Region Of Notch Research Articles

TM2D3, a mammalian homologue of Drosophila neurogenic gene product Almondex, regulates surface presentation of Notch receptors

Notch signaling is an evolutionarily conserved mechanism required for numerous types of cell fate decisions in metazoans. It mediates short-range communication between cells with receptors and ligands, both of which are expressed on the cell surfaces. In response to the ligand-receptor interaction, the ligand and the extracellular domain of the Notch receptor (NECD) in the complex are internalized into ligand-expressing cells by endocytosis, a prerequisite process for the conformational change of the membrane proximal region of Notch to induce critical proteolytic cleavages for its activation. Here we report that overexpression of transmembrane 2 (TM2) domain containing 3 (TM2D3), a mammalian homologue of Drosophila melanogaster Almondex (Amx), activates Notch1. This activation requires the ligand-binding domain in Notch1 and the C-terminal region containing TM2 domain in TM2D3. TM2D3 physically associates with Notch1 at the region distinct from the ligand-binding domain and enhances expression of Notch1 on the cell surface. Furthermore, cell surface expression of Notch1 and Notch2 is reduced in Tm2d3-deficient cells. Finally, amx-deficient Drosophila early embryos exhibit impaired endocytosis of NECD and Delta ligand, for which surface presentation of Notch is required. These results indicate that TM2D3 is an element involved in Notch signaling through the surface presentation.

Strength properties of unidirectional laminated engineered bamboo boards under off-axis tension and compression tests

The strength properties of 30-mm unidirectional laminated engineered bamboo boards under off-axis tension and compression tests at seven different loading directions were studied in this research. The different failure modes, stress-displacement curves, and the corresponding full-field surface strain field measured through the digital image correlation (DIC) method were reported. The probability plots of off-axis strength values and the estimated characteristic strength values were given. Based on the original test data, the strength criteria based on Tsai and Wu theory was developed for the engineered bamboo panels studied herein. The values of strength tensors Fi and Fij were estimated based on the test results, which can be used to accurately model engineered bamboo products under complex stress conditions such as joint or notch regions. The characteristic off-axis strength values based on the Hankinson's formula given by the current standards are suggested to be further calibrated for design applications.

New Mutations in the 5' Region of the Notch Gene Affect Drosophila melanogaster Oogenesis.

The Notch pathway is an important and evolutionarily conserved signaling system involved in the development of multicellular organisms. Notch signaling plays an important role in the regulation of proliferation and differentiation of many cell types. In this study, we report new aspects of Notch gene participation in oogenesis using our previously generated mutations. The mutations consist of an insertion of an auxiliary element of a transgene construct into the first intron of the gene and a series of directed deletions within the 5′ regulatory region of Notch. We showed that some of these mutations affect Drosophila oogenesis. This insertion, either alone or in combination with the deletion of an insulator sequence, led to lower expression of Notch in the ovaries. As a result, the formation of egg chambers was disturbed in middle oogenesis. These abnormalities have not been described previously and imply one more function of Notch in oogenesis. It can be assumed that Notch is associated with not only follicular epithelium morphogenesis but also cellular mechanisms of oocyte growth.

Protein Kinase MpYAK1 Is Involved in Meristematic Cell Proliferation, Reproductive Phase Change and Nutrient Signaling in the Liverwort Marchantia polymorpha.

Plant growth and development are regulated by environmental factors, including nutrient availability and light conditions, via endogenous genetic signaling pathways. Phosphorylation-dependent protein modification plays a major role in the regulation of cell proliferation in stress conditions, and several protein kinases have been shown to function in response to nutritional status, including dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs). Although DYRKs are widely conserved in eukaryotes, the physiological functions of DYRKs in land plants are still to be elucidated. In the liverwort Marchantia polymorpha, a model bryophyte, four putative genes encoding DYRK homologous proteins, each of which belongs to the subfamily yet another kinase 1 (Yak1), plant-specific DYRK, DYRK2, or pre-mRNA processing protein 4 kinase, were identified. MpYAK1-defective male and female mutant lines generated by the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease 9 (Cas9) system showed smaller sizes of thalli than did the wild-type plants and repressed cell divisions in the apical notch regions. The Mpyak1 mutants developed rhizoids from gemmae in the gemma cup before release. The Mpyak1 lines developed sexual organs even in non-inductive short-day photoperiod conditions supplemented with far-red light. In nitrogen (N)-deficient conditions, rhizoid elongation was inhibited in the Mpyak1 mutants. In conditions of aeration with 0.08% CO2 (v/v) and N depletion, Mpyak1 mutants accumulated higher levels of sucrose and lower levels of starch compared to the wild type. Transcriptomic analyses revealed that the expression of peroxidase genes was differentially affected by MpYAK1. These results suggest that MpYAK1 is involved in the maintenance of plant growth and developmental responses to light conditions and nutrient signaling.

