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This paper investigates the effect of KFRP composite sheets as a strengthening material in improving the load-carrying resistance of lightweight foam concrete beams using a FEA modelling framework. The study employed three parametric strengthening schemes (i.e., KFRP length, woven architecture types and KFRP thickness). Twenty-seven beam specimens were tested, and respective failure modes and ultimate load at failure were discussed. All the strengthened beam specimens failed mostly in shear mode and, to a lesser extent, in FRP fracture. Despite the absence of de-bonding failure, improvement of strengthening using KFRP sheet technique was exhibited. Later, Extended Finite Element Method (XFEM) Modelling was incorporated following failure mode exhibited. Strength predictions incorporating the traction-separation relationship using XFEM techniques. Validation work with experimental datasets showed good agreements with average discrepancies of less than 10%. The numerical approach can be used as a strength prediction tool in concrete beams with externally bonded FRPs. [ABSTRACT FROM AUTHOR]

Diphtheria toxin (DT) is the archetype for bacterial exotoxins implicated in human diseases and has played a central role in defining the field of toxinology since its discovery in 1888. Despite being one of the most extensively characterized bacterial toxins, the origins and evolutionary adaptation of DT to human hosts remain unknown. Here, we determined the first high-resolution structures of DT homologs outside of the Corynebacterium genus. DT homologs from Streptomyces albireticuli (17% identity to DT) and Seinonella peptonophila (20% identity to DT), despite showing no toxicity toward human cells, display significant structural similarities to DT sharing both the overall Y-shaped architecture of DT as well as the individual folds of each domain. Through a systematic investigation of individual domains, we show that the functional determinants of host range extend beyond an inability to bind cellular receptors; major differences in pH-induced pore-formation and cytosolic release further dictate the delivery of toxic catalytic moieties into cells, thus providing multiple mechanisms for a conserved structural fold to adapt to different hosts. Our work provides structural insights into the expanding DT family of toxins, and highlights key transitions required for host adaptation. Toxic proteins are responsible for the disease symptoms accompanying bacterial infections. Sugiman-Marangos et al. report crystal structures of two diphtheria toxin homologs, therefore providing structural insights into this family of toxins and the evolutionary adaptation of these toxins to human hosts. [ABSTRACT FROM AUTHOR]

The aim of the current project is to carry out the FEA framework for predicting the flexural strength of notched foam concrete tested under three-point bending following the conducted experimental set-up. The investigated testing series have a variation of notch size opening in the foamed concrete beam. The Tractionseparation relationship was used as a constitutive model to incorporate independent material properties and used in the modelling framework. Modelling techniques of 2D XFEM and CZM were adopted and later expanded to 3D XFEM models. Good agreement was found between the predicted structure response and experimental observation for all the investigated models. Crack was initiated at the crack tip and propagated to the beam edge under the applied load. It was found that the average discrepancies below 20% were found within XFEM techniques. Less agreement was found using the CZM models, partly due to the simplification of the adopted failure path. The modelling framework implemented in this project is potentially used as a predictive tool in estimating the flexural strength of the concrete beam with notches. [ABSTRACT FROM AUTHOR]

The article presents a study which adopted the strategy by diphtheria toxin to enter into the endolysosomal network of cells by creating a chimera between the receptor-binding fragment of diphtheria toxin and lysosomal hydrolase tripeptidyl peptidase-1 (TPP1) to improve the effectiveness of enzyme replacement therapy as treatment of lysosomal storage diseases (LSD). Based on the results, chimeric TPP1 binds strongly to target cells.

The current paper aimed to model failures and fractures in single-lap bolted joints of woven fabric kenaf fiber reinforced polymer (KFRP) composite plate to fail in net-tension. The approach was based on the assumptions that micro-damage events were densely concentrated ahead of the notch tip and crack growth were readily seen along net-tension plane in a self-similar fashion. A 3-D finite element modelling framework were developed to explicitly incorporate bolt clamp-up in a range of KFRP series following tested experimental datasets. Lay-up types, normalized W/d, temperature exposure with constant bolt torque of 5 Nm were considered. It was found that KFRP plates under elevated temperature were stronger than under room temperature due to matrix toughening. Traction-separation relationship was incorported within Extended Finite Element Method (XFEM) framework to model damage within KFRP composite plate by using independent experimental datasets, here incorporates un-notched plate strength, so and fracture toughness, Gc of all testing lay-ups. Constitutive model used is associated with stress concentration, therefore good agreement between predicted and experimental bearing stress at failure with net-tension failure mode is perhaps not suprising. [ABSTRACT FROM AUTHOR]

