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As the demand for biobased lubricating oils continues to rise, there is a growing focus on exploring diverse oil types. Particularly noteworthy is the surge in demand for high oleic oils, which offer enhanced stability, and a richer oleic acid content compared to their regular oil counterparts. However, the performance of high oleic soybean oil (HOSO) with additives compared to regular soybean oil (RSO), remains unclear. This study is focused on revealing the compatibility of both regular soybean oil (RSO) and high oleic soybean oil (HOSO) with select antiwear and antioxidant additives, specifically zinc dialkyl dithiophosphate (ZDDP), and zinc dialkyl dithiocarbamate (ZDDC) combined with antimony dialkyldithiocarbamate (ADDC), along with a comparative performance analysis of these additives. Reciprocating friction, wear, and electrical contact resistance-based analyses were conducted to evaluate additive compatibility and wear mechanisms at room temperature lubrication conditions. Interestingly, it was observed that for the select additives, the compatibility with regular soybean oil (RSO) was better than that of high oleic soybean oil (HOSO). RSO with additives showed around 28% reduction of wear volume whereas, it was only 8% for HOSO with additives. Additional physiochemical property analyses were conducted on the lubricants to correlate the observed tribological behavior. The worn-out surfaces of the test samples were characterized thoroughly to reveal the dominant wear mechanisms. [ABSTRACT FROM AUTHOR]

The NiTi alloy has attracted significant interest owing to its notable wear and corrosion resistance, suggesting the significant promise of utilizing additively manufactured NiTi alloys in tribological applications. In this study, dry sliding wear tests with sliding velocity of 0.1 m/s for total distance of 250 m at room temperature, 50 °C, 100 °C, and 200 °C were carried out on samples of NiTi alloy samples fabricated using laser powder and laser wire directed energy deposition (LP-DED and LW-DED) processes. Enhanced friction and wear behavior of LP-DED samples were captured at lower temperatures due to higher hardness and the stable dominating NiTi B2 austenite phase in the sample microstructure as confirmed from x-ray diffraction (XRD) analysis. Accumulated transferred material at lower temperatures played a crucial role in modifying the wear mechanisms. However, at higher temperatures both LP-DED and LW-DED samples presented similar wear mechanisms. [ABSTRACT FROM AUTHOR]

In this work, a new scheme is developed and experimentally tested for fabricating family of MAX–metal composites. This scheme combines the combustion synthesis (CS) process to obtain a porous MAX‐phase skeleton and process of metal melt infiltration spontaneously, which is then used to fabricate Ti3SiC2–TiC–Sn and Ti3SiC2–TiC–(Sn–Pb) composites. The resultant composite samples have an uneven density along the length, which steadily decrease from the point of contact of the sample with the molten tin to the opposite edge. Existence of Ti3SiC2, TiC, Sn, and (Sn and Pb) phases in the composite samples is confirmed using X‐ray diffraction and energy‐dispersive spectroscopy analyses. Comparative tribological characterizations are performed on fabricated Ti3SiC2–TiC–Sn and Ti3SiC2–TiC–(Sn–Pb) composite samples. Herein, these results are compared against standalone Sn and Sn–Pb samples as baseline and reveal major differences in friction and wear mechanisms due to addition of select MAX phases via novel CS process. As a whole, in the present study, a novel synthesis process is established to fabricate MAX‐phase composites and its enhanced tribological behavior and wear mechanisms which can have plethora of applications ranging from aerospace, automotive to biomedical sectors, are validated. [ABSTRACT FROM AUTHOR]

