A good comprehension of the uniaxial ratchetting behaviour is an effective method to improve the reliability and the durability of 2024 Aluminium alloy components during in-service loading conditions. For this purpose, experimental fatigue tests have been performed under stress range control. The maximum axial deformation proved to have an atypical oscillatory evolution which in turn has a doubly oscillatory form. This behaviour was found to experience two scenarios consisting of a succession of hardening and softening blocs. The interpretation of this behaviour, which found its origin at the microscopic scale, was in good agreement with previous experimental works performed under cyclic TC and TT90 loadings in strain-controlled mode. Indeed, it was assumed that this behaviour is attributed to dynamic strain ageing (DSA) due to the repeated locking and unlocking of dislocations by the diffusive solute atoms and precipitates during cyclic loadings.

Level of Evidence: 3 Objective(s) To identify the risk factors for Cholesteatoma in a large UK cohort. Although some risk factors are well established (male sex, history of chronic otitis media), others require further evidence (deprivation, smoking). Design and Setting 1,140 cholesteatoma cases from UK BioBank were compared to 4,551 non-cholesteatoma middle ear disease and 493,832 ear disease-free controls. Adjusted odds ratios were calculated for demographic factors including age, sex, ethnicity, deprivation and smoking status with logistic regressions. Odds ratios for overlapping ICD-10 codes are also calculated. Results Cholesteatoma was significantly associated with sex (Adjusted odds ratio (AOR) for males=1.33), age (AOR=1.02) and deprivation (AOR=1.08) compared to ear disease-free controls ( p<0.001). Age and deprivation distributions for cholesteatoma and non-cholesteatoma ear disease were similar. Although there was no significant association with smoking status, cholesteatoma was significantly associated with the ICD-10 code mental and behavioural disorders due to tobacco use (OR=2.34, p<0.001). Cholesteatoma was also strongly associated with a wide range of inflammatory middle ear conditions and chronic sinus inflammation, suggesting an increased susceptibility to inflammation of the upper airways. Conclusion This study shows a large overlap between cholesteatoma and non-cholesteatoma ear disease in terms of numbers and demographics, with sex being a key factor distinguishing between the two, suggesting that there are both common and distinct risk factors exist.

This work reports the development of a MoS2@MWCNTs core–shell heterostructure synthesized through an optimized hydrothermal process, designed to enhance the oxygen evolution reaction (OER) efficiency in alkaline water electrolysis. By employing continuous tumbling during synthesis, a uniform and precise thickness of MoS2 was grown on the MWCNTs, striking a balance between maximal catalytic activity at the MoS2 edges, and leveraging the high electrical conductivity of the MWCNTs. The resulting MoS2@MWCNTs catalyst exhibited outstanding electrocatalytic performance for OER, with low overpotential of 285 mV at current density of 10 mA·cm−2, Tafel slope of 42 mV·dec−1, and exceptional durability, maintaining stable operation over 900 hours. Furthermore, the catalyst demonstrated robust performance under dynamic and unstable operating conditions, highlighting its potential for real-world applications in green hydrogen production. This study showcases the successful application of a core–shell structure for OER catalysis, while contributing to the advancement of sustainable energy technologies by providing a cost-effective and efficient solution for hydrogen production through water electrolysis.

Chemical looping gasification (CLG) is a clean and efficient technology that uses oxygen carriers (OCs) to convert carbon energy. Industrial waste phosphogypsum (PG) as raw material for OCs has been proven to be a feasible strategy. Single PG for the preparation of OCs has certain limitations; however, two or more types of elements to modified PG has not been applied in biomass CLG process. In this work, PG was used as carrier and modified with iron and cerium for syngas production through CLG. The PG prepared OCs significantly reduce the costs and improve the utilization rate of solid waste. The reaction conditions of the OCs for syngas production were investigated in a batch fluidized bed. Experimental results show that the best syngas performance is achieved when the PG content is 20 wt.%, Fe/Ce = 2:1, gasification temperature of 800 °C and steam injection rate = 40 μL/min. Multiple redox manifest that the additives of Fe2O3 and CeO2 in the prepared PG carriers increase reaction activity and its stability can be kept at a high level. Finally, the reaction mechanism of modified PG used in biomass CLG was analyzed by combining various characterization methods and density functional theory (DFT) simulations. The possible mechanism suggests that variations of syngas are affected by the calcium roles and valence change of iron. This research provides an effective pathway for the conversion of biomass and the utilization of solid waste PG.

