Types Of Connections Research Articles

Access to Network Social Capital and Health Outcomes in Later Life: Understanding the Role of Tie Strength

Our study contributes to the scholarship by examining the concrete ways in which two distinct types of interpersonal connection—strong/close versus weak/distant—are independently related to self-rated health and life satisfaction cross-nationally. In addition, we explore whether and how the two types of interpersonal connection modify the magnitude of the associations between subjective social status (SSS) and health and well-being of older populations cross-nationally. According to results from our multilevel analysis, social capital available through strong ties (family and friends) is positively associated with both outcomes. On the other hand, social capital via weak ties (acquaintances) is positively related to health but negatively related to well-being. We also find that social capital mediated by strong ties significantly buffers the harmful implications of status disadvantage or low SSS on health and well-being of older adults. In comparison, weak tie-mediated social capital provides buffering against status disadvantage only for well-being.

ANGLED DENTAL IMPLANTS: IMPLICATIONS FOR CLINICAL PRACTICE AND BIOMECHANICAL CONSIDERATIONS

Angled dental implants have emerged as an effective solution in clinical settings where the placement of straight implants is constrained by unfavorable bone positions or the presence of adjacent anatomical structures. The angulation of implants significantly influences stress distribution around the implant, impacting its stability and longevity. Research highlights that the direction of applied loads is critical, as angled implants can generate greater bending and shear forces compared to straight implants, potentially leading to stress concentrations in surrounding bone. Finite element analysis (FEA) is commonly used to model these conditions, offering insights into stress zones and predicting potential failure areas. Bone quality plays a vital role in how implants respond to applied forces, with denser bones effectively dissipating forces while more porous bones are at higher risk of resorption and integration failure. Studies indicate that excessive stresses on angled implants can lead to bone resorption, compromising long-term stability. Therefore, careful consideration of implant angulation, connection type, bone quality, and thorough surgical planning is essential. Recent studies, including those investigating the effects of implant design and bone density on stress distribution, have demonstrated that varying implant threads and angulated abutments affect the stresses experienced by surrounding bone and implants. The findings emphasize the need for appropriate implant selection and a detailed assessment of bone anatomy and patient-specific clinical conditions. By incorporating advanced technologies like FEA, clinicians can enhance their understanding of biomechanical interactions, ultimately leading to improved clinical outcomes and patient satisfaction. Continuous education and the implementation of best practices in dentistry remain vital for the successful application of angled dental implants.

Investigation into the flexural performance of novel precast sandwich wall panels

The paper focuses on investigating a novel sandwich panel, which incorporates extruded polystyrene foam boards placed between the inner and outer concrete panels. These are connected using various types of shear connectors to achieve a composite action, meeting the bending resistance requirements. To study the structural performance of the sandwich panels, three representative specimens were designed. These specimens employed different types of shear connectors, namely, steel truss connectors with inclined bars at 45°, and GFRP connectors with inclined bars at 45° and 30°, respectively. The specimens underwent full-scale testing using a step-by-step four-point loading method. The test results indicated shear-compression failure of the specimens, exhibiting consistent failure modes across all specimens, and a composite action in resisting bending moments. Based on theoretical stress–strain diagrams and considering the slip phenomenon between the concrete panel and the connectors, this paper establishes an analytical model. It can reasonably estimate the ultimate load-carrying capacity of sandwich insulation panels under shear-compression failure, which has implications for subsequent engineering applications.

Behavior of Concrete Beam Encasing Castellated Steel Section with Different Opening Size

This research aims to investigate the behavior of castellated steel sections with varying hole sizes enclosed in a concrete beam. Should two different opening size types (depth 140mm and depth 280mm) be used? When we use two types of shear connectors with full and partial interaction, stud connections integrate the steel and concrete parts. This research demonstrates We examined five simply-supported composite beams under two-point loading conditions. We constructed four examples using castellated steel beams and produced one specimen using standard steel beams as a control. We examine the maximum load support capacity. Examined are the specimens of composite beams' deformations. Among the many characteristics assessed are the castellated beam size of the aperture and the whole and partial composite interactions. According to test results, the sample had a 140mm hexagonal hole. The sample experienced an increase in final load percentages of approximately 11.11%. Compared to the sample featuring a 280mm hexagonal opening size, the mid-deflection and horizontal displacement showed a significant increase. The figures indicate a final load of approximately 18.82% and 16.7%, respectively. Full interaction also revealed a higher ultimate load for the sample with the same aperture. When the sample was fitted with a 140mm hexagonal hole, the percentages increased by approximately 6%. Additionally, the percentage of deflection at midspan and the percentage of horizontal displacement decreased by approximately 16.7% and 26.8%, respectively, compared to the sample with a hexagonal opening size of 280 mm.

