Small Strands Research Articles

Numerical modeling of the transfer length of 17.8 mm (0.7 in) diameter prestressing strands in pretensioned members

The bond between concrete and reinforcing steel bars in reinforced concrete structures is crucial. Prestressing strands with a diameter of 17.8 mm (0.7 in) transfer higher compression per unit area than smaller strands, improving moment capacity and shear strength and extending the girder span. However, limited research on the bond performance of these 17.8 mm diameter prestressing strands has restricted their widespread use despite their advantages. This study presents a methodology to determine the transfer length of pretensioned members numerically. The influence of pretension force and bond strength on a 17.8 mm diameter strand was assessed through the validation of a finite element model using experimental results from a standardized pretensioned pull-out test. Analytical calculations using different code formulas were also conducted, encompassing strands of varying diameters. Our finite element analysis suggests that a 50.8 mm spacing between adjacent 17.8 mm diameter strands is applicable, ensuring there is no stress overlap in the transfer zones, which can lead to concrete cracking and reduced structural integrity. Existing code formulas, such as ACI 318–19 and AASHTO LRFD 9th edition, require longer transfer lengths when compared with the numerical results. The fib MC 2010 and EC2 formulas offer closer results to numerical results of smaller diameter strands but underestimate the transfer length for the 17.8 mm diameter strand. Therefore, improvements to code formulations may be necessary for more accurate transfer length predictions for this specific strand size.

DNA and its Mosaic Structure

We consider that the DNA is an information processing system, receiving, registering and transferring information. In DNA we encounter four different nucleotides, which may be considered as the “letters” of an alphabet. Each distinct DNA base may be represented equally well by a specific number and a DNA strand by a unique Gödel number G, where G is a product of prime numbers raised to appropriate powers. We studied the statistical distribution of g, the logarithm of G, in the case of equal probability for the four DNA bases. In the present work we extend our analysis in two different directions We consider unequal probabilities for the DNA bases We raise the issue of scaling. For relatively small DNA strands we use the prime number theorem and we obtain a Poisson distribution for the average g. The Poisson distribution depends upon a parameter λ, which connects together the DNA pattern and the prime number density. Different values for λ lead to a mosaic structure of DNA. Our work indicates a strong link between DNA structure, its representation by Gödel’s numbers and the distribution of the prime numbers.

P1-xTa8+xN13 (x=0.1-0.15): A Phosphorus Tantalum Nitride Featuring Mixed-Valent Tantalum and P/Ta Disorder Visualized by Scanning Transmission Electron Microscopy.

We report on the synthesis, crystal, and electronic structure, as well as the magnetic, and electric properties of the phosphorus-containing tantalum nitride P1-xTa8+xN13 (x=0.1-0.15). A high-pressure high-temperature reaction (8 GPa, 1400 °C) of Ta3N5 and P3N5 with NH4F as a mineralizing agent yields the compound in the form of black, rod-shaped crystals. Single-crystal X-ray structure elucidation (space group C2/m (no. 12), a=16.202(3), b=2.9155(4), c=11.089(2) Å, β=126.698(7)°, Z=2) shows a network of face- and edge-sharing Ta-centered polyhedra that contains small vacant channels and PN6 octahedra strands. Atomic resolution transmission electron microscopy reveals an unusual P/Ta disorder. Mixed-valent tantalum atoms exhibit interatomic distances similar to those in metallic tantalum, however, the electrical resistivity is quite high in the order of 101 Ω cm. The density of states and the electron localization function indicate localized electrons in both covalent and ionic bonds between P/Ta and N atoms, combined with less localized electrons that do not contribute to interatomic bonds.

