Enzymes are the most proficient catalysts, offering much more competitive processes compared to chemical catalysts. The number of industrial applications for enzymes has exploded in recent years, ...mainly owing to advances in protein engineering technology and environmental and economic necessities. Herein, we review recent progress in enzyme biocatalysis, and discuss the trends and strategies that are leading to broader industrial enzyme applications. The challenges and opportunities in developing biocatalytic processes are also discussed.
This paper focusses on hot underground tunnels and studies the effect of ground source heat pump (GSHP) intermittent operation and changing tunnel air temperature profile on energy tunnel thermal ...efficiency. The effects of heat pump operation on the tunnel surrounding soil and the soil recovery rate when the heat pump is not in operation were also studied. A 3D numerical model was developed to simulate the transient heat transfer intermittent operation of an energy tunnel. The intermittent operation was reproduced by controlling the convective heat flux at the boundary between the absorber pipe and the tunnel lining. Variation in the tunnel air temperature was defined in the model as a periodic sink amplitude. Results show that in energy tunnels, strategic intermittent operation increases thermal efficiency and allows the surrounding soil to thermally recover and prevent any adverse effect on the system. A high daily intermittent operation ratio increases the average thermal output but might lead to higher operating costs. Therefore for a given site, it is important to determine the optimum intermittent ratio. The paper also shows how the variation in tunnel air temperature affects the thermal performance of the energy tunnel. The importance of including this variation (rather than assuming a constant average value) when estimating the geothermal potential of underground tunnels was also highlighted. Insights are also provided on the soil temperature recovery rates after prolonged operation. These would serve as a basis for working out a seasonal intermittent operation strategy to optimise the use of ground source heat pumps in underground tunnels.
•An improved finite element model to simulate heat transfer in energy tunnels.•Effect of intermittent operations on thermal efficiency of energy tunnels.•Influence of seasonal variations in air temperature on thermal performance.•Intermittent operation minimises thermal disturbance on the surrounding soil.•Different operation scenarios serve as a basis for optimum operation.
We explored the associations of actigraphy-derived rest-activity patterns and circadian phase parameters with clinical symptoms and level 1 polysomnography (PSG) results in patients with chronic ...insomnia to evaluate the clinical implications of actigraphy-derived parameters for PSG interpretation. Seventy-five participants underwent actigraphy assessments and level 1 PSG. Exploratory correlation analyses between parameters derived from actigraphy, PSG, and clinical assessments were performed. First, participants were classified into two groups based on rest-activity pattern variables; group differences were investigated following covariate adjustment. Participants with poorer rest-activity patterns on actigraphy (low inter-day stability and high intra-daily variability) exhibited higher insomnia severity index scores than participants with better rest-activity patterns. No between-group differences in PSG parameters were observed. Second, participants were classified into two groups based on circadian phase variables. Late-phase participants (least active 5-h and most active 10-h onset times) exhibited higher insomnia severity scores, longer sleep and rapid eye movement latency, and lower apnea-hypopnea index than early-phase participants. These associations remained significant even after adjusting for potential covariates. Some actigraphy-derived rest-activity patterns and circadian phase parameters were significantly associated with clinical symptoms and PSG results, suggesting their possible adjunctive role in deriving plans for PSG lights-off time and assessing the possible insomnia pathophysiology.
The advent of farming around 12 millennia ago was a cultural as well as technological revolution, requiring a new system of property rights. Among mobile hunter–gatherers during the late Pleistocene, ...food was almost certainly widely shared as it was acquired. If a harvested crop or the meat of a domesticated animal were to have been distributed to other group members, a late Pleistocene would-be farmer would have had little incentive to engage in the required investments in clearing, cultivation, animal tending, and storage. However, the new property rights that farming required—secure individual claims to the products of one’s labor—were infeasible because most of the mobile and dispersed resources of a forager economy could not cost-effectively be delimited and defended. The resulting chicken-and-egg puzzle might be resolved if farming had been much more productive than foraging, but initially it was not. Our model and simulations explain how, despite being an unlikely event, farming and a new system of farming-friendly property rights nonetheless jointly emerged when they did. This Holocene revolution was not sparked by a superior technology. It occurred because possession of the wealth of farmers—crops, dwellings, and animals—could be unambiguously demarcated and defended. This facilitated the spread of new property rights that were advantageous to the groups adopting them. Our results thus challenge unicausal models of historical dynamics driven by advances in technology, population pressure, or other exogenous changes. Our approach may be applied to other technological and institutional revolutions such as the 18th- and 19th-century industrial revolution and the information revolution today.
