Weak Effect Research Articles

Hydrofluoric Acid-Free Broadband Near-Infrared Phosphors K2LiMF6:Cr3+ with Zero-Thermal Quenching: Structure, Luminescence, and Application.

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are considered promising light sources for night vision, food analysis, biomedicine, and plant growth. Yet, the application potential of this technology is vulnerable to the function degradation of the phosphors used, such as thermal quenching, which needs to be addressed urgently. Herein, the NIR phosphors K2LiMF6:Cr3+ (M = Al, Ga, In) with a cubic double-perovskite structure synthesized by a green hydrofluoric acid-free hydrothermal method exhibit outstanding thermal stability. Under 450 nm excitation, the as-synthesized K2LiMF6:Cr3+ phosphors all exhibited broadband NIR emission covering 650-1000 nm peaking at 755-780 nm. The prepared K2LiAlF6:Cr3+ phosphor shows a unique zero-thermal quenching performance (I423K/I298K = 102%). The comprehensive effects of a wide band gap, large thermal energy barrier, weak electron-phonon coupling effect, and high structural rigidity are responsible for the suppression of thermal quenching in this material. The output power of the NIR pc-LED device reached 285 mW at 100 mA. This series of phosphors has promise in night vision and bioimaging applications.

Structure of the human TIP60-C histone exchange and acetyltransferase complex.

Chromatin structure is a key regulator of DNA transcription, replication and repair1. In humans, the TIP60-EP400 complex (TIP60-C) is a 20-subunit assembly that affects chromatin structure through two enzymatic activities: ATP-dependent exchange of histone H2A-H2B for H2A.Z-H2B, and histone acetylation. In yeast, however, these activities are performed by two independent complexes-SWR1 and NuA4, respectively2,3. How the activities of the two complexes are merged into one supercomplex in humans, and what this association entails for the structure and mechanism of the proteins and their recruitment to chromatin, are unknown. Here we describe the structure of the endogenous human TIP60-C. We find a three-lobed architecture composed of SWR1-like (SWR1L) and NuA4-like (NuA4L) parts, which associate with a TRRAP activator-binding module. The huge EP400 subunit contains the ATPase motor, traverses the junction between SWR1L and NuA4L twice and constitutes the scaffold of the three-lobed architecture. NuA4L is completely rearranged compared with its yeast counterpart. TRRAP is flexibly tethered to NuA4L-in stark contrast to its robust connection to the completely opposite side of NuA4 in yeast4-7. A modelled nucleosome bound to SWR1L, supported by tests of TIP60-C activity, suggests that some aspects of the histone exchange mechanism diverge from what is seen in yeast8,9. Furthermore, a fixed actin module (as opposed to the mobile actin subcomplex in SWR1; ref. 8), the flexibility of TRRAP and the weak effect of extranucleosomal DNA on exchange activity lead to a different, activator-based mode of enlisting TIP60-C to chromatin.

Analysis of High-Dose Ascorbate-Induced Cytotoxicity in Human Glioblastoma Cells and the Role of Dehydroascorbic Acid and Iron.

Several studies have demonstrated, both in vitro and in animal models, the anti-tumor efficacy of high-dose ascorbate treatment against a variety of tumor entities, including glioblastoma, the most common and aggressive primary malignant brain tumor. The aim of this study was to investigate the effects of high-dose ascorbate as well as dehydroascorbic acid on human glioblastoma cell lines and to evaluate different treatment conditions for the combined administration of ascorbate with magnesium (Mg2+) and iron (Fe3+). Intracellular levels of reactive oxygen species and the induction of cell death following ascorbate treatment were also investigated. We demonstrated high cytotoxicity and antiproliferative efficacy of high-dose ascorbate in human glioblastoma cells, whereas much weaker effects were observed for dehydroascorbic acid. Ascorbate-induced cell death was independent of apoptosis. Both the reduction in cell viability and the ascorbate-induced generation of intracellular reactive oxygen species could be significantly increased by incubating the cells with Fe3+ before ascorbate treatment. This work demonstrates, for the first time, an increase in ascorbate-induced intracellular ROS formation and cytotoxicity in human glioblastoma cells by pre-treatment of the tumor cells with ferric iron, as well as caspase-3 independence of cell death induced by high-dose ascorbate. Instead, the cell death mechanism caused by high-dose ascorbate in glioblastoma cells shows evidence of ferroptosis. The results of the present work provide insights into the efficacy and mode of action of pharmacological ascorbate for the therapy of glioblastoma, as well as indications for possible approaches to increase the effectiveness of ascorbate treatment.

