Edge states and the bulk-boundary correspondence in Dirac Hamiltonians

We present an analytic prescription for computing the edge dispersion E(k) of a tight-binding Dirac Hamiltonian terminated at an abrupt crystalline edge. Specifically, we consider translationally invariant Dirac Hamiltonians with nearest-layer interaction. We present and prove a geometric formula that relates the existence of surface states as well as their energy dispersion to properties of the bulk Hamiltonian. We further prove the bulk-boundary correspondence between the Chern number and the chiral edge modes for quantum Hall systems within the class of Hamiltonians studied in the paper. Our results can be extended to the case of continuum theories which are quadratic in the momentum, as well as other symmetry classes.Comment: 8 pages + appendice

Effects of Gravity Modulation and Internal Heat Generation on the onset of Rayleigh-Benard convection in a Micropolar Fluid

The effect of gravity modulation (time periodic body force or g-jitter) on the onset of Rayleigh-Bénard convection in a micropolar fluid with internal heat generation is investigated by making a linear stability analysis. The stability of a horizontal layer of fluid heated from below is examined by assuming time periodic body force in the presence of internal heat source. A regular perturbation method is used to arrive at an expression to compute the critical Rayleigh number for small amplitude of modulation and dimensionless internal heat source. The Venezian approach is adopted to obtain the eigen value of the problem. The results obtained during the analysis have been presented graphically

High-sensitivity C-reactive protein, lipid profile, malondialdehyde and total antioxidant capacity in psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by epidermal hyperproliferation and lymphocytic infiltration. The ongoing inflammatory process in psoriasis affects the arterial wall promoting the atherosclerotic process, increasing the risk of cardiovascular disease in a younger group of patients. Atherosclerotic processes involve an inflammatory component and high-sensitivity C-reactive protein considered as a marker of the inflammatory component in atherosclerosis. This study was undertaken to evaluate the levels of hsCRP and the traditional risk markers like lipid profile in psoriasis. A case control study as done with 40 cases of psoriasis and 40 healthy controls. The biochemical parameters: lipid profile, hsCRP, malondialdehyde and total antioxidant capacity were estimated on the fasting blood samples. There was a significant increase in lipid profile in cases but these levels were well within the reference ranges for the same. There was a significant rise in hsCRP and malondialdehyde with decreased levels of total antioxidant capacity in cases suggesting a state of inflammation and oxidative stress which co-exists with psoriasis and also plays a role in atherosclerosis.Keywords: Inflammation; atherosclerosis; cardiovascular disease; oxidative stres

Quantitative Discourse Cohesion Analysis of Scientific Scholarly Texts using Multilayer Networks

Discourse cohesion facilitates text comprehension and helps the reader form a coherent narrative. In this study, we aim to computationally analyze the discourse cohesion in scientific scholarly texts using multilayer network representation and quantify the writing quality of the document. Exploiting the hierarchical structure of scientific scholarly texts, we design section-level and document-level metrics to assess the extent of lexical cohesion in text. We use a publicly available dataset along with a curated set of contrasting examples to validate the proposed metrics by comparing them against select indices computed using existing cohesion analysis tools. We observe that the proposed metrics correlate as expected with the existing cohesion indices. We also present an analytical framework, CHIAA (CHeck It Again, Author), to provide pointers to the author for potential improvements in the manuscript with the help of the section-level and document-level metrics. The proposed CHIAA framework furnishes a clear and precise prescription to the author for improving writing by localizing regions in text with cohesion gaps. We demonstrate the efficacy of CHIAA framework using succinct examples from cohesion-deficient text excerpts in the experimental dataset.Comment: 26 pages, 8 figures, 4 table

Rapid Detection of Staphylococcus aureus Using Graphene Oxide Coated Screen-Printed Sensor Strips

340–343Staphylococcus aureus (S. aureus) is the most common reason behind bacterial infections in humans. They cause a wide array of infections on skin, bone and joint medical implants and blood stream. In order to mitigate these infections, detecting the presence of this bacterium is of prime importance. This paper explores a new rapid detection technique to identify S aureus bacteria. A screen-printed sensor coated with graphene oxide was used as an identification platform. Graphene oxide was synthesized using modified Hummer’s method and was characterized using X-ray Diffractometer and Scanning Electron Microscope. The developed sensors showed significant decrease in the bulk resistance with the increase in bacterial concentrations. The developed sensors were subjected to selectivity, repeatability and reusability tests and showed good results

Genomic insights into triple-negative and HER2-positive breast cancers using isogenic model systems

Introduction In general, genomic signatures of breast cancer subtypes have little or no overlap owing to the heterogeneous genetic backgrounds of study samples. Thus, obtaining a reliable signature in the context of isogenic nature of the cells has been challenging and the precise contribution of isogenic triple negative breast cancer (TNBC) versus non-TNBC remains poorly defined. Methods We established isogenic stable cell lines representing TNBC and Human Epidermal Growth Factor Receptor 2 positive (HER2+) breast cancers by introducing HER2 in TNBC cell lines MDA-MB-231 and MDA-MB-468. We examined protein level expression and functionality of the transfected receptor by treatment with an antagonist of HER2. Using microarray profiling, we obtained a comprehensive gene list of differentially expressed between TNBC and HER2+ clones. We identified and validated underlying isogenic components using qPCR and also compared results with expression data from patients with similar breast cancer subtypes. Results We identified 544 and 1087 statistically significant differentially expressed genes between isogenic TNBC and HER2+ samples in MDA-MB-231 and MDA-MB-468 backgrounds respectively and a shared signature of 49 genes. By comparing results from MDA-MB-231 and MDA-MB-468 backgrounds with two patient microarray datasets, we identified 17 and 22 common genes with same expression trend respectively. Additionally, we identified 56 and 78 genes from MDA-MB-231 and MDA-MB-468 comparisons respectively present in our published RNA-seq data. Conclusions Using our unique model system, we have identified an isogenic gene expression signature between TNBC and HER2+ breast cancer. A portion of our results was also verified in patient data samples, indicating an existence of isogenic element associated with HER2 status between genetically heterogeneous breast cancer samples. These findings may potentially contribute to the development of molecular platform that would be valuable for diagnostic and therapeutic decision for TNBC and in distinguishing it from HER2+ subtype

