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The development of rigid polyaromatic building blocks for narrowband violet fluorophores has received tremendous attention. Herein, we designed and synthesized two new triangle-shaped rigid building blocks, namely, 2,5-di-tert-butylindolo[3,2,1-jk]carbazole (tBuICz) and 2,11-di-tert-butylindolo[3,2,1-jk]carbazole-4-carbonitrile (tBuICzCN), and tethered them with different chromophores to yield a series of violet-blue fluorophores, viz., ICzTPA-ICzPICN, and studied their structure-function relationship. The appended chromophores and cyano unit played a vital role in controlling the optical and electrical properties of the compounds. Except triphenylamine-substituted derivatives, the compounds showed pure violet emission (λem ≤ 403 nm). Intriguingly, the compounds exhibited narrow-band emission with a full-width at half-maximum ≤ 40 nm, attributed to the rigidity of the ICz core. The emission of the compounds displayed positive solvatochromism, which is ascribed to the photoinduced intramolecular charge transfer in the excited state. The compounds revealed excellent thermal robustness with T5d ≥ 363 °C. The triphenylamine-featuring derivatives displayed a high-lying HOMO compared to their congeners due to their electron-rich nature. When we applied these materials in organic light-emitting diodes, ICzPI outperformed in the series with an EQEmax of 3.07% and a current efficiency of 1.04 cd/A. Notably, its CIEy â¼ 0.046 precisely matched with the Rec.2020 standard of deep-blue color (CIEy â¼ 0.046).
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When we develop wearable assistive devices, comfort and support are two main issues that need to be considered. In conventional design approaches, the degree of freedom of the wearer's joint movements tends to be oversimplified. Accordingly, the wearer's motion becomes restrained and bone/ligament injuries might occur in case of an unexpected fall. To mitigate these issues, this paper proposes a novel joint link mechanism inspired by a human spine structure as well as functionalities. The key feature of the proposed spine-like joint link mechanism is that hemispherical blocks are concatenated via flexible synthetic fiber lines so that their concatenation stiffness can be adjusted according to a tensile force. This feature has a great potentiality for designing a wearable assistive device that can support aged people's sit-to-stand action or augment spinal motion by regulating the concatenation stiffness. In addition, the concatenated hemispherical blocks enable the wearer to move his/her joint with full freedom, which in turn increases the wearer's mobility and prevents joint misalignment. The experimental results with a testbed and a pilot wearer substantiated that the spine-like joint link mechanism can serve as a key component in the design of wearable assistive devices for better mobility.
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Dispositivos de Autoayuda , Dispositivos Electrónicos Vestibles , Accidentes por Caídas , Anciano , Femenino , Humanos , Masculino , Movimiento/fisiología , Columna VertebralRESUMEN
This paper presents a wheel cylinder pressure control algorithm for application to the vehicle electronic stability control (ESC) systems for commercial trucks. An ESC system is an active system that improves the driving stability by distributing the appropriate braking pressure to each wheel, which is an essential system for safe driving. It is important that the ESC system, through proper braking pressure supply, delivers the correct pressure under control. However, to reduce the cost involved, commercial trucks use a solenoid valve of the on/off-type, rather than a proportional valve that has good pressure control capability. The performance of a proposed wheel pressure control system based on an on/off solenoid valve control was verified by means of experiments conducted using the wheel pressure control algorithm presented in this paper.
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This paper details the new design and dynamic simulation of an electro-hydraulic camless engine valve actuator (EH-CEVA) and experimental verification with lift position sensors. In general, camless engine technologies have been known for improving fuel efficiency, enhancing power output, and reducing emissions of internal combustion engines. Electro-hydraulic valve actuators are used to eliminate the camshaft of an existing internal combustion engines and used to control the valve timing and valve duration independently. This paper presents novel electro-hydraulic actuator design, dynamic simulations, and analysis based on design specifications required to satisfy the operation performances. An EH-CEVA has initially been designed and modeled by means of a powerful hydraulic simulation software, AMESim, which is useful for the dynamic simulations and analysis of hydraulic systems. Fundamental functions and performances of the EH-CEVA have been validated through comparisons with experimental results obtained in a prototype test bench.