Research on a macro joint model for progressive collapse analysis of L-CFST column frames

In this study, a macro joint model was developed to evaluate the progressive collapse resistance of L-shaped column composed of concrete-filled steel tubes (L-CFST column) frames, accounting for joint performance. The methods used to calculate the spring stiffness in each part of the macro joint model were derived using the component method and deformation coordination principle. Additionally, an L-CFST frame model consisting of fibre beam elements and macro joint models was created. For frame models with different parameters, the dynamic response of column removal was analysed. These parameters included the loading conditions, the connection types, the location of the failed columns, the height and number of floors, and the span-depth ratio of the steel beams. The results indicated that the macro joint model had high accuracy in predicting progressive collapse resistance. The L-CFST column frames with novel side-plate reinforced connections fully exploited the catenary mechanism and Vierendeel action. All the variables affected the vertical displacement at the position of the failed columns, with the span-depth ratio having the most significant impact.

Natural Landscapes and the Psychological Impact of Environment on Architecture: Examining the Synergy Between Nature and Spatial Design

One of the most important characteristics of architectural art is the quality and type of connection it establishes with nature. Nature has a historical depth spanning hundreds of millions of years, having been shaped, evolved, and grown over time. It presents a structured and regulated form, within which a profound harmony can be observed in its diverse components. This homogeneous and dynamic structure has created a coherent language, which requires an understanding and decoding of this symbolic language to establish an interactive and constructive relationship with nature. This research examines the connection between natural landscapes and the psychological impacts of the environment on architectural design. The main objective of the study is to analyze the synergy between nature and designed spaces, investigating how this interaction can affect the quality of human life. The results indicate that the presence of natural elements in living and working spaces reduces stress, increases satisfaction, and improves mental health. Additionally, sustainable design that considers environmental principles and human needs can lead to the creation of spaces that provide a sense of tranquility and pleasure for users. Despite the economic and cultural challenges in implementing these approaches, collaboration among designers, engineers, and local communities is essential. Ultimately, this paper emphasizes the importance of considering the psychological impacts of the environment and the necessity of creating spaces that promote the synergy between nature and architecture.

Implants as Surveyed Crowns for Implant-Assisted Removable Partial Dentures: A Long-Term Case Series Study.

Long-term data on the use of implants as surveyed crowns for implant-assisted removable partial dentures (IARPDSCs) are limited. This study evaluated the long-term outcomes and assessed the risk factors associated with marginal bone loss (MBL) in IARPDSCs. A total of 51 implants were placed in 14 partially or fully edentulous patients and restored using IARPDSCs. Implant crowns or bridges served as abutments for the removable partial dentures (RPDs) to enhance their esthetics, comfort, and function. All patients attended regular follow-up appointments every 3-6 months for up to 12.5 years; these visits included professional cleaning and oral hygiene reinforcement. The collected data included patient demographics, treatment modality, arch restoration, Kennedy classification, RPD connection and retention design, opposing dentition, implant characteristics (location, connection type, and diameter), and any complications. The clinical assessments included plaque score, bleeding on probing, probing depth, marginal tissue recession, and keratinized mucosa width. Univariate and multivariate analyses were performed to identify factors influencing the MBL of implants in IARPDSCs. One implant failed during follow-up; thus, the implant survival rate was 98%. All patients were satisfied with their prostheses and reported only minor complications. Univariate analysis showed a significantly higher MBL in maxillary implants than in mandibular implants (P = .045). Multiple regression analysis revealed that bruxism (P = .002) and maxillary implants (P = .013) were significantly associated with a higher MBL. Female sex (P = .051) and anterior implants (P = .058) exhibited a trend toward an association with higher MBL. Within the limitations of this retrospective clinical study, IARPDSCs demonstrated predictable long-term success in carefully selected and well-maintained patients.