Stress distribution pattern in the distal radioulnar joint before and after ulnar shortening osteotomy in patients with ulnar impaction syndrome

Ulnar shortening osteotomy (USO) for ulnar impaction syndrome potentially leads to degenerative changes of the distal radioulnar joint (DRUJ). This study was performed to evaluate the effect of the sigmoid notch morphology on the stress distribution pattern of the DRUJ using computed tomography (CT) osteoabsorptiometry (CT-OAM). We reviewed the pre- and postoperative transverse CT images of 15 wrists that had undergone USO. The examined wrists were classified into two groups based on the sigmoid notch morphology: the linear-type notch (type L) and the curved-type notch (type C). We calculated and statistically compared the percentage of the high-density area (%HDA) in each divided region of the sigmoid notch. In type L, %HDA was significantly larger in the distal-dorsal region of the sigmoid notch before USO. Postoperatively, in type L, no specific regions showed a significantly different %HDA. In type C, %HDA was significantly larger in the distal-volar region of the sigmoid notch before USO. Postoperatively, %HDA of type C was significantly larger in the proximal-volar region. Our results suggest that in patients with ulnar impaction syndrome, morphological evaluation of the sigmoid notch can serve as a predictor of osteoarthritis in the DRUJ with or without USO.

Influence of Ga back grading on voltage loss in low‐temperature co‐evaporated Cu(In,Ga)Se2 thin film solar cells

AbstractThe performance of Cu(In,Ga)Se2 (CIGS) solar cells is limited by the presence of the highly recombinative CIGS/Mo interface. The recombination at the CIGS/Mo interface is influential for the open circuit voltage (VOC) in high quality CIGS absorbers with increased charge carriers diffusion length. A quantitative understanding of the role of the Ga back grading height (ΔGGI) in suppressing back interface recombination is needed. In this work, we take advantage of a low temperature process to modify the ΔGGI while keeping the composition in the notch and front regions almost unchanged. Improvement in both VOC deficit and time‐resolved photoluminescence lifetime are observed with increasing ΔGGI. With a combination of back surface modification experiments and numerical simulations, we quantify a voltage loss in ungraded devices of approximately 100 mV solely from the back interface recombination. Nice agreement between simulation and experimental data is reached while constraining the values of possible diffusion lengths. Our results suggest that a ΔGGI of about 0.50 is required to effectively suppress the back interface recombination, highlighting the importance of grading control in high‐performance CIGS solar cells and devices.

Transcription factors regulate early Tcell development via redeployment of other factors: Functional dynamics of constitutively required factors in cell fate decisions.

Establishment of cell lineage identity from multipotent progenitors is controlled by cooperative actions of lineage-specific and stably expressed transcription factors, combined with input from environmental signals. Lineage-specific master transcription factors activate and repress gene expression by recruiting consistently expressed transcription factors and chromatin modifiers to their target loci. Recent technical advances in genome-wide and multi-omics analysis have shed light on unexpected mechanisms that underlie more complicated actions of transcription factors in cell fate decisions. In this review, we discuss functional dynamics of stably expressed and continuously required factors, Notch and Runx family members, throughout developmental stages of early Tcell development in the thymus. Pre- and post-commitment stage-specific transcription factors induce dynamic redeployment of Notch and Runx binding genomic regions. Thus, together with stage-specific transcription factors, shared transcription factors across distinct developmental stages regulate acquisition of T lineage identity.

