Attractive Alternative Research Articles

High-Level Production of l-Methionine by Dynamic Deregulation of Metabolism with Engineered Nonauxotroph Escherichia coli.

l-Methionine is the only sulfur-containing amino acid among the essential amino acids, and it is mainly produced by the chemical method in industry so far. The fermentation production of l-methionine by genetically engineered strains is an attractive alternative. Due to the complex metabolic mechanism and multilevel regulation of the synthesis pathway in the organism, the fermentation production of l-methionine by genetically engineered strains was still not satisfied. In this study, the biosynthesis pathway of l-methionine was regulated based on the previous studies. As the competitive pathway and an essential amino acid for cell growth, the biosynthesis pathway of l-lysine was first repaired by complementation of the lysA gene in situ on the genome and then replaced the in situ promoter with the dynamically regulated promoter PfliA to construct a nonauxotroph strain. In addition, the central metabolic pathway and l-cysteine catabolism pathway were further modified to promote the cell growth and enhance the l-methionine production. Finally, the l-methionine fermentation yield in a 5 L bioreactor reached 17.74 g/L without adding exogenous amino acids. These strategies can effectively balance the contradiction between cell growth and l-methionine production and alleviate the complexity of fermentation operation and the cost with auxotroph strains, which provide a reference for the industrial production of l-methionine by microbial fermentation.

Tailoring Self‐Assembled Monolayers for High‐Performance Polymer Solar Cells with Improved Stability

Self‐assembly monolayers (SAMs) of small molecules are attractive alternatives of traditional transporting materials to reconcile interfaces with tunable interface properties in polymer solar cells (PSCs). Herein, it is found that benzylphosphonic acid (BnPA)/pentafluorobenzylphosphonic acid (F5BnPA) mixture could form an ordered SAM on indium tin oxide (ITO) due to the strong arene–perfluoroarene interaction, thus the hole‐transport‐layer‐free PSCs based on poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]‐dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione)] (PM6): BO‐4Cl achieves a power conversion efficiency (PCE) of 18.0%. The high performance is attributed to the improved energy level alignment, excellent carrier‐extraction ability, and reduced recombination. The device also shows much better stability compared with the devices based on BnPA‐ or F5BnPA‐modified ITO, and shows comparable stability to the device based on ITO/poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Furthermore, the device with an area of 1.05 cm2 shows a PCE of 15.3%, which is among the highest reported values. Herein, the potential of SAMs is highlighted for highly stable and high‐performance PSCs toward commercialization.

Stock market performance differences between fintech and traditional financial firms

Nowadays, Fintech firms are making the most of new technologies to expand and improve financial services, displacing traditional financial companies in some cases. These Fintech firms are playing an increasingly relevant role, not only in the economic and financial sphere, but also in the stock markets, as they have become an attractive investment alternative. However, our knowledge of these companies’ stock performance is still limited. In this context, the aim of this study is to analyse the return and risk associated to investing in the FinTech companies comprising the Nasdaq Financial Technology index as well as the return and risk associated to investing in traditional financial companies comprising the Standard & Poor’s 500 Financials index. The study is completed by analysing the results of a zero-cost investment strategy based on buying shares in FinTech companies and selling shares in traditional financial companies. This allows us to analyse whether there are significant differences between the two types of investment. Our overall results show that the risk-adjusted return, as well as the systematic risk, are conditioned by the state of the economy in both types of investment and that the significant differences in investment style boil down to the fact that traditional companies are value firms. Meanwhile, fintech firms have greater capacity for growth in the stock market. These findings provide relevant information for current research on Fintech firms in comparison to traditional financial firms. Moreover, these findings can be used by investors for their trading strategies

Phosphorus Recovery from Municipal Wastewater: Brucite from MgO Hydrothermal Treatment as Magnesium Source