Pregnenolone (P5) is synthesized as the first bioactive steroid in the mitochondria from cholesterol. Clusters of differentiation 4 (CD4+) and Clusters of differentiation 8 (CD8+) immune cells synthesize P5 de novo; P5, in turn, play important role in immune homeostasis and regulation. However, P5’s biochemical mode of action in immune cells is still emerging. We envisage that revealing the complete spectrum of P5 target proteins in immune cells would have multifold applications, not only in basic understanding of steroids biochemistry in immune cells but also in developing new therapeutic applications. We employed a CLICK-enabled probe to capture P5-binding proteins in live T helper cell type 2 (Th2) cells. Subsequently, using highthroughput quantitative proteomics, we identified the P5 interactome in CD4+ Th2 cells. Our study revealed P5’s mode of action in CD4+ immune cells. We identified novel proteins from mitochondrial and endoplasmic reticulum membranes to be the primary mediators of P5’s biochemistry in CD4+ and to concur with our earlier finding in CD8+ immune cells. Applying advanced computational algorithms and molecular simulations, we were able to generate near-native maps of P5–protein key molecular interactions. We showed bonds and interactions between key amino acids and P5, which revealed the importance of ionic bond, hydrophobic interactions, and water channels. We point out that our results can lead to designing of novel molecular therapeutics strategies. [ABSTRACT FROM AUTHOR]

Objectives: From the treatment of damaged teeth to replacing missing teeth, dental biomaterials cover the scientific interest of many fields. Dental biomaterials are one of the implants whose effective life depends vastly on their material and manufacturing techniques. The purpose of this review is to summarize the important aspects for metallic dental implants from biomedical, mechanical and materials science perspectives. The review article will focus on five major aspects as mentioned below. Tooth anatomy: Maximizing the implant performance depends on proper understanding of human tooth anatomy and the failure behavior of the implants. Major parts from tooth anatomy including saliva characteristics are explored in this section. Wear mechanisms: The prominent wear mechanisms having a high impact on dental wear are abrasive, adhesive, fatigue and corrosion wear. To imitate the physiological working condition of dental implants, reports on the broad range of mastication force and various composition of artificial saliva have been included in this section, which can affect the tribo-corrosion behavior of dental implants. Dental implants classifications: The review paper includes a dedicated discussion on major dental implants types and their details for better understanding their applicability and characteristics. Implant materials: As of today, the most established dental implant materials are SS316L, cobalt chrome alloy and titanium. Detailed discussion on their material properties, microstructures, phase transformations and chemical compositions have been discussed here. Manufacturing techniques: In terms of different production methods, the lost wax casting method as traditional manufacturing is considered. Selective Laser Melting (SLM) and Directed Energy Deposition (DED) as additive manufacturing techniques (AM) have been discussed. For AM, the relationships between process–property–performance details have been explored briefly. The effectiveness of different manufacturing techniques was compared based on porosity distribution, mechanical and biomechanical properties. Summary: Despite having substantial research available on dental implants, there is a lack of systematic reviews to present a holistic viewpoint combining state-of-the-art from biomedical, mechanical, materials science and manufacturing perspectives. This review article attempts to combine a wide variety of analyzing approaches from those interdisciplinary fields to deliver deeper insights to researchers both in academia and industry to develop next-generation dental implants. [ABSTRACT FROM AUTHOR]

Dinoflagellate clocks are unique as they show no resemblance to any known model eukaryotic or prokaryotic clock architecture. Dinoflagellates are unicellular, photosynthetic, primarily marine eukaryotes are known for their unique biology and rhythmic physiology. Their physiological rhythms are driven by an internal oscillator whose molecular underpinnings are yet unknown. One of the primary reasons that slowed the progression of their molecular studies is their extremely large and repetitive genomes. Dinoflagellates are primary contributors to the global carbon cycle and oxygen levels, therefore, comprehending their internal clock architecture and its interaction with their physiology becomes a subject of utmost importance. The advent of high throughput Omics technology provided the momentum to understand the molecular architecture and functioning of the dinoflagellate clocks. We use these extensive databases to perform meta-analysis to reveal the status of clock components in dinoflagellates. In this article, we will delve deep into the various "Omics" studies that catered to various breakthroughs in the field of circadian biology in these organisms that were not possible earlier. The overall inference from these omics studies points toward an uncommon eukaryotic clock model, which can provide promising leads to understand the evolution of molecular clocks. [ABSTRACT FROM AUTHOR]