Influence of pelvic shape on strain patterns: A computational analysis using finite element mesh morphing techniques

The pelvis functions to transmit upper body loads to the lower limbs and is critical in human locomotion. Semi-automated, finite element (FE) morphing techniques eliminate the need for segmentation and have shown to accelerate the generation of multiple specimen-specific pelvic FE models to enable the study of pelvic mechanical behaviour. The purpose of this research was to produce simulated human pelvic FE models representing android, gynecoid, anthropoid and platypelloid morphologies and to isolate differences in strain patterns due to anatomic shape under physiologic loading. Using five initially generated specimen-specific FE models, each specimen-specific FE model was reconfigured into three different morphologies using FE mesh morphing techniques. Significantly different strains were found comparing the gynecoid (classical female pelvis’) to the android (‘true male pelvis’) models (p = 0.040), with strains twice as high in the superior pubic rami. No significant differences were seen in comparing overall strains between the other pelvic shapes (p = 0.61–0.126). The highest strain regions in all models were found in the supra-acetabular regions, with high strains also found in the regions of the superior pubic rami, the greater sciatic notch and sacral regions about the L5 vertebrae. Quantifying the contributions of shape to strain in the pelvis may increase the understanding of sex and patient-specific differences in fracture risk and motivate the consideration of treatment strategies that account for anatomic pelvic differences.

A Numerical Study of Strain-Rate and Triaxiality Effects in Magnesium Alloys

We report a preliminary computational study of the rate-dependent behavior of a polycrystal magnesium alloy under varying levels of stress triaxiality conditions. Smooth and notched round bar specimens with a strong initial texture are considered to achieve different levels of stress triaxiality. Full three-dimensional crystal plasticity simulations are conducted, which mimic tensile Kolsky bar experiments. The results indicate that the material rate sensitivity couples with the stress state to produce qualitatively different macroscopic responses that are governed by the interacting microscale deformation mechanisms. While the smooth specimens show macroscopic strain localization resulting in stress softening immediately following the initial yield, notched bars exhibit increasingly stable responses with increasing notch acuity. Deformation anisotropy is tempered with increasing stress triaxiality and strain rate. A micromechanical analysis of the deformation activities is presented to explain the macroscale responses. Stress triaxiality distributions in the notch regions provide insights into probable damage mechanisms as a function of the imposed strain rate.

On the influence of crystallography on creep of circular notched single crystal superalloy specimens

The present work contributes to a better understanding of the effect of stress multiaxiality on the creep behavior of single crystal Ni-base superalloys. For this purpose we studied the creep deformation and rupture behavior of double notched miniature creep tensile specimens loaded in three crystallographic directions [100], [110] and [111] (creep conditions: 950 °C and 400 MPa net section stress). Crystal plasticity finite element method (CPFEM) was used to analyze the creep stress and strain distributions during creep. Double notched specimens have the advantage that when one notch fails, the other is still intact and allows to study a material state which is close to rupture. No notch root cracking was observed, while microstructural damage (pores and micro cracks) were frequently observed in the center of the notch root region. This is in agreement with the FEM results (high axial stress and high hydrostatic stress in the center of the notched specimen). Twinning was observed in the notch regions of [110] and [111] specimens, and <112> {111} twins were detected and analyzed using orientation imaging scanning electron microscopy. The present work shows that high lattice rotations can be detected in SXs after creep fracture, but they are associated with the high strains accumulated in the final rupture event.

Notched tensile response and damage mechanism of the GLARE laminate

Glass laminate aluminum reinforced epoxy, as an attractive material for advanced aerospace applications, is most likely to face the challenge of various blunt notched damages. In this paper, the tensile tests of the glass laminate aluminum reinforced epoxy with circular and square blunt notches are conducted. The effects of notch geometry, such as notch diameter, notch corner radius, and off-axis angle, on the laminated tensile behaviors of glass laminate aluminum reinforced epoxy laminate are explored. A characteristic distance function representing the damage-affected region of notch is empirically constructed to predict the residual strength of the circular notched glass laminate aluminum reinforced epoxy based on a modified point stress criterion. For the square notched laminate, the strength is almost equal to that of the laminate with its circumscribed circle notch. Furthermore, the variation of two fracture patterns observed with the notch geometry is studied, and the evolution of the interlaminar delamination damage is analyzed after the metal chemical removal.

Maisonneuve fracture.