Domain truncation studies reveal that the streptokinase-plasmin activator complex utilizes long range protein-protein interactions with macromolecular substrate to maximize catalytic turnover

To explore the interdomain co-operativity during human plasminogen (HPG) activation by streptokinase (SK), we expressed the cDNAs corresponding to each SK domain individually (α , β , and γ ), and also their two-domain combinations, viz. αβ and βγ in Escherichia coli. After purification, α and β showed activator activities of approximately 0.4 and 0.05%, respectively, as compared with that of native SK, measured in the presence of human plasmin, but the bi-domain constructs αβ and βγ showed much higher co-factor activities (3.5 and 0.7% of native SK, respectively). Resonant Mirror-based binding studies showed that the single-domain constructs had significantly lower affinities for "partner" HPG, whereas the affinities of the two-domain constructs were remarkably native-like with regards to both binary-mode as well as ternary mode ("substrate") binding with HPG, suggesting that the vast difference in co-factor activity between the two- and three-domain structures did not arise merely from affinity differences between activator species and HPG. Remarkably, when the co-factor activities of the various constructs were measured with microplasminogen, the nearly 50-fold difference in the co-factor activity between the two- and three-domain SK constructs observed with full-length HPG as substrate was found to be dramatically attenuated, with all three types of constructs now exhibiting a low activity of approximately 1-2% compared to that of SK·HPN and HPG. Thus, the docking of substrate through the catalytic domain at the active site of SK-plasmin(ogen) is capable of engendering, at best, only a minimal level of co-factor activity in SK·HPN. Therefore, apart from conferring additional substrate affinity through kringle-mediated interactions, reported earlier (Dhar et al., 2002; J. Biol. Chem. 277, 13257), selective interactions between all three domains of SK and the kringle domains of substrate vastly accelerate the plasminogen activation reaction to near native levels

Involvement of a nine-residue loop of streptokinase in the generation of macromolecular substrate specificity by the activator complex through interaction with substrate kringle domains

The selective deletion of a discrete surface-exposed epitope (residues 254-262; 250-loop) in the β domain of streptokinase (SK) significantly decreased the rates of substrate human plasminogen (HPG) activation by the mutant (SKdel254-262). A kinetic analysis of SKdel254-262 revealed that its low HPG activator activity arose from a 5-6-fold increase in Km for HPG as substrate, with little alteration in kcat rates. This increase in the Km for the macromolecular substrate was proportional to a similar decrease in the binding affinity for substrate HPG as observed in a new resonant mirror-based assay for the real-time kinetic analysis of the docking of substrate HPG onto preformed binary complex. In contrast, studies on the interaction of the two proteins with microplasminogen showed no difference between the rates of activation of microplasminogen under conditions where HPG was activated differentially by nSK and SKdel254-262. The involvement of kringles was further indicated by a hypersusceptibility of the SKdel254-262. plasmin activator complex to ε-aminocaproic acid-mediated inhibition of substrate HPG activation in comparison with that of the nSK.plasmin activator complex. Further, ternary binding experiments on the resonant mirror showed that the binding affinity of kringles 1-5 of HPG to SKdel254-262.HPG was reduced by about 3-fold in comparison with that of nSK.HPG. Overall, these observations identify the 250 loop in the β domain of SK as an important structural determinant of the inordinately stringent substrate specificity of the SK.HPG activator complex and demonstrate that it promotes the binding of substrate HPG to the activator via the kringle(s) during the HPG activation process

Bilateral reversed palmaris longus muscle with trifid insertion, a rare variation

Normally the palmaris longus muscle originates from the medial epicondyle of the humerus from common flexor origin. In the middle of the forearm, the muscle belly forms a tendon which is inserted into the flexor retinaculum and the palmar aponeurosis. In our study after dissection of both forearms of a 45-year-old male cadaver we found a reversed palmaris longus muscle. This means that the palmaris longus muscle was tendinous in its proximal part and muscular in its distal part. The fleshy belly of muscle was passing over flexor retinaculum, was ensheathed by separate fascia. The muscle belly was spreading on both the sides of each palm for insertion which was trifid, that is centrally into palmar aponeurosis, laterally continuous with the fascia covering the thenar muscles and medially with Abductor digit minimi. It was having tendinous interconnection with the muscle mass of both the sides. Bilateral reversed palmaris longus muscle mentioned in the literature, was a surgical finding in a patient who suffered from edema and pain in the wrist. The overuse of the reversed palmaris longus muscle can lead to the muscle’s local hypertrophy. As per the literature a reversed palmaris longus muscle may cause a compartment syndrome with pain and edema in the wrist area, the carpal tunnel syndrome and Guyon’s syndrome. The variation is also useful to the hand surgeon, as the palmaris longus muscle is an anatomical landmark for operations in this area