How signaling proteins generate a multitude of information to organize tissue patterns is critical to understanding morphogenesis. In Drosophila, FGF produced in wing-disc cells regulates the development of the disc-associated air-sac-primordium (ASP). Here, we show that FGF is Glycosylphosphatidylinositol-anchored to the producing cell surface and that this modification both inhibits free FGF secretion and promotes target-specific cytoneme contacts and contact-dependent FGF release. FGF-source and ASP cells extend cytonemes that present FGF and FGFR on their surfaces and reciprocally recognize each other over distance by contacting through cell-adhesion-molecule (CAM)-like FGF-FGFR binding. Contact-mediated FGF-FGFR interactions induce bidirectional responses in ASP and source cells that, in turn, polarize FGF-sending and FGF-receiving cytonemes toward each other to reinforce signaling contacts. Subsequent un-anchoring of FGFR-bound-FGF from the source membrane dissociates cytoneme contacts and delivers FGF target-specifically to ASP cytonemes for paracrine functions. Thus, GPI-anchored FGF organizes both source and recipient cells and self-regulates its cytoneme-mediated tissue-specific dispersion. Cytonemes are signaling filopodia that mediate target-specific long-distance communications of signals like FGFs. Du et al. show that a Drosophila FGF is anchored to the FGF-producing cell surface, inhibiting free FGF secretion and activating contact-dependent bidirectional FGF-FGFR interactions, controlling target-specific cytoneme contacts and contact-dependent FGF release. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) is the process by which large, metallic structures are built, layer-by-layer, using a welding arc to melt wire feedstock. In this process, the proper selection of the shielding gas plays a vital role in the achievement of structurally acceptable part geometries and quality surface finishes. In this study, the authors used either a ternary mix (He, Ar and CO2) or a binary mix (Ar and CO2) of shielding gases to deposit wall geometries using an open loop-controlled WAAM system developed at Oak Ridge National Laboratory's Manufacturing Demonstration Facility. The binary blend produced a wider and shorter geometry, while the ternary blend resulted in a narrower build that was more equivalent to the CAD geometry. The data indicated that the binary blend provided a higher oxygen concentration in the weld as compared to that of the ternary blend. The results imply that the arc characteristics and heat input had a significantly higher impact on the weld penetration than the surface tension effect of surface active elements. This was further verified by developing and applying a high-fidelity computational fluid dynamics (CFD) model of the thermophysical properties of gas mixtures. The results from the model showed that, while the influence of increased oxygen concentration on the surface tension for the binary blend led to a deeper penetration, the ternary blend gave rise to heat flux to the workpiece. [ABSTRACT FROM AUTHOR]

Asymmetric signaling and organization in the stem-cell niche determine stem-cell fates. Here, we investigate the basis of asymmetric signaling and stem-cell organization using the Drosophila wing-disc that creates an adult muscle progenitor (AMP) niche. We show that AMPs extend polarized cytonemes to contact the disc epithelial junctions and adhere themselves to the disc/niche. Niche-adhering cytonemes localize FGF-receptor to selectively adhere to the FGF-producing disc and receive FGFs in a contact-dependent manner. Activation of FGF signaling in AMPs, in turn, reinforces disc-specific cytoneme polarity/adhesion, which maintains their disc-proximal positions. Loss of cytoneme-mediated adhesion promotes AMPs to lose niche occupancy and FGF signaling, occupy a disc-distal position, and acquire morphological hallmarks of differentiation. Niche-specific AMP organization and diversification patterns are determined by localized expression and presentation patterns of two different FGFs in the wing-disc and their polarized target-specific distribution through niche-adhering cytonemes. Thus, cytonemes are essential for asymmetric signaling and niche-specific AMP organization. Asymmetric signaling and organization in the stem cell niche determine cell fates. Here the authors show that polarized contact-dependent signaling through specialized cytonemes forms the basis of niche-specific asymmetric signaling and stem cell organization. [ABSTRACT FROM AUTHOR]

