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1. Seasonal decrease in thermogenesis and increase in vasoconstriction explain seasonal response to N 6 ‐cyclohexyladenosine‐induced hibernation in the Arctic ground squirrel ( Urocitellus parryii )

   https://doi.org/10.1111/jnc.14814  

   Frare, Carla ; Jenkins, Mackenzie E. ; McClure, Kelsey M. ; Drew, Kelly L. ( August 2019 , Journal of Neurochemistry)

   Hibernation is a seasonal phenomenon characterized by a drop in metabolic rate and body temperature. Adenosine A₁receptor agonists promote hibernation in different mammalian species, and the understanding of the mechanism inducing hibernation will inform clinical strategies to manipulate metabolic demand that are fundamental to conditions such as obesity, metabolic syndrome, and therapeutic hypothermia. Adenosine A₁receptor agonist‐induced hibernation in Arctic ground squirrels is regulated by an endogenous circannual (seasonal) rhythm. This study aims to identify the neuronal mechanism underlying the seasonal difference in response to the adenosine A₁receptor agonist. Arctic ground squirrels were implanted with body temperature transmitters and housed at constant ambient temperature (2°C) and light cycle (4L:20D). We administered CHA (N⁶‐cyclohexyladenosine), an adenosine A₁receptor agonist in euthermic‐summer phenotype and euthermic‐winter phenotype and used cFos and phenotypic immunoreactivity to identify cell groups affected by season and treatment. We observed lower core and subcutaneous temperature in winter animals and CHA produced a hibernation‐like response in winter, but not in summer. cFos‐ir was greater in the median preoptic nucleus and the raphe pallidus in summer after CHA. CHA administration also resulted in enhanced cFos‐ir in the nucleus tractus solitarius and decreased cFos‐ir in the tuberomammillary nucleus in both seasons. In winter, cFos‐ir was greater in the supraoptic nucleus and lower in the raphe pallidus than in summer. The seasonal decrease in the thermogenic response to CHA and the seasonal increase in vasoconstriction, assessed by subcutaneous temperature, reflect the endogenous seasonal modulation of the thermoregulatory systems necessary for CHA‐induced hibernation.

   Cover Image for this issue: doi:10.1111/jnc.14528.

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2. Bubble Column Enables Higher Reaction Rate for Deracemization of ( R,S )‐1‐Phenylethanol with Coupled Alcohol Dehydrogenase/NADH Oxidase System

   https://doi.org/10.1002/adsc.201900213  

   Dias Gomes, Mafalda ; Bommarius, Bettina R. ; Anderson, Shelby R. ; Feske, Brent D. ; Woodley, John M. ; Bommarius, Andreas S. ( April 2019 , Advanced Synthesis & Catalysis)

   One of the major drawbacks for many biocatalysts is their poor stability under industrial process conditions. A particularly interesting example is the supply of oxygen to biooxidation reactions, catalyzed by oxidases, oxygenases or alcohol dehydrogenases coupled with NAD(P)H (reduced nicotinamide adenine dinucleotide phosphate) oxidases, which all require the continuous supply of molecular oxygen as an oxidant or electron acceptor. Commonly, oxygen is supplied to the bioreactor by air sparging. To ensure sufficient oxygen transfer from the gas to the liquid phase, stirring is essential to disperse the gas bubbles and create high gas‐liquid interfacial area. Studies indicate that the presence of gas‐liquid interface induces enzyme deactivation by protein unfolding which then readily aggregates and can subsequently precipitate. This contribution has examined the effects of stirring and the presence of gas‐liquid interface on the kinetic stability of water‐forming NAD(P)H oxidase (NOX) (EC1.6.3.2).

   These effects were studied separately and a bubble column apparatus was successfully employed to investigate the influence of gas‐liquid interfaces on enzyme stability. Results showed that NOX deactivation increases in proportion to the gas‐liquid interfacial area. While air enhances the rate of stability loss compared to nitrogen, stirring causes faster loss of activity in comparison to a bubble column. Finally, deracemization of 1‐phenylethanol, using a coupled alcohol dehydrogenase /NADH oxidase system (ADH/NOX), proceeded with a higher rate in the bubble column than in quiescent or in a stirred solution, although, inactivation was also accelerated in the bubble column over a quiescent solution.

