Peptide-Decorated Microneedles for the Detection of Microplastics.

The escalating utilization of plastics in daily life has resulted in pervasive environmental pollution and consequent health hazards. The challenge of detecting and capturing microplastics, which are imperceptible to the naked eye, is exacerbated by their diminutive size, hydrophobic surface properties, and capacity to absorb organic compounds. This study focuses on the application of peptides, constituted of specific amino acid sequences, and microneedles for the rapid and selective identification of microplastics. Peptides, due to their smaller size and greater environmental stability compared with antibodies, emerge as a potent solution to overcome the limitations inherent in existing detection methodologies. To immobilize peptides onto microneedles, this study employed microneedles embedded with gold nanorods, augmenting them with sulfhydryl (SH) groups at the peptides' termini. The sensor developed through this methodology exhibited efficient peptide binding to the microneedle tips, thereby facilitating the capture of microplastics. Raman spectroscopy was employed for the detection of microplastics, with the results demonstrating successful attachment to the microneedles. This novel approach not only facilitates localized analysis but also presents a viable strategy for the detection of microplastics across diverse environmental settings.

Thinning enhances forest soil C storage by shifting the soil toward an oligotrophic condition.

Forests are significant carbon reservoirs, with approximately one-third of this carbon stored in the soil. Forest thinning, a prevalent management technique, is designed to enhance timber production, preserve biodiversity, and maintain ecosystem functions. Through its influence on biotic and abiotic factors, thinning can profoundly alter soil carbon storage. Yet, the full implications of thinning on forest soil carbon reservoirs and the mechanisms underpinning these changes remain elusive. In this study, we undertook a two-year monitoring initiative, tracking changes in soil extracellular enzyme activities (EEAs), microbial communities, and other abiotic parameters across four thinning intensities within a temperate pine forest. Our results show a marked increase in soil carbon stock following thinning. However, thinning also led to decreased dissolved organic carbon (DOC) content and a reduced DOC to soil organic carbon (SOC) ratio, pointing toward a decline in soil carbon lability. Additionally, fourier transform infrared spectroscopy (FTIR) analysis revealed an augmented relative abundance of aromatic compounds after thinning. There was also a pronounced increase in absolute EEAs (per gram of dry soil) post-thinning, implying nutrient limitations for soil microbes. Concurrently, the composition of bacterial and fungal communities shifted toward oligotrophic dominance post thinning. Specific EEAs (per gram of soil organic matter) exhibit a significant reduction following thinning, indicating a deceleration in organic matter decomposition rates. In essence, our findings reveal that thinning transitions soil toward an oligotrophic state, dampening organic matter decomposition, and thus bolstering the soil carbon storage potential of forest. This study provides enhanced insights into the nuanced relationship between thinning practices and forest soil carbon dynamics, serving as a robust foundation for enlightened forest management strategies.

A Novel Passive Shoulder Exoskeleton Using Link Chains and Magnetic Spring Joints.

Work-related musculoskeletal disorders represent a major occupational disability issue, and 53.4% of these disorders occur in the back or shoulders. Various types of passive shoulder exoskeletons have been introduced to support the weight of the upper arm and work tools during overhead work, thereby preventing injuries and improving the work environment. The general passive shoulder exoskeleton is constructed with rigid links and joints to implement shoulder rotation, but there exists a challenge to align with the flexible joint movements of the human shoulder. Also, a force-generating part using mechanical springs require additional mechanical components to generate torque similar to the shoulder joint, resulting in increased overall volume and inertia to the upper arm. In this study, we propose a new type of passive shoulder exoskeleton that uses magnetic spring joint and link chain. The redundant degrees of freedom in the link chains enables to follow the shoulder joint movement in the horizontal direction, and the magnetic spring joint generates torque without additional parts in a compact form. Conventional exoskeletons experience a loss in the assisting torque when the center of shoulder rotation changed during arm elevation. Our exoskeleton minimizes the torque loss by customizing the installation height and initial angle of the magnetic spring joint. The performances of the proposed exoskeleton were verified by an electromyographic evaluation of shoulder-related muscles in overhead work and box lifting task.