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"Gel-type" soft and stretchable magneto-mechanical composites made of silicone rubber and iron particles are in focus because of their high magnetic sensitivity, and intelligence perspective. The "intelligence" mentioned here is related to the "smartness" of these magneto-rheological elastomers (MREs) to tune the "mechanical stiffness" and "output voltage" in energy-harvesting applications by switching magnetic fields. Hence, this work develops "gel-type" soft composites based on rubber reinforced with iron particles in a hybrid with piezoelectric fillers such as barium titanate. A further aspect of the work relies on studying the mechanical stability of intelligence and the stretchability of the composites. For example, the stretchability was 105% (control), and higher for 158% (60 per 100 parts of rubber (phr) of barium titanate, BaTiO3), 149% (60 phr of electrolyte iron particles, EIP), and 148% (60 phr of BaTiO3 + EIP hybrid). Then, the magneto-mechanical aspect will be investigated to explore the magnetic sensitivity of these "gel-type" soft composites with a change in mechanical stiffness under a magnetic field. For example, the anisotropic effect was 14.3% (60 phr of EIP), and 4.4% (60 phr of hybrid). Finally, energy harvesting was performed. For example, the isotropic samples exhibit ~20 mV (60 phr of BaTiO3), ~5.4 mV (60 phr of EIP), and ~3.7 mV (60 phr of hybrid). However, the anisotropic samples exhibit ~5.6 mV (60 phr of EIP), and ~8.8 mV (60 phr of hybrid). In the end, the composites prepared have three configurations, namely one with electro-mechanical aspects, another with magnetic sensitivity, and a third with both features. Overall, the experimental outcomes will make fabricated composites useful for different intelligent and stretchable applications.
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The latest progress (the year 2021-2024) on multifunctional sensors based on silicone rubber is reported. These multifunctional sensors are useful for real-time monitoring through relative resistance, relative current change, and relative capacitance types. The present review contains a brief overview and literature survey on the sensors and their multifunctionalities. This contains an introduction to the different functionalities of these sensors. Following the introduction, the survey on the types of filler or rubber and their fabrication are briefly described. The coming section deals with the fabrication methodology of these composites where the sensors are integrated. The special focus on mechanical and electro-mechanical properties is discussed. Electro-mechanical properties with a special focus on response time, linearity, and gauge factor are reported. The next section of this review reports the filler dispersion and its role in influencing the properties and applications of these sensors. Finally, various types of sensors are briefly reported. These sensors are useful for monitoring human body motions, breathing activity, environment or breathing humidity, organic gas sensing, and, finally, smart textiles. Ultimately, the study summarizes the key takeaway from this review article. These conclusions are focused on the merits and demerits of the sensors and are followed by their future prospects.
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Vulcanization is a chemical modification of rubber that requires a considerable amount of thermal energy. To save thermal energy, the kinetics of rubber vulcanization should be improved. In this article, the curing properties of rubber vulcanization are thoroughly investigated using the moving die rheometer (MDR) technique. To enhance the kinetics in different stages of ZnO-based sulfur vulcanization systems, small amounts of MgO were added. The results revealed that the small amount of 1 to 2 phr (per hundred grams of rubber) of MgO in the controlled 5 phr ZnO-based curing systems can significantly improve the curing kinetics. For example, the optimum curing time of 1 phr MgO added to the 5 phr ZnO-containing semi-efficient vulcanization system at different temperatures was more than half that of the controlled 5 phr ZnO-only compound. While maintaining a similar rate of vulcanization, the vulcanization temperature can be reduced by up to 20 °C by using MgO as a co-cure activator, which exhibits similar or better rheometric mechanical properties compared to the controlled compounds. With the addition of MgO as a co-cure activator, the vulcanization reactions become very fast, enabling vulcanization to be completed, even at the boiling point of water (100 °C) with an affordable curing time (<1 h). By reducing the vulcanization temperature, the scorch safety time can be enhanced in the ZnO/MgO-based binary cure activator-containing vulcanizates. Overall, MgO could be a potential candidate as a co-cure activator with ZnO for the vulcanization of rubber, offering better economical and eco-friendly methods.