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3. Data‐driven battery degradation prediction: Forecasting voltage‐capacity curves using one‐cycle data

   https://doi.org/10.1002/eom2.12213  

   Tian, Jinpeng ; Xiong, Rui ; Shen, Weixiang ; Lu, Jiahuan ( April 2022 , EcoMat)

   With the wide deployment of rechargeable batteries, battery degradation prediction has emerged as a challenging issue. However, battery life defined by capacity loss provides limited information regarding battery degradation. In this article, we explore the prediction of voltage‐capacity curves over battery lifetime based on a sequence to sequence (seq2seq) model. We demonstrate that the data of one present voltage‐capacity curve can be used as the input of the seq2seq model to accurately predict the voltage‐capacity curves at 100, 200, and 300 cycles ahead. This offers an opportunity to update battery management strategies in response to the predicted consequences. Besides, the model avoids feature engineering and is flexible to incorporate different numbers of input and output cycles. Therefore, it can be easily transplanted to other battery systems or electrochemical components. Furthermore, the model features data generation, that is, we can use the data of only one cycle to generate a large spectrum of aging data at the future cycles for developing other battery diagnosis or prognosis methods. In this way, the time and energy consuming battery degradation tests can be sharply reduced.image

    

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4. Effect of Additives in the Hydroamination/Cyclization of Aminoalkenes Catalyzed by a Binaphtholate Yttrium Catalyst

   https://doi.org/10.1002/adsc.202201344  

   Nawara‐Hultzsch, Agnieszka J. ; Goswami, Anandarup ; Hultzsch, Kai C. ( February 2023 , Advanced Synthesis & Catalysis)

   A series of various solvents and additives were tested in enantioselective hydroamination/cyclization reactions of aminoalkenes catalyzed by a binaphtholate yttrium catalyst. The functional group tolerance of the catalyst and the influence on the reaction rate and enantioselectivity was studied. Some weakly coordinating polar solvents, such as Et₂O, MTBE, and chlorobenzene led to slightly increased reaction rates compared to the less polar solvent benzene, presumably due to a better stabilization of the polar transition state. Stronger binding solvents and additives, such as THF, DMAP, pyrrolidine,n‐propylamine, and 1‐phenylethylamine, decrease the reaction rate and diminish the enantioselectivity of the hydroamination product. Some additives, such as THF, Et₂O, MTBE, chloro‐ and bromobenzene, as well as (+)‐sparteine resulted in slightly higher enantioselectivities in the cyclization of the model substrateC‐(1‐allylcyclohexyl)methylamine, although this observation was not generally true for other aminoalkene substrates. The reaction rates and enantioselectivities were depressed in the presence of (−)‐sparteine using the (R)‐binaphtholate‐ligated catalyst. In case ofC‐(1‐allylcyclohexyl)methylamine, the enantioselectivity was switched from 76% ee favoring the (S)‐enantiomer of the hydroamination product when using (+)‐sparteine to 22% ee in favor of the (R)‐enantiomer when (−)‐sparteine was used. The rates of cyclization of aminoalkenes and the resulting enantioselectivities significantly depend on substrate concentration with the highest rate (13.6 h⁻¹) and enantioselectivity (68% ee) observed in dilute conditions (0.05 M) compared to a concentrated solution (0.5 M, 5.0 h⁻¹, 35% ee) for 2,2‐dimethylpent‐4‐enylamine. These observations indicate that the reaction mechanism is shifted in favor of a slower, less enantioselective catalytic cycle involving a higher coordinate species when higher substrate concentrations or stronger binding additives are present.

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5. Localization lifetime of a many‐body system with periodic constructed disorder

   https://doi.org/10.1002/andp.201600366  

   Schecter, Michael ; Shapiro, Michael ; Dykman, Mark I. ( March 2017 , Annalen der Physik)

   We show that, in a many‐body system, all particles can be strongly confined to the initially occupied sites for a time that scales as a high power of the ratio of the bandwidth of site energies to the hopping amplitude. Such time‐domain formulation is complementary to the formulation of the many‐body localization of all stationary states with a large localization length. The long localization lifetime is achieved by constructing a periodic sequence of site energies with a large period in a one‐dimensional chain. The scaling of the localization lifetime is independent of the number of particles for a broad range of the coupling strength. The analytical results are confirmed by numerical calculations.image

    

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