Net global warming potential index rather than soil carbon stock change could provide better understanding of the carbon balance in soil systems.

This study was conducted to determine the soil organic carbon (SOC) stock change factor for green manure crops that was developed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 method and compare this with the net global warming potential (GWP) index that is used to evaluate the contribution of green manuring to global warming. Four treatments were barley (Hordeum vulgare L.; B), hairy vetch (Vicia villosa R.; HV), a barley/hairy vetch mixture (BHV) and a conventional treatment (C). The aboveground biomass of green manure crops was incorporated into the soil on 25 May 2018, 26 April 2019, 29 April 2020, 30 April 2021 and 2 May 2022. Maize (Zea mays L.) was transplanted as the subsequent crop after the incorporation of green manures. SOC stock decreased with green manures, even though carbon input with green manures, including B, HV and BHV, was greater than that with C. The mean value of the SOC stock change factor for green manure crops, including B, HV and BHV was 0.627 and was significantly lower than that of the C. However, the net GWP also decreased with the incorporation of green manure crops, and the mean value of the relative net GWP index across B, HV and BHV was 0.853. These conflicting results were caused by different estimation methods between annual SOC change (△SOC) and net GWP. The estimation of SOC stock change using △SOC suggested by the IPCC method may overestimate the contribution of green manure crops to global warming. The net GWP method with comprehensive input and output of carbon in the soil system could provide a better understanding of the carbon balance in soil systems. In the current study, the comparison of △SOC and net GWP was conducted for at one site of upland soil for 5 years. Therefore, further research on estimating the effect of green manure crops on net GWP in various types of soil for longer years should be conducted.

Characteristics of Synaptic Function of Mesoporous Silica-Titania and Mesoporous Titania Lateral Electrode Devices.

In this paper, we have fabricated non-volatile memory resistive switching (RS) devices and analyzed analog memristive characteristics using lateral electrodes with mesoporous silica-titania (meso-ST) and mesoporous titania (meso-T) layers. For the planar-type device having two parallel electrodes, current-voltage (I-V) curves and pulse-driven current changes could reveal successful long-term potentiation (LTP) along with long-term depression (LTD), respectively, by the RS active mesoporous two layers for 20~100 µm length. Through mechanism characterization using chemical analysis, non-filamental memristive behavior unlike the conventional metal electroforming was identified. Additionally, high performance of the synaptic operations could be also accomplished such that a high current of 10-6 Amp level could occur despite a wide electrode spacing and short pulse spike biases under ambient condition with moderate humidity (RH 30~50%). Moreover, it was confirmed that rectifying characteristics were observed during the I-V measurement, which was a representative feature of dual functionality of selection diode and the analog RS device for both meso-ST and meso-T devices. The memristive and synaptic functions along with the rectification property could facilitate a chance of potential implementation of the meso-ST and meso-T devices to neuromorphic electronics platform.

Low Dielectric Constant Characteristics of Styrene and Maleimide Anhydride Copolymer with Modification for High Frequency Application of Printed Circuit Board.

Recently, due to the intensive and fast progress of the high frequency wireless communication environment, including 5th generation (5G) wireless communication, more robust substrate for printed circuit board (PCB) application, especially with less power consumption, is required. In this study, modified resins based on styrene-maleic anhydride (SMA) copolymer were prepared and evaluated as binder resin to accomplish a low dielectric constant or relative permittivity (εr: <3.0) substrate for the PCB application under ultrahigh frequencies (UHF; 1 GHz~9.4 GHz). The low εr dielectric characteristics of the modified SMA copolymer could be correlated with effects from the stereo-structure of carbon chains or conformational orientation, where the degree of crystallization was analyzed by X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) spectroscopies. Prepreg films of the low εr modified SMA copolymers and their compounds with epoxy resins were also characterized in terms of dielectric loss or dissipation factor (Df), which have shown more noticeable relation with their stereo-structures as well.