Shear performance of glued and screwed timber-steel composite connections for composite timber-steel beams

Mid- to high-rise mass timber buildings gained popularity in the last decade. Yet, engineered wood products (EWPs) used to erect these buildings have structural limitations. EWPs present brittle failure modes, particularly in bending, shear and tension, and have a low modulus of elasticity resulting in shorted spans and deeper beams relative to those in the steel and reinforced concrete counterparts. Timber-steel hybrid beams represent a potential sustainable solution to overcome these limitations by taking advantages of the high strength, stiffness and ductility of steel, and the high capacity to weight ratio of timber. However, for this solution to be structurally performant, it is essential to create effective composite action between the two materials. This study therefore compares the structural efficiency of various bonding techniques between the steel and the timber materials. Two sets of assembly solutions, representing four connection types, were proposed and experimentally investigated: (1) connecting an embedded steel plate into the timber elements by using either polyurethane (PUR) structural adhesive with two manufacturing variations or 14 G×75 mm heavy duty screws, and (2) connecting a steel plate on the surface of the timber element using either PUR structural adhesive with self-tapping M4×40 mm screws or only self-tapping screws. Softwood Laminated Veneer Lumbers (LVL) and Grade 350 steel plates were used in the experimental tests. All bonding techniques were tested in shear. The shear capacity, the slip stiffness and the failure mode were evaluated. Additionally, the efficiency of the proposed manufacturing solutions was quantified by analytically evaluate the effective bending stiffness of a timber-steel composite beam manufactured with different bonding techniques being investigated. Results indicated that the glued connections allowed a significantly more efficient composite action, with failure occurring in the timber instead of at the composite interface and near-full composite action was reached, than the screwed connections. To achieve high composite action with the screwed solutions, a large number of screws was needed which may incur high manufacturing costs.

Experimental study to assess the impact of different connection types on the fire resistance of composite concrete-topped CLT slabs

This paper summarizes the results of an experimental study of fire resistance of composite concrete-topped cross-laminated timber (CT-CLT) slabs exposed to fire at their soffit. Six composite CT-CLT slabs and one untopped CLT slab were tested under ISO 834 standard fire exposure while subject to an applied load equal to 20 % of the slab ultimate capacity. Test variables included the type and configuration of shear connection between the topping and CLT. Large bending deflections were observed as the slabs reached their fire resistance. Although the untopped CLT slab exhibited a fire resistance of only 16 min, all CT-CLT exhibited fire resistance greater than 1 h. The improved behavior is attributed to the stiffer CT-CLT behavior. CT-CLT slabs exhibited delamination of the lowermost layer of the CLT following through-layer charring. Observed charring rates were approximately 46 mm/h. Observed charring depths were well-predicted by existing design standard-recommended equations. Importantly, the interface between the concrete topping and CLT remained close to 30 °C and never exceeded 65 °C in any test. This is a promising result for employing adhesive systems to affect composite behavior between the topping and CLT.

Numerical Analysis of the Bond Behaviour of High-Strength Concrete-Filled Steel Square Columns with Different Shear Connectors

This paper deals with a numerical method of analysis of the performance of shear connectors in transferring load in high-strength concrete-filled steel tube square sections. The novelty of the model is that it considers all the important parameters that affect performance at once: bond strength, the transfer rate of each connector, and the stress distribution and deformation of each element. Four specimens fabricated using different types of connectors were validated using ABAQUS version 2017 software. The deformation of the connectors, concrete damage, and the local instability of the steel tube were extensively investigated. The main parameters considered were the ultimate bond strength and load transfer ratio. The shear connector arrangement consisting of four specimens, namely C1 with 16 studs, a circular rib (C2), a circular rib with 8 studs (C3), and a circular rib with 8 vertical ribs (C4), had a significant influence on the key parameters. Connectors C2, C3, and C4 transferred more than 80% of the total load. The circular rib was more effective in transferring the load and limiting slip than the vertical rib and the studs. The circular rib (C2) transferred the load mainly through the four corners. The deterioration of the concrete and local instability of the steel tube had complex deformations which were influenced by the geometry of the inserted connectors.

