A New Estimate of B→(ρ,ω)+γB \to (\rho, \omega)+ \gamma In The Light-Cone QCD Sum Rule

We propose a new estimate of the process $B \to (\rho, \omega)+ \gamma$ by using the light-cone QCD sum rule. The aim is to choose the chiral quark current operators in order to eliminate the uncertainty arising from the chiral-even operators in the correlator. In the case of neglecting the corrections from $\rho$-meson mass, the sum rules for form factors are obtained, which are valid to the twist-three accuracy. The resulting branching ratios are consistent with the experimental data.Comment: Latex, 12 pages including 3 ps figure

String interactions on the random lattice

AbstractWe combine two partons on a random lattice as a vector state. In the ladder approximation, we find that such states have 1/p2 propagators (after tuning the mass to vanish). We also construct some diagrams which are very similar to 3-string vertices in string field theory for the first oscillator mode. Attaching 3 such lattice states to these vertices, we get Yang–Mills and F3 interactions up to 3-point as from bosonic string (field) theory. This gives another view of a gauge field as a bound state in a theory whose only fundamental fields are scalars

Effect of section geometry on development of shrinkage-induced deformations in box girder bridges

Non-uniform shrinkage strains can lead to significant additional deflections in large box girder bridges, leading to serviceability problems. This article examines experimentally and analytically the effect of different cross-section geometries on the shrinkage camber of bridge box girders. Small-scale beams were tested to determine the development of shrinkage strains across the beams of depth. Parameters investigated include cross section thickness, drying conditions, and type of concrete mix. Based on the experimental results, inverse analysis is utilised to obtain a surface factor and a hydro-shrinkage coefficient. In this study, such vales are used to determine, for the first time, shrinkage-induced bending deformations of long-span bridges using a hydro-mechanical approach. The results are then used to examine numerically the effect of different section geometries on the development of shrinkage camber. It is shown that the analytical predictions match the experimental results with an accuracy of 85%. A further parametric study is carried out to investigate the effects of specimen geometry and ambient relative humidity. The hydro-mechanical approach is further validated using shrinkage field data from the 230 m two-span box girder Yiju River Bridge (China). The approach proposed in this study is expected to contribute towards improving the predictions of the long term behaviour of box girder bridges and towards better bridge management

Cylindrical nano-indentation on metal film/elastic substrate system with discrete dislocation plasticity analysis: A simple model for nano-indentation size effect

AbstractThe cylindrical nano-indentation on metal film/elastic substrate is computationally studied using two-dimensional discrete dislocation plasticity combined with the commercial software ANSYS®, with a focus on the storage volume for geometrically necessary dislocations (GNDs) inside the films and the nano-indentation size effect (NISE). Our calculations show that almost all GNDs are stored in a rectangular area determined by the film thickness and the actual contact width. The variations of indentation contact width with indentation depth for various film thicknesses and indenter radii are fitted by an exponential relation, and then the GND density underneath the indenter is estimated. Based on the Taylor dislocation model and Tabor formula, a simple model for the dependence of the nano-indentation hardness of the film/substrate system on the indentation depth, the indenter radius and the film thickness is established, showing a good agreement with the present numerical results

AcrFinder: genome mining anti-CRISPR operons in prokaryotes and their viruses

Anti-CRISPR (Acr) proteins encoded by (pro)phages/(pro)viruses have a great potential to enable a more controllable genome editing. However, genome mining new Acr proteins is challenging due to the lack of a conserved functional domain and the low sequence similarity among experimentally char- acterized Acr proteins. We introduce here AcrFinder, a web server (http://bcb.unl.edu/AcrFinder) that combines three well-accepted ideas used by pre- vious experimental studies to pre-screen genomic data for Acr candidates. These ideas include ho- mology search, guilt-by-association (GBA), and CRISPR-Cas self-targeting spacers. Compared to existing bioinformatics tools, AcrFinder has the following unique functions: (i) it is the first online server specifically mining genomes for Acr-Aca operons; (ii) it provides a most comprehensive Acr and Aca (Acr-associated regulator) database (populated by GBA-based Acr and Aca datasets); (iii) it combines homology-based, GBA-based, and self-targeting approaches in one software package; and (iv) it provides a user-friendly web interface to take both nucleotide and protein sequence files as inputs, and output a result page with graphic representation of the genomic contexts of Acr-Aca operons. The leave-one-out cross-validation on ex- perimentally characterized Acr-Aca operons showed that AcrFinder had a 100% recall. AcrFinder will be a valuable web resource to help experimental microbiologists discover new Anti-CRISPRs

Enhancing thermoelectric properties of isotope graphene nanoribbons via machine learning guided manipulation of disordered antidots and interfaces