Aged G Protein-Coupled Receptor Kinase 3 (Grk3)-Deficient Mice Exhibit Enhanced Osteoclastogenesis and Develop Bone Lesions Analogous to Human Paget's Disease of Bone.

Paget's Disease of Bone (PDB) is a metabolic bone disease that is characterized by dysregulated osteoclast function leading to focal abnormalities of bone remodeling. It can lead to pain, fracture, and bone deformity. G protein-coupled receptor kinase 3 (GRK3) is an important negative regulator of G protein-coupled receptor (GPCR) signaling. GRK3 is known to regulate GPCR function in osteoblasts and preosteoblasts, but its regulatory function in osteoclasts is not well defined. Here, we report that Grk3 expression increases during osteoclast differentiation in both human and mouse primary cells and established cell lines. We also show that aged mice deficient in Grk3 develop bone lesions similar to those seen in human PDB and other Paget's Disease mouse models. We show that a deficiency in Grk3 expression enhances osteoclastogenesis in vitro and proliferation of hematopoietic osteoclast precursors in vivo but does not affect the osteoclast-mediated bone resorption function or cellular senescence pathway. Notably, we also observe decreased Grk3 expression in peripheral blood mononuclear cells of patients with PDB compared with age- and gender-matched healthy controls. Our data suggest that GRK3 has relevance to the regulation of osteoclast differentiation and that it may have relevance to the pathogenesis of PDB and other metabolic bone diseases associated with osteoclast activation.

Optimizing calcium materials for minimizing arsenate phytoavailability in upland arable soil based on geochemical analysis.

This study aimed to evaluate the reducing effects of calcite and phosphogypsum on arsenate [As(V)] availability to plants and elucidate the mechanisms of As(V) immobilization. The concentration of available As(V) to plants in upland arable soils with 1% calcite and phosphogypsum decreased to 17.4% and 36.9%, respectively, compared to the control. As(V) phytoavailability depends on the soil pH and calcium materials. The process of stabilizing As(V) (F3; anion exchange) with phosphogypsum is faster and easier compared to that with calcite (F4; bind to carbonate), but it results in a less stable form. New Ca-As(V) minerals (Ca52(HAsO4)x(AsO4)∙yH2O, Ca5H2x(AsO4)∙yH2O, or Ca32(AsO4)∙10 H2O) were identified in X-ray diffraction (XRD) patterns with calcite treatment. Precipitation, the primary mechanism induced by calcite, was activated at a soil pH above 8.0. Based on the deconvolution of calcium and sulfur X-ray photoelectron spectroscopy spectra and the peak shift in the XRD pattern in phosphogypsum, the substitution in which SO42- is exchanged with HAsO42- is the primary mechanism for As(V) immobilization. Substitution induced by phosphogypsum is a suitable reaction in upland arable soils, the predominant form of As(V) in the soil, with a pH range of 5-7.

Characterization and applicability of novel alkali-tolerant carbonatogenic bacteria as environment-friendly bioconsolidants for management of concrete structures and soil erosion.

