Delamination of laminated composites under the combined effect of nonuniform heating and absorbed moisture

During service exposure, composite structures may be subjected to local heating under which three‐dimensional temperature gradients may develop with temperature differences that can exceed 150°C. The different thermal expansion that is associated with such temperature gradients can generate a range of thermal stresses such as compressive thermal stresses around the periphery of the heated zone, leading potentially to delamination. In this article the combined effects of nonuniform heating and moisture in glass‐ and carbon fiber‐reinforced epoxy laminates are presented, detailing the results of the effect of moisture on the mechanical properties, the simulation experiments of nonuniform heating including in situ measurement of temperatures and strains, and a schematic model of the observed delamination by bulging. The main conclusion is that delamination damage in a form of bulging occurs only in the presence of a threshold level of moisture of about 1 wt%. This threshold level corresponds to the critical moisture content found to produce major mechanical property reduction and interlamina separation. The proposed mechanism comprises a chain of consequences induced by moisture, wherein chemical degradation of the interlamina hot region is followed by mechanical interlamina separation and bulging caused by steam pressure. POLYM. COMPOS., 26:770–777, 2005. © 2005 Society of Plastics Engineers     

A Comprehensive Review on the Single Gate,Double Gate,Tri-Gate,and Heterojunction Tunnel FET for Future Generation Devices

Silicon - Today’s generation of the technological world needs low-power application devices and low-cost transistors. Recently researchers have developed a 3 nm MOSFET...     

Negative Regulation of Innate Immune Signaling by Components of the Button Mushroom Agaricus bisporus

Scope: Mushrooms are valued as an edible and medical resource for millennia. As macrofungi, they possess conserved molecular components recognized by innate immune cells like macrophages, yet unlike pathogenic fungi, they do not trigger the immune system in the same way. That these well-tolerated foods both avoid immuno-surveillance and have positive health benefits, highlights the dearth of information on the interactions of mushroom-derived products with the immune system. Methods and results: Using powders produced from the common white button mushroom, Agaricus bisporus, it is observed that pre-treatment of mouse and human macrophages with mushroom powders attenuates innate immune signaling triggered by microbial ligands like LPS and  β-glucans, including NFκB activation and pro-inflammatory cytokine production. This effect of mushroom powders is observed at lower doses of TLR ligands, suggesting a model of competitive inhibition whereby mushroom compounds bind and occupy innate immune receptors, precluding activation by microbial stimuli. This effect is preserved following simulated digestion of the powders. Moreover, in vivo delivery of mushroom powders attenuates the development of colitis in a DSS-mouse model. Conclusion: This data highlights an important anti-inflammatory role for powdered A. bisporus mushrooms, which can be further utilized to develop complementary approaches to modulate chronic inflammation and disease.     

Structures and Mechanisms of a Novel Bacterial Transport System for Fatty Acids

Bacterial acquisition of metabolites is largely facilitated by transporters with unique substrate scopes. The tripartite ATP-independent periplasmic (TRAP) transporters comprise a large family of bacterial proteins that facilitate the uptake of a variety of small molecules. It has been reported that some TRAP systems encode a fourth protein, the T component. The T-component, or TatT, is predicted to be a periplasmic-facing lipoprotein that enables the uptake of metabolites from the outer membrane. However, no substrates were revealed for any TatT and their functional role(s) remained enigmatic. We recently identified a homolog in Methylococcus capsulatus that binds to sterols, and herein, we report two additional homologs that demonstrate a preference for long-chain fatty acids. Our bioinformatics, quantitative analyses of protein-ligand interactions, and high-resolution crystal structures suggest that TatTs might facilitate the trafficking of hydrophobic or lipophilic substrates and represent a new class of bacterial lipid and fatty acid transporters.     

Eradicating Biofilms of Carbapenem-Resistant Enterobacteriaceae by Simultaneously Dispersing the Biomass and Killing Planktonic Bacteria with PEGylated Branched Polyethyleneimine

Carbapenem-resistant Enterobacteriaceae (CRE) are emerging pathogens that cause variety of severe infections. CRE evade antibiotic treatments because these bacteria produce enzymes that degrade a wide range of antibiotics including carbapenems and β-lactams. The formation of biofilms aggravates CRE infections, especially in a wound environment. These difficulties lead to persistent infection and non-healing wounds. This creates the need for new compounds to overcome CRE antimicrobial resistance and disrupt biofilms. Recent studies in our lab show that 600 Da branched polyethyleneimine (BPEI) and its derivative PEG350-BPEI can overcome antimicrobial resistance and eradicate biofilms in methicillin-resistant S. aureus, methicillin-resistant S. epidermidis, P. aeruginosa, and E. coli. In this study, the ability of 600 Da BPEI and PEG350-BPEI to eradicate carbapenem-resistant Enterobacteriaceae bacteria and their biofilms is demonstrated. We show that both BPEI and PEG350-BPEI have anti-biofilm efficacy against CRE strains expressing Klebsiella pneumoniae carbapenemases (KPCs) and metallo-β-lactamases (MBLs), such as New Delhi MBL (NDM-1). Furthermore, our results illustrate that BPEI affects planktonic CRE bacteria by increasing bacterial length and width from the inability to proceed with normal cell division processes. These data demonstrate the multi-functional properties of 600 Da BPEI and PEG350-BPEI to reduce biofilm formation and mitigate virulence in carbapenem-resistant Enterobacteriaceae.     