Analysis of secondary metabolites and morphology in Streptomyces rimosus microparticle-enhanced cultivation (MPEC) at various initial organic nitrogen concentrations

The influence of talc microparticles on metabolism and morphology of S. rimosus at various initial organic nitrogen concentrations was investigated. The shake flask cultivations were conducted in the media with yeast extract (nitrogen source) concentration equal to 1 g YE L− 1 and 20 g YE L− 1. Two talc microparticle concentrations of 5 g TALC L− 1 and 10 g TALC L− 1 were tested in microparticle-enhanced cultivation (MPEC) runs. A high nitrogen concentration of 20 g YE L− 1 promoted the development of small agglomerates (pellets) of projected area lower than 105 µm2 and dispersed pseudohyphae. A low nitrogen concentration of 1 g YE L− 1 led to the limitation of S. rimosus growth and, in consequence, the development of the smaller number of large pseudohyphal agglomerates (pellets) of projected area higher than 105 µm2 compared to the culture containing a high amount of nitrogen source. In both cases talc microparticles were embedded into pellets and caused the decrease in their sizes. The lower amount of talc (5 g TALC L− 1) usually caused the weaker effect on S. rimosus morphology and metabolite production than the higher one. This correlation between the microparticles effect on morphology and metabolism of S. rimosus was especially noticeable in the biosynthesis of oxytetracycline, 2-acetyl-2-dicarboxamide oxytetracycline (ADOTC) and spinoxazine A. Compared to the control run, in MPEC their levels increased 4-fold, 5-fold and 1.6-fold respectively. The addition of talc also improved the production of 2-methylthio-cis-zeatin, lorneic acid J and milbemycin A3.

Lateral Electronic Junction of a Single Ultrathin Silicon Induced by Interfacial Dipole of Self-Assembled Monolayer.

Interface engineering is pivotal for enhancing the performance and stability of devices with layered structures, including solar cells, electronic devices, and electrochemical systems. Incorporating the interfacial dipole between the bulk layers effectively modulates the energy level difference at the interface and does not significantly influence adjacent layers overall. However, interfaces can drastically affect adjoining layers in ultrathin devices, which are essential for next-generation electronics with high integrity, excellent performance, and low power consumption. In particular, the interfacial effect is pronounced in ultrathin semiconductors, which have a weak electric field screening effect. Herein, the substantial interfacial impact on the ultrathin silicon is shown, the p- to n-type inversion of the semiconductor solely through the deposition of a self-assembled monolayer (SAM) without external bias. The effects of SAMs with different interfacial dipoles are investigated by using Hall measurement and surface analytic techniques, such as UPS, XPS, and KPFM. Furthermore, the lateral electronic junction of the ultrathin silicon is engineered by the regioselective deposition of SAMs with opposite dipoles, and the device exhibits rectification behavior. When the interfacial dipole of SAM is manipulated, the rectification ratio changes sensitively, and thus the fabricated diode shows potential to be developed as a sensing platform.

Preventive Effect of Royal Jelly and 10-HDA on Skin Damage in Diabetic Mice through Regulating Keratinocyte Wnt/β-Catenin and Pyroptosis Pathway.

The objective of this study is to elucidate how Royal jelly (RJ) and 10-hydroxy-2-decanoic acid (10-HDA) prevents diabetic skin dysfunction by modulating the pyroptosis pathway. Type 2 diabetes models are induced by fat diet consumption and low dose of streptozotocin (STZ) in C57BL/6J mice and treated with RJ (100 mg kg-1 day-1) and 10-HDA, the major lipid component of royal jelly (100 mg kg-1 day-1) for 28 weeks. The results show that serum concentrations of glucose and triglyceride are significantly lower in the RJ group or 10-HDA than diabetes mellitus (DM)group. Compared to the control group, pyroptosis proteins, GSDMD, ASC, Caspase-1, and IL-1β are increased in the skin of the diabetic model, accompanied by the activation of the Wnt/β-catenin signal pathway. Further evaluations by RJ exhibit superior improvement of skin damage, repress activation of the Wnt/β-catenin pathway, and attenuate keratinocyte pyroptosis, but 10-HDA cannot completely suppress the activation of Wnt/β-catenin pathway and pyroptosis, which shows a relatively weak protective effect on skin damage which shows that RJ is a better effect on skin injury after DM.