Fragile X syndrome (FXS) is the most common cause of heritable intellectual disability and autism and affects ~1 in 4000 males and 1 in 8000 females. The discovery of effective treatments for FXS has been hampered by the lack of effective animal models and phenotypic readouts for drug screening. FXS ensues from the epigenetic silencing or loss-of-function mutation of the fragile X mental retardation 1 (FMR1) gene, which encodes an RNA binding protein that associates with and represses the translation of target mRNAs. We previously found that the activation of LIM kinase 1 (LIMK1) downstream of augmented synthesis of bone morphogenetic protein (BMP) type 2 receptor (BMPR2) promotes aberrant synaptic development in mouse and Drosophila models of FXS and that these molecular and cellular markers were correlated in patients with FXS. We report that larval locomotion is augmented in a Drosophila FXS model. Genetic or pharmacological intervention on the BMPR2-LIMK pathway ameliorated the synaptic abnormality and locomotion phenotypes of FXS larvae, as well as hyperactivity in an FXS mouse model. Our study demonstrates that (i) the BMPR2-LIMK pathway is a promising therapeutic target for FXS and (ii) the locomotion phenotype of FXS larvae is a quantitative functional readout for the neuromorphological phenotype associated with FXS and is amenable to the screening novel FXS therapeutics. [ABSTRACT FROM AUTHOR]

Background and Aims: Since December 2019, an increasing number of pneumonia cases of unknown reasons emerged in Wuhan, China. Deep-sequencing analysis from nasopharyngeal swabs, sputum, lower respiratory tract samples, and blood indicated a novel coronavirus, known as 2019-nCoV. Our aim was to determine the association of haematological parameters such as haemoglobin (Hb%), total leukocyte count (TLC), platelet count (Plt) with severity of coronavirus disease 19 (COVID 19) infection among patients admitted in the COVID intensive care unit (ICU) and COVID ward, and our objectives were to estimate haemoglobin (Hb), TLC, differential leukocyte count (DLC), and platelet count of patients admitted in the COVID ward and ICU; to derive neutrophil lymphocyte ratio (NLR) from the DLC of the patients admitted in the COVID ward and ICU; and to determine the correlation between Hb, platelet count, TLC, and NLR with severity of disease among COVID patients. Methods: After receiving approval from institutional ethics committee, data were collected according to our study parameter (age, weight, height, Hb%, TLC, platelet, NLR) from the medical record section for ICU-admitted (Group A) and ward-admitted (Group B) patients and compared. Here, SPSS version 22 was used for analysis, and a p value <0.05 was considered significant. Results: A decreasing trend in Hb%, TLC, and platelet count was seen in both the groups but more in group A than group B, which is statistically significant; NLR got an increasing trend in these two groups, and the increase in group A is more and statistically significant compared to group B. Conclusion: Our study tries to explore the feasibility of such parameters in this regard and found that a combination of NLR, Hb%, TLC, and platelet count can be considered together as an effective prognostic indicator in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). [ABSTRACT FROM AUTHOR]

Recent findings in several organ systems show that cytoneme-mediated signaling transports signaling proteins along cellular extensions and targets cell-to-cell exchanges to synaptic contacts. This mechanism of paracrine signaling may be a general one that is used by many (or all) cell types in many (or all) organs. We briefly review these findings in this perspective. We also describe the properties of several signaling systems that have previously been interpreted to support a passive diffusion mechanism of signaling protein dispersion, but can now be understood in the context of the cytoneme mechanism. Also watch the . [ABSTRACT FROM AUTHOR]

Background Almost all cells display circadian rhythms, ~24 hour period changes in their biochemistry, physiology or behavior. These rhythms are orchestrated by an endogenous circadian clock whose mechanism is based on transcription-translation feedback loops (TTFL) where the translated products of clock genes act to inhibit their own transcription. Results We have used RNA-Seq to measure the abundance of all transcripts in an RNA-Seq-derived de novo gene catalog in two different experiments. One compared midday and midnight in a light-dark cycle (ZT6 and ZT18) and under constant light (CT6 and CT18). The second compared four different times (ZT2, ZT6, ZT14 and ZT18) under a light dark cycle. We show here that despite an elaborate repertoire of biological rhythms, the unicellular dinoflagellate Lingulodinium had no detectable daily variation in the abundance of any transcript in an RNA-Seq-derived de novo gene catalog. We also examined the timing of the bioluminescence and photosynthesis rhythms in the presence of the transcription inhibitors actinomycin D and cordycepin. We found that the timing of the two rhythms was unchanged even when transcription rates had decreased to roughly 5% the levels of untreated cells. Conclusions The lack of detectable daily variation in transcript levels indicates that the endogenous circadian timer of Lingulodinium does not require rhythmic RNA. If the circadian timer is considered as a limit cycle oscillator, then cellular time in this organism must be defined by variations in state variables that do not include the amount of a clock gene transcript. [ABSTRACT FROM AUTHOR]