Crystallization of struvite (MgNH4PO4·6H2O, MAPH) for both N and P recovery from municipal wastewater is an attractive alternative. The low magnesium concentration in municipal wastewater calls for low-cost magnesium sources. In the present work, the precipitation of struvite from supersaturated solutions was investigated. The supersaturated solutions were prepared by the addition of either slurry of Mg(OH)2 (brucite) obtained from the hydrothermal treatment of magnesium oxide (MgO) or using the aqueous solution equilibrated with brucite after separation from the solid. In both cases, in the supersaturated solutions prepared by the addition of ammonium dihydrogen phosphate, the Mg:NH4:P ratio was 1:1:1, pH 7.0–11.0. The apparent order for the precipitation suggested that the dominant mechanism was surface diffusion according to the polynuclear model. The apparent rate constant for struvite precipitation was two orders of magnitude smaller for the slurry prepared supersaturated solution in comparison with the respective prepared from the brucite-equilibrated solution. Simulated wastewater (SWW), was supersaturated with respect to struvite, by inoculation with brucite. The apparent rate constant was two orders of magnitude higher than that corresponding to the supersaturated solutions prepared by the addition of solution equilibrated with brucite. The P recovery from SWW reached 70%.

Parametric investigation on the performance-emissions trade-off and knocking occurrence of dual fuel engines using CFD

Dual fuel (DF) engines have been an attractive alternative of traditional diesel engines for reducing both the environmental impact and operating cost. The major challenge of DF engine design is to deal with the performance-emissions trade-off via operating settings optimisation. This study aims at parametrically investigating the engine settings optimisation for a simultaneous reduction of NOx emissions and brake specific fuel consumption (BSFC) of marine DF engines while avoiding knocking accurrence by using a computational fluid dynamics (CFD) model. The model is developed in the CONVERGE software and validated by employing the measured in-cylinder pressure and emissions. Subsequently, the model is used to parametrically investigate the engine operating settings (pilot injection timing, equivalence ratio and natural gas mass) that allow simultaneous reduction of NOx and BSFC emissions at three engine operating conditions (1800 r/min, 1629 r/min and 1457 r/min). Result shows that the optimal solution at 1800 r/min and 1629 r/min operation conditions can be achieved by controlling the pilot injection timing, equivalence ratio variation and NG mass variation within –5 to –7.5 °CA, –5% to +5 % and 0 % to +20 %, respectively. For the 1457 r/min operation condition, the appropriate ranges of pilot injection timing and the equivalence ratio variation are the same with those at 1800 r/min and 1629 r/min, whilst the NG mass variation range should be between –10 % and +10 %. The derived results in this study are expected to support the combustion analysis and enhancement of marine DF engines during the design phase, whilst the derived optimal solution is expected to provide guidelines of DF engine management for reducing operating cost and environmental footprint.

Protein Biocargo and Anti-Inflammatory Effect of Tomato Fruit-Derived Nanovesicles Separated by Density Gradient Ultracentrifugation and Loaded with Curcumin

Plant-derived nanovesicles (PDNVs) have become attractive alternatives to mammalian cell-derived extracellular vesicles (EVs) both as therapeutic approaches and drug-delivery vehicles. In this study, we isolated tomato fruit-derived NVs and separated them by the iodixanol density gradient ultracentrifugation (DGUC) into twelve fractions. Three visible bands were observed at densities 1.064 ± 0.007 g/mL, 1.103 ± 0.006 g/mL and 1.122 ± 0.012 g/mL. Crude tomato PDNVs and DGUC fractions were characterized by particle size-distribution, concentration, lipid and protein contents as well as protein composition using mass spectrometry-based proteomics. Cytotoxicity and anti-inflammatory activity of the DGUC fractions associated to these bands were assessed in the lipopolysaccharide (LPS)-stimulated human monocytic THP-1 cell culture. The middle and the low-density visible DGUC fractions of tomato PDNVs showed a significant reduction in LPS-induced inflammatory IL-1β cytokine mRNA production. Functional analysis of proteins identified in these fractions reveals the presence of 14-3-3 proteins, endoplasmic reticulum luminal binding proteins and GTP binding proteins associated to gene ontology (GO) term GO:0050794 and the regulation of several cellular processes including inflammation. The most abundant middle-density DGUC fraction was loaded with curcumin using direct loading, sonication and extrusion methods and anti-inflammatory activity was compared. The highest entrapment efficiency and drug loading capacity was obtained by direct loading. Curcumin loaded by sonication increased the basal anti-inflammatory activity of tomato PDNVs.