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Energy harvesting systems fabricated from rubber composite materials are promising due to their ability to produce green energy with no environmental pollution. Thus, the present work investigated energy harvesting through piezoelectricity using rubber composites. These composites were fabricated by mixing titanium carbide (TiC) and molybdenum disulfide (MoS2) as reinforcing and electrically conductive fillers into a silicone rubber matrix. Excellent mechanical and electromechanical properties were produced by these composites. For example, the compressive modulus was 1.55 ± 0.08 MPa (control) and increased to 1.95 ± 0.07 MPa (6 phr or per hundred parts of rubber of TiC) and 2.02 ± 0.09 MPa (6 phr of MoS2). Similarly, the stretchability was 133 ± 7% (control) and increased to 153 ± 9% (6 phr of TiC) and 165 ± 12% (6 phr of MoS2). The reinforcing efficiency (R.E.) and reinforcing factor (R.F.) were also determined theoretically. These results agree well with those of the mechanical property tests and thus validate the experimental work. Finally, the electromechanical tests showed that at 30% strain, the output voltage was 3.5 mV (6 phr of TiC) and 6.7 mV (6 phr of MoS2). Overall, the results show that TiC and MoS2 added to silicone rubber lead to robust and versatile composite materials. These composite materials can be useful in achieving higher energy generation, high stretchability, and optimum stiffness and are in line with existing theoretical models.
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The relationship between smoking and nutrient intake has been widely investigated in several countries. However, Korea presents a population with a smoking rate of approximately 50% and dietary consumption of unique foods. Thus, the aim of this study was to evaluate the association of dietary patterns with smoking in Korean men using a nationally representative sample. The study subjects were comprised of 4,851 Korean men over 19 yr of age who participated in the fourth Korean National Health and Nutrition Examination Survey. Dietary data were assessed by the 24-hr recall method. The smoking group comprised 2,136 men (46.6%). Five dietary patterns were derived using factor analysis: 'sugar & fat', 'vegetables & seafood', 'meat & drinks', 'grains & eggs', and 'potatoes, fruits and dairy products.' Current smokers showed a more significant 'sugar & fat' pattern (P = 0.001) while significantly less of the 'vegetables & seafood' and 'potatoes, fruits and dairy products' patterns (P = 0.011, P < 0.001, respectively). As found in similar results from Western studies, Korean male smokers showed less healthy dietary patterns than nonsmokers. Thus, the result of this study underlines the need for health professionals to also provide advice on dietary patterns when counseling patients on smoking cessation.
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Dieta/estadística & datos numéricos , Fumar , Adulto , Pueblo Asiatico , Índice de Masa Corporal , Carbohidratos , Dislipidemias/epidemiología , Ingestión de Energía , Conducta Alimentaria , Frutas , Humanos , Masculino , Carne , Persona de Mediana Edad , Encuestas Nutricionales , Oportunidad Relativa , República de Corea/epidemiología , Alimentos Marinos , VerdurasRESUMEN
Mechanical robustness and high energy efficiency of composite materials are immensely important in modern stretchable, self-powered electronic devices. However, the availability of these materials and their toxicities are challenging factors. This paper presents the mechanical and energy-harvesting performances of low-cost natural rubber composites made of stearic acid-modified diatomaceous earth (mDE) and carbon nanotubes (CNTs). The obtained mechanical properties were significantly better than those of unfilled rubber. Compared to pristine diatomaceous earth, mDE has higher reinforcing efficiencies in terms of mechanical properties because of the effective chemical surface modification by stearic acid and enhanced filler-rubber interactions. The addition of a small amount of CNT as a component in the hybrid filler systems not only improves the mechanical properties but also improves the electrical properties of the rubber composites and has electromechanical sensitivity. For example, the fracture toughness of unfilled rubber (9.74 MJ/m3) can be enhanced by approximately 484% in a composite (56.86 MJ/m3) with 40 phr (per hundred grams of rubber) hybrid filler, whereas the composite showed electrical conductivity. At a similar mechanical load, the energy-harvesting efficiency of the composite containing 57 phr mDE and 3 phr CNT hybrid filler was nearly double that of the only 3 phr CNT-containing composite. The higher energy-harvesting efficiency of the mDE-filled conductive composites may be due to their increased dielectric behaviour. Because of their bio-based materials, rubber composites made by mDE can be considered eco-friendly composites for mechanical and energy harvesting applications and suitable electronic health monitoring devices.