Diphtheria toxin (DT), produced by Corynebacterium diphtheria, is the causative agent of diphtheria and one of the most potent protein toxins known; however, it has an unclear evolutionary history. Here, we report the discovery of a DT‐like gene family in several bacterial lineages outside of Corynebacterium, including Austwickia and Streptomyces. These DT‐like genes form sister lineages in the DT phylogeny and conserve key DT features including catalytic and translocation motifs, but possess divergent receptor‐binding domains. DT‐like genes are not associated with corynephage, but have undergone lateral transfer through a separate mechanism. The discovery of the first non‐Corynebacterium homologs of DT sheds light on its evolutionary origin and highlights novelties that may have resulted in the emergence of DT targeting humans. [ABSTRACT FROM AUTHOR]

Abstract: Experimental and numerical studies have been undertaken on hybrid fibre–metal (aluminium–Glare) laminate (FML) doubler joints to investigate their static response under tension loading. The specimens either have the fibres parallel to the loading direction (spanwise) or perpendicular to the loading direction (chordwise). Inevitably sheets in these laminates butt together and these butts can affect the joint strength. The effect of the butt position was investigated. The spanwise specimen was found to have the highest strength followed by chordwise specimens without butts and finally chordwise specimens with butts. The most critical position for a butt was found to be adjacent to the doubler end. The ultimate strength for spanwise and chordwise specimens without butts was controlled by the failure in the Glare layer, however, for specimens with butts, the butts control the ultimate strength. A progressive damage numerical analysis was undertaken using cohesive zone elements to model failure in the Glare and in the adhesive layers. This modelling was found to be in good agreement with the experiment data both in terms of the strength and the failure mechanisms. [Copyright &y& Elsevier]

Accurate pairing of DNA strands is essential for repair of DNA double-strand breaks (DSBs). How cells achieve accurate annealing when large regions of single-strand DNA are unpaired has remained unclear despite many efforts focused on understanding proteins, which mediate this process. Here we report the crystal structure of a single-strand annealing protein [DdrB (DNA damage response B)] in complex with a partially annealed DNA intermediate to 2.2 Å. This structure and supporting biochemical data reveal a mechanism for accurate annealing involving DdrB-mediated proofreading of strand complementarity. DdrB promotes high-fidelity annealing by constraining specific bases from unauthorized association and only releases annealed duplex when bound strands are fully complementary. To our knowledge, this mechanism provides the first understanding for how cells achieve accurate, protein-assisted strand annealing under biological conditions that would otherwise favor misannealing. [ABSTRACT FROM AUTHOR]

Type IV pili (T4P) contain hundreds of major subunits, but minor subunits are also required for assembly and function. Here we show that Pseudomonas aeruginosa minor pilins prime pilus assembly and traffic the pilus-associated adhesin and anti-retraction protein, PilY1, to the cell surface. PilV, PilW, and PilX require PilY1 for inclusion in surface pili and vice versa, suggestive of complex formation. PilE requires PilVWXY1 for inclusion, suggesting that it binds a novel interface created by two or more components. FimU is incorporated independently of the others and is proposed to couple the putative minor pilin-PilY1 complex to the major subunit. The production of small amounts of T4P by a mutant lacking the minor pilin operon was traced to expression of minor pseudopilins from the P. aeruginosa type II secretion (T2S) system, showing that under retraction-deficient conditions,T2Sminor subunits can prime T4P assembly. Deletion of all minor subunits abrogated pilus assembly. In a strain lacking the minor pseudopilins, PilVWXY1 and either FimU or PilE comprised the minimal set of components required for pilus assembly. Supporting functional conservation of T2S and T4P minor components, our 1.4 Å crystal structure of FimU revealed striking architectural similarity to its T2S ortholog GspH, despite minimal sequence identity. We propose that PilVWXY1 form a priming complex for assembly and that PilE and FimU together stably couple the complex to the major subunit. Trafficking of the anti-retraction factor PilY1 to the cell surface allows for production of pili of sufficient length to support adherence and motility. [ABSTRACT FROM AUTHOR]

