Mechanical Treatment Research Articles

Comparative assessment of Ti‐6Al‐4 V titanium alloy fatigue life improvement by vibratory peening, shot peening, and vibratory finishing

AbstractThe effects of vibratory peening (VP), shot peening (SP), and SP followed by vibratory finishing (SPVF) on the surface and fatigue properties of Ti‐6Al‐4 V were compared to conventional low‐stress grinding (LSG). VP processing produced seven times smoother surface finish than SP and 66% deeper compressive residual stresses (CRS) but with 12% lower magnitudes. SPVF produced optimal surface properties with a perfectly flat surface and CRS‐like SP. All three mechanical surface treatments generated similar fatigue life improvements (108–122%) over LSG when the cyclic stress was below the yield stress. Above the yield stress, most of the CRS relaxed during the first cycle in VP specimens, resulting in up to 97% fatigue life improvement over LSG. The CRS relaxed more gradually in SP specimens leading to larger (up to 239%) fatigue life improvement. This shows the need to amplify CRS magnitudes produced in VP to maximize fatigue life improvement.

Optimizing Surface Hardness and Corrosion Resistance in 316L Stainless Steel via SMRT and Plasma Nitriding.

Increasing the mechanical strength of stainless steel is fundamental to expanding its applications and extending its useful life, especially due to its impressive corrosion resistance. However, many processes that make possible increasing the hardness and wear resistance of these steels also compromise their performance when they are subjected to corrosive environments. Because of the need to increase surface hardness without jeopardizing corrosion resistance, this study explores the impact of a surface mechanical rolling treatment (SMRT) with volumetric reductions of 50% and 70%, together with high-temperature plasma nitriding (PN) (450, 500, and 550 °C), on 316L steel. X-ray diffraction analysis analyzed the composition and structure of the resulting coatings. Mechanical strength was assessed using Vickers microhardness, while corrosion resistance was tested in a 3.5%-by-weight NaCl solution. The results indicate a substantial increase in surface hardness in all of the nitrided samples. Notably, the samples were subjected to rolling with 50% and 70% volumetric reduction, and subsequent nitriding at 550 °C showed a reduced impairment of corrosion resistance. This shows that the methodology adopted in this study, consisting of SMRT and PN, can increase the useful life and expand the applicability of stainless steels commonly used in various industry sectors.

The role of processing on phenolic bioaccessibility and antioxidant capacity of apple derivatives

Fruit derivatives are commonly obtained by applying processing operations deemed responsible for the loss of phenol compounds, but very little information is available on the fate of phenols upon digestion of these products. The present study evaluated the effect of thermal and mechanical treatments, commonly applied to turn apple pulp into puree and homogenate, on phenolic bioaccessibility and antioxidant activity.Despite a 20 % decrease in polyphenols due to processing, their bioaccessibility was higher in apple derivatives (>20 %) compared to pulp (∼2 %). Polyphenol oxidase (PPO), inactivated by thermal treatments in apple derivatives but not in the pulp, was hypothesized to be responsible for this difference. Results acquired on an unprocessed PPO-free apple model, only featuring quercetin-3-glucoside and pectin, actually exhibited similar bioaccessibility as processed derivatives.The radical scavenging capacity was unaffected by the structural integrity of apples, indicating independence from the plant tissue's hierarchical arrangement. After digestion, radical scavenging capacity decreased in the real apple matrices, correlating with phenolic content, while it was retained in the apple model, further suggesting the pivotal food matrix role in modulating polyphenols bioaccessibility and subsequent biological activity.Translating these results to an industrial scale, processing conditions can be optimized not only to guarantee that the quality requirements are met, but also to achieve desired nutritional benefits.

Fast diffusion kurtosis imaging for venous stroke caused by cerebral venous thrombosis

