38 research outputs found
Complete One-Loop Matching for a Singlet Scalar in the Standard Model EFT
We present the results of the first complete one-loop matching calculation
between the real singlet scalar extension of the Standard Model and the
Standard Model effective field theory (SMEFT) at dimension six. Beyond their
immediate relevance to the precision calculation of observables in singlet
extensions of the Standard Model, our results illustrate a variety of general
features of one-loop matching. We explore the interplay between
non-supersymmetric non-renormalization theorems, the logarithmic dependence of
Wilson coefficients, and the relevance of mixed diagrams in theories with large
scale separation. In addition, we highlight some of the subtleties involved in
computing observables at next-to-leading order in SMEFT by mapping our results
to the parameter at one loop.Comment: 21 page
Selective formation of biphasic thin films of metalāorganic frameworks by potential-controlled cathodic electrodeposition
Cathodic electrodeposition lends itself to the formation of biphasic metalāorganic framework thin films at room temperature from single deposition baths using potential bias as the main user input. Depending on the applied potential, we selectively deposit two different phases as either bulk mixtures or bilayer films.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0006937)3M CompanyMISTI (Hayashi Seed Fund)National Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374
Loops and trees in generic EFTs
We consider aspects of tree and one-loop behavior in a generic 4d EFT of
massless scalars, fermions, and vectors, with a particular eye to the
high-energy limit of the Standard Model EFT at operator dimensions 6 and 8.
First, we classify the possible Lorentz structures of operators and the subset
of these that can arise at tree-level in a weakly coupled UV completion,
extending the tree/loop classification through dimension 8 using functional
methods. Second, we investigate how operators contribute to tree and one-loop
helicity amplitudes, exploring the impact of non-renormalization theorems
through dimension 8. We further observe that many dimension 6 contributions to
helicity amplitudes, including rational parts, vanish exactly at one-loop
level. This suggests the impact of helicity selection rules extends beyond one
loop in non-supersymmetric EFTs.Comment: 29+1 pages, 5 figures, 6 table
A Zinc Finger Motif in the P1 N Terminus, Highly Conserved in a Subset of Potyviruses, Is Associated with the Host Range and Fitness of Telosma Mosaic Virus
P1 is the first protein translated from the genomes of most viruses in the family Potyviridae, and it contains a C-terminal serine-protease domain that cis-cleaves the junction between P1 and HCPro in most cases. Intriguingly, P1 is the most divergent among all mature viral factors, and its roles during viral infection are still far from understood. In this study, we found that telosma mosaic virus (TelMV, genus Potyvirus) in passion fruit, unlike TelMV isolates present in other hosts, has two stretches at the P1 N terminus, named N1 and N2, with N1 harboring a Zn finger motif. Further analysis revealed that at least 14 different potyviruses, mostly belonging to the bean common mosaic virus subgroup, encode a domain equivalent to N1. Using the newly developed TelMV infectious cDNA clones from passion fruit, we demonstrated that N1, but not N2, is crucial for viral infection in both Nicotiana benthamiana and passion fruit. The regulatory effects of N1 domain on P1 cis cleavage, as well as the accumulation and RNA silencing suppression (RSS) activity of its cognate HCPro, were comprehensively investigated. We found that N1 deletion decreases HCPro abundance at the posttranslational level, likely by impairing P1 cis cleavage, thus reducing HCPro-mediated RSS activity. Remarkably, disruption of the Zn finger motif in N1 did not impair P1 cis cleavage and HCPro accumulation but severely debilitated TelMV fitness. Therefore, our results suggest that the Zn finger motif in P1s plays a critical role in viral infection that is independent of P1 protease activity and self-release, as well as HCPro accumulation and silencing suppression.This work is supported by grants from the Hainan Provincial National Science Foundation (grant nos. 2019RC010 and 322CXTD505), Sanya Yazhou Bay Sci-Tech City (SYND-2022-32 and SYND-2022-02), the National Natural Science Foundation of China (32060603), and the Central Public Interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (19CXTD-33). We thank Fangfang Li (Chinese Academy of Agricultural Sciences) for providing pCHF3-35S-GFP and P19-expressing plasmidPeer reviewe
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DNA methylation-based biological age, genome-wide average DNA methylation, and conventional breast cancer risk factors.