DNA-dependent protein kinase (DNA-PK) orchestrates DNA repair by regulating access to breaks through autophosphorylations within two clusters of sites (ABCDE and PQR). Blocking ABCDE phosphorylation (by alanine mutation) imparts a dominant negative effect, rendering cells hypersensitive to agents that cause DNA double-strand breaks. Here, a mutational approach is used to address the mechanistic basis of this dominant negative effect. Blocking ABCDE phosphorylation hypersensitizes cells to most types of DNA damage (base damage, cross-links, breaks, and damage induced by replication stress), suggesting that DNA-PK binds DNA ends that result from many DNA lesions and that blocking ABCDE phosphorylation sequesters these DNA ends from other repair pathways. This dominant negative effect requires DNA-PK's catalytic activity, as well as phosphorylation of multiple (non-ABCDE) DNA-PK catalytic subunit (DNA-PKcs) sites. PSIPRED analysis indicates that the ABCDE sites are located in the only contiguous extended region of this huge protein that is predicted to be disordered, suggesting a regulatory role(s) and perhaps explaining the large impact ABCDE phosphorylation has on the enzyme's function. Moreover, additional sites in this disordered region contribute to the ABCDE cluster. These data, coupled with recent structural data, suggest a model whereby early phosphorylations promote initiation of nonhomologous end joining (NHEJ), whereas ABCDE phosphorylations, potentially located in a "hinge" region between the two domains, lead to regulated conformational changes that initially promote NHEJ and eventually disengage NHEJ. [ABSTRACT FROM AUTHOR]

Summary: The study of biological transporters can be hampered by a dearth of methodology for tracking their activity within cells. Here, we present a means of monitoring the function of transport machinery within bacteria, exploiting a genetically encoded riboswitch-based sensor to detect the accumulation of the substrate in the cytoplasm. This method was used to investigate the model ABC transporter BtuC2D2F, which permits vitamin B12 uptake in Escherichia coli. We exploited the wealth of structural data available for this transporter to probe the functional and mechanistic importance of key residues of the substrate binding protein BtuF that are predicted to support its interaction with its substrate or with the BtuC channel-forming subunits. Our results reveal molecular interaction requirements for substrate binding proteins and demonstrate the utility of riboswitch-based sensors in the study of biological transport. [ABSTRACT FROM AUTHOR]

Abstract: A cohesive zone model has been used to model the progressive damage in adhesively bonded aluminium monolithic single lap joints and laminated doublers. The backface strain technique was used to monitor the damage process in the adhesive layer and was also key in the calibration of a unique set of cohesive zone properties in the single lap joint. Further, this backface strain technique has been successfully used to assess the effect of substrate plasticity, position of cohesive elements, traction and fracture energy, and adhesive fillet in a monolithic single joint. The calibrated cohesive properties have then been successfully used to predict the static strength and backface strain response of the doublers in bending. [Copyright &y& Elsevier]

Abstract: Experimental and numerical studies have been undertaken on metal laminate (ML) doublers and hybrid fibre-metal (aluminium–Glare) laminate (FML) doublers to investigate their static and fatigue response under tension loading. Inevitably sheets in these laminates butt together and these butts can affect the joint strength. Progressive damage modelling, including the damage in the adhesive bondline, the butt, the metal and the fibre has been undertaken in both static and fatigue loading. This modelling was found to be in good agreement with the experiment data in terms both of the strength and the failure mechanisms. In ML, the butt influenced the static and fatigue response. In hybrid FML, the specimens either have the fibres parallel to the loading direction (spanwise) or perpendicular to the loading direction (chordwise). The spanwise specimen was found to have the highest strength followed by chordwise specimens without butts and finally chordwise specimens with butts. The most critical position for a butt was found to be adjacent to the doubler end. Without butts the static strength for spanwise and chordwise specimens was controlled by the failure in the Glare layer whilst the fatigue failure was precipitated by failure in the aluminium sheet. [Copyright &y& Elsevier]

