Modular bootstrap revisited Collier, Scott; Lin, Ying-Hsuan; Yin, Xi
The journal of high energy physics,
09/2018, Volume:
2018, Issue:
9
Journal Article
Peer reviewed
Open access
A
bstract
We constrain the spectrum of two-dimensional unitary, compact conformal field theories with central charge
c >
1 using modular bootstrap. Upper bounds on the gap in the dimension of primary ...operators of any spin, as well as in the dimension of scalar primaries, are computed numerically as functions of the central charge using semi-definite programming. Our bounds refine those of Hellerman and Friedan-Keller, and are in some cases saturated by known CFTs. In particular, we show that unitary CFTs with
c <
8 must admit relevant deformations, and that a nontrivial bound on the gap of scalar primaries exists for
c <
25. We also study bounds on the dimension gap in the presence of twist gaps, bounds on the degeneracy of operators, and demonstrate how “extremal spectra” which maximize the degeneracy at the gap can be determined numerically.
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•Design of artificial metalloenzymes has achieved significant progress in the last decade.•Artificial metalloenzymes were designed from single to multiple active sites in native or de ...novo proteins.•Artificial metalloenzymes exhibit diverse functions, even beyond those of natural metalloenzymes.•The progress elucidates the structure-function relationship of natural metalloenzymes.•The progress provides clues for design of advanced artificial metalloenzymes with potential applications.
Artificial metalloenzymes combine the advantages of both natural enzymes and chemically synthesized models, which have achieved significant progress in the last decade. This review summarizes the recent achievements in rational design of metalloenzymes from single to multiple active sites in natural or de novo protein scaffolds, with a diverse range of functionalities, even beyond those of natural metalloenzymes. These achievements include construction of mononuclear active site by metal substitution or incorporation, design of homo- or hetero-dinuclear site, introduction of Fe-sulfur or other metal clusters, reconstitution of metallo-porphyrins or other metal complexes, and design of dual or multiple active sites in single, dimeric proteins, de novo proteins, protein-protein interfaces, as well as protein oligomers and polymers. Other new trends in recent designs are also discussed. The progress not only elucidates the structural and functional relationship of natural metalloenzymes, but also provides practical clues for design of advanced artificial metalloenzymes with potential applications.
Cryptococcus neoformans is a ubiquitous environmental fungus that can cause life-threatening meningitis and fungemia, often in the presence of acquired immunodeficiency syndrome (AIDS), liver ...cirrhosis, diabetes mellitus, or other medical conditions. To distinguish risk factors from comorbidities, we performed a hospital-based, density-sampled, matched case-control study.
All new-onset cryptococcal meningitis cases and cryptococcemia cases at a university hospital in Taiwan from 2002-2010 were retrospectively identified from the computerized inpatient registry and were included in this study. Controls were selected from those hospitalized patients not experiencing cryptococcal meningitis or cryptococcemia. Controls and cases were matched by admission date, age, and gender. Conditional logistic regression was used to analyze the risk factors.
A total of 101 patients with cryptococcal meningitis (266 controls) and 47 patients with cryptococcemia (188 controls), of whom 32 patients had both cryptococcal meningitis and cryptococcemia, were included in this study. Multivariate regression analysis showed that AIDS (adjusted odds ratio aOR = 181.4; p < 0.001), decompensated liver cirrhosis (aOR = 8.5; p = 0.008), and cell-mediated immunity (CMI)-suppressive regimens without calcineurin inhibitors (CAs) (aOR = 15.9; p < 0.001) were independent risk factors for cryptococcal meningitis. Moreover, AIDS (aOR = 216.3, p < 0.001), decompensated liver cirrhosis (aOR = 23.8; p < 0.001), CMI-suppressive regimens without CAs (aOR = 7.3; p = 0.034), and autoimmune diseases (aOR = 9.3; p = 0.038) were independent risk factors for developing cryptococcemia. On the other hand, diabetes mellitus and other medical conditions were not found to be risk factors for cryptococcal meningitis or cryptococcemia.
The findings confirm AIDS, decompensated liver cirrhosis, CMI-suppressive regimens without CAs, and autoimmune diseases are risk factors for invasive C. neoformans diseases.
In urban traffic management, the timely detection of road faults plays a crucial role in improving traffic efficiency and safety. However, conventional methods often fail to fully leverage the ...information from road topology and traffic data.
To address this issue, we propose an innovative detection system that combines Artificial Neural Networks (ANNs), specifically Graph Convolutional Networks (GCN), Bidirectional Gated Recurrent Units (BiGRU), and self-attention mechanisms. Our approach begins by representing the road topology as a graph and utilizing GCN to model it. This allows us to learn the relationships between roads and capture their structural dependencies. By doing so, we can effectively incorporate the spatial information provided by the road network. Next, we employ BiGRU to model the historical traffic data, enabling us to capture the temporal dynamics and patterns in the traffic flow. The BiGRU architecture allows for bidirectional processing, which aids in understanding the traffic conditions based on both past and future information. This temporal modeling enhances our system's ability to handle time-varying traffic patterns. To further enhance the feature representations, we leverage self-attention mechanisms. By combining the hidden states of the BiGRU with self-attention, we can assign importance weights to different temporal features, focusing on the most relevant information. This attention mechanism helps to extract salient features from the traffic data. Subsequently, we merge the features learned by GCN from the road topology and BiGRU from the traffic data. This fusion of spatial and temporal information provides a comprehensive representation of the road status.