DNA methylation-based biological age (DNAm age), as well as genome-wide average DNA methylation, have been reported to predict breast cancer risk. We aimed to investigate the associations between these DNA methylation-based risk factors and 18 conventional breast cancer risk factors for disease-free women. A sample of 479 individuals from the Australian Mammographic Density Twins and Sisters was used for discovery, a sample of 3354 individuals from the Melbourne Collaborative Cohort Study was used for replication, and meta-analyses pooling results from the two studies were conducted. DNAm age based on three epigenetic clocks (Hannum, Horvath and Levine) and genome-wide average DNA methylation were calculated using the HumanMethylation 450āK BeadChip assay data. The DNAm age measures were positively associated with body mass index (BMI), smoking, alcohol drinking and age at menarche (all nominal Pā<ā0.05). Genome-wide average DNA methylation was negatively associated with smoking and number of live births, and positively associated with age at first live birth (all nominal Pā<ā0.05). The association of DNAm age with BMI was also evident in within-twin-pair analyses that control for familial factors. This study suggests that some lifestyle and hormonal risk factors are associated with these DNA methylation-based breast cancer risk factors, and the observed associations are unlikely to be due to familial confounding but are likely causal. DNA methylation-based risk factors could interplay with conventional risk factors in modifying breast cancer risk
Solenoid-free current drive via ECRH in EXL-50 spherical torus plasmas
As a new spherical tokamak (ST) designed to simplify engineering requirements
of a possible future fusion power source, the EXL-50 experiment features a low
aspect ratio (A) vacuum vessel (VV), encircling a central post assembly
containing the toroidal field coil conductors without a central solenoid.
Multiple electron cyclotron resonance heating (ECRH) resonances are located
within the VV to improve current drive effectiveness. Copious energetic
electrons are produced and measured with hard X-ray detectors, carry the bulk
of the plasma current ranging from 50kA to 150kA, which is maintained for more
than 1s duration. It is observed that over one Ampere current can be maintained
per Watt of ECRH power issued from the 28-GHz gyrotrons. The plasma current
reaches Ip>80kA for high density (>5e18me-2) discharge with 150kW ECHR heating.
An analysis was carried out combining reconstructed multi-fluid equilibrium,
guiding-center orbits of energetic electrons, and resonant heating mechanisms.
It is verified that in EXL-50 a broadly distributed current of energetic
electrons creates smaller closed magnetic-flux surfaces of low aspect ratio
that in turn confine the thermal plasma electrons and ions and participate in
maintaining the equilibrium force-balance
Reductive electrosynthesis of crystalline metal-organic frameworks
Electroreduction of oxoanions affords hydroxide equivalents that induce selective deposition of crystalline metalāorganic frameworks (MOFs) on conductive surfaces. The method is illustrated by cathodic electrodeposition of Zn[subscript 4]O(BDC)[subscript 3] (MOF-5; BDC = 1,4-benzenedicarboxylate), which is deposited at room temperature in only 15 min under cathodic potential. Although many crystalline phases are known in the Zn[superscript 2+]/BDCsuperscript 2ā] system, MOF-5 is the only observed crystalline MOF phase under these conditions. This fast and mild method of synthesizing MOFs is amenable to direct surface functionalization and could impact applications requiring conformal coatings of microporous MOFs, such as gas separation membranes and electrochemical sensors.Massachusetts Institute of Technology. Energy Initiative (Seed Fund Program)National Science Foundation (U.S.) (Grant CHE-9808061)National Science Foundation (U.S.) (Grant DBI-9729592)National Science Foundation (U.S.) (Grant DMR- 0819762
Cathodic electrodeposition of metal-organic frameworks