Background: Diffusion kurtosis imaging (DKI) has been found to be more precise than diffusion weighted imaging (DWI) for detecting irreversible infarction in acute ischemic stroke. This study aimed to evaluate whether fast DKI has distinctive advantages in detecting venous stroke caused by cerebral venous thrombosis (CVT). Methods: All data from patients diagnosed with venous stroke due to CVT and qualified for mechanical recanalization treatment were collected. Fast DKI and DWI were obtained both before and after revascularization therapy, and lesions were measured. Lesion volumes on T2 weighted imaging (T2WI) were followed up at six months. Results: A total of 11 patients were recruited. Compared to the contralateral brain, ADC values of the lesions in pre-operation increased significantly (1340.12±235.42 vs 919.75±128.98, P < 0.05), while MK decreased (0.59±0.11 vs 0.81±0.12, P < 0.05). And the same changing trend about ADC values (1258.94±185.08 vs 949.81±148.52, P < 0.05) and MK values (0.64±0.12 vs 0.83±0.12, P < 0.05) in post-operation. There was no significant difference in the volume of lesions between DKI and DWI during the same examination period (26.97 vs 29.28, Ppre > 0.05; 13.34 vs 13.14, Ppost > 0.05). However, the lesion volume after revascularization was significantly reduced compared to the first DKI and DWI examinations (26.97 vs 13.34, P < 0.05), and the same as DWI (29.28 vs 13.14, P < 0.05). Volume of T2WI lesions after the 6th month diminished significantly compared with both DKI lesions and DWI lesions before treatment (7.25 vs 26.97, P < 0.05; 7.25 vs 31.19, P < 0.05). Fast DKI had a higher signal to noise ratio (SNR) than traditional DKI and DWI. Conclusion: The MK of the venous stroke lesions decreased significantly in the subacute stage of CVT, suggesting reversible infarction. Fast DKI has more distinctive superiority in the evaluation of venous stroke. Fast DKI approach may hold great promise for patients in clinical setting because of a higher SNR than DWI. But the sample need to be further expanded because of only 11 patients recruited.

Rolling contact fatigue property of gradient rare earth addition M50 bearing steel with surface nano-grains and its inhibited martensite decay

A gradient nanostructured surface layer of ∼600 μm in thickness was prepared on M50 steel with rare earth additions by a surface mechanical rolling treatment. The initial microstructure was refined into nanosized grains (∼29 nm in diameter) in the top surface layer, causing a significant increase of surface hardness. Meanwhile, the grain size increases, and the microhardness decreases gradually to the matrix values with increasing depth. Rolling contact fatigue tests showed that the fatigue lives are significantly increased by the gradient nanostructured surface layer. Analysis of failure mechanism revealed that both softening in the near surface layer and hardening in the subsurface occur under rolling contact testing. And surface spalling is the predominant failure mode, of which the cracks initiate from primary carbides in the top surface layer owing to surface softening. In gradient nanostructured samples, the nano-grains inhibit carbon migration by impeding dislocation movement in the near surface layer, so that martensite decay is suppressed. Consequently, the crack initiation is inhibited, and the fatigue property is enhanced.

Boosting deep-ultraviolet photodetector performance via ferroelectric effect based on HfAlOx@PEI composite

In this study, hafnium-aluminum oxide (HfAlOx) was used as an effective active layer in a self-powered deep-ultraviolet (UV) photodetector. For the first time, we exploited the ferroelectric properties of crystalline HfAlOx to enhance device performance. The HfAlOx powder obtained at an annealing temperature of 850 °C exhibited the highest-intensity peak for the orthorhombic phase (o-phase), representing the ferroelectric property of the material. The HfAlOx particles were reduced to a small size using mechanical treatment to facilitate the preparation of a composite thin film with a polyethyleneimine (PEI) polymer matrix. First, the HfAlOx@PEI composite film-based photodetector demonstrated a remarkable on/off ratio of more than 103 and a rapid response (trise/tfall of 0.127/2.7 s) at zero bias under 254-nm UV illumination. Second, the photocurrent of the device was dramatically boosted under an external bias owing to the injection of carriers, supported by the ferroelectric effect of the o-phase HfAlOx. As a result, the external quantum efficiency and responsivity approached 2628 % and 5.37 A/W at −1 V bias, respectively. Furthermore, the device exhibited excellent photostability, demonstrating almost no change in the photocurrent after 1000 s of UVC irradiation. Our findings provide guidance for the preparation of optoelectronic devices, particularly self-powered high-performance UV photodetectors.