Maisonneuve fracture (MF) is agenerally known entity in ankle trauma. However, details about this type of injury can be found only rarely in the literature. For these reasons we have decided to perform astudy on MF epidemiology and pathoanatomy. The group comprised 70 patients (47 men, 23 women), with the mean age of 48 years, who sustained an ankle fracture-dislocation involving the proximal quarter of the fibula. Ankle radiographs in three views and lower leg radiographs in two views were performed in all patients. Atotal of 59 patients underwent CT examination in three views, including 3D CT reconstruction in 49 of these patients. MRI was performed in 4 patients. Operative treatment was used in 67 patients; open reduction of the distal fibula into the fibular notch was opted for in 54 of them. The highest MF incidence rate was recorded in the 5th decade in the whole group and in men, while in women the peak incidence was in the 6th decade. After the age of 50, the share of women significantly increased. In 64 cases, the fibular fracture was subcapital, and in 6 cases it involved the fibular head. In 24% of the patients, the fibular fracture was seen only in the lateral radiograph of the lower leg. Widening of the tibiofibular clear space was shown by radiographs in 40 cases. Posterior dislocation of the fibula (Bosworth fracture) and tibiofibular diastasis were recorded in 2 cases each. An injury to the anterior and posterior tibiofibular ligaments was found in all 54 patients with open reduction of the distal fibula. Afracture of the medial malleolus was identified in 27 cases (39%) and acomplete lesion of the deltoid ligament in 36 cases (51%); in 7 cases (10%) the medial structures were intact. Afracture of the posterior malleolus occurred in 54 (77%) patients. Osteochondral fracture of the talar dome was diagnosed in 2 patients and compression of the articular surface of the distal tibia in the region of the fibular notch in 1 patient. Maisonneuve fracture includes awide range of injuries both to bone and ligamentous structures of the ankle. Therefore, CT examination is an indispensable part of assessment of this type of fracture.

Experimental investigation and numerical prediction of static strength and fracture behaviour of notched epoxy-based structural adhesives

The influence of stress concentrations on the tensile static strength and fracture behaviour of notched bulk specimens was investigated by comparing the response of two epoxy-based structural adhesives (a rubber-toughened and a polyurethane-toughened). Numerical predictions of failure stress were carried out using a 3D-FEA model with a hydrostatic dependent elastoplastic material behaviour and the equivalent plastic strain for failure assessment. The ductile adhesive, which plastically deforms more under high stresses, provided experimental evidence of a notch strengthening effect. Conversely, the less ductile adhesive has shown a reduction in tensile strength compared to un-notched samples. For both adhesives fracture surface analysis showed the presence of stress whitening and voids close to the notch regions. These regions could be correlated to higher values of stress triaxiality using numerical simulation. The more ductile adhesive underwent widespread stress whitening prior to failure, whereas the response of the less ductile adhesive was more localised. Numerically based predictions showed excellent agreement with experimental results with average error of 5.1% for different notch types in both adhesives.

A novel technique for bone marrow concentrate aspiration from the intercondylar notch during arthroscopic ACL reconstruction

Objectives:Anterior cruciate ligament Reconstruction (ACL-R) is a frequent surgery with a failure rate of 8-10%, being a cause the lack of integration of the graft. Methods of biological augmentation have been developed, such as the extraction of human mesenchymal cells by aspiration of BMC.Objective:describe and demonstrate the safety of a new arthroscopic technique of BMC aspiration from the femoral intercondylar notch.Methods:Prospective non-randomized clinical study of 45 consecutive patients undergoing anatomic ACL-R with hamstring autograft. Patients with Multiligamentary injuries or revision ACL surgery were excluded. Control group was composed by 19 patients that underwent isolated ACL-R. Intervention group was composed by 29 patients who underwent ACL-R, BMC aspiration and subsequent instillation of the BMC.Variables assessed to compare both groups were: Demographics, Surgical Time and Complications (hemarthrosis, rate of infection and risk of fracture).BMC Aspiration Technique was performed before tunnel drilling and shutting-off the water pump. Through the medial portal, the 14-gauge trocar/needle aspiration device was introduced and positioned into the upper and central region of the intercondylar notch. With a clockwise-like twisting motion, the trocar was used to pierce the cortex 25 mm into the distal femur, obtaining 60 ml of BM which was processed with the Angel system (ArthrexR). Finally, under dry arthroscopic vision, the BMC was instilled in both bone tunnels and into the graft.Statistical analysis was performed in stata 11, considering a statistical significance of 5%.Results:No demographic differences were reported. The surgical time of the control group was 50.57 min (SD 8.44) and intervention group 65.69 min (SD 10.98) (p <0.011). 0% of complications associated with the procedure were reported.Conclusion:The aspiration of BMC through the femoral intercondylar notch during the arthroscopic ACL-R, is a safe, reproducible technique without associated complications, however, it significantly increases the surgical time.