The adjuvant effect of bacterium-like particles depends on the route of administration.

Direct administration of vaccines to mucosal surfaces, such as via oral or nasal vaccination, represents an attractive alternative, or complement, to current parenteral vaccination because it has a potential to induce antigen-specific immunity both at mucosal and systemic tissues. Although bacterium-like particles (BLPs), peptidoglycan structures derived from lactic acid bacteria, have been investigated as a novel adjuvant for oral or nasal vaccines, it remains unclear whether the administration routes differ the adjuvant effect of BLPs. Here, we showed that the adjuvant effect of BLPs from Lactococcus lactis NZ9000 is greater with the nasal administration than with the oral administration. We conjugated BLPs with Tir, a virulence factor of Citrobacter rodentium, as a model adjuvant-antigen complex, and found that nasal, but not oral, immunization of mice with BLP-Tir induced robust antigen-specific IgA responses at the respiratory and intestinal mucosa, IgG2b-skewed systemic responses, and Th17 cellular responses. As one of the underlying mechanisms, we demonstrated that the nasal administration has a greater delivery efficiency (~1,000-fold) of the BLPs-conjugated antigens to mucosal-associated lymphoid tissues than the oral administration. Furthermore, the nasal, but not oral, administration of BLP-Tir elicited robust innate immune responses that were characterized by the expression of various pro-inflammatory cytokines and chemokines in the mucosal-associated lymphoid tissues. Considering these findings together, we anticipate that BLPs can be an attractive novel adjuvant for nasal vaccines targeting not only respiratory but also gastrointestinal infectious diseases.

Uncovering the determinants of model Escherichia coli strain C600 susceptibility and resistance to lytic T4-like and T7-like phage

As antimicrobial resistance (AMR) continues to increase, the therapeutic use of phages has re-emerged as an attractive alternative. However, knowledge of phage resistance development and bacterium-phage interaction complexity are still not fully interpreted. In this study, two lytic T4-like and T7-like phage infecting model Escherichia coli strain C600 are selected, and host genetic determinants involved in phage susceptibility and resistance are also identified using TraDIS strategy. Isolation and identification of the lytic T7-like show that though it belongs to the phage T7 family, genes encoding replication and transcription protein exhibit high differences. The TraDIS results identify a huge number of previously unidentified genes involved in phage infection, and a subset (six in susceptibility and nine in resistance) are shared under pressure of the two kinds of lytic phage. Susceptible gene wbbL has the highest value and implies the important role in phage susceptibility. Importantly, two susceptible genes QseE (QseE/QseF) and RstB (RstB/RstA), encoding the similar two-component system sensor histidine kinase (HKs), also identified. Conversely and strangely, outer membrane protein gene ompW, unlike the gene ompC encoding receptor protein of T4 phage, was shown to provide phage resistance. Overall, this study exploited a genome-wide fitness assay to uncover susceptibility and resistant genes, even the shared genes, important for the E. coli strain of both most popular high lytic T4-like and T7-like phages. This knowledge of the genetic determinants can be further used to analysis the behind function signatures to screen the potential agents to aid phage killing of MDR pathogens, which will greatly be valuable in improving the phage therapy outcome in fighting with microbial resistance.