Environmental policy behavioral spillovers: The impact of California's single‐use carryout bag ban on the use of unregulated single‐use plastics

AbstractThis study examines the spillover effect of California's 2016 single‐use bag ban (SB 270) on unregulated single‐use plastics (SUPs) like cutlery, cups, and plates. We observed an insignificant 4.8% decrease in SUP sales over the entire post‐policy period, but a larger 8.1% drop in the second post‐year, which was only marginally significant. The findings suggest weak spillover effects from such environmental policies, indicating that direct regulations on certain environmentally harmful products might be more effective if jurisdictions aim to prohibit citizens from excessive use, rather than relying on the positive spillover effect from existing policies.

A Review of Integrated Photonic Devices Using Sb2Se3

AbstractThe silicon photonic technology is a highly promising option for photonic integrated circuits and has attracted intensive interests, particularly since it can utilize complementary metal‐oxide‐semiconductor processing techniques and facilities, thereby realizing high‐density photonic integrations with low‐cost. Unfortunately, the thermo‐optic and the carrier dispersion effects, which are the typical means of tuning silicon photonics devices, bring the drawbacks of high power consumption and large device size due to the relatively weak effect with a small refractive index change and being volatile. For overcoming these drawbacks, phase‐change materials are introduced into silicon photonic devices, where VO2 and Ge2Sb2Te5 are the most commonly used ones. However, the key disadvantage of large loss resulting from them limits further improving the performances of integrated photonic devices. Therefore, Sb2Se3 has seen increasing interests recently in the design of silicon photonic integrated devices, benefiting from the advantages of having extremely low loss over the C‐band and being non‐volatile. In this paper, the trending recent studies about integrated optical devices are systematically reviewed using Sb2Se3, which are classified according to the device function.

A randomized placebo controlled trial demonstrates the effect of dl-methylephedrine on brain functions is weaker than that of pseudoephedrine

Intellectual drug doping in athletics by using stimulants that affect central nervous system functions has been diversified. Stimulants are regulated by the World Anti-Doping Agency according to their levels of urinary concentration. Positron emission tomography could evaluate how stimulants affect central nervous system functions. We aimed to evaluate the effect of stimulants on brain function by examining the difference in brain dopamine transporter occupancy by PET after administration of dl-methylephedrine or pseudoephedrine at the clinical maximum daily dose. Four PET scans without and with drug administration (placebo, dl-methylephedrine 150 mg and pseudoephedrine 240 mg) were performed. The concentrations of dl-methylephedrine and pseudoephedrine in plasma and urine were measured. DAT occupancies in the striatum with placebo, dl-methylephedrine and pseudoephedrine were calculated by PET images. The urinary concentration of dl-methylephedrine (12.7 µg/mL) exceeded the prohibited concentration (10 µg/mL), but the DAT occupancy with dl-methylephedrine (6.1%) did not differ (p = 0.92) from that with placebo (6.2%). By contrast, although the urinary concentration of pseudoephedrine (144.8 µg/mL) was below the prohibited concentration (150 μg/mL), DAT occupancy with pseudoephedrine was 18.4%, which was higher than that with placebo (p = 0.009). At the maximum clinical dose, dl-methylephedrine was shown to have weaker effects on brain function than pseudoephedrine.

Dynamics and control of two-dimensional discrete-time biological model incorporating weak Allee's effect.

