Self-sustaining thermophotonic circuits

Zhao, Bo; Buddhiraju, Siddharth; Santhanam, Parthiban; Chen, Kaifeng; Fan, Shanhui

doi:10.1073/pnas.1904938116

Cited by 14 publications

(7 citation statements)

References 33 publications

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“…40 Its frequent mutations drive cancer. [41][42][43] Despite its paramount significance in signaling and cancer drug discovery, the structural basis for PI3Ka activation by Ras has been elusive. 44,45 Exploiting the BMHP protocol and MD simulations, we modeled the atomic structure of the KRas4B-PI3Ka-RBD complex, with properties in line with experiments.…”

Section: Discussionmentioning

confidence: 99%

The structural basis for Ras activation of PI3Kα lipid kinase

Zhang

Jang

Nussinov

2019

Phys. Chem. Chem. Phys.

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PI3Ka is a principal Ras effector that phosphorylates PIP 2 to PIP 3 in the PI3K/Akt/mTOR pathway. How Ras activates PI3K has been unclear: is Ras' role confined to PI3K recruitment to the membrane or does Ras activation also involve allostery? Recently, we determined the mechanism of PI3Ka activation at the atomic level. We showed the vital role and significance of conformational change in PI3Ka activation.Here, by a 'best-match for hydrogen-bonding pair' (BMHP) computational protocol and molecular dynamics (MD) simulations, we model the atomic structure of KRas4B in complex with the Ras binding domain (RBD) of PI3Ka, striving to understand the mechanism of PI3Ka activation by Ras. Point mutations T208D, K210E, and K227E disrupt the KRas4B-RBD interface in the models, in line with the experiments. We identify allosteric signaling pathways connecting Ras to RBD in the p110a subunit.However, the observed weak allosteric signals coupled with the detailed mechanism of PI3Ka activation make us conclude that the dominant mechanistic role of Ras is likely to be recruitment and restriction of the PI3Ka population at the membrane. Thus, RTK recruits the PI3Ka to the membrane and activates it by relieving its autoinhibition exerted by the nSH2 domain, leading to exposure of the kinase domain, which permits PIP 2 binding. Ras recruitment can shift the PI3Ka ensemble toward a population where the kinase domain surface and the active site position and orientation favor PIP 2 insertion. This work helps elucidate Ras-mediated PI3K activation and explores the structural basis for Ras-PI3Ka drug discovery.

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Section: Discussionmentioning

confidence: 99%

The structural basis for Ras activation of PI3Kα lipid kinase

Zhang

Jang

Nussinov

2019

Phys. Chem. Chem. Phys.

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“…The power efficiency is a product of the voltage-conversion ratio and the current conversion ratio (− I PV / I LED ). The voltage and current of the LED and each PV cell can be obtained from the detailed balance relations 20 , 21 : and where with a , b = LED, PV, and amb (the ambient), is the photon flux emitted from object a and absorbed by object b , q is the elementary charge, R is the total rate of nonradiative recombination. We use a sign convention such that a positive current flows from the p to the n region internally in each diode.…”

Section: Resultsmentioning

confidence: 99%

High-performance photonic transformers for DC voltage conversion

et al. 2021

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Direct current (DC) converters play an essential role in electronic circuits. Conventional high-efficiency DC voltage converters, especially step-up type, rely on switching operation, where energy is periodically stored within and released from inductors and/or capacitors connected in a variety of circuit topologies. Since these energy storage components, especially inductors, are fundamentally difficult to scale down, miniaturization of switching converters proves challenging. Furthermore, the resulting switching currents produce significant electromagnetic noise. To overcome the limitations of switching converters, photonic transformers, where voltage conversion is achieved through light emission and detection processes, have been demonstrated. However, the demonstrated efficiency is significantly below that of the switching converter. Here we perform a detailed balance analysis and show that with a monolithically integrated design that enables efficient photon transport, the photonic transformer can operate with a near-unity conversion efficiency and high voltage conversion ratio. We validate the theory with a transformer constructed with off-the-shelf discrete components. Our experiment showcases near noiseless operation and a voltage conversion ratio that is significantly higher than obtained in previous photonic transformers. Our findings point to the possibility of a high-performance optical solution to miniaturizing DC power converters and improving the electromagnetic compatibility and quality of electrical power.

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“…The existing method is limited to cyclohexanone and acetone in the presence of 20 mol-% of CuBr to deliver trisubstituted propargylamines in moderate to low yields. [33] As α-amino ester side chains are present in various important drugs and can be used to functionalize peptide chains with a range of different functional groups, [34] several ketimines (i.e., 4k-4o), which were derived from natural α-amino acids such as L-valine methyl ester, L-alanine methyl ester, and L-lysine methyl ester were prepared (see Supporting Information). The reactions of these functionalized ketimines with various alkynes in the presence of 15 mol-% of Zn(OTf) 2 proved feasible and led to diastereomeric mixtures of secondary propargylic amines that have an α-tetrasubstituted carbon center (Scheme 5, products 5ka-5oa, 5ox, 5oh, 5oo).…”

Section: Resultsmentioning

confidence: 99%