Thick electrode, with its feasibility and cost-effectiveness, has attracted significant attention as a promising approach to maximize the energy density of lithium-ion batteries (LIBs). Through raising the mass loading of active materials without altering the fundamental chemical attributes, thick electrodes can boost the energy density of the batteries effectively. Nevertheless, as the thickness of the electrode increases, the ionic conductivity of the electrode decreases, leading to abominable polarization in the thickness direction, which severely hampers the practical application of a thick electrode. This work proposes a novel porous gradient design of high-performance thick electrodes for LIBs. By constructing a porous structure that serves as a fast transport pathway for lithium (Li) ions, the ion transport kinetics within thick electrodes are significantly enhanced. Meanwhile, a particle size gradient design is incorporated to further mitigate polarization effects within the electrode, leading to substantial improvements in reaction homogeneity and material utilization. Employing this strategy, we have fabricated a porous gradient nanocellulose-carbon-nanotube based thick electrode, which exhibits an impressive capacity retention of 86.7% at a high mass loading of LiCoO2 (LCO) active material (20 mg cm⁻²) and a high current density of 5 mA cm⁻².

This study explores the synthesis of high-entropy alloy (HEA) nanoparticles with core-shell structures using hydrogen reduction-assisted ultrasonic spray pyrolysis (USP). The focus is on synthesizing nanoparticles with transition metal based CoCuFeNi and CoCuFeNiZn HEA shells over iron oxide cores. The USP method enabled precise control over particle composition and morphology, resulting in spherical nanoparticles with complex core-shell configurations. The first synthesized particles with a CoCuFeNi shell over an Fe3O4 core (Fe3O4@CoCuFeNi) exhibited an average grain size of 144.9 nm. Subsequent synthesis involving the addition of Zn resulted in a CoCuFeNiZn shell over an FeO core (FeO@CoCuFeNiZn). The addition of Zn not only contributed to the shell composition but also modified the type of iron oxide core from Fe3O4 to FeO, increasing the grain size of the nanospheres to an average diameter of 224.4 nm. Electrocatalytic testing showed that Fe3O4@CoCuFeNi exhibited outstanding oxygen evolution reaction (OER) activity in 1 M KOH alkaline media. These nanospheres required overpotentials of 306 mV at 10 mA cm², with a Tafel slope of 61.5 mV dec⁻¹. Meanwhile, FeO@CoCuFeNiZn demonstrated a higher overpotential of 378 mV at 10 mA cm² and a Tafel slope of 65.4 mV dec⁻¹, underlining the influence of zinc addition on catalytic activity. Compared to some other HEAs and commercial IrO2 electrocatalysts, both core-shell nanosphere variants show improved charge transfer and reaction kinetics, underscoring their potential as cost-effective and highly efficient electrocatalysts for sustainable water electrolysis.

The limited space in urban areas often presents a challenge for harnessing renewable energy, particularly solar energy. However, this obstacle can be overcome by using building facades to generate energy. The global energy consumption significantly affected by building, contributing significantly demand and greenhouse gases. These buildings require energy (electrical & thermal) for various processes. Photovoltaic/thermal (PV/T) systems can offer a solution by producing both electrical and thermal energies, simultaneously. The circulating working fluid within the system will reduce the surface temperatures of PV panels and subsequently improving the electrical efficiency. Integrating PV/T systems into building facades, known as building-integrated PV/T (BIPV/T) systems, enables efficient production of energy, enhancing the overall energy consumption of buildings. The aim of the current review is to provide an outline of BIPV/T systems; explaining how they work, their classification, the benefits of their utilization in buildings, and techniques for energy enhancement in buildings. The primary objective of this review is to offer researchers up-to-date information on BIPV/T systems available in the literature. It includes recent published technological advancements in BIPV/T systems, focuses on the cited works and their key areas of interest, and provide readers with a comprehensive and systematic overview of the topic rather than an exhaustive analysis of BIPV/T systems.