This paper presents the experimental and numerical investigation of the residual strength of steel-composites joints aged in distilled and salt water under steady and fluctuating conditions at a temperature of 45 °C. The adhesive and the composites adherend had been characterized to obtain water absorption behavior and water-dependent mechanical properties. It was found that under the steady condition, the residual strength of the joints aged in distilled water was lower than that aged in salt water; however, under the fluctuating condition, the residual strength of the joints aged in salt water was lower than that aged in distilled water. Overall, the residual strength of the joints aged in salt water under the fluctuating condition was the lowest. Sequentially water diffusion and progressive damage finite element modeling of the joints considering the failure mode have been undertaken. The predicted residual strengths included the cohesive and interfacial failures were in reasonably agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Type III secretion (T3S) is an essential virulence factor used by Gram-negative pathogenic bacteria to deliver effector proteins into the host cell to establish and maintain an intracellular infection. Chlamydia is known to use T3S to facilitate invasion of host cells but many proteins in the system remain uncharacterized. The C. trachomatis protein CT584 has previously been implicated in T3S. Thus, we analyzed the CT584 ortholog in C. pneumoniae (Cpn0803) and found that it associates with known T3S proteins including the needle-filament protein (CdsF), the ATPase (CdsN), and the C-ring protein (CdsQ). Using membrane lipid strips, Cpn0803 interacted with phosphatidic acid and phosphatidylinositol, suggesting that Cpn0803 may associate with host cells. Crystallographic analysis revealed a unique structure of Cpn0803 with a hydrophobic pocket buried within the dimerization interface that may be important for binding small molecules. Also, the binding domains on Cpn0803 for CdsN, CdsQ, and CdsF were identified using Pepscan epitope mapping. Collectively, these data suggest that Cpn0803 plays a role in T3S. [ABSTRACT FROM AUTHOR]

Pleckstrin is a major substrate of protein kinase C in platelets and leukocytes and appears to play an important role in exocytosis through a currently unknown mechanism. Pleckstrin function is regulated by phosphorylation, which is thought to cause dissociation of pleckstrin dimers, thereby facilitating phosphoinositide interactions and membrane localization. Evidence also exists suggesting that phosphorylation causes a subtle conformational change in pleckstrin. Structural studies of pleckstrin have been initiated in order to characterize these structural changes and ultimately advance understanding of pleckstrin function. Here, the crystallization and preliminary X-ray diffraction analysis of a truncated version of pleckstrin consisting of the N-terminal PH domain, the protein kinase C phosphorylation sites and the DEP domain (NPHDEP) are reported. In addition, the oligomeric state and phospholipid-binding properties of NPHDEP were analyzed. This work demonstrates that NPHDEP behaves as a monomer in solution and suggests that all three pleckstrin domains contribute to the dimerization interface. Furthermore, based on the binding properties of NPHDEP, the C-terminal PH domain appears to increase the specificity of pleckstrin for phosphoinositides. This work represents a significant step towards determining the structure of pleckstrin. [ABSTRACT FROM AUTHOR]

The article presents the author's perception about the Japanese Canadian internment during World War II, which relies on personal narrative, family memoir and oral history. The author relates that as racial persecution and its memory come across the generations, people use shared pasts and arrived at different historical understandings. However, the author notes that it is important to keep in mind that personal memory should be rooted in the social context in which people remember. The author pertains that she uses her family's narratives in which its different locations have shaped their memories and thereby produced it with lessons of struggle.

This paper attempts to bridge the dichotomy of "historical truth" and personal recollection by exploring the sociological concept of memory. Drawing on 30 oral testimonies of Nisei (second generation) Japanese Canadian women, I explore the diverse and often complex ways in which Nisei women remember the internment, with particular attention to the intermingling of past and present, the relationship between teller and listener, as well as the layering of personal and public narratives, in the construction of these memories. The theme of silence and telling is also explored, with the understanding that the literacization of memories is always a political act. [ABSTRACT FROM AUTHOR]

IN MOST STUDIES of the automotive industry in Canada, the workforce has been constructed as uniformly white and male. However, a tiny number of Black men have long had a presence in the industry, occupying the dirtiest, most hazardous, and least desirable jobs in the auto foundries of St. Catharines and Windsor, Ontario. This paper attempts to reconstruct the working lives and union involvements of these men. The paper highlights the themes of racialization and gendering within the sphere of capitalist production. In examining multiple oppressions, simultaneously experienced and resisted, the study furthermore demonstrates the ways in which relations of domination are far more complex and historically-contingent than most analyses of industry and "the auto worker" have suggested. [ABSTRACT FROM AUTHOR]