An efficient two-stage hybrid framework to evaluate vortex-induced vibration for bridge deck based on divergent vibration

High-fidelity CFD (computational fluid dynamics) numerical modeling offers an attractive alternative of VIV investigation for bridge deck. Conventional strategy to perform VIV prediction using CFD is to directly characterize the two-way coupled free vibration of structure and flow which could become dramatically expensive in computational cost. To bridge the gap, this study presents an efficient two-stage hybrid approach that combines a divergent vibration simulation for fast aerodynamic damping extraction and a nonlinear model to predict the VIV. A negative structural damping is imposed in the motion equation to intentionally create a divergent vibration which significantly accelerates the growth of motion and takes less than 1/3 of the elapsed time compared with a conventional VIV simulation whereas maintains reasonable accuracy in aerodynamic identification. A Π-shaped bridge deck is employed as a demonstration of the proposed approach. The modeled steady-state VIV performance is well validated against wind tunnel tests. The effect of negative damping on instantaneous flow field, surface pressure and amplitude prediction are discussed and the optimal damping ratio achieving balanced accuracy and efficiency is suggested. The proposed framework shows favorable efficiency while simultaneously retains satisfactory accuracy and is a potential numerical alternative of VIV investigation for bridge deck.

Statically Resolvable Ambiguity

Traditionally, a grammar defining the syntax of a programming language is typically both context free and unambiguous. However, recent work suggests that an attractive alternative is to use ambiguous grammars,thus postponing the task of resolving the ambiguity to the end user. If all programs accepted by an ambiguous grammar can be rewritten unambiguously, then the parser for the grammar is said to be resolvably ambiguous. Guaranteeing resolvable ambiguity statically---for all programs---is hard, where previous work only solves it partially using techniques based on property-based testing. In this paper, we present the first efficient, practical, and proven correct solution to the statically resolvable ambiguity problem. Our approach introduces several key ideas, including splittable productions, operator sequences, and the concept of a grouper that works in tandem with a standard parser. We prove static resolvability using a Coq mechanization and demonstrate its efficiency and practical applicability by implementing and integrating resolvable ambiguity into an essential part of the standard OCaml parser.

CAR-T cell therapy in myeloma: hopes and hurdles.

CAR-T cell therapy in myeloma: hopes and hurdles.

Aptamer-Based Technologies for Parasite Detection.

Centuries of scientific breakthroughs have brought us closer to understanding and managing the spread of parasitic diseases. Despite ongoing technological advancements in the detection, treatment, and control of parasitic illnesses, their effects on animal and human health remain a major concern worldwide. Aptamers are single-stranded oligonucleotides whose unique three-dimensional structures enable them to interact with high specificity and affinity to a wide range of targets. In recent decades, aptamers have emerged as attractive alternatives to antibodies as therapeutic and diagnostic agents. Due to their superior stability, reusability, and modifiability, aptamers have proven to be effective bioreceptors for the detection of toxins, contaminants, biomarkers, whole cells, pathogens, and others. As such, they have been integrated into a variety of electrochemical, fluorescence, and optical biosensors to effectively detect whole parasites and their proteins. This review offers a summary of the various types of parasite-specific aptamer-based biosensors, their general mechanisms and their performance.

Producción de lechuga en invernadero fertilizada con extracto de sargazo o lixiviado de vermicomposta

The presence of sargassum on the Caribbean coast causes ecological problems, as does the sludge from water treatment plants. Fertilizers like Nutrkam (sargassum extract) and Biofertex (leachate from the vermicomposting of sludge from a textile plant) have been prepared from these two materials. Both biostimulants were applied to a lettuce crop in a greenhouse, the doses were 2, 5, 7.5, 10 and 20% by volume, the results were compared with urea fertilization. At eight weeks, height, number of green leaves and senescent leaves, fresh and dry weight, antioxidant capacity, and flavonoid content were evaluated. With NutrKam at 5, 10 and 20% and Biofertex at 7.5, 10 and 20%, the height of the leaves was statistically equal to that obtained with urea; there was no significant difference in the weight of leaves when fertilizing with 20% NutrKam, 7.5% Biofertex and urea. With all the treatments, except with Biofertex at 10 %, the antioxidant content was higher than that of lettuces fertilized with urea. The use of both materials to prepare fertilizers is an attractive alternative, since on the one hand the pollution caused by their inadequate disposal is reduced, and on the other, their agricultural application would help reduce the use of chemical fertilizers, without impairing the yield and crop properties.