Discovery and Biosynthesis of Anthrochelin,a Growth-Promoting Metallophore of the Human Pathogen Luteibacter anthropi

Various human pathogens have emerged from environmental strains by adapting to higher growth temperatures and the ability to produce virulence factors. A remarkable example of a pathoadapted bacterium is found in the genus Luteibacter, which typically comprises harmless soil microbes, yet Luteibacter anthropi was isolated from the blood of a diseased child. Up until now, nothing has been known about the specialized metabolism of this pathogen. By comparative genome analyses we found that L. anthropi has a markedly higher biosynthetic potential than other bacteria of this genus and uniquely bears an NRPS gene locus tentatively coding for the biosynthesis of a metallophore. By metabolic profiling, stable isotope labeling, and NMR investigation of a gallium complex, we identified a new family of salicylate-derived nonribosomal peptides named anthrochelins A–D. Surprisingly, anthrochelins feature a C-terminal homocysteine tag, which might be introduced during peptide termination. Mutational analyses provided insight into the anthrochelin assembly and revealed the unexpected involvement of a cytochrome P450 monooxygenase in oxazole formation. Notably, this heterocycle plays a key role in the binding of metals, especially copper(II). Bioassays showed that anthrochelin significantly promotes the growth of L. anthropi in the presence of low and high copper concentrations, which occur during infections.     

Highly Tuneable Photochromic Sodalites for Dosimetry,Security Marking and Imaging

Photochromic sodalites are considered for a plethora of possible applications, such as UV indexing and X-ray imaging, but for many of these the materials are yet to be optimized. UV indexing can be improved through incremental adjustment of the activation energy of coloration from 300 to 410 nm through replacement of sulfur with selenium. By combining this and other methods of tuning presented in the literature, the excitation threshold and photochromism color can be tuned independently of one another. The range of possible absorption maxima is expanded to 420–680 nm, or almost the entire visible spectrum. Mixing low-cost and easy-to-synthesize sodalites further broadens the possible range of colors and facilitates development of a unique sodalite mix capable of quantifying the doses of two types of UV radiation simultaneously. Finally, the response to X-rays of these highly tuned sodalites is investigated, and it is found that they can be sensitized to produce clear, high-contrast X-ray images at significantly lower doses of radiation than those required by classic photochromic sodalite, Na₈(AlSiO₄)₆(Cl,S)₂.     

A Degron Blocking Strategy Towards Improved CRL4CRBN Recruiting PROTAC Selectivity**

Small molecules inducing protein degradation are important pharmacological tools to interrogate complex biology and are rapidly translating into clinical agents. However, to fully realise the potential of these molecules, selectivity remains a limiting challenge. Herein, we addressed the issue of selectivity in the design of CRL4^CRBN recruiting PROteolysis TArgeting Chimeras (PROTACs). Thalidomide derivatives used to generate CRL4^CRBN recruiting PROTACs have well described intrinsic monovalent degradation profiles by inducing the recruitment of neo-substrates, such as GSPT1, Ikaros and Aiolos. We leveraged structural insights from known CRL4^CRBN neo-substrates to attenuate and indeed remove this monovalent degradation function in well-known CRL4^CRBN molecular glues degraders, namely CC-885 and Pomalidomide. We then applied these design principles on a previously published BRD9 PROTAC (dBRD9-A) and generated an analogue with improved selectivity profile. Finally, we implemented a computational modelling pipeline to show that our degron blocking design does not impact PROTAC-induced ternary complex formation. We believe that the tools and principles presented in this work will be valuable to support the development of targeted protein degradation.     

Enzymatic Late-Stage Halogenation of Peptides

The late-stage site-selective derivatisation of peptides has many potential applications in structure-activity relationship studies and postsynthetic modification or conjugation of bioactive compounds. The development of orthogonal methods for C−H functionalisation is crucial for such peptide derivatisation. Among them, biocatalytic methods are increasingly attracting attention. Tryptophan halogenases emerged as valuable catalysts to functionalise tryptophan (Trp), while direct enzyme-catalysed halogenation of synthetic peptides is yet unprecedented. Here, it is reported that the Trp 6-halogenase Thal accepts a wide range of amides and peptides containing a Trp moiety. Increasing the sequence length and reaction optimisation made bromination of pentapeptides feasible with good turnovers and a broad sequence scope, while regioselectivity turned out to be sequence dependent. Comparison of X-ray single crystal structures of Thal in complex with d -Trp and a dipeptide revealed a significantly altered binding mode for the peptide. The viability of this bioorthogonal approach was exemplified by halogenation of a cyclic RGD peptide.     

GrowliFlower: An image time-series dataset for GROWth analysis of cauLIFLOWER

In this paper, we present GrowliFlower, a georeferenced, image-based unmanned aerial vehicle time-series dataset of two monitored cauliflower fields (0.39 and 0.60 ha) acquired in 2 years, 2020 and 2021. The proposed dataset contains RGB and multispectral orthophotos with coordinates of approximately 14,000 individual cauliflower plants. The coordinates enable the extraction of complete and incomplete time-series of image patches showing individual plants. The dataset contains the collected phenotypic traits of 740 plants, including the developmental stage and plant and cauliflower size. The harvestable product is completely covered by leaves, thus, plant IDs and coordinates are provided to extract image pairs of plants pre- and post-defoliation. In addition, to facilitate classification, detection, segmentation, instance segmentation, and other similar computer vision tasks, the proposed dataset contains pixel-accurate leaf and plant instance segmentations, as well as stem annotations. The proposed dataset was created to facilitate the development and evaluation of various machine-learning approaches. It focuses on the analysis of growth and development of cauliflower and the derivation of phenotypic traits to advance automation in agriculture. Two baseline results of instance segmentation tasks at the plant and leaf level based on labeled instance segmentation data are presented. The complete GrowliFlower dataset is publicly available ( http://rs.ipb.uni-bonn.de/data/growliflower/ ).