticles into micrometer-scale planar aggregates. Chemical evidence points to interfacial (hydr)oxo bridging, alongside hydrogen bonding, that resists disaggregation. These mechanisms lock nanoparticles into mesocrystal-like assemblages that retain their nanoscale identity but inhibit dissolution–reprecipitation to goethite, instead favoring solid-state transformation to hematite. Ice formation thus acts as a geochemical reactor, driving aggregation and interfacial bonding that redirect iron speciation, with broad implications for nutrient cycling and carbon preservation across the cryosphere.

Nutrition Therapy in Critically Ill Adults

EBCS-SDN: an enhanced blockchain-based framework for control plane security in multi-domain SDN

Abstract Software Defined Networking (SDN) enhances network programmability and management by decoupling control and data planes. However, this logically centralized control plane introduces scalability issues and security vulnerabilities. In multi-domain SDN architectures malicious entities can compromise controllers to inject false flow rules, disrupting network integrity. Existing solutions often rely on static cryptographic authorizations, failing to monitor the real-time operational integrity of controllers. To address these limitations, this paper proposes an enhanced blockchain-based control layer security framework in multi-domain SDN (EBCS-SDN). The framework introduced a dynamic trust scoring model, an optimized dual-phase controller authentication mechanism and a decentralized behavioral-deviation hijack detection system to ensure continuous controller accountability. The empirical evaluations in a simulated multi-domain SDN environment demonstrated significant performance and security improvements over existing baselines models Voting-based, Proof-of-work (PoW)-based, DLCA_R_P, and BCS. Simulations in an emulated environment show that the proposed framework optimally reduces controller authentication latency by up to 75% and achieves a hijack detection accuracy of 96.78%. Under these simulated proof-of-concept conditions, the system demonstrated a post-attack throughput of 980 Mbps with detection and isolation times under 1.2 s. The proposed framework optimized the CPU utilization at full network nodes. Ultimately, the proposed system provides a scalable, computationally lightweight, and operationally resilient security foundation for SDN deployments.

Relativistic collapse of the classical triple bond in the CBi ⁻ molecular ion

The conventional framework for chemical bonding between main-group elements involves separate σ and π orbitals to describe multiple bonds. However, relativistic effects mix these orbitals in molecules containing heavy elements through spin–orbit coupling, leaving the total angular-momentum projection (ω) as the only good quantum number. Direct experimental evidence that relativistic effects change the σ-π bonding framework has remained elusive. Here, we probe the carbon-bismuth triple bond in the CBi − anion using high-resolution cryogenic photoelectron spectroscopy, coupled with relativistic four-component Dirac-Coulomb coupled-cluster calculations. Even though the CBi − anion is isovalent to the well-known CN − species, we demonstrate that the traditional σ + 2π triple-bond picture collapses into a pure π-like |ω| = 3/2 and two |ω| = 1/2 Kramers pairs containing substantial σ/π mixing.