P1–xTa8+xN13 (x = 0.1–0.15): A Phosphorus Tantalum Nitride Featuring Mixed‐Valent Tantalum and P/Ta Disorder Visualized by Scanning Transmission Electron Microscopy

We report on the synthesis, crystal, and electronic structure, as well as the magnetic, and electric properties of the phosphorus‐containing tantalum nitride P1–xTa8+xN13 (x = 0.1–0.15). A high‐pressure high‐temperature reaction (8 GPa, 1400 °C) of Ta3N5 and P3N5 with NH4F as a mineralizing agent yields the compound in the form of black, rod‐shaped crystals. Single‐crystal X‐ray structure elucidation (space group C2/m (no. 12), a = 16.202(3), b = 2.9155(4), c = 11.089(2) Å, β = 126.698(7)°, Z = 2) shows a network of face‐ and edge‐sharing Ta‐centered polyhedra that contains small vacant channels and PN6 octahedra strands. Atomic resolution transmission electron microscopy reveals an unusual P/Ta disorder. Mixed‐valent tantalum atoms exhibit interatomic distances similar to those in metallic tantalum, however, the electrical resistivity is quite high in the order of 10‑1 Ω cm. The density of states and the electron localization function indicate localized electrons in both covalent and ionic bonds between P/Ta and N atoms, combined with less localized electrons that do not contribute to interatomic bonds.

DNA-Modulated and Mechanoresponsive Excitonic Couplings Reveal Chiroptical Correlation of Conformation, Tension, and Dynamics of DNA Self-Assembly.

Study of the conformational and mechanical behaviors of biomolecular assemblies is vital to the rational design and realization of artificial molecular architectures with biologically relevant functionality. Here, we revealed DNA-modulated and mechanoresponsive excitonic couplings between organic chromophores and verified strong correlations between the excitonic chiroptical responses and the conformational and mechanical states of DNA self-assemblies irrespective of fluorescence background interference. Besides, the excitonic chiroptical effect allowed sensitive monitoring of DNA self-assembled nanostructures due to small molecule bindings or DNA strand displacement reactions. Moreover, we developed a new chiroptical reporter, a DNA-templated dimer of an achiral cyanine5 and an intrinsically chiral BODIPY, that exhibited unique multiple-split spectral line shape of exciton-coupled circular dichroism, largely separated response wavelengths, and enhanced anisotropy dissymmetry factor (g-factor). These results shed light on a promising chiroptical spectroscopic tool for studying biomolecular recognition and binding, conformation dynamics, and soft mechanics in general.

Repetitive transcranial magnetic stimulation (rTMS) as a tool for cognitive enhancement in healthy adults: a review study.

As human beings, we have always sought to expand on our abilities, including our cognitive and motor skills. One of the still-underrated tools employed to this end is repetitive transcranial magnetic stimulation (rTMS). Until recently, rTMS was almost exclusively used in studies with rehabilitation purposes. Only a small strand of literature has focused on the application of rTMS on healthy people with the aim of enhancing cognitive abilities such as decision-making, working memory, attention, source memory, cognitive control, learning, computational speed, risk-taking, and impulsive behaviors. It, therefore, seems that the findings in this particular field are the indirect results of rehabilitation research. In this review paper, we have set to investigate such studies and evaluate the rTMS effectuality in terms of how it improves the cognitive skills in healthy subjects. Furthermore, since the most common brain site used for rTMS protocols is the dorsolateral prefrontal cortex (DLPFC), we have added theta burst stimulation (TBS) wave patterns that are similar to brain patterns to increase the effectiveness of this method. The results of this study can help people who have high-risk jobs including firefighters, surgeons, and military officers with their job performance.