Features of Worldview Perception Among Speakers of Yakut and Russian: Associative Field Analysis of Stimulus Words DYOL — SCHASTYE

This article analyzes the associative fields of the stimulus words DYOL and SCHASTYE, which are central to the linguistic consciousness of Yakut and Russian speakers. Investigating the underlying processes within language enables us to uncover the ethnocultural specificity of a community’s linguistic consciousness — a snapshot of the real-world image at a particular period in the life of an ethnic group. The focus is on identifying both commonalities and distinctions in the perception of happiness among speakers of the two languages, as well as the ethnocultural nuances in their worldviews. A comparative analysis of the associative fields of the stimulus words DYOL — SCHASTYE is conducted using Y.N. Karaulov’s “semantic gestalt” methodology, which includes delineating semantic zones, determining types of connections between stimuli and responses, and employing a quantitative assessment method to measure the overlap of associative fields. The analysis reveals significant shifts in the value priorities of Yakut speakers in recent years. While happiness was previously associated with family, children, and material wealth, con-temporary perspectives increasingly emphasize aspects such as fulfilling work, travel, career advancement, and self-care. This reflects modern social trends where happiness is linked not only to material factors but also to personal growth and self-actualization.

Experimental and numerical investigation on composite beam–column joint connection behavior using different types of connection schemes

Abstract Over the past few decades, composite joints have been regarded as one of the most promising approaches. After reviewing the research articles dealing with composite beam-column joints, it can be withdrawn that few researchers studied and developed different types of composite beam-column joints. The objectives of this paper to study the effect and behavior of different connection types on the composite beam – column joint under repeated loading as well as to investigate new forms of slab connection with column flange in composite connection joints, aiming to enhance the behaviors of the joints and make the slab endure a part of the load in a more efficient way. Five specimens with various connection types were tested to failure; the composite model number two (CM2) was considered the control specimen. Regarding the ultimate moment, the result found that CM5 has moment 50.47% more than control specimen, the lowest rotation value was in CM5. The general behaviours of the FEM were in good accordance with the experiment results. According to the parametric a higher yield strength is more rigid stiffer, the effect of web thickness on the load is too small and increase in load resistance with an increase in beam flange thickness.

Moment capacity of cold-formed steel trusses with Howick Rivet Connectors: Tests, modelling and design

Cold-formed steel (CFS) trusses are increasingly used in lightweight building construction. A new type of pin-jointed connector, known as the Howick Rivet Connectors (HRCs), has been developed for CFS trusses. Previous studies focused on testing T-stub connections and shear strengths of CFS trusses with HRCs, providing insights into their structural performance and shear capacity. This paper extends the research by testing ten new CFS trusses with HRCs to determine their moment capacity. The study involved two different cross-sections: lipped channel sections and hat sections, used as truss chords. Variations in the number and locations of lateral supports were introduced to simulate different boundary conditions. A parametric study explored the effects of span-height ratio and variability in lateral support locations on truss strength and failure modes. Finally, the trusses with lipped section chords were designed according to the American Iron and Steel Institute (AISI 2016) and Australia/New Zealand standards (AS/NZS 2018), achieving an average test-to-design strength ratio of 0.86.

Spatiotemporal desynchronization in the propagation from meteorological to soil moisture drought in the Loess Plateau, China

Study RegionThe Loess Plateau (LP) of China Study FocusMeteorological drought (MD) would propagate to soil moisture drought (SMD) with spatiotemporal desynchronization. The spatial desynchronization between them has frequently been ignored in previous studies due to limitation of identified droughts, which did not consider their 3-dimensional (3D, i.e. longitude, latitude and time) properties. This study presents a 3D perspective on the spatiotemporal desynchronization in the propagation from meteorological to soil moisture drought in the the Loess Plateau (LP) of China, using an improved drought matching method. Event Synchronization (ES) is extended to determine temporal linkage of the two types of droughts and spatial connection is tested using overlapping area. New Hydrological Insights for the RegionThe results showed that: (1) the improved method is reasonable for identifying MDs that trigger SMDs, down to specific clusters; (2) 8 SMDs preceded MDs 1 month, while approximately 79 % of SMDs did not recover after the determination of MDs; (3) severity of MD is an impact factor on recovery lag, while antecedent soil moisture dominates onset lag with the relative importance of approximately 50 %; and (4) incompletely overlap in migration trajectory between the two types of droughts was mainly caused by temperature, followed by antecedent soil moisture and potential evapotranspiration, with relative importance of 55 %, 14 % and 12 %, respectively.