Minimum quantity lubrication technology is emerging as a potential alternative to flood cooling to effectively control cutting temperature during machining. In this study, an in-house developed minimum quantity lubrication delivery system has been used for minimum quantity lubrication delivery of cutting fluid at the machining zone. An advanced nanofluid coolant was also used for the purpose of minimum quantity lubrication. Different methods have been attempted to measure the near tool-tip temperature during turning of AISI 4140 steel with multi-layered coated insert under dry, flood cooled and minimum quantity lubrication cooled condition. It was further attempted to identify the best technique for assessing near tool-tip temperature. Infrared thermography has shown the closest result to that obtained through a finite element analysis (DEFORM 3DTM) simulation. Potential of multi-walled carbon nanotube–based nanofluid in minimum quantity lubrication application has been thoroughly investigated in this case study, where high-speed turning of AISI 4140 steel was carried out by a multi-layered coated carbide insert. Design of experiments, based on Taguchi method, was used to find out the significance of cutting parameters on machinability under nanofluid environment. Multi-walled carbon nanotube–based nanofluid was found to outperform the rest in all conditions. [ABSTRACT FROM PUBLISHER]

Dinoflagellates are microscopic, eukaryotic, and primarily marine plankton. Temporary cyst formation is a well-known physiological response of dinoflagellate cells to environmental stresses. However, the molecular underpinnings of cold-induced cyst physiology have never been described. Cultures of the photosynthetic dinoflagellate Lingulodinium polyedrum readily form temporary cysts when placed at low (8°C ± 1°C) temperature and excyst to form normal motile cells following a return to normal temperature (18°C ± 1°C) The normal circadian bioluminescence rhythm and the expected changes in Luciferin Binding Protein abundance were arrested in L. polyedrum cysts. Furthermore, after excystment, the bioluminescence rhythm initiates at a time corresponding to zeitgeber 12, independent of the time when the cells encysted. Phosphoprotein staining after two-dimensional polyacrylamide gel electrophoresis, as well as column-based phosphoprotein enrichment followed by liquid chromatography tandem mass spectrometry, showed cyst proteins are hy-pophosphorylated when compared with those from motile cells, with the most marked decreases found for predicted Casein Kinase2 target sites. In contrast to the phosphoproteome, the cyst proteome is not markedly different from motile cells, as assessed by two-dimensional polyacrylamide gel electrophoresis. In addition to changes in the phosphoproteome, RNA sequencing revealed that cysts show a significant decrease in the levels of 132 RNAs. Of the 42 RNAs that were identified by sequence analysis, 21 correspond to plastid-encoded gene products and 11 to nuclear-encoded cell wall/plasma membrane components. Our data are consistent with a model in which the highly reduced metabolism in cysts is achieved primarily by alterations in the phosphoproteome. The stalling of the circadian rhythm suggests temporary cysts may provide an interesting model to address the circadian system of dinoflagellates. [ABSTRACT FROM AUTHOR]

Fatigue performance of stiffened pole-to-base plate socket connection in high-mast lighting structures was evaluated by experimental and analytical studies. In absence of sufficient experimental data, constant amplitude fatigue limit (CAFL) of longitudinal stiffener terminations on pole walls is classified as Category E′ in the existing American Association of State Highway and Transpiration Officials (AASHTO) specification. Fatigue performance of this connection in the thin-walled tubular structures is controlled by localized secondary bending stress, the magnitude of which depends on the relative stiffness of the connecting elements. Ten full-size high-mast specimens having stiffened socket connection were tested under constant amplitude reversal loading to determine the fatigue resistance of this connection in finite and infinite life regimes. The specimen design was optimized by parametric finite-element analysis (FEA) and local stress approaches. FEA results were verified by conducting static tests on an elaborately instrumented specimen. The test results demonstrated that an optimized stiffened connection can provide a CAFL of AASHTO fatigue Category D in commonly used high-mast structures. [ABSTRACT FROM AUTHOR]