Aicardi-Goutières Syndrome (AGS) is a rare neuroinflammatory condition characterized by early-onset symptoms that extend outside the nervous system. Due to the rarity of the disease, the pathogenesis is not well understood and its diagnosis and treatment remain elusive. We recently demonstrated mitochondrial abnormalities and increased reactive oxygen species (ROS) levels in lymphoblastoid cell lines (LCLs) derived from RNASEH2B- and RNASEH2A-mutated AGS patients. On this background, we turned our attention to metformin, the first-choice drug for type 2 diabetes, as a possible treatment acting on the oxidative stress condition in RNASEH2-mutant AGS cells. By means flow cytometry; we reported that metformin treatment significantly decreases ROS production in RNASEH2B- and RNASEH2A-mutated AGS LCLs. Of note, metformin treatment reduces the green JC-1 monomeric signal and, concurrently, increases the red JC-1 signal in both mutated LCLs, accounting for a restoration of the mitochondrial membrane potential. Immunofluorescence staining shows a decrease in 8-oxoG levels only in RNASEH2B- mutated AGS LCLs. Finally, the significant upregulation of FOXO3, cytochrome C somatic (CYCS) and superoxide dismutase 2 (SOD2) mRNA levels in RNASEH2B-mutated AGS LCLs after metformin treatment, points to FOXO3 signaling as a possible mechanism to reduce oxidative stress. In conclusion, even if these pilot results need to be confirmed on a larger cohort, we shed light on metformin as a valid approach to ameliorate the oxidative stress-related inflammatory condition in AGS patients.

Eosinophilic Esophagitis Masquerading as Steakhouse Syndrome: A Case ReportEmanuel-Youssef Dib1, Jessy Fadel2, Karam Karam3, Sarah Saleh4, Houssein Chebbo5, Elias Fiani6*[1] Department of Internal Medicine, University of Balamand, Beirut, Lebanon. Email: emanuelyoussef.dib@std.balamand.edu.lb[2] Department of Gastroenterology, Saint George University Medical Center, Beirut, Lebanon. Email:

Antibacterial lysozyme hydrogels show attractive advantages in wound dressings due to their intrinsic antibacterial activity, excellent biochemical and mechanical properties. Unfortunately, the development of such hydrogels is still greatly limited due to the lack of universal gelation strategies. Herein, a universal gelation strategy between lysozyme-nanofiber (LZF) and inorganic salts is proposed for the first time to construct functional nanofibrous lysozyme-based hydrogels. Specially, divalent anions are found to universally drive LZF for the aggregation and transformation into three-dimensional nanofibrous network hydrogels via electrostatic interaction, and the key role of divalent anions in the gelation is further proved by molecular dynamics simulation. In addition, near infrared light-mediated photothermal characteristics are endowed for LZF to enhance its inhibitory activity of multi-drug-resistant bacteria by the skeleton modification with genipin to produce genipin-conjuagted LZF (GLZF). As a distinct application paradigm, the brilliant immunomemory MnSO 4-crosslinked GLZF hydrogel is constructed to sensitize cGAS-STING pathway and skillfully establish an antibacterial immune microenvironment. It can excellently realize the infected anti-recurrence of diabetic wound via photo-enhanced bacterial killing and cGAS-STING pathway. Thereby, it paves the way to employ the universal divalent anion-mediated gelation strategy for future developing functional inorganic salt-hybrided lysozyme hydrogels.

To address the contradiction between a small number of grid lobes and a narrow main lobe in the range dimension beampattern of conventional FDA-MIMO radar, a Cantor Multi-stage frequency offset FDA-MIMO(CMSEO FDA-MIMO) structure is introduced. Moreover, a combination of frequency offset and array element number configuration methods is proposed. We derived the relationship between the main lobe width and periodic range with frequency offset and fractal order. Furthermore, the frequency offset and array element order relation closed-form solutions for main lobe invariance and grid lobe reduction are derived. Simulation experiments demonstrate the effectiveness of the proposed method.