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Electro-mechanical configurations can be piezo-electric transducers, triboelectric generators, electromagnetic induction, or hybrid systems. Our present study aims at developing energy generation through the piezoelectric principle. Gel-type soft SR with Shore A hardness below 30 was used as a versatile material for an elastomeric substrate. Also, multi-wall carbon nanotube (MWCNT), and diatomaceous earth (DE) were used as reinforcing fillers. This "gel-type" soft SR has crosslinking polymer networks with silicone encapsulated within its structure. Mechanical properties such as modulus or stretchability are of utmost importance for such devices based on "gel-type" soft. From the experiments, some of the mechanical aspect's values are summarized. For example, the stretchability was 99% (control) and changes to 127% (3 phr, MWCNT), 76% (20 phr DE), and 103% (20 phr hybrid). From electro-mechanical tests, the output voltage was 0.21 mV (control) and changed to 0.26 mV (3 phr, MWCNT), 0.19 mV (20 phr DE), and 0.29 mV (20 phr hybrid). Moreover, from real-time biomechanical human motion tests in "gel-type" soft-based composites, a relationship among output voltage from machine to human motions was established. Overall, these configurations make them promising against traditional portable devices such as batteries for small power applications such as mobile phones.
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The demand for multi-functional elastomers is increasing, as they offer a range of desirable properties such as reinforcement, mechanical stretchability, magnetic sensitivity, strain sensing, and energy harvesting capabilities. The excellent durability of these composites is the key factor behind their promising multi-functionality. In this study, various composites based on multi-wall carbon nanotubes (MWCNT), clay minerals (MT-Clay), electrolyte iron particles (EIP), and their hybrids were used to fabricate these devices using silicone rubber as the elastomeric matrix. The mechanical performance of these composites was evaluated, with their compressive moduli, which was found to be 1.73 MPa for the control sample, 3.9 MPa for MWCNT composites at 3 per hundred parts of rubber (phr), 2.2 MPa for MT-Clay composites (8 phr), 3.2 MPa for EIP composites (80 phr), and 4.1 MPa for hybrid composites (80 phr). After evaluating the mechanical performance, the composites were assessed for industrial use based on their improved properties. The deviation from their experimental performance was studied using various theoretical models such as the Guth-Gold Smallwood model and the Halpin-Tsai model. Finally, a piezo-electric energy harvesting device was fabricated using the aforementioned composites, and their output voltages were measured. The MWCNT composites showed the highest output voltage of approximately 2 milli-volt (mV), indicating their potential for this application. Lastly, magnetic sensitivity and stress relaxation tests were performed on the hybrid and EIP composites, with the hybrid composite demonstrating better magnetic sensitivity and stress relaxation. Overall, this study provides guidance on achieving promising mechanical properties in such materials and their suitability for various applications, such as energy harvesting and magnetic sensitivity.