Dinoflagellates are an important component of the marine biota, but a large genome with high-copy number (up to 5,000) tandem gene arrays has made genomic sequencing problematic. More importantly, little is known about the expression and conservation of these unusual gene arrays. We assembled de novo a gene catalog of 74,655 contigs for the dinoflagellate Lingulodinium polyedrum from RNA-Seq (Illumina) reads. The catalog contains 93% of a Lin-gulodinium EST dataset deposited in GenBank and 94% of the enzymes in 16 primary metabolic KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, indicating it is a good representation of the transcriptome. Analysis of the catalog shows a marked underrepresentation of DNA-binding proteins and DNA-binding domains compared with other algae. Despite this, we found no evidence to support the proposal of polycistronic transcription, including a marked underrepresentation of sequences corresponding to the intergenic spacers of two tandem array genes. We also have used RNA-Seq to assess the degree of sequence conservation in tandem array genes and found their transcripts to be highly conserved. Interestingly, some of the sequences in the catalog have only bacterial homologs and are potential candidates for horizontal gene transfer. These presumably were transferred as single-copy genes, and because they are now all GC-rich, any derived from AT-rich contexts must have experienced extensive mutation. Our study not only has provided the most complete dinoflagellate gene catalog known to date, it has also exploited RNA-Seq to address fundamental issues in basic transcription mechanisms and sequence conservation in these algae. [ABSTRACT FROM AUTHOR]

Background: Dinoflagellates typically lack histones and nucleosomes are not observed in DNA spreads. However, recent studies have shown the presence of core histone mRNA sequences scattered among different dinoflagellate species. To date, the presence of all components required for manufacturing and modifying nucleosomes in a single dinoflagellate species has not been confirmed. Methodology and Results: Analysis of a Lingulodinium transcriptome obtained by Illumina sequencing of mRNA shows several different copies of each of the four core histones as well as a suite of histone modifying enzymes and histone chaperone proteins. Phylogenetic analysis shows one of each Lingulodinium histone copies belongs to the dinoflagellate clade while the second is more divergent and does not share a common ancestor. All histone mRNAs are in low abundance (roughly 25 times lower than higher plants) and transcript levels do not vary over the cell cycle. We also tested Lingulodinium extracts for histone proteins using immunoblotting and LC-MS/MS, but were unable to confirm histone expression at the protein level. Conclusion: We show that all core histone sequences are present in the Lingulodinium transcriptome. The conservation of these sequences, even though histone protein accumulation remains below currently detectable levels, strongly suggests dinoflagellates possess histones. [ABSTRACT FROM AUTHOR]

Study of activity of cloned promoters in slow-growing Mycobacterium tuberculosis during long-term growth conditions in vitro or inside macrophages, requires a genome-integration proficient promoter probe vector, which can be stably maintained even without antibiotics, carrying a substrate-independent, easily scorable and highly sensitive reporter gene. In order to meet this requirement, we constructed pAKMN2, which contains mycobacterial codon-optimized gfpm2+ gene, coding for GFPm2+ of highest fluorescence reported till date, mycobacteriophage L5 attP-int sequence for genome integration, and a multiple cloning site. pAKMN2 showed stable integration and expression of GFPm2+ from M. tuberculosis and M. smegmatis genome. Expression of GFPm2+, driven by the cloned minimal promoters of M. tuberculosis cell division gene, ftsZ ( MtftsZ), could be detected in the M. tuberculosis/pAKMN2-promoter integrants, growing at exponential phase in defined medium in vitro and inside macrophages. Stable expression from genome-integrated format even without antibiotic, and high sensitivity of detection by flow cytometry and fluorescence imaging, in spite of single copy integration, make pAKMN2 useful for the study of cloned promoters of any mycobacterial species under long-term in vitro growth or stress conditions, or inside macrophages. [ABSTRACT FROM AUTHOR]