The Long and Winding Road: On-Demand DNA Synthesis in High Demand

The Long and Winding Road: On-Demand DNA Synthesis in High Demand

TRPS1 Is Differentially Expressed in a Variety of Malignant and Benign Cutaneous Sweat Gland Neoplasms

Neoplasms of sweat glands and the breast may be morphologically and immunophenotypically similar. A recent study showed that TRPS1 staining is a highly sensitive and specific marker for breast carcinoma. In this study, we analyzed TRPS1 expression in a spectrum of cutaneous sweat gland tumors. We stained five microcystic adnexal carcinomas (MACs), three eccrine adenocarcinomas, two syringoid eccrine carcinomas, four hidradenocarcinomas, six porocarcinomas, one eccrine carcinoma-NOS, 11 hidradenomas, nine poromas, seven cylindromas, three spiradenomas, and 10 syringomas with TRPS1 antibodies. All of the MACs and syringomas were negative. Every cylindroma and two of the three spiradenomas demonstrated intense staining in cells lining the ductular spaces, with negative to relatively weak expression in surrounding cells. Of the 16 remaining malignant entities, 13 were intermediate to high positive, one was low positive, and two were negative. From the 20 hidradenomas and poromas, intermediate to high positivity was revealed in 14 cases, low positivity in three cases, and negative staining in three cases. Our study demonstrates a very high (86%) expression of TRPS1 in malignant and benign adnexal tumors that are mainly composed of islands or nodules with polygonal cells, e.g., hidradenomas. On the other hand, tumors with small ducts or strands of cells, such as MACs, appear to be completely negative. This differential staining among types of sweat gland tumors may represent either differential cells of origin or divergent differentiation and has the potential to be used as a diagnostic tool in the future.

MiR-140-5p and miR-140-3p: Key Actors in Aging-Related Diseases?

microRNAs (miRNAs) are small single strand non-coding RNAs and powerful gene expression regulators. They mainly bind to the 3′UTR sequence of targeted mRNA, leading to their degradation or translation inhibition. miR-140 gene encodes the pre-miR-140 that generates the two mature miRNAs miR-140-5p and miR-140-3p. miR-140-5p/-3p have been associated with the development and progression of cancers, but also non-neoplastic diseases. In aging-related diseases, miR-140-5p and miR-140-3p expressions are modulated. The seric levels of these two miRNAs are used as circulating biomarkers and may represent predictive tools. They are also considered key actors in the pathophysiology of aging-related diseases. miR-140-5p/-3p repress targets regulating cell proliferation, apoptosis, senescence, and inflammation. This work focuses on the roles of miR-140-3p and miR-140-5p in aging-related diseases, details their regulation (i.e., by long non-coding RNA), and reviews the molecular targets of theses miRNAs involved in aging pathophysiology.

Implications of Nanotechnology in Ameliorating Cancer

Despite medical advances, cancer is still one of the most dreaded disorders. Surgery, chemotherapies and radiotherapies have typically been the preferred form of treatment. However, their limited solubility and unstable nature hinder their widespread application. Drug resistance, hair loss, and the destruction of healthy cells are all frequent side effects. Nanotechnology provides new cancer treatment options in this regard and have emerged as an efficient platform in targeting chemotherapies to malignant cells and neoplasms particularly. It has also been known to improve the therapeutic efficacy of radiation based and other modern treatment modalities. All these factors tend to lower the risk of a patient suffering from cancer, thereby increasing its survival.
 Research on cancer therapy using nanotechnology extends beyond the development of existing drugs to create new ones that are only made possible by the special properties of nanomaterials. Despite being much smaller than cells, nanoparticles are large enough to hold a variety of microscopic substances. Additionally, ligands like small molecules, DNA or RNA strands, peptides, aptamers, or antibodies can be employed to functionalize the relatively large surface area of nanoparticles. These characteristics allow the targeted delivery of many drugs with theranostic action. Their physical characteristics such as energy absorption and re-radiation can also be employed to destroy malignant cells.
 By enabling therapeutic substances to be enclosed in nanoparticulate materials and delivered specifically to tumours via passive permeation and active internalisation mechanisms, nanomedicine technologies have paved the way for revolutionary targeted cancer therapies. One of the biggest barriers to traditional therapy, resistance, has been discovered to be reduced by employing nanotechnology for therapeutic purposes. Many cancer treatments using nanomedicines are already available on the market, and many more are in advanced stages of development and clinical testing. These treatments use a variety of nanosystems, including metallic nanoparticles, liposomes, quantum dots, carbon nanotubes, polymeric micelles, and nanospheres.