Marginal Bone Loss and Clinical Evaluation of Angled Implants: A Retrospective Study

Aim: The volume of the edentulous crest and its proximity to critical anatomical structures are important limiting factors for implant surgery. Surgical procedures with complications can be avoided by placing angled implants. The aim of this clinical study was to evaluate marginal bone loss and the complications of angled implants. Materials and Methods: Fifty-eight dental implants were examined in 32 patients (16 females, 16 males) with cone beam computed tomography (CBCT) images from patients with angled implants and complete edentation. The marginal bone loss in angled implants that were functional for 15 to 30 months was evaluated according to factors such as implant angle, connection type, opposing arch restoration type and planning of superstructure restoration. Marginal bone loss measurements were recorded from CBCT sections. Results: It was determined that 3.44% of the implants placed had an inclination of less than 15°, 75.86% had an inclination between 15° and 30° and 20.68% had an inclination of more than 30°. While there was no marginal bone loss on the mesial and distal surfaces, the average marginal bone loss was 0.66 on the buccal surfaces and 0.93 in the lingual region. Only one of the implants examined failed. No pain or infection was observed in any of the implants examined. Conclusion: According to the results of this retrospective clinical study, further clinical studies with larger sample sizes are needed to evaluate angled implants supported by full arch fixed prostheses as a predictable and valid treatment method in the prosthetic rehabilitation of edentulous jaws.

Seismic behavior of hybrid post-tensioned special steel moment frames

Generally, conventional moment-resisting frames are prone to substantial residual displacements. To overcome this disadvantage, self-centering systems were introduced. Post-tensioned self-centering (PTSC) moment-resisting systems are a variation of conventional moment-resisting systems that drastically reduce the large residual displacements of the moment frames. However, one of the uncommon drawbacks identified in PTSC systems is their low energy dissipation. This study aims to compensate for this by innovatively combining conventional self-centering systems with special moment-resisting frames (SMRF) in various formats to retain the advantages of both systems. Another disadvantage of PTSC systems is the high cost and complexity of the structural design procedure required to maintain an elastic response in the framing beam-column elements. To address this issue, a practical and cost-effective design procedure was proposed. The study also included the influence of different dual SMRF-PTSC frame actions and base column connection types. A set of 35 structures comprising 4, 8, 12, and 16-story buildings were considered for nonlinear static/dynamic analysis and seismic response assessment. The nonlinear static analyses were carried out in a cyclic format due to the self-centering characteristics of the system. Additionally, 22 far-field records per FEMA P695 were chosen for the time history analyses. The results show that structures equipped with post-tensioned self-centering connections (PTSC) designed according to the proposed procedure are successful in drastically decreasing residual drifts. However, the total elimination of residual drifts relies on providing a self-centering connection for the base level columns and considering an overstrength factor for the base level columns' moment capacity design. The proposed value in this investigation was derived as 5, which significantly strengthens the base level columns while resulting in an overall notably cost-efficient PTSC-equipped frame. In the case of dual frames, the conventional SMRF spans should not exceed the number of PTSC-equipped spans, as doing so will diminish the self-centering characteristics of the lateral system.

Cyclic axial loading tests on mortar-filled rectangular tube with various connection details

Although a mortar-filled rectangular hollow structural section (RHS) under monotonic loading has achieved large tensile capacity using various connection details and buckling capacity of RHS members, the structural capacity of the mortar-filled RHS tubes has not been investigated under cyclic loading. In this study, the seismic performances of newly developed mortar-filled RHS tubes with various connection details were evaluated under cyclic axial loading. The major test parameters included the end connection type, the thicknesses of the RHS tube, cap plate, and cleat plate, as well as the length of the RHS tube. The test results showed that the RHS tube in all specimens failed by tensile fracture before axial compression failure. The seismic performance of the embedded shear plate end connection with penetrating rebar was superior to that of a conventional welded T-end connection. The test results were compared with the current design code to evaluate the seismic capacity of the RHS tube according to the connection details. Design considerations for the connections of the mortar-filled rectangular tubes were also provided.