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Recently, hybrid fillers have been found to be more advantageous in energy-harvesting composites. This study investigated the mechanical and electromechanical performances of silicone rubber-based composites made from hybrid fillers containing conductive nanocarbon black (NCB) and molybdenum disulfide (MoS2). A hybrid filler system containing only 3 phr (per hundred grams of rubber) MoS2 and 17 phr NCB provided higher fracture strain, better tensile strength, and excellent toughness values compared to the 20 phr NCB-only-filled and 5 phr MoS2-only-filled rubber composites. The chemical cross-link densities suggest that NCB promoted the formation of cross-links, whereas MoS2 slightly reduced the cross-link density. The higher mechanical properties in the hybrid filler systems suggest that the filler particles were more uniformly distributed, which was confirmed by the scanning electron microscope study. Uniformly distributed filler particles with moderate cross-link density in hybrid filler systems greatly improved the fracture strain and fracture toughness. For example, the hybrid filler with a 17:3 ratio of NCB to MoS2 showed a 184% increment in fracture toughness, and a 93% increment in fracture strain, compared to the 20 phr NCB-only-filled composite. Regarding electromechanical sensing with 2 kPa of applied cyclic pressure, the hybrid filler (17:3 CB to MoS2) performed significantly better (~100%) than the 20 phr NCB-only compound. This may have been due to the excellent distribution of conducting NCB networks and piezoelectric MoS2 that caused symmetric charging-discharging in the toughened hybrid composite. Thus, hybrid composites with excellent fatigue resistance can find dynamic applications, such as in blood pressure measurement.
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Objective: Posttraumatic stress disorder (PTSD) is characterized by increased inflammatory processing and altered brain volume. In this study, we investigated the relationship between inflammatory markers and brain volume in patients with PTSD. Methods: Forty-five patients with PTSD, and 70 healthy controls (HC) completed clinical assessments and self-reported psychopathology scales. Factors associated with inflammatory responses including brain-derived neurotrophic factor and four inflammatory biomarkers (C-reactive protein, cortisol, Interleukin-6, and homocysteine) and T1-magnetic resonance imaging of the brain were measured. Results: In the PTSD group, cortisol level was significantly lower (t = 2.438, p = 0.046) than that of the HC. Cortisol level was significantly negatively correlated with the left thalamus proper (r = -0.369, p = 0.035), right thalamus proper (r = -0.394, p = 0.014), right frontal pole (r = -0.348, p = 0.039), left occipital pole (r = -0.338, p = 0.044), and right superior occipital gyrus (r = -0.397, p = 0.008) in patients with PTSD. However, these significant correlations were not observed in HC. Conclusion: Our results indicate that increased cortisol level, even though its average level was lower than that of HC, is associated with smaller volumes of the thalamus, right frontal pole, left occipital pole, and right superior occipital gyrus in patients with PTSD. Cortisol, a major stress hormone, might be a reliable biomarker to brain volumes and pathophysiological pathways in patients with PTSD.
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Zinc oxide performs as the best cure activator in sulfur-based vulcanization of rubber, but it is regarded as a highly toxic material for aquatic organisms. Hence, the toxic cure activator should be replaced by a non-toxic one. Still, there is no suitable alternative industrially. However, binary activators combining ZnO and another metal oxide such as MgO can largely reduce the level of ZnO with some improved benefits in the vulcanization of rubber as investigated in this research. Curing, mechanical, and thermal characteristics were investigated to find out the suitability of MgO in the vulcanization of rubber. Curing studies reveal that significant reductions in the optimum curing times are found by using MgO as a co-cure activator. Especially, the rate of vulcanization with conventional 5 phr (per hundred grams) ZnO can be enhanced by more than double, going from 0.3 Nm/min to 0.85 Nm/min by the use of a 3:2 ratio of MgO to ZnO cure activator system that should have high industrial importance. Mechanical and thermal properties investigations suggest that MgO as a co-cure activator used at 60% can provide 7.5% higher M100 (modulus at 100% strain) (0.58 MPa from 0.54 MPa), 20% higher tensile strength (23.7 MPa from 19.5 MPa), 15% higher elongation at break (1455% from 1270%), 68% higher fracture toughness (126 MJ/m3 from 75 MJ/m3), and comparable thermal stability than conventionally using 100 % ZnO. Especially, MgO as a co-cure activator could be very useful for improving the fracture toughness in rubber compounds compared to ZnO as a single-site curing activator. The significant improvements in the curing and mechanical properties suggest that MgO and ZnO undergo chemical interactions during vulcanization. Such rubber compounds can be useful in advanced tough and stretchable applications.