Use of lignocellulosic biomaterials for sustainable development of bamboo strand lumber for structural applications

Bamboo is one of the fastest growing plants and has mechanical properties similar to timber. The main reasons for the popularity of bamboo in construction can be attributed to its low cost, local availability, and adequacy of simple, local tools, and skills for fabrication. Application of bamboo in construction is, however, normally limited to low-cost housing and temporary structures due to several factors including irregular shapes, hollow circular cross sections, and durability issues. This report presents the results of an investigation into production of an engineered bamboo lumber product. Bamboo culms were cut into smaller strands and were re-constituted into rectangular sections by gluing and pressing at 140 °C to 145 °C. This approach overcomes the presence of the inherent hollow core and randomizes the inter-nodes and other growth characteristics found in bamboo. The reconstituted bamboo strand lumber (RBSL) was developed using crushed Bambusa bambos species and phenol formaldehyde resin. The physical and mechanical properties of reconstituted bamboo strand lumber were evaluated as per IS 1734 (1983). From the results it was found that the BSL can be used as an alternate to timber to meet Sustainable Development Goals (SDGs) for building applications that will effectively transform the world.

Study of surface modification strategies to create glassy carbon-supported, aptamer-based sensors for continuous molecular monitoring

Electrochemical, aptamer-based (E-AB) sensors uniquely enable reagentless, reversible, and continuous molecular monitoring in biological fluids. Because of this ability, E-AB sensors have been proposed for therapeutic drug monitoring. However, to achieve translation from the bench to the clinic, E-AB sensors should ideally operate reliably and continuously for periods of days. Instead, because these sensors are typically fabricated on gold surfaces via self-assembly of alkanethiols that are prone to desorption from electrode surfaces, they undergo significant signal losses in just hours. To overcome this problem, our group is attempting to migrate E-AB sensor interfaces away from thiol-on-gold assembly towards stronger covalent bonds. Here, we explore the modification of carbon electrodes as an alternative substrate for E-AB sensors. We investigated three strategies to functionalize carbon surfaces: (I) anodization to generate surface carboxylic groups, (II) electrografting of arenediazonium ions, and (III) electrografting of primary aliphatic amines. Our results indicate that electrografting of primary aliphatic amines is the only strategy achieving monolayer organization and packing densities closely comparable to those obtained by alkanethiols on gold. In addition, the resulting monolayers enable covalent tethering of DNA aptamers and support electrochemical sensing of small molecule targets or complimentary DNA strands. These monolayers also achieve superior stability under continuous voltammetric interrogation in biological fluids relative to benchmark thiol-on-gold monolayers when a positive voltage scan window is used. Based on these results, we postulate the electrografting of primary aliphatic amines as a path forward to develop carbon-supported E-AB sensors with increased operational stability.Graphical abstract

Molecular and bioinformatics analysis of mir29b in liver diseases

Rationale: Liver is the largest solid organ which is more susceptible to get diseases, including Non-alcoholic fatty liver disease (NAFLD), hepatitis, haemochromatosis, liver cancer. MicroRNAs(miRNAs), the small single strand non-coding RNA, involved in a variety of biological processes by regulating gene expression at transcriptional or translational levels. MiR29b has been regarded as a potential antifibrotic agent by regulating several key pathological pathways. Thus, this study will provide a comprehensive understanding of the molecular role of miR29b in physiological and pathological processes, which will add knowledge on the therapeutic potential of miR29b in ameliorating liver diseases.