Simultaneous improvement in mechanical properties, corrosion resistance and antibacterial properties of Ti-Ag sintered alloy with gradient nanostructure

Bioinert titanium (Ti) with antibacterial properties is crucial for bone implantations. Alloying Ag can endow Ti with antibacterial properties, while the mechanical, corrosion and antibacterial properties of Ti-Ag alloys are not satisfactorily balanced. In this work, Ti-x wt%Ag alloys (x=0.5, 1 and 3) were sintered by spark plasma sintering and then subjected to a surface mechanical rolling treatment (SMRT). The Ti-Ag alloys are composed of Ti, Ti-Ag and Ti2Ag phases. After SMRT, a gradient nanostructured (GNS) layer formed on the Ti-Ag surface, the mean grain size is ∼ 6 nm at the top surface and increases gradually with depth. The GNS layer endows Ti-Ag alloys with better wettability, higher nano-roughness and compressive residual stress. Incorporating limited Ag (≤1 wt%) in Ti can effectively enhance its mechanical (surface hardness, wear resistance and compressive strength) and anti-corrosion properties, and they can be further improved by forming a GNS layer. The antibacterial efficiency of Ti-Ag is positively proportional to Ag content, and they are significantly enhanced after surface nanocrystallization. The bacteriostatic mechanism is the synergistic interaction between leach Ag+ and nano Ag-containing phases of GNS Ti-Ag alloy. Both Ti-Ag and GNS Ti-Ag alloys possess good cytocompatibility, the GNS layer has the potential to encourage early differentiation of osteoblasts. The GNS Ti-Ag alloy with 1 wt% Ag has excellent comprehensive properties, which shows larger potential in orthopedic applications.

Enhanced mechanical strength and texture of (Ba,K)Fe2As2 Cu/Ag composite sheathed tapes with Nb barrier layer

Abstract Iron-based superconductors with ultra-high upper critical fields and low anisotropy have attracted much attention for superconducting mechanisms and high-field applications. In practical applications, improving the mechanical strength and heat treatment temperature of superconducting tapes is of great significance for the improvement of transport current as well as stability. In this paper, (Ba, K)Fe2As2(Ba-122) superconducting tapes with Cu/Nb/Ag composite sheaths were successfully fabricated using a pre-composite process, which provides a feasible method for the fabrication of high-strength superconducting wires and tapes. It is shown that Cu/Nb/Ag composite sheathed tapes can be sintered at 880 °C, and tapes sintered at 880 °C have the highest transport properties as well as excellent superconductivity of the superconducting cores, as demonstrated by a series of characterizations. In addition, other superconducting properties of the tapes sintered at 880 °C, including grain orientation, flux pinning, upper critical field and irreversible field, were also studied. It was found that none of the three sheaths fractured after sintering and the superconducting core had a high c-axis texture and densities. The high mechanical strength of the Cu/Nb/Ag composite sheathed tape was also demonstrated by comparative tensile experiments. The results indicate that the low-cost Ba-122 tapes with Cu/Nb/Ag composite sheaths hold great promise for future practical applications.

Quantum-limited transmission distance of optically repeating systems using a hybrid EDFA/Raman-amplifier.

The transmission distance of optically repeating systems is ultimately bounded by quantum noises arising from attenuation and amplification. It is known that fiber Raman amplifiers (FRAs) can achieve longer quantum-limited distances than other amplification schemes owing to their distributed amplification characteristics. However, all-FRA systems are difficult to implement in practice. Therefore, a hybrid erbium-doped fiber amplifier (EDFA)/FRA system may be a reasonable solution for long-haul transmission. In this study, the quantum-limited transmission distance of hybrid EDFA/FRA systems is investigated. A formula for the quantum fluctuation variance during transmission was derived based on quantum mechanical treatment. Calculation results obtained with the derived formula quantitatively indicate that the quantum-limited transmission distance increases as the EDFA/FRA hybrid ratio varies from EDFAs alone to FRAs alone.

Role of nanostructured surface layers in enhancing pure titanium diffusion bonding above their destabilization temperatures

The benefits of the nanostructured materials are believed to be probably absent if they are used at high temperatures. In this study, enhanced diffusion bonding of pure Ti was investigated by introducing a nanostructured surface layer through the surface mechanical attrition treatment (SMAT) technique. Complete recrystallization and remarkable grain growth have taken place in the original nanostructured surface layer due to the diffusion bonding conditions far beyond the nanostructured Ti destabilization temperatures. However, they still played a significant role in enhancing the Ti/Ti interfacial bonding. The consistency analysis of relative grain boundary energy, relaxation time, and microstrain reveals that although the original nanocrystalline has disappeared, the newly formed grain boundaries (GBs) during recrystallization probably inherit part of non-equilibrium state of the corresponding GBs in the as-SMATed surface layer, where the atomic diffusivity may increase greatly compared to the general relaxed GBs in their coarse-grained polycrystalline counterparts. The presence of these high-energy non-equilibrium GBs retains ultrafast atomic diffusion paths, leading to a diffusion bonding temperature of at least 100 °C lower than the traditional approach. The joint achieved at a low temperature of 750 °C exhibited a shear strength approximately 2 times higher than that prepared using raw substrates.