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Simultaneously exhibiting both a magnetic response and piezoelectric energy harvesting in magneto-rheological elastomers (MREs) is a win-win situation in a soft (hardness below 65) composite-based device. In the present work, composites based on iron oxide (Fe2O3) were prepared and exhibited a magnetic response; other composites based on the electrically conductive reinforcing nanofiller, graphite nanoplatelets (GNP), were also prepared and exhibited energy generation. A piezoelectric energy-harvesting device based on composites exhibited an impressive voltage of ~10 V and demonstrated a high durability of 0.5 million cycles. These nanofillers were added in room temperature vulcanized silicone rubber (RTV-SR) and their magnetic response and piezoelectric energy generation were studied both in single and hybrid form. The hybrid composite consisted of 10 per hundred parts of rubber (phr) of Fe2O3 and 10 phr of GNP. The experimental data show that the compressive modulus of the composites was 1.71 MPa (virgin), 2.73 (GNP), 2.65 MPa (Fe2O3), and 3.54 MPa (hybrid). Similarly, the fracture strain of the composites was 89% (virgin), 109% (GNP), 105% (Fe2O3), 133% (hybrid). Moreover, cyclic multi-hysteresis tests show that the hybrid composites exhibiting higher mechanical properties had the shortcoming of showing higher dissipation losses. In the end, this work demonstrates a rubber composite that provides an energy-harvesting device with an impressive voltage, high durability, and MREs with high magnetic sensitivity.
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New and soft composites with good mechanical stretchability are constantly addressed in the literature due to their use in various industrial applications such as soft robotics. The stretchable magnetic materials presented in this work show a promising magnetic effect of up to 28% and improved magnetic sensitivity. The composites are soft in nature and possess hardness below 65. These composites were prepared by mixing silicone rubber with fillers such as graphene nanoplatelets (GNP), electrolyte-iron particles (EIP), and their hybrid via solution mixing. The final composites were cured at room temperature for 24 h and their isotropic and anisotropic properties were studied and presented. The mechanical properties under compressive and tensile strain were studied in detail. The results show that the compressive modulus was 1.73 MPa (control) and increased to 3.7 MPa (GNP) at 15 per hundred parts of rubber (phr), 3.2 MPa (EIP), and 4.3 MPa (hybrid) at 80 phr. Similarly, the mechanical stretchability was 112% (control) and increased to 186% (GNP) at 15 phr, 134% (EIP), and 136% (hybrid) at 60 phr. Thus, GNP emerges as a superior reinforcing filler with high stiffness, a high compressive modulus, and high mechanical stretchability. However, the GNP did not show mechanical sensitivity under a magnetic field. Therefore, the hybrids containing GNP and EIP were considered and an improved mechanical performance with magnetic sensitivity was noticed and reported. The mechanism involves the orientation of EIP under a magnetic field causing a magnetic effect, which is 28% for EIP and 5% for hybrid.
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New technologies are constantly addressed in the scientific community for updating novel stretchable devices, such as flexible electronics, electronic packaging, and piezo-electric energy-harvesting devices. The device promoted in the present work was found to generate promising ~6V and durability of >0.4 million cycles. This stretchable device was based on rubber composites. These rubber composites were developed by solution mixing of room temperature silicone rubber (RTV-SR) and nanofiller, such as multi-wall carbon nanotube (MWCNT) and micron-sized copper particles and their hybrid. The hybrid composite consists of 50:50 of both fillers. The mechanical stretchability and compressive modulus of the composites were studied in detail. For example, the compressive modulus was 1.82 MPa (virgin) and increased at 3 per hundred parts of rubber (phr) to 3.75 MPa (MWCNT), 2.2 MPa (copper particles) and 2.75 MPa (hybrid). Similarly, the stretching ability for the composites used in fabricating devices was 148% (virgin) and changes at 3 phr to 144% (MWCNT), 230% (copper particles) and 199% (hybrid). Hence, the hybrid composite was found suitable with optimum stiffness and robust stretching ability to be useful for stretching electronic devices explored in this work. These improved properties were tested for a real-time stretchable device, such as a piezoelectric energy-harvesting device and their improved voltage output and durability were reported. In the end, a series of experiments conducted were summarized and a discussion on the best candidate with higher properties useful for prospective applications was reported.