Single-stranded DNA binding proteins influence APOBEC3A substrate preference

The cytidine deaminase, APOBEC3A (A3A), is a prominent source of mutations in multiple cancer types. These APOBEC-signature mutations are non-uniformly distributed across cancer genomes, associating with single-stranded (ss) DNA formed during DNA replication and hairpin-forming sequences. The biochemical and cellular factors that influence these specificities are unclear. We measured A3A’s cytidine deaminase activity in vitro on substrates that model potential sources of ssDNA in the cell and found that A3A is more active on hairpins containing 4 nt ssDNA loops compared to hairpins with larger loops, bubble structures, replication fork mimics, ssDNA gaps, or linear DNA. Despite pre-bent ssDNAs being expected to fit better in the A3A active site, we determined A3A favors a 4 nt hairpin substrate only 2- to fivefold over linear ssDNA substrates. Addition of whole cell lysates or purified RPA to cytidine deaminase assays more severely reduced A3A activity on linear ssDNA (45 nt) compared to hairpin substrates. These results indicate that the large enrichment of A3A-driven mutations in hairpin-forming sequences in tumor genomes is likely driven in part by other proteins that preferentially bind longer ssDNA regions, which limit A3A’s access. Furthermore, A3A activity is reduced at ssDNA associated with a stalled T7 RNA polymerase, suggesting that potential protein occlusion by RNA polymerase also limits A3A activity. These results help explain the small transcriptional strand bias for APOBEC mutation signatures in cancer genomes and the general targeting of hairpin-forming sequences in the lagging strand template during DNA replication.

Band Alignment with Self‐Assembled 2D Layer of Carbon Derived from Waste to Balance Charge Injection in Perovskite Crystals Based Rigid and Flexible Light Emitting Diodes

AbstractThe halide perovskite nanocrystals (P‐NCs) can address a plethora of issues of the light‐emission technologies, due to its low temperature processing. To successfully employ P‐NCs for light‐emitting diodes (LEDs), one needs to resolve the issues of stability of the LEDs. The stability of device can be achieved by charge balance of electrons and holes recombination in active material. To investigate this herein, a self‐assembled carbon dots (CDs) layer is fabricated from waste small strands of human hair. The self‐assembled CDs layer is used beneath P‐NCs layer to reduce the band‐off set for hole transport, thus balancing the electron and holes carrier in active layer. The layer is used as an active light‐emitting layer to fabricate a LED device that exhibits green luminescence of 4800 cd m−2 at a current efficiency of 10.7 cd A−1 and external quantum efficiency of 4.8%. The LED exhibits operational stability of nearly 200 h. The same film is used to demonstrate a flexible device with maximum luminescence of 2259 cd m−2, with a high current density of 474 mA cm−2, current efficiency of 1.37 cd A−1 and a low turn‐on voltage of 3.5 V. All the display devices are measured in air without encapsulation.

Electrochemical biosensors combining aptamers and enzymatic activity: Challenges and analytical opportunities

The combination between the specific recognition abilities of aptamers and the catalytic power of enzymes represents a powerful tool in bioanalysis to achieve the highly selective and sensitive detection of various molecules. Enzymes attached to biomolecules and nanomaterials facilitate the highly amplified detection of electroactive compounds. Meanwhile DNAzymes, small DNA strands showing enzyme-like activity are increasingly used as replacements of natural enzymes in electrochemical aptasensors. Moreover, nucleic acid catalysts have been integrated together with aptamer domains in aptazymes, where the aptamer-ligand interaction acts as a switch for the enzyme-like activity. The review discusses enzyme and DNAzyme based amplification, as the preferred approaches in electrochemical aptasensors. DNA and nanomaterial based signal enhancement is briefly mentioned, while a larger discussion is dedicated to aptasensors for the measurement of enzymatic activity and for the development of “universal” detection tools based on the aptamer-enzyme combination. This includes assays combining aptamers with glucometers for the detection of various molecules and promising “aptameric enzyme subunits”-yet to be integrated with electrochemical detection. The outlooks of the electrochemical biosensors coupling aptamers and enzymes are presented.