By employing a Multilayer Perceptron (MLP) as a classifier, we can effectively determine whether a road is experiencing a fault. The MLP model is trained using labeled road fault data through supervised learning, optimizing its performance for fault detection. Experimental evaluations of our system demonstrate excellent performance in road fault detection. Compared to traditional methods, our system achieves more accurate fault detection, thereby improving the efficiency of urban traffic management. This is of significant importance for city administrators, as they can promptly identify road faults and take appropriate measures for repair and traffic diversion.
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•Biodegradation of environmental pollutants has been favored for decades.•Significant progress has been made in the biodegradation of aromatic pollutants by metalloenzymes.•Both ...native and artificial metalloenzymes have been applied for biodegradation.•The progress sheds light on the structure-function relationship of metalloenzymes.•The progress provides clues for applications of metalloenzymes in environmental protection.
Environmental security is closely related to public health. Aromatic pollutants constitute a class of hazardous environmental chemicals, such as halophenols and polycyclic aromatic hydrocarbons. Biodegradation of environmental pollutants has been favored for decades. As reviewed herein, significant progress has been made in biodegradation of aromatic pollutants by native metalloenzymes, including heme enzymes (peroxidases and cytochrome P450s), non-heme iron-containing enzymes (Rieske dioxygenases), and copper-containing enzymes (catechol oxidase, tyrosinase, and laccase), and artificial metalloenzymes, including engineered myoglobins, designed manganese peroxidase and de novo designed metalloenzymes, such as those in helical bundles and peptide assemblies, as well as synthetic structural and functional models of natural enzymes. These advances shed light on the structure–function relationship of metalloenzymes, providing clues for potential applications in environmental protection. Future directions for making full use of native and artificial metalloenzymes in environmental science are also prospected.
In this work, several commonly used conductive substrates as electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline conditions were studied, ...including nickel foam (Ni foam), copper foam (Cu foam), nickel mesh (Ni mesh) and stainless steel mesh (SS mesh). Ni foam and SS mesh are demonstrated as high-performance and stable electrocatalysts for HER and OER, respectively. For HER, Ni foam exhibited an overpotential of 0.217 V at a current density of 10 mA cm
−2
with a Tafel slope of 130 mV dec
−1
, which were larger than that of the commercial Pt/C catalyst, but smaller than that of the other conductive substrates. Meanwhile, the SS mesh showed the best electrocatalytic performance for OER with an overpotential of 0.277 V at a current density of 10 mA cm
−2
and a Tafel slope of 51 mV dec
−1
. Its electrocatalytic performance not only exceeded those of the other conductive substrates but also the commercial RuO
2
catalyst. Moreover, both Ni foam and SS mesh exhibited high stability during HER and OER, respectively. Furthermore, in the two-electrode system with Ni foam used as the cathode and SS mesh used as the anode, they enable a current density of 10 mA cm
−2
at a small cell voltage of 1.74 V. This value is comparable to or exceeding the values of previously reported electrocatalysts for overall water splitting. In addition, NiO on the surface of Ni foam may be the real active species for HER, NiO and FeO
x
on the surface of SS mesh may be the active species for OER. The abundant and commercial availability, long-term stability and low-cost property of nickel foam and stainless steel mesh enable their large-scale practical application in water splitting.
Efficient electrocatalytic overall water splitting is achieved with commercially-available and low-cost nickel foam and stainless steel mesh as cathode and anode electrodes.
The novel coronavirus disease 2019 (COVID-19) infection has rapidly grown worldwide,
and many governments have implemented policies to control the infection rate. For example, school suspension, ...self-quarantine, requirement of citizens to stay at home,
travel and border controls, and discouragement of outdoor activities
have been used. Although these actions emphasizing the importance of "spatial distancing" are based on the perspective of public health, they may result in health problems other than COVID-19 infection, such as psychological distress and fear.
Therefore, the present authors examined the potential predictors for psychological distress among schoolchildren during COVID-19 school suspension.
This paper investigated how second- and third-trimester gestational weight gain relates to perinatal outcomes among normal weight women with twin pregnancies in Fujian, China.
A retrospective study ...examining the medical records of 931 normal weight twin-pregnant women was conducted in Fujian Maternity and Child Health Hospital from 2014 to 2018.The 2
and 3
trimester weekly weight gain rates were calculated, and women were categorized as gaining below, within, or above the 2009 Institute of Medicine (IOM) recommended rates. The association between the trimester-specific weight gain rate and perinatal outcome was determined by traditional regression analysis among groups.