Structural manipulation at the nanoscale breaks the intrinsic correlations among different energy carrier transport properties, achieving high thermoelectric performance. However, the coupled multifunctional (phonon and electron) transport in the design of nanomaterials makes the optimization of thermoelectric properties challenging. Machine learning brings convenience to the design of nanostructures with large degree of freedom. Herein, we conducted comprehensive thermoelectric optimization of isotopic armchair graphene nanoribbons (AGNRs) with antidots and interfaces by combining Green's function approach with machine learning algorithms. The optimal AGNR with ZT of 0.894 by manipulating antidots was obtained at the interfaces of the aperiodic isotope superlattices, which is 5.69 times larger than that of the pristine structure. The proposed optimal structure via machine learning provides physical insights that the carbon-13 atoms tend to form a continuous interface barrier perpendicular to the carrier transport direction to suppress the propagation of phonons through isotope AGNRs. The antidot effect is more effective than isotope substitution in improving the thermoelectric properties of AGNRs. The proposed approach coupling energy carrier transport property analysis with machine learning algorithms offers highly efficient guidance on enhancing the thermoelectric properties of low-dimensional nanomaterials, as well as to explore and gain non-intuitive physical insights

Association between hypoalbuminemia and complications after degenerative and deformity-correcting spinal surgeries: A systematic review and meta-analysis

ObjectiveThe current review was designed to explore if hypoalbuminemia is associated with increased complications in patients undergoing spinal degenerative and deformities surgeries.MethodsThe search for eligible studies was conducted on the databases of PubMed, Embase, Web of Science, and CENTRAL up to 20th June 2022. Complication rates were pooled to obtain odds ratio (OR) and 95% confidence intervals.ResultsThirteen studies were included. We found that hypoalbuminemia was significantly associated with increased risk of all complications (OR: 2.72 95% CI: 2.04, 3.63 I2 = 58% p < 0.00001), mortality (OR: 7.73 95% CI: 3.81, 15.72 I2 = 0% p < 0.00001), revision surgery (OR: 3.15 95% CI: 1.53, 6.48 I2 = 87% p = 0.002), readmissions (OR: 1.96 95% CI: 1.29, 2.98 I2 = 23% p = 0.02), surgical site infections (OR: 2.97 95% CI: 1.90, 4.63 I2 = 38% p < 0.00001), wound complications (OR: 2.31 95% CI: 1.17, 4.56 I2 = 48% p = 0.02), pulmonary complications (OR: 3.74 95% CI: 2.66, 5.26 I2 = 0% p < 0.00001), renal complications (OR: 3.04 95% CI: 1.22, 7.54 I2 = 0% p = 0.02), cardiac complications (OR: 4.33 95% CI: 2.14, 8.77 I2 = 0% p < 0.0001), urinary tract infections (OR: 2.08 95% CI: 1.80, 2.41 I2 = 0% p < 0.00001), and sepsis (OR: 4.95 95% CI: 1.87, 13.08 I2 = 64% p = 0.01) as compared to those with normal albumin.ConclusionHypoalbuminemia is a significant risk factor for complications after spinal degenerative and deformity surgeries. Research is also needed on the role of nutritional support in improving outcomes after spinal degenerative and deformity surgeries.Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero/, identifier: CRD42022340024

Fractional exhaled nitric oxide in Chinese children with asthma and allergies–A two-city study

SummaryFractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of eosinophilic airway inflammation. Our aim was to study associations between FeNO in Chinese children in two cities and asthma, asthmatic symptoms, rhinitis, eczema, and selected childhood and home environmental factors.A random sample of children in Shanghai (n = 187) and Taiyuan (n = 127), and additional randomly selected children reporting current wheeze (n = 115) were invited for FeNO measurements by NIOX MINO. A questionnaire survey was performed among all subjects (12–14 y) in 59 classes in Shanghai and 44 in Taiyuan. Associations were studied using multiple linear regression using 10log transformed FeNO data and mutual adjustment.The geometric mean FeNO in the random sample (GM ± GSD) was higher in Shanghai (16.2 ± 1.9 ppb) as compared to Taiyuan (12.8 ± 1.6 ppb) (P < 0.001). In the total material (n = 429), Shanghai residency (P = 0.001), male gender (P = 0.02), parental asthma/allergy (P = 0.04), doctors' diagnosed asthma (DDA) (P < 0.001) and current wheeze (P < 0.001) were associated with higher FeNO levels. In non-wheezers (n = 291), Shanghai residency (P = 0.007), male gender (P = 0.002), DDA (P = 0.04), current rhinitis (P = 0.004) and reported pollen/furry pet allergy (P = 0.04) were positively associated with FeNO. In wheezers (n = 138), DDA was the only significant factor (P = 0.009). In conclusion, male gender, current wheeze, DDA, parental asthma/allergy, current rhinitis, pollen/furry pet allergy can be independent determinants of increased FeNO. The lower level of FeNO in Taiyuan is in agreement with previous studies showing lower prevalence of asthma and allergy in Taiyuan as compared to Shanghai