Game Technologies to Assist Learning of Communication Skills in Dialogic Settings for Persons with Aphasia

Persons with aphasia suffer from a loss of communication ability as a consequence of a brain injury. While rare, a small strand of research indicates effectiveness of dialogic interventions for communication development for persons with aphasia, but a vast amount of research studies shows its effectiveness for other target groups. In this paper, we describe the main parts of the hitherto technological development of an application named Dialogica that is (i) aimed at facilitating increased communicative participation in dialogic settings for persons with aphasia and other communication disorders, (ii) based on computer game technology as well as on theory in dialogic education and argumentation theory, and (iii) designed for mobile devices with larger screens.

Polarization influences the evolution of nucleobase-graphene interactions.

In recent years, graphene has attracted attention from researchers as an atomistically thin solid state material for the study on the self-assembly of nucleobases. Non-covalent interactions between nucleobases and graphene sheets play a fundamental role in understanding the self-assembly of nucleobases on the graphene sheet. A fundamental understanding of the effect of molecular polarizability on these non-covalent interactions between the nucleobases and the underlying graphene sheet is absent in the literature. In this paper, we present the results from polarizable molecular dynamics simulation studies to understand the effect of polarization on the strength of non-covalent interactions. To this end, we report the development of Drude parameters for describing the polarizable graphene sheet. The developed parameters were used to study the self-aggregation phenomenon of nucleobases on a graphene support. We observe a significant change in the interaction patterns upon the inclusion of polarization into the system, with polarizable simulations yielding results that closely resemble the experimental studies. Two of the key observations were the probability of the formation of stacks in guanine-rich systems, and the spontaneous formation of H-bonded structures over the graphene sheet, which allude to the importance of the DNA sequence and composition. Both these effects were not observed in the additive simulations. The present study sheds light on the effect of polarization on the adsorption of DNA nucleobases on a graphene sheet, but the methodology can be extended to include a variety of small molecules and complete DNA strands.

Structure optimization of woven fabric composites for improvement of mechanical properties using a micromechanics model of woven fabric composites and a genetic algorithm

This research aims to optimize the mechanical properties of woven fabric composites, especially the elastic modulus. A micromechanics model of woven fabric composites was used to obtain the mechanical properties of the fiber composite, and a genetic algorithm (GA) was employed for the optimization tool. The structure of the fabric fiber was expressed using the width, thickness, and wave pattern of the fiber strands in the woven fabric composites. In the GA, the chromosome string consisted of the thickness and width of the fill and warp strands, and the objective function was determined to maximize the elastic modulus of the composite. Numerical analysis showed that the longitudinal mechanical properties of the strands contributed significantly to the overall elastic modulus of the composites because the longitudinal property was notably larger than the transverse property. Therefore, to improve the in-plane elastic modulus, the resulting geometry of the composites possessed large volumes of related strands with large cross-sectional areas and small strand waviness. However, the numerical results of the out-of-plane elastic modulus generated large strand waviness, which contributed to the fiber alignment in the out-of-plane direction. The findings of this research are expected to be an excellent resource for the structural design of woven fabric composites.

Desmoplastic ameloblastoma in the mandible: A case report

Introduction: 0.9 – 12.1% of all cases of ameloblastoma account to be Desmoplastic Ameloblastoma (DA). The presentation of the tumor is often similar to benign fibro-osseous lesions both clinically as well as radiographically. Histologically, DA is made up of small nests and strands of odontogenic epithelium which seem to be compressed by the highly collagenized stroma. We report a case of DA in a 44-year-old female with a mildly painful swelling in the anterior region of mandible. The lesion had a multilocular appearance on both panoramic radiographs as well as in the computed tomography scan. Histologically, the lesion was confirmed to be a case of DA. Regardless of the fact that DA is a rare entity, its aggressive nature binds the clinician to be cautious enough to include DA in the differential diagnosis of any lesion/growth clinically and radiographically mimicking a benign fibro osseous lesion. Keywords: Ameloblastoma, Desmoplasia, Mandible.