Fluorescence Intensity and Fluorescence Lifetime Imaging Microscopies (FLIM) of Cell Differentiation in the Small Intestinal Organoids Using Cholera Toxin.

Live cell microscopies of in vitro, ex vivo, and in vivo experimental intestinal models enable visualizing cell proliferation, differentiation, and functional cellular status in response to intrinsic and extrinsic (e.g., in the presence of microbiota) factors. While the use of transgenic animal models expressing biosensor fluorescent proteins can be laborious and not compatible with clinical samples and patient-derived organoids, the use of fluorescent dye tracers is an attractive alternative. In this protocol, we describe how the differentiation-dependent intestinal cell membrane composition can be labeled using fluorescent cholera toxin subunit B (CTX) derivatives. By using the culture of mouse adult stem cell-derived smallintestinal organoids, we show that CTX can bind specific plasma membrane domains in differentiation-dependent manner. Green (Alexa Fluor 488) and red (Alexa Fluor 555) fluorescent CTX derivatives also display additional contrast in a fluorescence lifetime domain, when probed by the fluorescence lifetime imaging microscopy (FLIM), and can be used together with other fluorescent dyes and cell tracers. Importantly, CTX staining remains confined to specific regions in the organoids after fixation, which enables using it in both live cell and fixed tissue immunofluorescence microscopies.

Impact of dietary leaf extracts of Black pepper Piper nigrum L. on the growth, hematological and immunological parameters of Labeo rohita (Hamilton, 1822) cultured in glass aquaria

A study was conducted to evaluate the effect of Piper nigrum (black pepper) leaf extract on on the growth performance, proximate composition, hematological parameters, and immune response of Labeo rohita fingerlings with an average weight of 22.14 ± 0.98g. Aftrer acclimation for two weeks, fish (n=25) were randomly selected and placed in four glass aquaria (T0, T1, T2 and T3) at constant water temperature (30.0 ± 1.0 °C), pH (7.50 ± 0.5) and total hardness (200 ± 2.0 mgL,-1) for a period of 12 weeks, with three replicates each. Fish were fed with P. nigrum leaf extract supplemented feed @ 0.0%, 1.0%, 2.0% and 3.0% in T0, T1,T2 and T3, respectively. At the end of experiment, five fish were randomly selected from each aquaria for proximate composition, gut and skin microbial load, hematological parameters. Total proteins, albumins, and globulins were also recorded to evaluate immunological memory. The result revealed that fish in T2 showed better growth performance with an average weight gain of 56.11 ± 0.51 g. Thus, it had been concluded that Piper nigrum, a medicinal plant, can also be used to enhance the growth performance and immune response of Labeo rohita as attractive alternatives against antibiotics and vaccines and has shown no negative side effects on fish health as well as on its environment.

Hybrid SAG-FSO/SH-FSO/RF Transmission for Next-Generation Satellite Communication Systems