This is the case of a 4-year-old girl, who was admitted to our pediatric orthopedic department to investigate a lameness associated with fever that had been evolving for 5 days. Mobilization of the right hip was painful. The laboratory tests were normal, as well as the X-ray of the pelvis. Ultrasound revealed a slight effusion in the right hip. MRI showed two anomalies located at the anterior and posterior walls of the right acetabulum, which appeared as hypo-intense on T1 and enhanced after contrast injection (fig1). An infectious or tumoral origin was suspected, and a CT-guided biopsy was planned. However, the day before the biopsy, it was discovered that the girl had developed right exophthalmos and periorbital ecchymosis (fig2). A cerebral CT scan was performed, revealing a lytic lesion of the greater wing of the right sphenoid bone with periosteal reaction invading the right external oculomotor muscle (fig3). A metastatic origin was suspected for both the orbital and acetabular lesions. A thoracoabdominal CT scan was performed in order to identify the primary tumor. A left retroperitoneal mass was found opposite L3 and L4, extending over 4 cm (fig3). A CT-guided biopsy confirmed the diagnosis of neuroblastoma. The patient was transferred to a specialized pediatric oncology center for further therapeutic management. The important clinical teaching of our case is to remember that exophthalmos with periorbital ecchymosis, excluding a traumatic context, in a child under 5 years old, should lead to suspicion of metastatic neuroblastoma, known as Hutchinson’s syndrome [1].References: 1. Dari D, Merad S, Medjahedi A. Syndrome d’Hutchinson : impact diagnostique de la scintigraphie à la 131I-MIBG et de l’imagerie hybride TEMP/TDM dans la prise en charge du neuroblastome. Médecine Nucléaire 2021; 45(4):218–9.

Abstract: In the past two decades, extensive attention has been drawn to the use of plants for developing vaccines. Despite plenty of efforts made on the research and development of plant-based vaccines worldwide, there remain challenges in their productions. With the rapid progress in genetic engineering technology, immunology and molecular biology technology, vaccines are diversified. Meanwhile, various production methods emerge and are improved. Currently, transgenic technology, which involves plants as bioreactors, has become one of the research hotspots. In general, the preparation of transgenic plant vaccine requires the determination of target antigen, the selection of recipient plant, the construction of plant expression vector, transformation, expression and detection. There are various advantages exhibited by transgenic plant vaccine platforms over insect baculovirus, bacterial fermentation and mammalian cell protein expression platforms: low production cost, short growth cycle, the ease of expansion, complete protein processing system, and the prospect of inducing immune response. The application of transgenic plant vaccines is considered promising from two perspectives: vaccine efficacy and immune strategy. In this paper, the basic process of transgenic plant vaccine production and the progress in its research were reviewed to provide reference for the development and application of transgenic plant vaccines in the future.

We study the following fractional Choquard equation ε 2 s ( − ∆ ) s u + V ( x ) u = ε − µ ( K µ ∗ F ( u ) ) F ′ ( u ) , x ∈ R N , where ε>0 is a small parameter, s∈(0 ,1), N⩾3, µ∈(0 ,N), F ∈ C 1 ( R , R ) , K µ is the Riesz potential. By applying a new variational approach, under some appropriate conditions on V( x), we obtain there exist at least cupl ( V ) + 1 solutions to the above equation when ϵ→0. In addition, we have demonstrated that the concentration behavior of positive solutions occurs around V as ϵ→0, where V is the set where the potential attains its minimum values.

Sharks are vital to marine ecosystems as apex predators, maintaining ecological balance through unique physiological and behavioral adaptations. However, the study of their brain activity and its relation to behavior is less advanced compared to terrestrial animals. Understanding shark neurobiology can provide insights into their predatory, migratory, and sleep behaviors, informing conservation strategies and helping mitigate human-wildlife conflicts. Further research into the cognitive and ecological functions of these ancient marine guardians is essential for appreciating their role in ocean health.

A case report on retrograde approach for recanalization of stumpless chronic total occlusion (CTO)Dayu Wang, MM1; Ruibin Wei, MM1; Junteng Zheng, MM1; Zhen Liu, MM 1; Jian Hou, PhD1#;Jianhao Li, MM1#;1 Department of Cardiology, The Affiliated Panyu Central Hospital of Guangzhou Medical University, Guangzhou, China#Correspondence to:Jian Hou, Department of Cardiology, The Affiliated Panyu Central Hospital of Guangzhou Medical University, Guangzhou, China 511400, GD, China; E-mail: chnhouj@163.comJianhao Li, Department of Cardiology, The Affiliated Panyu Central Hospital of Guangzhou Medical University, Guangzhou, China 511400, GD, China; E-mail: pydoctor_ljh@163.com