Cracking and erosion are critical factors that reduce the mechanical properties and stability of concrete structures and soil, respectively. They are recognized worldwide as severe disasters causing the collapse of many structures including stone heritage and dams, and landslides. Therefore, it is essential to propose effective and environment-friendly management methods to prevent them. Carbonatogenesis has recently received considerable attention as a reliable biological process for remediating cracks in calcareous structures, stabilizing loose soils, and sequestering CO2 in the environment. Isolating and characterizing carbonatogenic bacteria with excellent performance is crucial for applying this process to the field of environmental and civil engineering. The aim of this study was to isolate new CaCO3-precipitating bacteria and investigate various properties for their use as bioconsolidants. Furthermore, the possibility of restoring damaged structures and stabilizing loose sandy soil using isolated strain was investigated. Strain LC13 with urease and CaCO3-precipitating activity was isolated from limestone cave soil in Korea and identified as Arthrobacter sulfureus by phenotypic characterization and 16S rRNA gene analysis. Although cell growth was observed after an adaptation period at pH 11, strain LC13 grew well at pH 7-11, indicating alkali tolerance. The optimal conditions for CaCO3 precipitation were 1.0% yeast extract, 2.5% urea, 0.35% NaHCO3, and 400 mM CaCl2, with an initial pH of 6.5 at 30 °C. Under optimized conditions, maximal CaCO3 (22.92 ± 0.14 g/l) precipitated after 3 days, which was 10.8-fold higher than the value in a urea-CaCl2 medium. CaCO3 precipitation by strain LC13 was associated with an increased pH due to ureolysis and protein deamination. Using an optimized medium as a cementation solution, strain LC13 completely remediated 340-760 µm wide cracks over 3 days, and also restored the spalling of concrete surfaces. Furthermore, the sand treated with LC13 solidified with a surface strength of 14.9 kPa. Instrumental analysis confirmed that the crystals precipitated were a mixture of CaCO3 polymorphs composed of rhombohedral calcite and spherical vaterite. These results suggest that A. sulfureus LC13 may be useful for implementing sustainable biorestoration and environmental management technologies such as the in situ remediation of structural cracks and in situ prevention of soil erosion.

Peptide Specific Nanoplastic Detection Based on Sandwich Typed Localized Surface Plasmon Resonance.

Recently, various waste microplastics sensors have been introduced in response to environmental and biological hazards posed by waste microplastics. In particular, the detrimental effects of nano-sized plastics or nanoplastics have been reported to be severe. Moreover, there have been many difficulties for sensing microplastics due to the limited methodologies for selectively recognizing nanoplastics. In this study, a customized gold nanoparticles (Au NPs) based localized surface plasmon resonance (LSPR) system having bio-mimicked peptide probes toward the nanoplastics was demonstrated. The specific determination through the oligo-peptide recognition was accomplished by chemical conjugation both on the LSPR chip's 40~50 nm Au NPs and sandwiched 5 nm Au NPs, respectively. The peptide probe could selectively bind to polystyrene (PS) nanoplastics in the forms of fragmented debris by cryo-grinding. A simple UV-Vis spectrophotometer was used to identify the LSPR sensing by primarily measuring the absorbance change and shift of absorption peak. The sandwich-binding could increase the LSPR detection sensitivity up to 60% due to consecutive plasmonic effects. In addition, microwave-boiled DI water inside of a styrofoam container was tested for putative PS nanoplastics resource as a real accessible sample. The LSPR system could be a novel protocol overcoming the limitations from conventional nanoplastic detection.

Mechanical Properties of Porcine and Fish Skin-Based Collagen and Conjugated Collagen Fibers.

Collagen is a protein that is a major component of animal skins and tendons. It is used in various medical, cosmetic, and food products through extraction and purification. The fibrous products of purified collagen fibers extracted from raw mammal materials have relatively excellent mechanical properties and are used for high-end medical products. In this study, we examined collagen materials produced from porcine and fish skins, which are major sources of collagen raw materials. We examined a method for spinning collagen fibers from fish skin-based collagen and analyzed the physical properties of those collagen fibers. In addition, we examined the characteristics and advantages of conjugated fibers according to their porcine- and/or fish skin-based compositions. The spinnability and mechanical properties of these conjugated fibers were analyzed according to their compositions. The mechanical properties of collagen structure are determined by hydroxyproline content and can be manipulated by the composition of collagen in the conjugated fibers.

Mitigation of global warming potential and greenhouse gas intensity in arable soil with green manure as source of nitrogen.