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BACKGROUND: Although transcranial direct stimulation (tDCS) has been proposed as an alternative treatment option for various psychiatric disorders, there is inconsistent information regarding the treatment effects of tDCS for patients with post-traumatic stress disorder (PTSD). This study aimed to investigate the tDCS efficacy and identify predictors of treatment response to tDCS in patients with PTSD. METHOD: Fifty-one patients received 10 sessions of tDCS involving the position of the anode over the F3 area and cathode over the F4 as a condition of 2.0 mA and 20 min duration. Digit span test and 10 questionnaires (Clinician-Administered PTSD Scale (CAPS), Cognitive Emotion Regulation Questionnaire (CERQ), Multidimensional Experiential Avoidance Questionnaire (MEAQ), etc.) were used to measure tDCS effects on PTSD symptoms and identify predictors of response to tDCS. RESULTS: 1) 50.9 % of patients had a significant reduction in the frequency and severity of PTSD symptoms, 2) PTSD-related symptoms such as depression, anxiety, rumination, and quality of life were significantly improved, 3) baseline scores on rumination and digit span test significantly predicted treatment response to tDCS. LIMITATIONS: This study was open design without a sham control group. Also, the patients' medications were not controlled. CONCLUSION: This study highlighted the efficacy of frontal tDCS for the treatment of patients with PTSD and identified rumination and digit span as favorable predictive factors for the outcomes of tDCS.
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Trastornos por Estrés Postraumático , Estimulación Transcraneal de Corriente Directa , Método Doble Ciego , Humanos , Corteza Prefrontal/fisiología , Calidad de Vida , Trastornos por Estrés Postraumático/psicología , Trastornos por Estrés Postraumático/terapia , Estimulación Transcraneal de Corriente Directa/métodos , Resultado del TratamientoRESUMEN
INTRODUCTION: Several in vitro studies have suggested the effects of adipokines and insulin resistance on breast cancer cell proliferation and survival. However, little is known about the clinical significance of these findings. METHODS: We examined associations between breast cancer recurrence and adiponectin, leptin, insulin resistance, and metabolic syndrome (MetS) in a cohort of 747 patients from 2001 to 2004. RESULTS: Adjusted hazard ratios showed an inverse trend across the quartiles for serum adiponectin concentration in estrogen receptor (ER)/progesterone receptor (PR) -negative patients (P for trend = 0.027) but not in ER/PR-positive patients. Compared to the highest quartile for adiponectin level, the lowest quartile showed a hazard ratio of 2.82 (1.03 to 7.68). Homeostasis model assessment for insulin resistance (HOMA-IR) showed a positive trend for recurrence in the ER/PR-negative group (P for trend = 0.087) and a negative trend in the ER/PR-positive group (P for trend = 0.081). Leptin did not show any associations (P for trend >0.05). A linear trend was observed with the number of components of MetS in ER/PR-negative patients (P for trend = 0.044). This association disappeared when adjusted for adiponectin and HOMA-IR. CONCLUSIONS: Adiponectin and HOMA-IR have prognostic significance in breast cancer recurrence and interventions related to these factors may protect against recurrence in ER/PR-negative patients. These findings were not observed in the case of ER/PR-positive patients. Further evaluation of these insignificant associations is needed because it might be biased by adjuvant chemotherapy or other confounders.