A total of 25.9%, 19.8% and 54.3% of women had rates of weight gain across the 2
and 3
trimesters less than, greater than or within the recommended rates respectively. Multivariate logistic regression analysis showed that weight gain greater than the recommended rate in the 2
trimester was associated with a decreased risk of preeclampsia (aOR:0.489,95%CI:0.289 ~ 0.974). Weight gain less than the recommended rate of weight gain in the 3
trimester was associated with increased risks of premature delivery(aOR:2.079, 95%CI:1.467 ~ 2.968), gestational diabetes mellitus (aOR: 2.048, 95%CI:1.411 ~ 2.971), intrahepatic cholestasis syndrome (aOR:3.015,95%CI: 1.058 ~ 8.587), pre-labour rupture of membrane (aOR: 1.708,95%CI: 1.169 ~ 2.493), average twin birth weight < 2500 g(aOR:1.532,95%CI: 1.125 ~ 2.084) and neonatal respiratory distress syndrome (aOR:4.934,95%CI:1.626 ~ 15.083) and was associated with decreased risks of caesarean section (aOR:0.589,95%CI:0.386 ~ 0.898) and preeclampsia (aOR:0.471, 95%CI:0.274 ~ 0.808). In addition, weight gain greater than the recommended rate of weight gain in the 3
trimester was associated with increased risks of premature delivery (aOR:1.589,95%CI:1.428 ~ 2.951) and gestational hypertension (aOR:2.137,95% CI:1.034 ~ 4.415) as well as preeclampsia (aOR:2.246, 95%CI:1.462 ~ 3.452). The stratified analysis of weight gain in the 3
trimester showed that there was no significant difference in the incidence of adverse pregnancy outcomes compared to the 2
trimester weight gain groups.
While this study showed that a gestational weight gain rate above or below the recommendation in the 3
trimester was associated with some adverse maternal and neonatal outcomes, further prospective and multicentre studies are required to explore alternate ranges of gestational weight gain rates in twin pregnancies.
The sudden outbreak of 2019 novel coronavirus (2019-nCoV, later named SARS-CoV-2) in Wuhan, China, which rapidly grew into a global pandemic, marked the third introduction of a virulent coronavirus ...into the human society, affecting not only the healthcare system, but also the global economy. Although our understanding of coronaviruses has undergone a huge leap after two precedents, the effective approaches to treatment and epidemiological control are still lacking. In this article, we present a succinct overview of the epidemiology, clinical features, and molecular characteristics of SARS-CoV-2. We summarize the current epidemiological and clinical data from the initial Wuhan studies, and emphasize several features of SARS-CoV-2, which differentiate it from SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), such as high variability of disease presentation. We systematize the current clinical trials that have been rapidly initiated after the outbreak of COVID-19 pandemic. Whereas the trials on SARS-CoV-2 genome-based specific vaccines and therapeutic antibodies are currently being tested, this solution is more long-term, as they require thorough testing of their safety. On the other hand, the repurposing of the existing therapeutic agents previously designed for other virus infections and pathologies happens to be the only practical approach as a rapid response measure to the emergent pandemic, as most of these agents have already been tested for their safety. These agents can be divided into two broad categories, those that can directly target the virus replication cycle, and those based on immunotherapy approaches either aimed to boost innate antiviral immune responses or alleviate damage induced by dysregulated inflammatory responses. The initial clinical studies revealed the promising therapeutic potential of several of such drugs, including
, a broad-spectrum antiviral drug that interferes with the viral replication, and
, the repurposed antimalarial drug that interferes with the virus endosomal entry pathway. We speculate that the current pandemic emergency will be a trigger for more systematic drug repurposing design approaches based on big data analysis.
Heme proteins are crucial for biological systems by performing diverse functions. Nature has evolved diverse approaches to fine-tune the structure and function of heme proteins, of which ...post-translational modification (PTM) is a primary method. As reviewed herein, a multitude of PTMs have been discovered for heme proteins in the last several decades, including heme-protein cross-links with heme side chains (Cys-heme, Tyr-heme and Asp/Glu-heme, etc) or porphyrin ring (Lys-heme and Tyr-heme, etc), heme modifications (sulfheme and nitriheme, etc), amino acids cross-links between two or among multiple residues (Cys-Cys, Tyr-His, Tyr-Cys, Met-Tyr-Trp, etc), and amino acids modifications by oxidation, nitration, phosphorylation and glycation, etc. With the development of research methods and advances in research techniques, deep insights have been obtained for the formation mechanisms of PTMs, as well as their effects on the structure and function of heme proteins. Moreover, some positive PTMs have been successfully applied to create artificial heme proteins with advanced functions, whereas some negative PTMs have been regulated by rational design of inhibitors. The tremendous progress, together with those ongoing, will make it possible to rationally control the diverse PTMs of heme proteins, especially those associated with human diseases, toward our desired goals for a better life.
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•A multitude of post-translational modifications (PTMs) have been discovered for heme proteins.•Deep insights have been obtained for PTMs and their structural and functional consequences.•Positive PTMs have been applied to create functional artificial heme proteins.•Negative PTMs have been regulated by rational design of inhibitors.•It is possible to control the diverse PTMs of heme proteins toward our desired goals.
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