Insight into the phase equilibrium of mycophenolic acid cocrystals

In this study, mycophenolic acid-nicotinamide (MPA-NAM) and mycophenolic acid-acetoguanamine (MPA-AGA) cocrystals were synthesized and characterized using single-crystal X-ray diffraction, Fourier transform spectroscopy and thermal analysis. Intrinsic intermolecular interactions were investigated through Hirshfeld surface and electrostatic potential surface analysis. The results indicated that MPA-NAM and MPA-AGA cocrystals possessed the same types of hydrogen bonds but different hydrogen bond connectivity. Thermodynamic studies revealed that MPA-NAM and MPA-AGA cocrystals exhibited incongruent dissolution behaviors in the chosen solvent. Model regression results indicate that the 1:1 complex formation existed during the dissolution of the MPA-NAM cocrystal, whereas 1:1 and 1:2 solution complexes presented in the MPA-AGA cocrystal. The complicated complexation in the MPA-AGA cocrystal induced all fragments of MPA-AGA to possess higher energies, facilitating MPA-AGA cocrystal precipitation from the solution, which was testified by Energy calculations.

IMPLEMENTATION OF THE MAIN COLUMN STRUCTURE USING THE FREESTANDING METHOD & STUDY OF LAP SPLICE CONNECTIONS ON THE GGM MAJALENGKA BUILDING PROJECT IN MAJALENGKA DISTRICT

The GGM Building is a circular sports building, has 2 floors with circular columns. Columns are the most important structural part for a building to stand. In accordance with SK SNI T-15-1991-03 what is meant is a building structural component column whose main task is to support axial, compressive and vertical loads. In this report study, the method used for the main column reinforcement work is Free Standing which can be interpreted as a structure that is strong and stands upright. The GGM Building is a high-rise building which of course has a structure that can stand perfectly upright at any height. The type of connection used in column cuttings is a contact lap splice which is a passing connection between two reinforcing bars that touch each other and are tied with concrete wire. SAP2000 software is used to analyze the values ​​of the forces acting on the main structural columns. Based on the results of analysis of the main structural columns using SAP 2000, the load distribution value was obtained, namely 22.81 KN/m with an axial force value of -229.220 KN for column type K1-1. 27.14 KN/m with an axial force value of -272.97 KN for column K1-2 and 31.86 KN/m with an axial force value of -320,150 KN for column K2. Then with manual calculations related to the self-load value of the main structural columns, namely 1,189.56 KN in column K1-1, 1,614.14 KN in column K1-2 and 1,981.11 KN in column K2. Keywords: column, lap splice, selfweight calculation, SAP 2000.

Tumour-pleura relationship on computed tomography (CT) provides effective risk stratification for peripheral pulmonary nodules with Lung Imaging Reporting and Data System (Lung-RADS) score of 4X.

Pulmonary nodules with Lung Imaging Reporting and Data System (Lung-RADS) 4X are of greater clinical significance, and accurate differentiation of pathological types and visceral pleural invasion (VPI) of Lung-RADS 4X peripheral pulmonary nodules before treatment can aid in stratification. This study set out to investigate whether the tumour-pleura relationship on computed tomography (CT) can provide effective risk stratification for peripheral pulmonary nodules with Lung-RADS 4X. This was a single institution, retrospective study of 482 consecutive patients with Lung-RADS score 4X, who were pathologically diagnosed with tuberculous granuloma and adenocarcinoma from January 2019 to December 2023. We assessed clinical factors (baseline characteristics and tumour markers) and CT findings. Univariate and multivariate logistic regression analyses were used to determine the classification of pulmonary nodules and predictors of VPI. Multivariate analysis revealed that gender [odds ratio (OR) =0.392; P<0.001], carcinoembryonic antigen (CEA) level (OR =8.331; P<0.001), type of nodules (OR =13.551 and 7.478; P<0.001 and P=0.016) and maximum base width of soft tissue component on the pleura side (OR =0.857; P=0.005) were significant independent factors for distinguishing tuberculous granuloma from adenocarcinoma. And the type of linear connection between lesion and pleura (OR =3.936; P<0.001), and the maximum base width of soft tissue components on the pleura side (OR =1.359; P=0.001) were correlated independently with VPI. The area under the curve (AUC) for predicting pulmonary nodules classification was 82.60% [95% confidence interval (CI): 78.85-86.35%), and the AUC for predicting VPI was 76.10% (95% CI: 69.83-82.38%). The tumour-pleura relationship will be helpful in further risk stratification for peripheral pulmonary nodules with a score of Lung-RADS 4X.