This study was conducted to determine the effect of different green manure treatments on net GWP and GHGI in upland soil. Barley (B), hairy vetch (HV), and a barley/hairy vetch mixture (BHV) were sown on an upland soil on November 4, 2017 and October 24, 2018. The aboveground biomass of these green manures was incorporated into soil on June 1, 2018 and May 8, 2019. In addition, a fallow treatment (F) was installed as the control. Maize was transplanted as the subsequent crop after incorporation of green manures. Green manuring significantly affected CO2 and N2O emission, but not CH4. Average cumulative soil respiration across years with HV and BHV were 37.0 Mg CO2 ha-1 yr-1 and 35.8 Mg CO2 ha-1 yr-1, respectively and significantly higher than those with under F and B (32.7 Mg CO2 ha-1 yr-1 and 33.0 Mg CO2 ha-1 yr-1, respectively). Cumulative N2O emissions across years with F and HV were 6.29 kg N2O ha-1 yr-1 and 5.44 kg N2O ha-1 yr-1, respectively and significantly higher than those with B and BHV (4.26 kg N2O ha-1 yr-1 and 4.42 kg N2O ha-1 yr-1, respectively). The net ecosystem carbon budget for HV (-0.5 Mg C ha-1 yr-1) was the greatest among the treatments (F; -1.61 Mg C ha-1 yr-1, B; -3.98 Mg C ha-1 yr-1, and BHV; -0.91 Mg C ha-1 yr-1) because of its high biomass yields and the yield of maize after incorporation of HV. There was no significant difference of GHGI among F, HV, and BHV. Incorporation of HV or BHV could reduce net CO2 emissions per unit of maize grain production as well as F.

Highly Sensitive Colorimetric Assay of Cortisol Using Cortisol Antibody and Aptamer Sandwich Assay.

In this study, cortisol, which is a key stress hormone, could be detected sensitively via the colorimetric assay of a polycarbonate (PC) and glass substrate by the sandwich assay of cortisol monoclonal antibody (c-Mab) and cortisol specific binding aptamer (c-SBA). A highly sensitive change in colorimetry with a limit of detection (LOD) of cortisol of 100 fM could be attained on the optically transparent substrate using the antibody aptamer sandwich (AAS) assay by corresponding stacks of 5 nm gold nanoparticles (Au NPs). The Au NPs were conjugated by the c-SBA and the c-Mab was tethered on the PC and glass substrates. For the AAS method, a simple UV-Vis spectrophotometer was adopted to quantify the cortisol concentrations at an absorbance wavelength of 520 nm. Therefore, this study demonstrates the versatility of the AAS method to measure very low concentrations of cortisol in diagnostic applications.

Analog Memristive Characteristics of Square Shaped Lanthanum Oxide Nanoplates Layered Device.

Square-shaped or rectangular nanoparticles (NPs) of lanthanum oxide (LaOx) were synthesized and layered by convective self-assembly to demonstrate an analog memristive device in this study. Along with non-volatile analog memory effect, selection diode property could be co-existent without any implementation of heterogeneous multiple stacks with ~1 µm thick LaOx NPs layer. Current-voltage (I-V) behavior of the LaOx NPs resistive switching (RS) device has shown an evolved current level with memristive behavior and additional rectification functionality with threshold voltage. The concurrent memristor and diode type selector characteristics were examined with electrical stimuli or spikes for the duration of 10-50 ms pulse biases. The pulsed spike increased current levels at a read voltage of +0.2 V sequentially along with ±7 V biases, which have emulated neuromorphic operation of long-term potentiation (LTP). This study can open a new application of rare-earth LaOx NPs as a component of neuromorphic synaptic device.

Smart, soft contact lens for wireless immunosensing of cortisol.

Despite various approaches to immunoassay and chromatography for monitoring cortisol concentrations, conventional methods require bulky external equipment, which limits their use as mobile health care systems. Here, we describe a human pilot trial of a soft, smart contact lens for real-time detection of the cortisol concentration in tears using a smartphone. A cortisol sensor formed using a graphene field-effect transistor can measure cortisol concentration with a detection limit of 10 pg/ml, which is low enough to detect the cortisol concentration in human tears. In addition, this soft contact lens only requires the integration of this cortisol sensor with transparent antennas and wireless communication circuits to make a smartphone the only device needed to operate the lens remotely without obstructing the wearer's view. Furthermore, in vivo tests using live rabbits and the human pilot experiment confirmed the good biocompatibility and reliability of this lens as a noninvasive, mobile health care solution.