A new way to remedy anastomotic leakage after TaTME: a case reportKunli Du1# ，Pengfei Wang1# , Jinqiang Liu1# ，Jiahui Ren2, Gaozan Zheng1, Shisen Li1, Ling Chen3, Wei Hou4, Fan Feng1, Jianyong Zheng11 Department of Gastrointestinal Surgery, The First Affiliated Hospital of Air Force Medical University, Xi’an, China;2 Department of Anus and Intestine Surgery, Xi’an Mayinglong Anorectal Hospital, Xi’an, China;3 Department of Pathology, The First Affiliated Hospital of Air Force MedicalUniversity, Xi’an, China;4 Department of Radiology, The First Affiliated Hospital of Air Force Medical University, Xi’an, China;

Successful Endoscopic Endonasal Trans-Sphenoidal Resection for Pituitary Macro Adenoma with Apoplexy in a Twin Pregnancy: A Case Report.Ujjwal kumar jha1, Pragyan Basnet1 , Sunil kumar Das21Patan Academy of health sciences, Laganakhel lalitpur2General practice and emergency medicine, Rampur hospital, Rampur PalpaAuthors :Dr. sunil kumar das, GPEM Rampur hospital , Rampur, Palpa

The Sea Surface Temperature (SST) is one of the most examined and monitored ocean feature within the satellite era. A variety of SST datasets have been produced in recent years, each one of them with almost unique characteristics that differ from the SST variable of ocean general circulation models (OGCM), so that assimilating such datasets in an optimal way requires a mapping to the first model level. However, this projection is non-trivial and depends on the specific characteristics of the dataset. In this work we employ a data-driven approach to construct the projection operator with machine learning (ML). The benefit is that it can be used over different SST dataset by only re-training the network. We consider different convolutional neural networks, namely a U-Net, a pix2pix, and a random forest model for comparison. We train the ML models with L3 global diurnal subskin SST derived from AVHRR’s infrared channels on MetOp satellites to reproduce the ESA SST CCI taken as ground truth. The pix2pix is the most effective operator and we use it to produce several global one-year-long reanalysis-like experiments at 1/4° that assimilate the SST in different ways, e.g. direct satellite observations, unbiased approach, as observation operator. We find that the ML-unbiased approach improves the RMSE up to 10% w.r.t. direct assimilation in the global water column, while the observation operator is beneficial mainly in the tropics but degrades in the areas of strong mesoscale activities that probably requires higher resolution or longer training.

The paleoenvironments and ecosystem of northern China during the Miocene are complex issues, particularly because it relates to the impact of the uplift of the Tibetan Plateau on the surrounding areas and the ecological adaption of mammals. Our analyses using stable carbon and oxygen isotope analysis, cenograms, and hypsodonty of large herbivorous mammals reveal arid and open habitats in the northern Junggar Basin, and the different adaptations of mammalian taxa. In the early Middle Miocene, the Junggar Basin witnessed the emergence of savanna habitats characterized by an open landscape. This habitat further spread to northern China during the late Middle Miocene, indicating the widespread distribution of savannas in these regions. This shift is linked to the rapid elevation of the Tibetan Plateau's northern part, accelerating Central Asia's aridification. Our findings enhance our understanding of the Middle Miocene paleoecology in northern China and the adaptive strategies of mammals to environmental changes.