Incorporating a weak Allee effect in a two-dimensional biological model in ℜ2, the study delves into the application of bifurcation theory, including center manifold and Ljapunov-Schmidt reduction, normal form theory, and universal unfolding, to analyze nonlinear stability issues across various engineering domains. The focus lies on the qualitative dynamics of a discrete-time system describing the interaction between prey and predator. Unlike its continuous counterpart, the discrete-time model exhibits heightened chaotic behavior. By exploring a biological Mmdel with linear functional prey response, the research elucidates the local asymptotic properties of equilibria. Additionally, employing bifurcation theory and the center manifold theorem, the analysis reveals that, for all α1 (i.e., intrinsic growth rate of prey), ð1˙ (i.e., parameter that scales the terms yn), and m (i.e., Allee effect constant), the model exhibits boundary fixed points A1 and A2, along with the unique positive fixed point A∗, given that the all parameters are positive. Additionally, stability theory is employed to explore the local dynamic characteristics, along with topological classifications, for the fixed points A1, A2, and A∗, considering the impact of the weak Allee effect on prey dynamics. A flip bifurcation is identified for the boundary fixed point A2, and a Neimark-Sacker bifurcation is observed in a small parameter neighborhood around the unique positive fixed point A∗=(mð1˙-1,α1-1-α1mð1˙-1). Furthermore, it implements two chaos control strategies, namely, state feedback and a hybrid approach. The effectiveness of these methods is demonstrated through numerical simulations, providing concrete illustrations of the theoretical findings. The model incorporates essential elements of population dynamics, considering interactions such as predation, competition, and environmental factors, along with a weak Allee effect influencing the prey population.

Weak vs Strong Knowledge Spillover Effects. Evidence from Geographic Distribution of Innovative Startup in Italy

This paper introduces the concepts of weak and strong knowledge spillover effects within the context of the Knowledge Spillover Theory of Entrepreneurship. In this context, the fundamental idea of our proposition is to provide a comprehensive analysis of the factors and conditions promoting and supporting entrepreneurship development at the regional and provincial level using a unique unbalanced panel database, consisting of 9242 Italian Innovative startups for the period 2008-2018. In general terms, we argue that the evidence from our unbalanced panel dataset indicates that these dynamics are as follows. First, spillover effects deriving from competition are initially strong at the province level, and later decay to weak spillover effects at the regional level. Second, in terms of specialization (intra-industry) spillover effects, they are initially strong at the provincial level, and later become weak at the regional level. Third, spillover effects deriving from diversity (inter-industry) are predominantly strong at the regional level, yet weak at the provincial level of aggregation. At the provincial level, higher levels of competition result in strong knowledge spillover effects leading to higher new firm formation, with weak knowledge spillover effects deriving from specialization. Furthermore, in line with the Knowledge Spillover Theory of Entrepreneurship, the existence of non-homogeneous distribution of opportunities and related knowledge spillover effects create heterogeneity of patterns of new firm formation across different units of geographic aggregation. These results provide evidence of constraint potential for growth that remains a puzzle and challenge for academics and policymakers.

Little impact of new mutations on mammalian trait variation.

New mutations provide the source of all genetic variation but their impact on trait variation remains poorly understood. A new study published in PLOS Biology addresses this question, finding that new mutations exert only weak effects on some traits in mice.

Bergamot extract and red yeast rice in reducing high cholesterol - what is known?

Obtaining optimal levels of lipoproteins and total cholesterol is one of the main goals for reducing cardiovascular risk. Many patients insist on changing their statin treatment to a nutraceutical such as Bergamot extract or red yeast rice extract, due to statin intolerance affecting some of them and increasing disinformation on statin side effects. This is why, interest in lipid-lowering ability of available nutraceuticals, is growing. In our work, we tried to summarise what is known about nutraceuticals such as red yeast rice and bergamot extract and how they can be used in clinical practise. We searched two databases such us Pubmed and Medline byusing the terms “bergamot”, ”red yeast rice”, “dyslipidaemia” and “hypercholesterolaemia” Products containing red yeast rice and bergamot extract are dietary supplements which are sold over the counter. There is possibility that they can be seen as natural substances which significantly reduce cholesterol levels, however, they have weaker effect than strong statins. They cannot be replacement for them. Red yeast rice is the leading substance. It can be used in patients with moderate hypercholesterolemia or can be combined with ezetimibe if statins are badly tolerated. There is no clear opinion of experts on bergamot due to lack of larger and longer studies. As our article show it is crucial to conduct more scientific research on nutraceuticals especially Bergamot extract.