Clostridium difficile is a major nosocomial pathogen that produces two exotoxins, TcdA and TcdB, with TcdB thought to be the primary determinant in human disease. TcdA and TcdB are large, multidomain proteins, each harboring a cytotoxic glucosyltransferasedomainthat is delivered into the cytosol from endosomes via a translocation domain after receptor-mediated endocytosis of toxinsfromthe cell surface. Although there are currentlynoknown host cell receptors for TcdA, three cell-surface receptors for TcdB have been identified: CSPG4, NECTIN3, and FZD1/2/7. The sites on TcdB that mediate binding to each receptor are not defined. Furthermore, it is not known whether the combined repetitive oligopeptide (CROP) domain is involved in or required for receptor binding. Here, in a screen designed to identify sites inTcdBthat are essential for target cell intoxication, we identified a region at the junction of the translocation and the CROP domains that is implicated in CSPG4 binding. Using a series of C-terminal truncations, we show that the CSPG4-binding site on TcdB extends into the CROP domain, requiring three short repeats for binding and for full toxicityonCSPG4-expressing cells. Consistent with the location of the CSPG4-binding site on TcdB, we show that the anti-TcdB antibody bezlotoxumab, which binds partially within the first three short repeats, prevents CSPG4 binding to TcdB. In addition to establishing the binding region for CSPG4, this work ascribes for the first time a role in TcdB CROPs in receptor binding and further clarifies the relative roles of host receptors in TcdB pathogenesis. [ABSTRACT FROM AUTHOR]

Many bacterial pathogens, including Pseudomonas aeruginosa, use type IVa pili (T4aP) for attachment and twitching motility. T4aP are composed primarily of major pilin subunits, which are repeatedly assembled and disassembled to mediate function. A group of pilin-like proteins, the minor pilins FimU and PilVWXE, prime pilus assembly and are incorporated into the pilus. We showed previously that minor pilin PilE depends on the putative priming subcomplex PilVWX and the non-pilin protein PilY1 for incorporation into pili, and that with FimU, PilE may couple the priming subcomplex to the major pilin PilA, allowing for efficient pilus assembly. Here we provide further support for this model, showing interaction of PilE with other minor pilins and the major pilin. A 1.25 Å crystal structure of PilEΔ1-28 shows a typical type IV pilin fold, demonstrating how it may be incorporated into the pilus. Despite limited sequence identity, PilE is structurally similar to Neisseria meningitidis minor pilins PilXNm and PilVNm, recently suggested via characterization of mCherry fusions to modulate pilus assembly from within the periplasm. A P. aeruginosa PilE-mCherry fusion failed to complement twitching motility or piliation of a pilE mutant. However, in a retraction-deficient strain where surface piliation depends solely on PilE, the fusion construct restored some surface piliation. PilE-mCherry was present in sheared surface fractions, suggesting that it was incorporated into pili. Together, these data provide evidence that PilE, the sole P. aeruginosa equivalent of PilXNm and PilVNm, likely connects a priming subcomplex to the major pilin, promoting efficient assembly of T4aP. [ABSTRACT FROM AUTHOR]

Advanced structural adhesives are now an important joining technique in automobile and aerospace applications. The perceived uncertainty in the long-term structural performance of bonded members when subjected to static/fatigue loads in aggressive environments is probably restricting an even more widespread use of this joining technology. In this article, the effect of moisture on the static and fatigue resistances of adhesively bonded laminate joints was investigated. Experimental tests were performed on both aged and unaged adhesively bonded laminate joints for static and fatigue responses. Further, using a cohesive zone approach for the adhesive bondlines, a combined diffusion–stress analysis was developed to predict the progressive damage observed in the joints tested experimentally. The numerical predictions were found to be in good agreement with the experimental test results. [ABSTRACT FROM PUBLISHER]