A Recyclable Ionogel with High Mechanical Robustness Based on Covalent Adaptable Networks.

Ionogels are an emerging class of soft materials for flexible electronics, with high ionic conductivity, low volatility, and mechanical stretchability. Recyclable ionogels are recently developed to address the sustainability crisis of current electronics, through the introduction of non-covalent bonds. However, this strategy sacrifices mechanical robustness and chemical stability, severely diminishing the potential for practical application. Here, covalent adaptable networks (CANs) are incorporated into ionogels, where dynamic covalent crosslinks endow high strength (11.3MPa tensile strength), stretchability (2396% elongation at break), elasticity (energy loss coefficient of 0.055 at 100% strain), and durability (5000 cycles of 150% strain). The reversible nature of CANs allows the ionogel to be closed-loop recyclable for up to ten times. Additionally, the ionogel is toughened by physical crosslinks between conducting ions and polymer networks, breaking the common dilemma in enhancing mechanical properties and electrical conductivity. The ionogel demonstrates robust strain sensing performance under harsh mechanical treatments and is applied for reconfigurable multimodal sensing based on its recyclability. This study provides insights into improving the mechanical and electrical properties of ionogels toward functionally reliable and environmentally sustainable bioelectronics.

Photocatalytic treatment of diverse contaminants of potential concern in oil sands process-affected water

Oil sands process-affected water (OSPW), generated by surface mining in Canada's oil sands, require treatment of environmentally persistent dissolved organic compounds before release to the watershed. Conventional chemical and mechanical treatments have not proved suitable for treating the large quantities of stored OSPW, and the biological recalcitrance of some dissolved organics may not be adequately addressed by conventional passive treatment systems. Previous work has evaluated photocatalytic treatment as a passive advanced oxidation process (P-AOP) for OSPW remediation. This work expands upon this prior research to further characterize the effects of water chemistry on the treatment rate and detoxification threshold. Under artificial sunlight, buoyant photocatalysts (BPCs) detoxified all OSPW samples within 1 week of treatment time with simultaneous treatment of polycyclic aromatic hydrocarbons, naphthenic acid fraction components (NAFCs), and un-ionized ammonia. Overall, these results further demonstrate passive photocatalysis as an effective method for treatment of OSPW contaminants of potential concern (COPCs).

Parameter Optimization of a Surface Mechanical Rolling Treatment Process to Improve the Surface Integrity and Fatigue Property of FV520B Steel by Machine Learning.

Surface integrity is a critical factor that affects the fatigue resistance of materials. A surface mechanical rolling treatment (SMRT) process can effectively improve the surface integrity of the material, thus enhancing the fatigue property. In this paper, an analysis of variance (ANOVA) and signal-to-noise ratio (SNR) are performed by orthogonal experimental design with SMRT parameters as variables and surface integrity indicators as optimization objectives, and the support vector machine-active learning (SVM-AL) model is proposed based on machine learning theory. The entire model includes three rounds of AL processes. In each round of the AL process, the SMRT parameters with relative average deviation and high output values from cross-validation are selected for the additional experimental supplement. The results show that the prediction accuracy and generalization ability of the SVM-AL model are significantly improved compared to the support vector machine (SVM) model. A fatigue test was also carried out, and the fatigue property of the SMRT specimens predicted by the SVM-AL model is also higher than that of the other specimens.