Mobility Models Based on Forward Current-Voltage Characteristics of P-type Pseudo-Vertical Diamond Schottky Barrier Diodes.

Compared with silicon and silicon carbide, diamond has superior material parameters and is therefore suitable for power switching devices. Numerical simulation is important for predicting the electric characteristics of diamond devices before fabrication. Here, we present numerical simulations of p-type diamond pseudo-vertical Schottky barrier diodes using various mobility models. The constant mobility model, based on the parameter µconst, fixed the hole mobility absolutely. The analytic mobility model resulted in temperature- and doping concentration-dependent mobility. An improved model, the Lombard concentration, voltage, and temperature (CVT) mobility model, considered electric field-dependent mobility in addition to temperature and doping concentration. The forward voltage drop at 100 A/cm2 using the analytic and Lombard CVT mobility models was 2.86 and 5.17 V at 300 K, respectively. Finally, we used an empirical mobility model based on experimental results from the literature. We also compared the forward voltage drop and breakdown voltage of the devices, according to variations in p- drift layer thickness and cathode length. The device successfully achieved a low specific on-resistance of 6.8 mΩ∙cm2, a high breakdown voltage of 1,190 V, and a high figure-of-merit of 210 MW/cm2.

Enhancement of cortisol measurement sensitivity by laser illumination for AlGaN/GaN transistor biosensor.

In this study, high electron mobility transistor (HEMT) device was used as an immuno biosensor to measure concentration of a stress hormone, cortisol, by using selective binding on cortisol monoclonal antibody (c-Mab). Also, the HEMT sensor was enhanced in its sensitivity through light illumination to generate photocurrent. The optical pumping could assist the biosensor to discriminate more detailed change, which could result in an increment of limit of detection (LOD) to 1.0 pM cortisol level. It was the lowest level of detection with semiconductor device-based cortisol biosensors and the enhancement of surface potential sensitivity was induced by laser light (532 nm). Output current amplificated by photocurrent was higher than dark original current at about 3.39% when gate voltage is applied with -3 V. Since the device could be applied to not only standard cortisol solution but also real human salivary sample, it is expected to apply for in vitro direct diagnosis of point-of-care test (POCT).

Effectiveness of using a bioabsorbable implant (Latera) to treat nasal valve collapse in patients with nasal obstruction: systemic review and meta-analysis.

BACKGROUND: Nasal obstruction is a common cause of breathing problems with lateral wall insufficiency (LWI) a key anatomic contributor. Recently, a bioabsorbable nasal implant was introduced to correct LWI and treat nasal obstruction. The goal of this study was to perform a systematic review with meta-analysis to determine the efficacy of the bioabsorbable nasal implant for treating nasal obstruction caused by LWI. METHODS: Five databases (PubMed, SCOPUS, EMBASE, Web of Science, and the Cochrane Database) were independently reviewed by 2 researchers, starting at the earliest time point recorded in the database to September 2019. Studies that scored endoscopic lateral wall movement and nasal obstruction related to quality of life (QOL) postoperatively before and after bioabsorbable nasal implants and those that compared the outcomes of nasal implants (treatment group) with outcomes of sham surgery (control group) were included in the analysis. RESULTS: Five studies (396 patients) met the inclusion criteria. Bioabsorbable nasal implants significantly reduced endoscopic lateral wall motion compared to pretreatment values and also improved QOL at 12 months postoperatively. Most adverse effects following the nasal implant, such as skin or mucosal reaction, infection, or implant retrieval, were reported with a 5% incidence rate. All adverse outcomes were resolved without significant sequelae. Compared with sham surgery, bioabsorbable nasal implants significantly improved disease-specific QOL. CONCLUSION: Bioabsorbable nasal implants may reduce nasal wall movement and subjective symptom scores compared to preoperative status. More randomized clinical trials must be conducted to further verify the effectiveness of bioabsorbable nasal implants.