FimV is a Pseudomonas aeruginosa inner membrane protein that regulates intracellular cyclic AMP (cAMP) levels--and thus type IV pilus (T4P)-mediated twitching motility and type II secretion (T2S)--by activating the adenylate cyclase CyaB. Its cytoplasmic domain contains three predicted tetratricopeptide repeat (TPR) motifs separated by an unstructured region: two proximal to the inner membrane and one within the "FimV C-terminal domain," which is highly conserved across diverse homologs. Here, we present the crystal structure of the FimV C terminus, FimV861-919, containing a TPR motif decorated with solvent-exposed, charged side chains, plus a C-terminal capping helix. FimV689, a truncated form lacking this C-terminal motif, did not restore wild-type levels of twitching or surface piliation compared to the full-length protein. FimV689 failed to restore wild-type levels of the T4P motor ATPase PilU or T2S, suggesting that it was unable to activate cAMP synthesis. Bacterial two-hybrid analysis showed that TPR3 interacts directly with the CyaB activator, FimL. However, FimV689 failed to restore wild-type motility in a fimV mutant expressing a constitutively active CyaB (fimV cyaB-R456L), suggesting that the C-terminal motif is also involved in cAMP-independent functions of FimV. The data show that the highly conserved TPR-containing C-terminal domain of FimV is critical for its cAMP-dependent and -independent functions. [ABSTRACT FROM AUTHOR]

A number of Gram-negative pathogens utilize type III secretion systems (T3SSs) to inject bacterial effector proteins into the host. An important component of T3SSs is a conserved ATPase that captures chaperone-effector complexes and energizes their dissociation to facilitate effector translocation. To date, there has been limited work characterizing the chaperone-T3SS ATPase interaction despite it being a fundamental aspect of T3SS function. In this study, we present the 2.1 Å resolution crystal structure of the Salmonella enterica SPI-2-encoded ATPase, SsaN. Our structure revealed a local and functionally important novel feature in helix 10 that we used to define the interaction domain relevant to chaperone binding. Wemodeled the interaction between the multicargo chaperone, SrcA, and SsaN and validated this model using mutagenesis to identify the residues on both the chaperone and ATPase that mediate the interaction. Finally, we quantified the benefit of this molecular interaction on bacterial fitness in vivo using chromosomal exchange of wild-type ssaN with mutants that retain ATPase activity but no longer capture the chaperone. Our findings provide insight into chaperone recognition by T3SS ATPases and demonstrate the importance of the chaperone-T3SS ATPase interaction for the pathogenesis of Salmonella. [ABSTRACT FROM AUTHOR]

The understanding of pathological processes is based on the comparison between physiological and pathological conditions, and transcriptomic analysis has been extensively applied to various diseases for this purpose. However, the way in which the transcriptomic data of pathological cells relate to the transcriptomes of normal cellular counterparts has not been fully explored, and may provide new and unbiased insights into the mechanisms of these diseases. To achieve this, it is necessary to develop a method to simultaneously analyse components across different levels, namely genes, normal cells, and diseases. Here we propose a multidimensional method that visualises the cross-level relationships between these components at three different levels based on transcriptomic data of physiological and pathological processes, by adapting Canonical Correspondence Analysis, which was developed in ecology and sociology, to microarray data (CCA on Microarray data, CCAM). Using CCAM, we have analysed transcriptomes of haematological disorders and those of normal haematopoietic cell differentiation. First, by analysing leukaemia data, CCAM successfully visualised known relationships between leukaemia subtypes and cellular differentiation, and their characteristic genes, which confirmed the relevance of CCAM. Next, by analysing transcriptomes of myelodysplastic syndromes (MDS), we have shown that CCAM was effective in both generating and testing hypotheses. CCAM showed that among MDS patients, high-risk patients had transcriptomes that were more similar to those of both haematopoietic stem cells (HSC) and megakaryocyte-erythroid progenitors (MEP) than low-risk patients, and provided a prognostic model. Collectively, CCAM reveals hidden relationships between pathological and physiological processes and gene expression, providing meaningful clinical insights into haematological diseases, and these could not be revealed by other univariate and multivariate methods. Furthermore, CCAM was effective in identifying candidate genes that are correlated with cellular phenotypes of interest. We expect that CCAM will benefit a wide range of medical fields. [ABSTRACT FROM AUTHOR]