A Review of Adrenal Gland Disorders

Cortisol is a glucocorticoid hormone which is a potent anti-inflammatory that controls the body use of fat, protein and carbohydrates, control sleep-wake cycle, cortisol also regulates blood pressure, increases blood sugar and at times of stress helps to provide energy boost and better handle of stress response. Aldosterone is a mineralocorticoid hormone that mainly regulates blood pressure, and levels of sodium and potassium as well helps in preserving a neutral pH level. Androgens are converted into oestrogen in the ovaries, and into different androgens in the testes, they have weak male hormones effect, DHEA replacement showed some benefit on quality of life in females with Addison disease. Catecholamines (adrenaline and noradrenaline) are hormones which increase the heart rate, cardiac contractility, blood flow to muscles and brain, and major assist to glucose utility and metabolism. Vasoconstriction of blood vessels is mainly controlled by catecholamines, like cortisol to some degree these hormones are essential in stress response. Will discuss presentation and management for common adrenal gland diseases like cortisol excess and deficiency, pheochromocytoma, mineralocorticoid excess, adrenal incidentalomas, and congenital adrenal hyperplasia.

Shear-flow driven ion-acoustic instability in a non-thermal magnetoplasma

Relying on the kinetic model, we study linear properties of ion-acoustic waves in a non-thermal magnetoplasma, whose constituents are the electrons and singly charged positive ions. For this purpose, we solve a set of coupled Vlasov–Poisson equations within the framework of an unperturbed orbit theory and Fourier transformations. A generalized dielectric function is derived in a Cairns distributed plasma to investigate the electrostatic ion-acoustic waves with weak ion shear flows and ion streaming effects. It is found that the magnitude of the growth rate of the wave increases by varying the non-thermality and ion shear flow parameters. Furthermore, the wave spectrum and instability involving the ion-acoustic waves are analyzed with different plasma parameters in a non-thermal plasma. The present findings also reveal both analytical and numerical analyses of the electrostatic waves in the upper ionosphere, where non-thermal plasma particles are common.

A distribution-free method for reliability improvement based on design of experiments

Given growing consumer expectations for enhanced product lifespans, there is a particular focus on improving product reliability. Design of Experiments (DOE) is a useful tool for identifying significant factors and determining factor levels to enhance product reliability. Current research commonly assumes that the lifetime data follows a specific distribution. This overlooks the possibility that erroneous assumptions about the data distribution may lead to imprecise factors identification. Additionally, factorial effect principles are often disregarded in factors effects identification. In this paper, a distribution-free method named Factor-Effect Bayesian Quantile Regression (FEBQR) is proposed to address the aforementioned issues. We first construct a new set of factor indicator variables, considering the principles of effect sparsity, weak effect hierarchy, and effect heredity. Then we develop a novel model that extends the Bayesian quantile regression framework by incorporating the principle of factor effects to describe the relationship between percentile lifetimes and factor effects. Unknown parameter estimates are obtained through the Gibbs sampling algorithm, and significant factors are identified based on the posterior mean of the proposed factor indicator variables. Two practical examples are illustrated using the proposed method. Compared with traditional methods, the proposed method provides more accurate factor identification results.

RELATIONSHIP OF MANAGEMENT AND ECONOMIC INDICATORS IN THE HOSPITALITY SECTOR: THE SEARCH FOR OPTIMAL STRATEGIES

Optimal strategies are a key lever for business success in the current difficult conditions, and the hospitality sector is no exception. The aim of the study was to determine how management practices affect economic indicators in the hospitality sector.The research employed methods of regression and correlation analysis, and descriptive statistics analysis. Cost management was found to have a positive effect on the Return on Assets (ROA) (0.088) and the Occupancy Rate (0.191).The analysis showed that the factor of staff training investment has a positive but weak effect on the return on assets (0.068) and the utilization rate (0.005). It was identified that the seasonality factor also has a positive effect on the utilization rate (0.510). The market competition factor was found to have a slight negative effect on the profitability of assets (-0.018) and the utilization rate (-0.009). Key financial management tools such as the development of a detailed budget and regular updating of business financial forecasts are identified. Emphasis is placed on the importance of managing cash flows to ensure the necessary liquidity and planning short-term financial needs. Optimization of the tax burden through the use of tax benefits as an element of financial management in difficult business conditions is proposed. Further research will focus on the impact of digitalization on optimal business strategies and their impact on the main economic indicators in the hospitality sector in view of increased uncertainty in the business environment.