Identification of Notch binding protiens and localization of Notch to focal adhesions

The Notch signaling pathway begins at the cell surface when Notch receptors interact with Notch ligands on adjacent cells triggering an intramolecular cleavage that releases the NICD (or Notch Intracellular Domain fragment) that then enters the nucleus to drive transcription. In addition to this cannonical Notch mechanism, our lab previously demonstrated that Notch signaling is modified by integrin ligation, via a previously unknown non‐cannonical mechanism. In unpublished research performed by LaFoya et al, SRC kinase has now been determined to bind to, and phosphorylate a small peptide near the ankyrin domain of Notch 1, resulting in modification of Notch signaling. The goal of our project is to expand upon these results by discovering other proteins that may interact with this region of Notch. To accomplish this goal, we constructed a fusion protein of the Notch peptide and the BirA protein, and performed a proximity biotin ligation screen in 293T cells for interacting proteins. Biotinylated proteins were isolated by streptavidin magnetic beads, and identified by MS/MS. Amongst the many hits, we identified members of the SRC family of kinases and several proteins commonly associated with focal adhesions and/or tight junctions. Western blotting confirmed the presence of focal adhesion proteins α‐actinin 1 and α‐actinin 4, and tight junction protiens cingulin, and angiomotin, in the biotin precipitated fractions. Subsequent co‐immunoprecipitation experiments in HMEC endothelial cells positively determined an interaction between the NICD domain and α‐actinin1, but failed to confirm interactions with the other proteins. The functional significance of this Notch‐actinin interaction is currently unknown, although given that SRC and actinin both localize to focal adhesions, we speculate that Notch may localize to focal adhesions where it is phosphorylated by SRC kinases.Support or Funding InformationNIH Grant 2R15GM102852‐02This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Structural analysis of spherical pressure hull viewport for manned submersibles using biological growth method

ABSTRACTManned submersibles are important platforms for exploration and research under the oceans. One of the most important components of the manned submersible is the viewport, which develops high stresses due to the nature of its design. The basic dimensions of the viewport window and its flange are determined using ASME PVHO-1. Analysis of the viewport for given basic dimensions, shows that the corners of the low-pressure face of the viewport window and the notch regions of the flange are subjected to high stresses. Using the fillet radius method at the notch region results in stress reduction by 64%. The biological growth method helps in getting the naturally optimised shape at the corner. The use of the biological growth method for structural shape modification reduces the stress acting on the acrylic viewport by 71%. The same method applied to the flange notch region reduces its sharpness and the stress there by a considerable amount. This also helps in increasing the number of cycles of operation.

Effects of Scalloping on the Mixing Mechanisms of Forced Mixers With Highly Swirling Core Flow

This paper presents a detailed experimental and computational investigation of the effects of scalloping on the mixing mechanisms of a scaled 12-lobe turbofan mixer. Scalloping was achieved by eliminating approximately 70% of the lobe sidewall area. Measurements were made downstream of the mixer in a co-annular wind tunnel, and the simulations were carried out using an unstructured Reynolds averaged Navier–Stokes (RANS) solver, Numeca FINE/Hexa, with k-ω SST model. In the core flow, the swirl angle was varied from 0 deg to 30 deg. At high swirl angles, a three-dimensional separation bubble was formed on the lobe's suction surface penetration region and resulted in the generation of a vortex at the lobe valley. The valley vortex quickly dissipated downstream. The mixer lobes removed most of the swirl, but scalloped lobes removed less swirl in the region of the scalloped notch. The residual swirl downstream of the scalloped mixer interacted with the vortices and improved mixing rates compared to the unscalloped mixer. Core flow swirl up to 10 deg provided improved mixing rates and reduced pressure and thrust losses for both mixers. As core flow swirl increased beyond 10 deg, the mixing rate continued to improve, but pressure and thrust losses declined compared to the zero swirl case. Lobe scalloping, in high swirl conditions, resulted in better mixing and improved pressure loss over the unscalloped mixer but at the expense of reduced thrust.