Experimental Study of the Stress State of a Polymer Composite in a State of Compression

Long-term operation of the supporting surfaces of large-sized parts, in particular tubular units of thermal power plants, leads to the destruction of the contact surfaces. Moisture penetrates into the formed discontinuities, and the vibrations present in the equipment in use rapidly increase the gap, reaching values of 10–15 mm. The authors of this article proposed the application of a composite layer of multimetal 1018 material without performing additional preparatory operations, ensuring the mandatory penetration of the material into the body of the supporting surface. This depth provides additional stability by maintaining boundary conditions. To determine the rational thickness of the composite layer, mathematical modeling of static loading of samples with different thicknesses in a wide range of values (from 2 mm to 12 mm) was performed. It was determined that the effective implementation of the developed technology was possible due to an increase in the load-bearing capacity of the composite material by creating additional grooves, or artificially creating grooves by welding, in the body of the part with a depth of 2.5–3 mm. The optimal excess of the composite was 1.0–1.5 mm. The proposed technology increases the stability of the composite layer up to three times and allows restoration without the use of mechanical treatment. The increase in the maximum stress values was 770 MPa, compared to the standard technology of 205 MPa.

Investigations on microstructural, mechanical, and tribological properties of Al-Cu-Ni alloy in cast, heat-treated, and strain-softened conditions

This research investigates the microstructural, mechanical, and tribological properties of Al-Cu-Ni alloys in the as-cast, solutionized, artificially aged condition. In addition, the influence of cold-rolling followed by solutionizing/strain softening on the microstructure and microhardness was evaluated through a comprehensive analysis. Microstructural examination reveals that the addition of nickel to Al-Cu-Ni leads to refined dendritic structures and intermetallic phase formation. Texture analysis and microhardness measurements demonstrate the impact of mechanical and heat treatments on grain size, orientation, and material hardness. Tribological characterization reveals superior wear resistance in the heat treated Al-Cu-Ni alloy, attributed to intermetallic phases and refined microstructures.

Investigating microstructure dynamics and strain rate sensitivity in gradient nanostructured AISI 304 L stainless steel: TEM and nanoindentation insights

In recent years, gradient nanostructured (GNS) materials have gained significant attention due to their superior strength-ductility balance and enhanced functional properties compared to their coarse-grained counterparts. This research examines the microstructure evolution and nanomechanical responses of GNS AISI 304 L austenitic stainless steel using transmission electron microscopy (TEM) and nanoindentation techniques. Through surface mechanical attrition treatment (SMAT), a gradient nanostructured layer with ultrafine grains (∼15 nm) and nanoscale martensite (up to ∼40 %) within the austenite matrix has been successfully created on the steel’s surface. This treated surface exhibits a hardness of ∼6.7 GPa, nearly double the original value. The GNS layer demonstrates single-step (γ → α’) and two-step (γ → ε → α’) martensitic transformations, deformation twinning (γ -twin), a decrease in the density of deformation bands, compressive residual stress, lattice strain, and martensite content, along with an increase in grain size. Strain rate sensitivity (SRS) increases with austenitic grain size and inversely correlates with martensite proportion as depth increases in the GNS layer. A significant amount of ultrafine martensite is primarily responsible for the limited SRS in the topmost layer.

Overview of Leech Therapy as an Alternative Treatment for Varicose Ulcers: Mechanisms and Efficacy

Varicose ulcer, the most severe and debilitating complication of chronic venous insufficiency in the lower limbs, impart substantial obstacles in medical management because of their chronicity and propensity for recurrence. About 80 percent of ulcerations on the lower extremities are triggered by varicose ulcer. Despite advances in diagnosis and treatment, varicose ulceration remains a major healthcare concern due to its potential for life-threatening complications. The morbidity has a detrimental effect on life expectancy. Venous ulceration results from persistent venous pressure brought on by venous insufficiency. Although the diagnosis is primarily clinical, it must be distinguished from other lower limb ulcer causes. Reduction of edema, enhancement of ulcer healing, and avoidance of recurrence are the objectives of treatment. Although conservative care, mechanical treatment, pharmaceutical, and surgical methods are available for the treatment of venous ulcers, but Hirudotherapy, also known as leech therapy, has grown into a prominent complementary treatment option. It has the potential to promote wound healing and alleviate varicose ulcer symptoms. The objective of this review is to accord a thorough overview of the application of leech therapy to the management of varicose ulcers. The present study emphasizes on the mechanisms of action, efficacy and safety profile of leech therapy in the context of managing varicose ulcers by synthesizing a collection of available literature, clinical investigations, and case reports.