Recent advances demonstrate satellite communication (SatCom) as a potent enabler for future Terabit/s global connectivity. Existing SatCom systems, however, rely mostly on radio frequency (RF) transmission, whose limited available bandwidth is the main bottleneck for further data rate increases. Free-space optical (FSO) communication links, with huge license-free bandwidth, have emerged as an attractive alternative. Despite their ability to deliver high-throughput transmissions, FSO communications are weather-dependent and susceptible to atmospheric turbulence. Hybrid FSO/RF and space-air-ground (SAG) FSO transmissions are possible solutions to increase the reliability of FSO-based transmission systems. A strategically deployed unmanned-aerial vehicle, acting as a relay, can successfully mitigate the adverse effect of atmospheric turbulence, while the hybrid FSO/RF transmission can address weather-dependent effects. These solutions can also be integrated to create a system with significantly improved performance and reliability. To evaluate the performance of the resulting integrated transmission system, we analyze the outage probability and average symbol error probability in this work. Asymptotic expressions are also derived to get further insight into the system behavior and calculate the overall diversity gain. Furthermore, we consider the optimal design of switching thresholds. The numerical results show that the integrated transmission system achieves about 10 dB performance gain over existing solutions for both downlink and uplink scenarios.

Contemporary Review: Autograft Bone Use in Foot and Ankle Surgery.

Level V, expert opinion.

10 important financial investments for orthopods in India

10 important financial investments for orthopods in India

Improving the Performance of Underwater Wireless Optical Communications by Pointing Adjustable Beam Arrays

Considering the limited bandwidth of underwater wireless communications with radio frequency and acoustic waves and the constant increasing need for underwater high-speed data transmission, underwater wireless optical communication (UWOC) has been regarded as an attractive and viable alternative. However, UWOCs suffer from degradation attributed to underwater attenuation, oceanic turbulence, and pointing errors in oceanic channel. Therefore, performance enhancement technique plays a key role in the design and deployment of a UWOC system. In this article, we propose to improve the performance of a UWOC by transmitting with pointing adjustable beam arrays (PABA). In a PABA, we can adjust pointing directions of every single beam by reflectors. To decrease the path loss and turbulence-induced scintillations and weaken the influence of pointing errors in UWOCs, we make the one central beam and several surrounding beams in a PABA point toward the center of a receiver aperture, and make the remaining surrounding beams in a PABA point toward several target points located symmetrically on a ring with an adjustable radius around the center of a receiver aperture. This adjustable radius is set according to the average pointing errors in every specific UWOC link. To estimate the average pointing errors more accurate, we calculate pointing errors in view of both beam wander caused by oceanic turbulence and the misaligned displacements resulted by the changes in the position and attitude of an underwater platform. Finally, we validate the effect of PABA on improving the performance of UWOCs by simulations.

A pyridine-capped quaterthiophene as an alternative to PEDOT:PSS, processable from organic solvents and without acidity, for more stable electronic devices.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a material that has become ubiquitous in the field of organic electronics. It is most commonly used as a hole transport layer (HTL) in optoelectronic devices and can be purchased commercially in various formulations with different properties. Whilst it is a most convenient material to work with, there are stability issues associated with PEDOT:PSS that are detrimental to device stability and these are due to the acidic nature of the PSS component. In this paper, we present a molecular, non-acidic alternative to PEDOT:PSS. The parent structure is composed of a quater(3,4-ethylenedioxythiophene) unit capped either side of the short chain with two pyridine units. This compound, termed (BEDOTPy)2, can be prepared chemically and electrochemically to give doped materials with a choice of counteranions. Further functionalisation via quaternisation at the nitrogen atoms allows for modification of solubility and film-forming properties. The conductivity of the doped samples can reach up to 3.75 S cm-1. The materials are non-acidic and are therefore attractive alternatives to PEDOT:PSS for device applications. We demonstrate an OLED device using the compound (BEDOTPy-EtOH-I)2PF6 as an HTL, and compare the device performance to one made with PEDOT:PSS. Due to the non-acidic nature of the molecular material, the corresponding OLED device does not show a drop in luminance over time, whereas a loss of performance is observed for the device containing PEDOT:PSS over a short period. These results are presented to introduce the parent compound (BEDOTPy)2 as an attractive alternative to PEDOT:PSS, which can be easily modified chemically to provide a plethora of potential compounds with tunable properties.