Bacterial FtsE gene codes for the ATP-binding protein, FtsE, which in complex with the transmembrane protein, FtsX, participates in diverse cellular processes. Therefore, regulated expression of FtsE and FtsX might be critical to the human pathogen, Mycobacterium tuberculosis, under stress conditions. Although ftsX gene of M. tuberculosis ( MtftsX) is known to be transcribed from a promoter inside the upstream gene, ftsE, the transcriptional status of ftsE gene of M. tuberculosis ( MtftsE) remains unknown. Therefore, the authors initiated transcriptional analyses of MtftsE, using total RNA from M. tuberculosis cells that were grown under stress conditions, which the pathogen is exposed to, in granuloma in tuberculosis patients. Primer extension experiments showed the presence of putative transcripts, T1, T2, T3, and T4. T1 originated from the intergenic region between the upstream gene, MRA_3135, and MtftsE. T2 and T3 were found initiated from within MRA_3135. T4 was transcribed from a region upstream of MRA_3135. RT-PCR confirmed co-transcription of MRA_3135 and MtftsE. The cloned putative promoter regions for T1, T2, and T3 elicited transcriptional activity in Mycobacterium smegmatis transformants. T1, T2, and T3, but no new transcript, were present in the M. tuberculosis cells that were grown under the stress conditions, which the pathogen is exposed to in granuloma in tuberculosis patients. It showed lack of modulation of MtftsE transcripts under the stress conditions tested, indicating that ftsE may not have a stress response-specific function in M. tuberculosis. [ABSTRACT FROM AUTHOR]

Heat shock promoters of mycobacteria are strong promoters that become rapidly upregulated during macrophage infection and thus serve as valuable candidates for expressing foreign antigens in recombinant BCG vaccine. In the present study, a new heat shock promoter controlling the expression of the groESL1 operon was identified and characterized. Mycobacterium tuberculosis groESL1 operon codes for the immunodominant 10 kDa ( Rv3418c, GroES/Cpn10/Hsp10) and 60 kDa ( Rv3417c, GroEL1/Cpn60.1/Hsp60) heat shock proteins. The basal promoter region was 115 bp, while enhanced activity was seen only with a 277-bp fragment. No promoter element was seen in the groES– groEL1 intergenic region. This operon codes for a bicistronic mRNA transcript as determined by reverse transcriptase-PCR and Northern blot analysis. Primer extension analysis identified two transcriptional start sites (TSSs) TSS1 (−236) and TSS2 (−171), out of which one (TSS2) was heat inducible. The groE promoter was more active than the groEL2 promoter in Mycobacterium smegmatis. Further, it was found to be differentially regulated under stress conditions, while the groEL2 promoter was constitutive. [ABSTRACT FROM AUTHOR]

This work investigated the linear thermal expansion properties of a multi-material specimen fabricated with Invar M93 and A36 steel. A sequence of tests was performed to investigate the viability of additively manufactured Invar M93 for lowering the coefficient of thermal expansion (CTE) in multi-material part tooling. Invar beads were additively manufactured on a steel base plate using a fiber laser system, and samples were taken from the steel, Invar, and the interface between the two materials. The CTE of the samples was measured between 40 °C and 150 °C using a thermomechanical analyzer, and the elemental composition was studied with energy dispersive X-ray spectroscopy. The CTE of samples taken from the steel and the interface remained comparable to that of A36 steel; however, deviations between the thermal expansion values were prevalent due to element diffusion in and around the heat-affected zone. The CTEs measured from the Invar bead were lower than those from the other sections with the largest and smallest thermal expansion values being 10.40 μm/m-K and 2.09 μm/m-K. In each of the sections, the largest CTE was measured from samples taken from the end of the weld beads. An additional test was performed to measure the aggregate expansion of multi-material tools. Invar beads were welded on an A36 steel plate. The invar was machined, and the sample was heated in an oven from 40 °C and 160 °C. Strain gauges were placed on the surface of the part and were used to analyze how the combined thermal expansions of the invar and steel would affect the thermal expansion on the surface of a tool. There were small deviations between the expansion values measured by gauges placed in different orientations, and the elongation of the sample was greatest along the dimension containing a larger percentage of steel. On average, the expansion of the machined Invar surface was 42% less than the expansion of the steel surface. The results of this work demonstrate that additively manufactured Invar can be utilized to decrease the CTE for multi-material part tooling. [ABSTRACT FROM AUTHOR]