Bivalirudin in Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a mechanical support treatment modality utilized in patients with refractory cardiac and/or pulmonary failure. Bleeding and thrombotic complications associated with ECMO are inherent concerns that require careful management. Anticoagulation optimization may help mitigate these risks by providing more adequate therapeutic anticoagulation and lessen the bleed risk. Heparin, the most utilized anticoagulant, carries concerns for heparin-induced thrombocytopenia and possible resistance given its dependence on co-factors and circulating proteins to exert its pharmacologic effect. In contrast, bivalirudin, a direct thrombin inhibitor, exerts its effect independent of co-factors or plasma proteins, and possesses thrombin-binding and metabolism features that may confer advantages in ECMO management. This review of the evidence for bivalirudin utilization in ECMO suggests favorable outcomes in circuit-related thrombosis, bleeding, and dosing reliability. Additionally, blood product utilization, circuit interventions, and success in ECMO decannulation and survival were positive findings associated with bivalirudin that merit consideration. Common questions and concerns relative to bivalirudin utilization, including laboratory monitoring, utilization in low flow states, dosing considerations in renal replacement therapy, reversibility, and cost are also discussed in this review. Moreover, this review suggests that bivalirudin utilization presents the opportunity for ECMO management simplification.

Investigation of mechanical and wettability properties of commercial pure titanium by surface mechanical attrition treatment

The examination of mechanical and wettability properties of commercial pure titanium (CP-Ti) introduced a novel challenge. The microstructure of samples was analyzed by using OM and SEM micro-images. In this study, the hardness of the surface and cross section of samples was evaluated, and the effect of several surface mechanical attrition treatments (SMATed) on samples was examined. Also, the tensile test was done to compare the effect of SMAT duration on mechanical properties of samples. The contact angle method was then employed to investigate the impact of SAMT duration on the wettability trend. According to results, as the treatment time increases, twins become evident in the deeper layers of the samples. In contrast, the near-surface twins are shorter than those found in the deeper material, signifying the presence of finer grains. Moreover, the elevated hardness in SMATed samples can be attributed to several key factors, including cold work, a rise in defects and twins, and grain refinement. The surface hardness increases across the sample series (up to Ti6) due to the substantial energy input. Nevertheless, it is anticipated that further continuation of the process will result in a constant surface hardness. The increased strength observed in SMATed samples can be attributed to factors such as reduction in grain size and the formation of twins. The wettability results show that the treated surfaces exhibited a significant change in wettability compared to the untreated samples, with a 25% reduction in the contact angle. This is attributed to the surface modifications induced by the treatment process, which introduced more hydrophilic functional groups. The results also show that after 4 h of treatment, the contact angle increases, suggesting that the trend may plateau with additional treatment time.

A eficácia do canabidiol no tratamento de transtornos mentais: Uma revisão sistemática de ensaios clínicos randomizados duplo-cegos

INTRODUCTION: The therapeutic application of cannabidiol (CBD) is gaining interest due to the growing body of evidence supporting its use in the treatment of mental disorders. OBJECTIVES: To develop a systematic review to evaluate the scientific evidence supporting the use of CBD in the treatment of psychiatric disorders. METHODS: Only double-blind randomized clinical trials were used. The search for scientific evidence was carried out in the PubMed and VHL databases, with the descriptors "cannabidiol" and "mental disorders". Between 2020 and 2022, 219 articles were found in PubMed and 79 in the VHL. Review articles, observational studies, manuscripts, repeated articles, and articles that did not focus on the treatment of mental disorders by the use of cannabidiol were excluded. Thus, 10 relevant studies remained for the present systematic review. RESULTS: Of the 10 articles selected, 90% presented positive results for the use of CBD in the treatment of various mental disorders. Among them, there was a higher prevalence of drug use for the treatment of psychosis, anxiety and behavioral mechanisms; evidencing its usefulness and benefits. It was observed that in cases of psychosis, CBD significantly increased glutamate levels in the left hippocampus of patients, proving its effectiveness. In research involving behavioral mechanisms, it was possible to verify that the use of CBD linearly decreased the levels of cortisol linked to stress in the patient's body, evidencing its therapeutic capacity. CONCLUSION: The use of CBD was useful to relieve the symptoms of some mental disorders, such as psychosis, anxiety, schizophrenia, autism, behavioral problems and stress. In addition, research has still shown uncertain and sometimes even contradictory results, which reinforces the need for more research on the action of this drug in the treatment of mental disorders.