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 2015.Cataloged from PDF version of thesis. Vita.Includes bibliographical references.Metal-organic frameworks (MOFs) represent a class of functional coordination polymers with long-range order, great synthetic flexibility, and exceptionally high internal surface area. Although they have been proposed for a myriad of potential applications, many of these require that MOFs be processed as thin films or other nanostructures to reach peak performance. Thus, a general and facile fabrication process is still much desired. In this thesis, I describe cathodic electrodeposition as an alternative approach to MOF crystallization, which is traditionally achieved solvothermally via ligand deprotonation through in-situ formation of base (often by amine release from the decomposition of an amide solvent). In cathodic electrodeposition, electrochemical reduction of probase molecules produces base equivalents to initiate the metal-ligand bond formation and subsequently the self-assembly process. There are three major advantages to this process in the context of producing MOF films: 1) the formation of base can be controlled more precisely, 2) the acid-base reaction is spatially confined close to the electrode surface, and 3) electrodeposition is, by definition, conformal, and therefore lends itself to electrodes of any geometry, as will be shown in Appendix I. Using cathodic electrodeposition, several Zn-BDC (BDC: 1,4-benzenedicarboxylate) MOFs could be formed as polycrystalline coatings on electrodes. In particular, a microporous composite of ZnāO(BDC)ā i.e. MOF-5, and Zn metal could be synthesized at room temperature in less than 15 minutes. This work is described in Chapter 2. By modulating the pH at the electrode surface in the presence of an appropriate probase, biphasic or bilayer structures of different polymorphs could also be accessed with a simple change in the applied potential, thereby providing a facile means of making composite films described in Chapter 4. Lastly, systematic studies of the effects of various variables on the electrodeposition process brought unique mechanistic insights to the early stages of MOF crystallization, as described in Chapter 3. Chapters 1 and 5 provide a context for this research within the larger area of MOF film formation, and a preliminary account on the possible sources of the [mu]ā-OĀ²- atom in the iconic MOF-5 structure, respectively.by Minyuan Miller Li.Ph. D
Pt Electrodes Enable the Formation of Ī¼[subscript 4]-O Centers in MOF-5 from Multiple Oxygen Sources
The Ī¼[subscript 4]-O[superscript 2]ā ions in the Zn[subscript 4]O(O[subscript 2]Cā)[subscript 6] secondary building units of Zn[subscript 4]O(1,4-benzenedicarboxylate)[subscript 3] (MOF-5) electrodeposited under cathodic bias can be sourced from nitrate, water, and molecular oxygen when using platinum gauze as working electrodes. The use of Zn(ClO[subscript 4])[subscript 2]Ā·6H[subscript 2]O, anhydrous Zn(NO[subscript 3])[subscript 2], or anhydrous Zn(CF[subscript 3]SO[subscript 3])[subscript 2] as Zn2[superscript +] sources under rigorous control of other sources of oxygen, including water and O[subscript 2], confirm that the source of the Ī¼4-O2ā ions can be promiscuous. Although this finding reveals a relatively complicated manifold of electrochemical processes responsible for the crystallization of MOF-5 under cathodic bias, it further highlights the importance of hydroxide intermediates in the formation of the Zn[subscript 4]O(O[subscript 2]CāR) secondary building units in this iconic material and is illustrative of the complicated crystallization mechanisms of metalāorganic frameworks in general. Keywords: crystals; electrochemistry; electrodeposition; mechanism of reactions; metalāorganic frameworksUnited States. Department of Energy. Office of Basic Energy Sciences (Award DE-SC0006937)National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 122374)3M CompanyAlfred P. Sloan FoundationResearch Corporation for Science Advancemen
Pt Electrodes Enable the Formation of Ī¼<sub>4</sub>āO Centers in MOFā5 from Multiple Oxygen Sources
The
Ī¼<sub>4</sub>-O<sup>2ā</sup> ions in the Zn<sub>4</sub>OĀ(O<sub>2</sub>Cā)<sub>6</sub> secondary building units of
Zn<sub>4</sub>OĀ(1,4-benzenedicarboxylate)<sub>3</sub> (MOF-5) electrodeposited
under cathodic bias can be sourced from nitrate, water, and molecular
oxygen when using platinum gauze as working electrodes. The use of
ZnĀ(ClO<sub>4</sub>)<sub>2</sub>Ā·6H<sub>2</sub>O, anhydrous ZnĀ(NO<sub>3</sub>)<sub>2</sub>, or anhydrous ZnĀ(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub> as Zn<sup>2+</sup> sources under rigorous control of
other sources of oxygen, including water and O<sub>2</sub>, confirm
that the source of the Ī¼<sub>4</sub>-O<sup>2ā</sup> ions
can be promiscuous. Although this finding reveals a relatively complicated
manifold of electrochemical processes responsible for the crystallization
of MOF-5 under cathodic bias, it further highlights the importance
of hydroxide intermediates in the formation of the Zn<sub>4</sub>OĀ(O<sub>2</sub>CāR) secondary building units in this iconic material
and is illustrative of the complicated crystallization mechanisms
of metalāorganic frameworks in general