Wire-based metal additive manufacturing utilizes the ability of additive manufacturing to fabricate complex geometries with high deposition rates (above 7 kg/h), thus finding applications in the fabrication of large-scale components, such as stamping dies. Traditionally, the workhorse materials for stamping dies have been martensitic steels. However, the complex thermal gyrations induced during additive manufacturing can cause the evolution of an inhomogeneous microstructure, which leads to a significant scatter in the mechanical properties, especially the toughness. Therefore, to understand these phenomena, arc-based additive AISI 410 samples were fabricated using robotic gas metal arc welding (GMAW) and were subjected to a detailed characterization campaign. The results show significant scatter in the tensile properties as well as Charpy V-notch impact toughness data, which was then correlated to the microstructural heterogeneity and delta (δ) ferrite formation. Post-processing (austenitizing and tempering) treatments were developed and an ~70% reduction in the scatter of tensile data and a four-times improvement in the toughness were obtained. The changes in mechanical properties were rationalized based on the microstructure evolution during additive manufacturing. Based on these, an outline to tailor the composition of "printable" steels for tooling with isotropic and uniform mechanical properties is presented and discussed. [ABSTRACT FROM AUTHOR]

Gold (Au) and copper (Cu)-based nanostructures are of great interest due to their applicability in various areas including catalysis, sensing and optoelectronics. Nanostructures synthesized by the galvanic displacement method often lead to non-uniform density and poor size distribution. Here, density and size-controlled synthesis of Au and Cu-based nanostructures was made possible by galvanic displacement with limited exposure to hydrofluoric (HF) acid and the use of surfactants like L-cysteine (L-Cys) and cetyltrimethylammonium bromide (CTAB). An approach involving cyclic exposure to HF acid regulated the nanostructure density. Further, the use of surfactants generated monodisperse nanoparticles in the initial stages of the deposition with increased density. The characterization of Au and Cu-based nanostructures was performed by scanning electron microscopy, atomic force microscopy, UV-Visible spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. The surface enhanced Raman spectroscopic measurements demonstrated an increase in the Raman intensity by two to three orders of magnitude for analyte molecules like Rhodamine 6G dye and paraoxon. [ABSTRACT FROM AUTHOR]

The formation of white etching cracks (WECs) is a dominant failure mode in wind turbine gearbox bearings that can significantly shorten their operating life. Although the phenomenon of WECs has been communicated in the field for more than a decade, the driving mechanisms are still debated, and the impact of proposed mitigation techniques is not quantified. Leading hypotheses to inhibit the formation of WECs center on material solutions, including the use of steel with high levels of retained austenite (RA). The present work aims to explore the impact of RA on the formation of WECs within AISI 8620 steel under boundary lubrication. A three ring-on-roller benchtop test rig was used to replicate WECs in samples with different levels of RA. While varying levels of RA had a minimal effect on time until failure, a significant effect on crack morphology was observed. Additionally, potential underlying mechanisms of White Etching Area formation were elucidated. Under the current test conditions, the microstructural alterations adjacent to the cracks in the lower RA samples were more developed compared to those of the higher RA samples. Additionally, the WEC networks in the high RA samples contained significantly more crack branches than those of the low RA samples. [ABSTRACT FROM AUTHOR]

Dinoflagellates are unicellular protists that feature a multitude of unusual nuclear features, including large genomes, packaging of DNA without histones, and multiple gene copies organized as tandem gene arrays. Furthermore, all dinoflagellate mRNAs experience trans-splicing with a common 22-nucleotide splice leader (SL) sequence. These features challenge some of the concepts and assumptions about the regulation of gene expression derived from work on model eukaryotes such as yeasts and mammals. Translational control in the dinoflagellates, based on extensive study of circadian bioluminescence and by more recent microarray and transcriptome analyses, is now understood to be a crucial element in regulating gene expression. A picture of the translation machinery of dinoflagellates is emerging from the recent availability of transcriptomes of multiple dinoflagellate species and the first complete genome sequences. The components comprising the translational control toolkit of dinoflagellates are beginning to take shape and are outlined here. [ABSTRACT FROM AUTHOR]