IntroductionClimate change has emerged as a significant global challenge, affecting various sectors, particularly agriculture. In Nigeria, where agriculture is a primary livelihood for a large portion of the population, rural farmers are particularly vulnerable to the adverse impacts of climate change. Awareness of climate change is a critical first step in the adaptation process. Studies have shown varying levels of awareness among rural farmers, often influenced by education, access to information, and personal experiences with climate-related events (Oyekale, 2015; Ishaya & Abaje, 2008). In Nigeria, awareness campaigns and education programs have been instrumental in raising awareness, but there is still a significant knowledge gap (Nwankwo & Ogugua, 2020). However, the primary sources of information for rural farmers include radio, television, extension services, and community meetings (Maddison, 2007). Be that as it may, the accessibility and reliability of these sources vary, with many farmers relying on informal networks for information (Obayelu et al., 2014). Hence, the role of local leaders and Non-Governmental Organizations (NGOs) in disseminating information has also been highlighted as crucial (Ayanlade et al., 2017). Climate change affects agriculture through altered rainfall patterns, increased frequency of extreme weather events, and changes in temperature (IPCC, 2014). In Nigeria, these changes have led to reduced crop yields, increased pest and disease prevalence, and soil degradation (Adebayo et al., 2011). The impacts are more pronounced in rural areas where adaptive capacity is low (Ajetomobi et al., 2011). Thus, rural farmers employ various coping strategies to respond to the impacts of climate change, including crop diversification, use of drought-resistant varieties, and changes in planting and harvesting times (Deressa et al., 2009). Some farmers also engage in non-farm income-generating activities as a buffer against agricultural losses (Asfaw et al., 2010). However, the effectiveness of these strategies is often limited by resource constraints (Adger et al., 2003). On the other hands, several factors constrain the ability of rural farmers to implement effective coping strategies. These include limited access to financial resources, lack of technical knowledge, inadequate infrastructure, and policy barriers (Bryan et al., 2009). Additionally, social factors such as gender and age can influence access to resources and information, further complicating adaptation efforts (Below et al., 2012).However, the agricultural sector in Nigeria is highly susceptible to climate change due to its reliance on rainfall and limited access to advanced farming technologies. Despite this vulnerability, there is limited empirical data on how rural farmers perceive and respond to climate change. Understanding these responses is crucial for developing effective adaptation strategies that can enhance the resilience of rural farming communities in the country.This paper therefore, explores the responses of rural farmers in Nigeria to the effects of climate change, examine the level of awareness of climate change among rural farmers, identify the primary sources of information on climate change for rural farmers, evaluate the perceived effects of climate change on agricultural practices; explore the coping strategies employed by rural farmers in response to the impacts of climate change and identify the constraints faced by rural farmers in implementing coping strategies.

Background Estimating malnutrition risk among hospitalized patients is challenging, yet critical due to its association with adverse outcomes such as prolonged hospital stays, increased mortality, impaired wound healing, depression, and increased hospital costs. This research study aims to evaluate the risk of malnutrition among type 2 diabetic hospitalized patients and its impact on the patient’s length of stay in two tertiary hospitals based in Kigali. Method In this retrospective cross-sectional study, 300 adult hospitalized type 2 diabetic patients from Kigali’s tertiary hospital and King Faisal Hospital were enrolled between January 2021 and October 2022. Data collected includes demographics, anthropometrics, serum albumin, and length of hospital stay. The Nutrition Risk Index was used to determine malnutrition risk. Results 55.3% of hospitalized type 2 diabetes patients were found to be at risk of malnutrition based on the Nutrition Risk Index. Gender distribution showed no significant difference (p = 0.724), with 56.6% females and 54.5% males at risk. Significant associations were found with age (r=0.018, p= 0.017), hypertension as comorbidity (r=-0.169, p = 0.004), hospital stay duration (r=0.139, p= 0.016), and blood glucose levels (r=-0.087, p = 0.001). Conclusion A study finds high malnutrition risk in hospitalized type 2 diabetes patients, linked to longer stays and poor outcomes. Early malnutrition screening, proper nutrition support, and a multidisciplinary care team are crucial for improved clinical care and cost-effectiveness.

Males and females generally differ in resource investment strategies to maximise reproductive output, sometimes at the expense of important systemic processes such as self-maintenance and immune activity. Here, we used wild Lethrus apterus, a sexually dimorphic beetle with parental care, to investigate the influence of sex roles (e.g., offspring provisioning) on their sex-specific immune gene expression across a pseudo-longitudinal sampling framework. By determining immune gene activation of males and females at five successive moments within the active period, we showed that their sex-specific immune gene expression varies substantially, alternating between male bias and female bias across the active period. However, when pooling all sampling dates together, there was no overall difference in the number of up-regulated immune genes between the sexes. We discuss the potential influence of sex roles on our results and highlight the importance of sequential sampling schemes to understand ecological dynamics in the wild.

A Case Report of Granular Cell Tumor of the Left Mandibular CanalXing-Hong Zhou MD, Zheng-Da Zhu MD, Yue Yan MD, Rui-Juan Zhang MD, Shi-Min Chang MDDepartment of Stomatology, Beijing Friendship Hospital, Capital Medical UniversityCorrespondence: Shi-Min Chang, Department of Stomatology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China.Email: changsm2005@163.com