The diagnosis of severe acute respiratory syndrome 2 (SARS-CoV-2) infection by quantitative PCR with reverse transcription (RT-qPCR) typically involves bulky instrumentation in centralized ...laboratories and an assay time of 1-2 h. Here, we show that SARS-CoV-2 RNA can be detected in 17 min via a portable device integrating reverse transcription, fast thermocycling (via plasmonic heating through magneto-plasmonic nanoparticles) and in situ fluorescence detection following magnetic clearance of the nanoparticles. The device correctly classified all nasopharyngeal, oropharyngeal and sputum samples from 75 patients with COVID-19 and 75 healthy controls, with good concordance in fluorescence intensity with standard RT-qPCR (Pearson coefficients > 0.7 for the N1, N2 and RPP30 genes). Fast, portable and automated nucleic acid detection should facilitate testing at the point of care.
Coevolution of Parochial Altruism and War Choi, Jung-Kyoo; Bowles, Samuel
Science (American Association for the Advancement of Science),
10/2007, Volume:
318, Issue:
5850
Journal Article
Peer reviewed
Altruism--benefiting fellow group members at a cost to oneself--and parochialism--hostility toward individuals not of one's own ethnic, racial, or other group--are common human behaviors. The ...intersection of the two--which we term "parochial altruism"--is puzzling from an evolutionary perspective because altruistic or parochial behavior reduces one's payoffs by comparison to what one would gain by eschewing these behaviors. But parochial altruism could have evolved if parochialism promoted intergroup hostilities and the combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic analysis and agent-based simulations show that under conditions likely to have been experienced by late Pleistocene and early Holocene humans, neither parochialism nor altruism would have been viable singly, but by promoting group conflict, they could have evolved jointly.
Endometriosis is a disease characterized by implants of endometrial tissue outside the uterine cavity and is strongly associated with infertility. Focal adhesion of endometrial tissue to the ...peritoneum is an indication of incipient endometriosis. In this study, we examined the effect of various cytokines that are known to be involved in the pathology of endometriosis on endometrial cell adhesion. Among the investigated cytokines, transforming growth factor-β1 (TGF-β1) increased adhesion of endometrial cells to the mesothelium through induction of α2-6 sialylation. The expression levels of β-galactoside α2-6 sialyltransferase (ST6Gal) 1 and ST6Gal2 were increased through activation of TGF-βRI/SMAD2/3 signaling in endometrial cells. In addition, we discovered that terminal sialic acid glycan epitopes of endometrial cells engage with sialic acid-binding immunoglobulin-like lectin-9 expressed on mesothelial cell surfaces. Interestingly, in an in vivo mouse endometriosis model, inhibition of endogenous sialic acid binding by a NeuAcα2-6Galβ1-4GlcNAc injection diminished TGF-β1-induced formation of endometriosis lesions. Based on these results, we suggest that increased sialylation of endometrial cells by TGF-β1 promotes the attachment of endometrium to the peritoneum, encouraging endometriosis outbreaks.
Abstract
Atomic-resolution Cs-corrected scanning transmission electron microscopy revealed local shifting of two oxygen positions (O
I
and O
II
) within the unit cells of a ferroelectric (Hf
0.5
Zr
...0.5
)O
2
thin film. A reversible transition between the polar
Pbc
2
1
and antipolar
Pbca
phases, where the crystal structures of the 180° domain wall of the
Pbc
2
1
phase and the unit cell structure of the
Pbca
phase were identical, was induced by applying appropriate cycling voltages. The critical field strength that determined whether the film would be woken up or fatigued was ~0.8 MV/cm, above or below which wake-up or fatigue was observed, respectively. Repeated cycling with sufficiently high voltages led to development of the interfacial nonpolar
P
4
2
/
nmc
phase, which induced fatigue through the depolarizing field effect. The fatigued film could be rejuvenated by applying a slightly higher voltage, indicating that these transitions were reversible. These mechanisms are radically different from those of conventional ferroelectrics.
To replace precious platinum (Pt)‐based electrocatalysts for cathodic oxygen reduction reaction (ORR), edge‐selectively sulfurized graphene nanoplatelets (SGnP) are synthesized as efficient ...metal‐free electrocatalysts simply by ball‐milling pristine graphite in the presence of sulfur (S8). The resultant SGnPs exhibit remarkable electrocatalytic activity toward ORR with better tolerance to methanol crossover/CO poisoning effects and longer‐term stability than those of pristine graphite and commercial Pt/C electrocatalysts. Edge‐Selectively Sulfurized Graphene Nanoplatelets as Efficient Metal‐Free Electrocatalysts for Oxygen Reduction Reaction: The Electron Spin Effect
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