Complete noise analysis of a simple force spectroscopy AFM setup and its applications to study nanomechanics of mammalian Notch 1 protein

We describe a complete noise analysis and application of a custom made AFM force spectroscopy setup on pulling a recombinant protein with an NRR domain of mouse Notch 1. Our table top AFM setup is affordable, has an open architecture, and is easily transferable to other laboratories. Its calculated noise characteristics are dominated by the Brownian noise with 2% non-Brownian components integrated over the first thermally induced resonance of a typical cantilever. For a typical SiN cantilever with a force constant of ∼15 pN nm−1 and in water the force sensitivity and resolution are less than 10 pN, and the corresponding deflection sensitivities are less than 100 pm Hz−1/2. Also, we obtain a sub-ms time resolution in detecting the protein length change, and only few ms cantilever response times as measured in the force clamp mode on a well-known protein standard. Using this setup we investigate force-induced conformational transitions in the NRR region of a mouse Notch 1. Notch is an important protein related to leukemia and breast cancers in humans. We demonstrate that it is feasible to develop AFM-based studies of the force-induced conformational transitions in Notch. Our results match recent steered molecular dynamics simulations of the NRR unfolding and constitute a first step towards a detailed study of Notch activation with AFM.

The stress state of the fraenal notch region in complete upper dentures

The present study determines the stress field in the region of the labial flange of the complete upper denture (CUD).Using commercial edentulous molds and standardized procedures eight identical CUDs were fabricated with an initial fraenal notch of 5mm. Three addition notch conditions were produced by deepening the notch two times giving a total depth of the notch of 7 and 9mm respectively. Finally an incisal diastema of 7mm was created in every CUD.Three elements rosette strain gauge was cemented onto the midline of each denture specimen near the fraenal notch, for calculating the two principal stresses and the maximum shear stress.It is less possible that a failure crack in a CUD will be initiated from the region of the fraenal notch, due to the compressive nature of the principal stresses (they are varied significantly among the four notch conditions with P=0.035 for σ1 and P=0.007 for σ2) and the low value of the maximum shear stress. The creation of an incisal diastema significantly decreased the values of the principal stresses σ1 (P=0.012) and σ2 (P=0.025). Further investigation is needed to detect the region of the CUD where a failure crack may be initiated.

O-Glucose Trisaccharide Is Present at High but Variable Stoichiometry at Multiple Sites on Mouse Notch1

Notch activity is regulated by both O-fucosylation and O-glucosylation, and Notch receptors contain multiple predicted sites for both. Here we examine the occupancy of the predicted O-glucose sites on mouse Notch1 (mN1) using the consensus sequence C(1)XSXPC(2). We show that all of the predicted sites are modified, although the efficiency of modifying O-glucose sites is site- and cell type-dependent. For instance, although most sites are modified at high stoichiometries, the site at EGF 27 is only partially glucosylated, and the occupancy of the site at EGF 4 varies with cell type. O-Glucose is also found at a novel, non-traditional consensus site at EGF 9. Based on this finding, we propose a revision of the consensus sequence for O-glucosylation to allow alanine N-terminal to cysteine 2: C(1)XSX(A/P)C(2). We also show through biochemical and mass spectral analyses that serine is the only hydroxyamino acid that is modified with O-glucose on EGF repeats. The O-glucose at all sites is efficiently elongated to the trisaccharide Xyl-Xyl-Glc. To establish the functional importance of individual O-glucose sites in mN1, we used a cell-based signaling assay. Elimination of most individual sites shows little or no effect on mN1 activation, suggesting that the major effects of O-glucose are mediated by modification of multiple sites. Interestingly, elimination of the site in EGF 28, found in the Abruptex region of Notch, does significantly reduce activity. These results demonstrate that, like O-fucose, the O-glucose modifications of EGF repeats occur extensively on mN1, and they play important roles in Notch function.