The influence of genetic similarity, peroxidase activity and ascorbic acid content in the components of pumpkin crop grafts on their survival rate

Grafting of vegetable crops is widely used in industrial vegetable growing in Asia and Western Europe. However, the influence of the genetic relationship of the scion and rootstock, the activity of peroxidase and the content of ascorbic acid in the components of the graft during inosculation period on graft survival has been poorly studied. The objects of the research are nine species of the pumpkin family (Cucurbitaceae). The polymorphism of 11 taxa was studied based on ISSR-PCR of genomic DNA. The record of survival rate of scion-rootstock combinations was conducted on the 10-th day. The activity of peroxidase was determined by the spectrophotometric method, the content of ascorbic acid was determined by Murri. Significant differences in survival rate were noted when grafting momordica into pumpkin rootstock variants: large-fruited (94.6 %) and nutmeg (67.1 %). In experiments with watermelon, melon and trichosanthes, the influence of the type of rootstock on the viability of the graft was not revealed. According to the ISSR spectra, the taxa were divided into two clusters; interspecific groupings of each clade were supported by average bootstrap values (from 26 to 100 %). A medium effect (r = 0.36) of the degree of genetic similarity of the scion with the rootstock on the survival rate of watermelon and a weak effect on the survival rate of melon, momordica and trichosanthes were revealed. The activity of peroxidase and the content of ascorbic acid in the grafting components in different scionrootstock combinations had a weak and moderate effect on plant survival, respectively. The survival rate of trichosanthes on various types of rootstocks strongly depended on the content of ascorbic acid (r = 0.7). Genetic relatedness, peroxidase activity, and ascorbic acid content had a weak or moderate effect on the survival rate of plants in scion-rootstock combinations.

How disruptive are monocular reading conditions really?

Purpose. Based on the fact that reading with both eyes shows a binocular advantage of about 10 % (shorter reading and fixation times compared to monocular reading) with good binocular coordination, the present study aims to investigate the influence of the quality of binocular vision on the effectiveness of reading. Material and Methods. The binocular eye movements (Eyelink II) of 260 test subjects were reevaluated. All subjects read 60 sentences in German containing a target word occurring either frequently or rarely in this language. Additionally, the reading condition was changed from monocular to binocular for 30 sentences. Furthermore the objective heterophoria and MCH heterophoria for all participants were determined. Results. In the case of monocular reading conditions, there was only a weak general word-frequency effect (b = 7.21; t = 1.91; p = 0.06) but fixation times for frequent words shortened slightly when objective heterophoria increased (b = −4.24; t = −3.82; p < 0.001). For binocular reading conditions, on the other hand, there was a clear word-frequency effect (b = −48.77; t = −6.03; p < 0.001) and, at the same time, an interaction with individual heterophoria (objective: b = 8.19; t = 14.57; p < 0.001; MCH: b = 3.27; t = 4.40; p < 0.001). Conclusion. Monocular reading conditions can be proven to be disruptive when investigating people with good binocular coordination. However, this effect turns out to be much smaller than what is assumed by many optometrists. People with good binocular coordination clearly show greater benefits when reading with both eyes. Keywords: BINOCULAR COORDINATION, BINOCULAR ADVANTAGE, READING

DFT-aided stereo-structural and electronic structure studies of poly-hydroxyl substituted chlorophyllous molecules

Numerous chlorophyll-based derivatives have found applications in the dye and pharmaceutical industries. Here, we report the synthesis of a poly-hydroxyl substituted chlorophyll molecule (THM) and its absolute configuration determination using experimental electron circular dichroism (ECD), nuclear magnetic resonance (NMR) spectroscopy, and density functional theory (DFT) calculations. Furthermore, the photoreaction types of THM (type I and type II) were investigated through theoretical calculations and validated by biological experiments. We provide a detailed analysis of electron transfer and excitation processes in THM through theoretical calculation of hole-electron distribution, as well as study intramolecular weak interactions and conjugation effects using Reduced Density Gradient (RDG), Interaction Region Indicator (IRI), and Natural Bond Orbital Analysis (NBO). The photoreaction types (type I, type II) of THM in tumor cells have also been investigated by biological experimental measures and theoretical calculation of the single-triplet state energy gap and hole-electron distribution. Molecular electrostatic potential has also been investigated by DFT methods to give insight into the molecular structure. This study provides useful guidance for the structural and photochemical studies of the chlorophyll-derived photodynamic therapeutic drugs.