Effect of nitrogen-doping on drain current modulation characteristics of an indium-gallium-zinc oxide thin-film transistor.

The effect of nitrogen-doping (N-doping) in an indium-gallium-zinc oxide (IGZO) channel layer on the analog, linear, and reversible drain current modulation in thin-film transistors (TFTs) with Al-top-gate/SiOx/TaOx/IGZO stack is investigated for potential application to artificial synaptic devices. The N-doped devices exhibit a more linear increase of drain current upon repeating positive gate biasing, corresponding to synaptic potentiation, while the undoped device shows a highly non-linear and abrupt increase of drain current. Distinct from the increase of drain current at positive biasing for potentiation, the decrease of drain current for depression behavior at negative biasing is found to be the same. Whereas the increase of drain current becomes more linear, the channel conductance, the magnitude of its change, and its changing speed are decreased by the N-doping. The partial replacement of oxygen with nitrogen, having higher binding energy with metal-cations, suppresses oxygen vacancy formation, then decreases the channel conductance. It also retards the migration of oxygen ions, then leads to a linear increase of drain current. These results reveal that the characteristics of tunable drain current such as its linearity, dynamic range, and speed could be controlled by altering the internal state of the IGZO channel, which is crucial for application to an artificial synapse in a neuromorphic system.

Empagliflozin improved systolic blood pressure, endothelial dysfunction and heart remodeling in the metabolic syndrome ZSF1 rat.

BACKGROUND: Empagliflozin (empa), a selective sodium-glucose cotransporter (SGLT)2 inhibitor, reduced cardiovascular mortality and hospitalization for heart failure in patients with type 2 diabetes at high cardiovascular risk independent of glycemic control. The cardiovascular protective effect of empa was evaluated in an experimental model of metabolic syndrome, the obese ZSF1 rat, and its' lean control. METHODS: Lean and obese ZSF1 rats were either non-treated or treated with empa (30 mg/kg/day) for 6 weeks. Vascular reactivity was assessed using mesenteric artery rings, systolic blood pressure by tail-cuff sphygmomanometry, heart function and structural changes by echocardiography, and protein expression levels by Western blot analysis. RESULTS: Empa treatment reduced blood glucose levels from 275 to 196 mg/dl in obese ZSF1 rats whereas normoglycemia (134 mg/dl) was present in control lean ZSF1 rats and was unaffected by empa. Obese ZSF1 rats showed increased systolic blood pressure, and blunted endothelium-dependent relaxations associated with the appearance of endothelium-dependent contractile responses (EDCFs) compared to control lean rats. These effects were prevented by the empa treatment. Obese ZSF1 rats showed increased weight of the heart and of the left ventricle volume without the presence of diastolic or systolic dysfunction, which were improved by the empa treatment. An increased expression level of senescence markers (p53, p21, p16), tissue factor, VCAM-1, SGLT1 and SGLT2 and a down-regulation of eNOS were observed in the aortic inner curvature compared to the outer one in the control lean rats, which were prevented by the empa treatment. In the obese ZSF1 rats, no such effects were observed. The empa treatment reduced the increased body weight and weight of lungs, spleen, liver and perirenal fat, hyperglycemia and the increased levels of total cholesterol and triglycerides in obese ZSF1 rats, and increased blood ketone levels and urinary glucose excretion in control lean and obese ZSF1 rats. CONCLUSION: Empa reduced glucose levels by 28% and improved both endothelial function and cardiac remodeling in the obese ZSF1 rat. Empa also reduced the increased expression level of senescence, and atherothrombotic markers at arterial sites at risk in the control lean, but not obese, ZSF1 rat.